I just received a new Standard Motor IACV model # AC478. It is just like the first one I received. The resistance is 23,600 ohms on one side and 25,000 ohms on the other side. When power is applied, I get no movement of the valve. So either both valves are bad or I am doing something wrong. The Chiltons manual I have is for several Toyota models and for my 2000 Avalon is does not show the ohm spec. For the other models it shows 17-25 ohms from the center pin to either outside pin. The center pin is the 12 volt + and the outside pins are a ground signal from the PCM. Can someone explain what I am doing wrong? Or confirm that both valves are bad. Thanks in advance.

 

Can you provide a picture of your ohm meter as you are checking the idle control valve resistance? Want to see what pins you are checking and how your ohm meter is set up for your resistance value output.

 

Should be 6 files attached. I think it shows what you ask for. Photo 1 shows the 3 pins. The center pin is for 12 v+. The outer pins are signal grounds. Photo 2 shows the meter ohms which is 0.1 ohms. Photos 3-6 show the meter lead connections and meter displayed values. What i don't get is when I put 12 volts to the center pin and ground to one of the outer pins, I do not see valve actuation. Acts like it is dead.

 

Based on your meter model, you have it in auto range, and your red probe is on the center pin (+B) and the black probe on either RSC or RSO pins, which looks correct. I didn't see how your test probes were connected to your meter, but would have to assume the black test probe was connected to the COM jack and the red probe connected to the INPUT jack. If so, I trust your reading values.

I have a very similar set of idle air control valves on my 1990 Celica All-Trac (3S-GTE engine) and 1993 Celica GT convertible (5S-FE), and the tests match your approach, and the target values on these older IACV's should be between 19.3-22.3 ohms.

What were the resistance values from the original IACV you had on your engine (not the new replaced SMP units)? Were those resistances all the same?

 

The original 23 year old IACV had one side that measured about 65,000 ohms and the other side was over 1,000,000 ohms. Sometimes I would not get any reading on this side implying open circuit. When I applied voltage to the 65,000 side, I did see valve movement. It appeared weak, but I really don't know how strong the movement should be. The other side had no movement. From what I read in the Chiltons manual, similar model cars should see movement in both directions when voltage is applied. That is why I decided to replace the valve, plus it was dirty. Really didn't think it was going to be this big of a deal. Also, I am trying to solve my stalling problem at idle. Seemed like an overdue item to replace. Heck, I replaced everything else, why not this. I just sent an email to SMP asking them about the resistance spec and why I see no movement when voltage is applied. Hopefully, they will have an answer. I am curious to know if you think the IACV will solve my stalling problem. I am not optimistic, but it has to be replaced if its bad.

 

What I would do is head out to the salvage yard and get me two or three of those IACV's and bring them back, test them, see if the resistance of at least one makes sense, put power to it and see if it moves, and install it. I really don't trust aftermarket suppliers (like SMP) for their new replacement parts at all.

That said, on your year Carmy, the IACV did a lot more (due to improved range) that mine on my 1990 & 1993 models (there were other sources besides the IACV that switched on/off to change the amount of air that went into the intake manual). So if yours is not working problem, yes it could affect your idle a lot.

Your IACV part number is ether 22270-0A060 or 22270-20060 (depending on who manufactured the IACV for Toyota). It looks like those part numbers were used on all model year 2000-2002 Avalons and on 1998-2000 Siennas. I know there are some of these model year vehicles in a salvage yard by me. If you want, I can pull a few of these IACV's for you the next time I'm out there, if you don't have salvage yards local to you that you can go get a few.

 

What I would do is head out to the salvage yard and get me two or three of those IACV's and bring them back, test them, see if the resistance of at least one makes sense, put power to it and see if it moves, and install it. I really don't trust aftermarket suppliers (like SMP) for their new replacement parts at all.

That said, on your year Carmy, the IACV did a lot more (due to improved range) that mine on my 1990 & 1993 models (there were other sources besides the IACV that switched on/off to change the amount of air that went into the intake manual). So if yours is not working problem, yes it could affect your idle a lot.

Your IACV part number is ether 22270-0A060 or 22270-20060 (depending on who manufactured the IACV for Toyota). It looks like those part numbers were used on all model year 2000-2002 Avalons and on 1998-2000 Siennas. I know there are some of these model year vehicles in a salvage yard by me. If you want, I can pull a few of these IACV's for you the next time I'm out there, if you don't have salvage yards local to you that you can go get a few.

The part # on the original valve is 22270-20060. What do you think a salvage yard IACV would cost? I could probably get a used one from Ebay for a little extra cost over the salvage yard. I am curious to see what SMP comes back with. It looks to like I got two bad valves from Amazon. I won't be getting those again. I wonder if the SMP valves Rock Auto sells are the same quality. Probably should change brands. Thanks for your help.

 

Your call. If it were me, I would go with salvage yard parts (a couple of these IACV's, maybe 3) to test and verify at least one is fully passing all tests. Then that would be the one I would install. These don't typically go bad (OEM versions), so the chances of good salvage parts to me are high (in my opinion), and the cost is better, and still have OEM quality. But again, that is just my opinion, everyone is very much entitled to their own.

 

Thanks. I will check out a few salvage yards. I may go that route. I could bring my multimeter and check them before removing. That way I would only have to remove and pay for one. Wish I knew the ohm spec on these.

 

Maybe take along a small 12VDC battery too (those used on snowblowers/pressure washer engines for starting), that way, if you cut the harness pigtail off, you can also check for movement with a 12VDC power source.

 

good idea!

 

One day my 2000 Avalon would start then stall, but you could keep it running by tap-dancing on the accelerator / throttle. Once warmed up a little, the car acted normally.
Looking around here (iirc, it's been 15+ years) diagnosed the IAC as the problem, and once I opened it up, lots of sludge. Its function is very much like the choke on an engine with carburator. Cleaned it out with carb cleaner, back together with original gasket + some form-a-gasket, since it was a Sunday, nobody open. Problem cured.
Perhaps you could clean up your original IAC, reinstall, and see the results.
30-40 minute time investment might payoff handsomely...or be a dud.

 

One day my 2000 Avalon would start then stall, but you could keep it running by tap-dancing on the accelerator / throttle. Once warmed up a little, the car acted normally.
Looking around here (iirc, it's been 15+ years) diagnosed the IAC as the problem, and once I opened it up, lots of sludge. Its function is very much like the choke on an engine with carburator. Cleaned it out with carb cleaner, back together with original gasket + some form-a-gasket, since it was a Sunday, nobody open. Problem cured.
Perhaps you could clean up your original IAC, reinstall, and see the results.
30-40 minute time investment might payoff handsomely...or be a dud.

Thanks. I am currently in the process of replacing the IACV. The old original does not work electrically, so it needs replacing. The new SMP IACVs I purchased don't seem to work either when bench tested. So, I need to find a good one and install it.

 

Whoops... I saw the figures on ohm readings and ASSumed it was working. Shows to go you.

 

As I understand it, the ohm reading from the center pin to an outside pin should be in the 17-25 ohm range.

 

I received a new IACV that is supposed to be Aisin OEM. It had the same ohm readings as my original. So, I am now thinking this IACV just has high ohm readings. I cleaned the old IACV and put it back on the car. I no longer think that is my problem. Even if it was bad, I should be able to compensate by pressing the accelerator. I was able to return all 3 IACV that I purchased. Back to the drawing board.

 

93Celicaconv, you still out there? I don't seem to be getting much of a response to my original problem. Just you and Riick. Are all the old guys/gals dead and gone. Do you know if there is a different forum I should be using.

 

Sorry for the late reply. I somehow did not receive email notifications of updates to this thread.

I'm a bit confused now though. Regardless of the ohm reading issue, you said you tested your original IAC valve with a 12VDC power source and got weak movement going one direction, and no movement going the other. That doesn't pass the repair manual test process at all. I think you proved the original IAC valve is faulty, yet you said you no longer think that is your problem. That confuses me.

I will try to get out to the salvage yard this week and see if I can get a few IAC valves (22270-0A060 and/or 22270-20060), will test them with a DVOM for resistance, and will bring along a 12VDC small battery to test movement. If I find one or two that moves well in both directions, I'll advise what resistance values those have. If they are much lower than what you have (like in the 19-22 ohm range), I will bring them back with me. If you don't want them, I'll just try selling them on eBay. But I really think your problem lies here, at least part of the problem.

Let me know what you are thinking now.

 

Brynna, I went out to the salvage yard today. On a 2002 Avalon, I was able to check out the IAC valve on the throttle body. This throttle body was P/N 22270-0A060, which should be complimentary to your 22270-20060. I checked the resistance from the pin in the center to the two on the outside. The pin in the center had a BW wire (black w/white stripe). On one side was a pin with a GB (green w/black stripe) wire. The resistance between BW & GB was 0.66M-ohm (660,000 ohms). On the other side was a pin with a Br (brown) wire. The resistance between BW & Br was 53k-Ohm (53,000 ohms). These resistance values looked close to what you were getting from your original and your aftermarket others you had. As such, and because I did not hear back from you, I opted not to take it, as I wasn't sure this one would be any different that what you already tried. I had the 12VDC battery back in the car, but since I didn't bring it to the counter, I did not try to see what the motion looked like. Not sure what else I can do to help at this stage. But it is your turn to respond back.

 

Wow, I really appreciate your efforts to help me. I can understand why you might be confused. I am confused myself. When I first measured the ohms of my original IACV, I thought this can't be correct. The ohms are crazy high. Plus it only moved in one direction when energized. As I got new replacement IACVs, it just got more confusing. I got 2 valves from Standard Motor Products and they both had 23,500 - 25,000 ohms on each side. Neither moved any either direction when energized. I contacted SMP and they sent me a ProDemand printout that showed the resistance should be 17-24.5 ohms on either side. I returned those valves for a refund. I then bought a supposedly OEM Aisin IACV from Ebay. When I tested it, it was just like the old one I have. So, I returned it. I then ordered a supposedly OEM Toyota Aisin IACV from Amazon. It was the same. I am returning this too. So my ultimate conclusion was that the old IACV ohms are correct, as it closely matches the OEM valves I received. It also closely matches the one you tested. The Prodemand printout may be wrong. Also, the Chiltons manual I have shows "N/A" for the ohms for my particular car. For similar cars like Camry, Solara, ES300, it shows 17-24.5 ohms. I am thinking the 2000 Avalon is just different. I did send Oreillys a message yesterday asking them what their IACV have for ohms across the pins. I will see what they come back with . I did clean the old IACV really good and it does seem to move freely. Does not mean it is working correctly.
On a different note, I would like your opinion on the following observation regarding the MAF sensor. The old MAF sensor and a new one I got both show around 0.5 grams/sec when the car is in the on position, but not running. I just assumed that this was just wind blowing through it. I also noticed that both old and new MAF sensor are running high when car is running. Let me explain. I was able to keep the car running long enough by slowly pressing the gas pedal. I maintained the rpm at around 1600. I have a cheap scanner that shows live data. At 1600 rpm, the MAF was showing around 10 g/s. My understanding is that a 3.0 liter engine should have a MAF reading around 3 g/s at idle (~800 rpm). So, at 1600 (double idle rpm), I would expect 6 g/s. I am getting 10. Both MAF sensors are like this. The new sensor I got was supposedly Denso, but I got it off of Amazon, so who knows. While the car was running, I was able to get the car into closed loop and saw that my short term fuel trims were around -18% on both banks. This indicates a rich condition which could be caused by a MAF that is reading too high. If the car is really getting close to 6 g/s, but the MAF/PCM thinks it is getting 10 g/s and adjusting the fuel injectors to add too much fuel, could that be the problem. Could the stall at low rpm, just be a flooded engine? I do not smell gas coming out of the exhaust. I would expect that, but maybe the extra gas is getting burned off. The new spark plugs were very black, as well when I last looked at those. Could be just a bad MAF sensor.
I am also going to try unplugging the VVT solenoid valves and see if that changes things. I did have a mechanic look at the car back in May. He said he checked the timing and it was good. The VVT were checked and cleaned by me before and appeared to be working fine, but from what I read, they can be particular. What are you thoughts on this being a timing issue. I should note that when I checked compression, all cylinders were fine. Would that indicate that there is not a timing issues. Not sure?

 

According to the service manual, the engine should be prepped for a LTFT test by letting the engine warm up idling until at normal operating temperature, then driven in a sequence that allows a constant speed of about 31 MPH (50 KPH) for 3-5 minutes, then stop the car and let the engine idle for 2 minutes, then repeating this process again two more times (for a total of 3 cycles). Then the LTFT should be read with the scanner - both banks should be within -15% to +15%. If either or both of your banks are not within this range, the MAF should be inspected.

The MAF, with vehicle indoors (no potential for wind effects) on a level surface and engine off, key switch ON, the scanner on live data should show less than 0.54 g/s. You are pretty close to that level where the MAF should be replaced. The MAF also has an air temperature sensor that feeds data to the ECM, which is very important feedback to the ECM for fuel trim. That can be checked with an DVOM set to ohms, by checking resistance between terminals 4 (THA) and 5 (E2) on the MAF. Resistance values at temperatures should be:

• -4 deg F: 13.6 to 18.4 kilo-ohms
• 68 deg F: 2.21 to 2.69 kilo-ohms
• 140 deg F: 0.493 to 0.667 kilo-ohms

You might want to work through these tests to determine what you think about your MAF. That 2002 Avalon in the salvage yard had it's MAF installed on the air filter box, which I could still get for you if you want to consider a used Toyota OEM MAF.

There was another thread in this forum where the owner cleaned both oil control valves for VVTi but was still getting the engine running roughly, so opted to install two new oil control valves (got them from a Toyota dealer), and just that change resolved the rough running engine. Not saying that will happen for you, but it does appear those early oil control valves were weak spots on these Avalons.

 

Yes, I was not really able to follow the service manual procedure, as I can't drive the car as is. The short and long term trims may not be meaningful as tested. I did check the air temp sensor ohms and they were within spec. Will check again, just in case it changed. The sensor seemed to reading an accurate/reasonable temp though. I will let you know about the salvage yard MAF sensor. I assume you have done this before with others and know the best way to pay you and ship the part.

Ebay has both Toyota OEM VVTi solenoids for $112.50 plus tax (GENUINE TOYOTA SIENNA CAMRY ES300 RX330 6CYL CAM TIMING OIL CONTROL VALVE SET | eBay). I have been eyeing those for a while. What do you think? I will try the unplugging thing first. Not sure what that will tell me though. I guess if I unplug them and don't notice a change, that could indicate they are not working. Right? Not sure how soon these valves kick in and under what conditions.

 

Per the diagram below, your original oil control valves were part numbers 15330-20010 & 15340-20010. The ones offered in your eBay link was the first supersede to the originals. The current supersede to the originals are now 15330-0A010 & 15340-0A010. Given the wholesale price for the latest supersede P/N is $102.00 each before tax & shipping, the eBay seller has a tremendously positive feedback rating, and has sold 46 sets previously and only has this one remaining, at an attractive price, yeah, I would invest in them if I were you. You might want to give these a shot first before considering a MAF change.

 

Can bad vvt valves cause a hard to start condition? From what I have read, the vvt does not kick in until the engine is up to temperature. I have not replaced these because I have a hard start condition and the vvt does not seem a likely culprit. Maybe the valves are stuck open during idle when they should be closed. I guess that could cause a problem. Having said that, when the car does start and run, it does seem to stall when the car gets up to temp. I may be over thinking this.

 

Your ECM goes into closed-loop control well before your engine coolant is up to normal operating temperature. The ECU goes into closed loop control after your air:fuel ratio sensors start providing normal feedback information back to the ECM. A good way to help understand if the problem is present only when the ECU goes into closed-loop control is to leave your engine get cold, then turn the key to ON, put your scanner on it set to live data, find the ECM output that shows what control loop it is in (should be open when the engine is good and cold), then start the engine and watch when the live data switch is made from open-loop to closed-loop. When that switch is made, is that the same time the engine changes to running rough?

You should also check your ECM again for all codes (both active and pending) to see what you have at this moment. If you engine runs roughly, and even stalls, there should be at least a pending code set, if not an active one. There may be multiple codes. Do this and advise back what all your codes are, and if they are active or pending.

 

I will check for codes again when I get home. At work right now. I am pretty sure there will be no codes active or pending. I say this because I have been checking for codes and there have been none. That is my problem. I get no codes to guide me.
My point above was that the car is hard to start (in open loop). Can a bad VVT somehow cause this? I may have more than one problem. Still thinking the MAF g/s is higher than it should be. I believe a bad MAF could explain all the problems I am seeing (hard to start, stalling, running rough). One thing I forgot to mention was that prior to cleaning the IACV, I was not able to start the car with the MAF sensor unplugged. After cleaning it, I was able to run the car with the MAF unplugged. It was hard to start and ran poorly and still stalled eventually. This may indicate that the problem is not the MAF. My understanding is that if your only problem is the MAF sensor, you should be able to unplug it and the car should run, just not optimal. More later.

 

Sounds good. You may have wiring issues as well - not sensor issues. Did a rodent damage some wiring? Did some prior work damage some wiring? Is something disconnected after doing some work that wasn't reconnected (by accident)? This kind of stuff happens all the time.

 

I agree it is possible. I have been all over the engine area and could not find anything. Even had a mechanic look it over. He could not find anything either. He actually complemented me on the work I had done. My car is kept in a rodent free garage most of the time and has never shown any signs of rodent activity. Not saying it can't happen, just not likely. I did check the MAF and VVT connectors for proper voltage and they were ok.

 

You might want to check ignition timing as well, the old fashioned way (with a timing light). That might tell you something. I'm not sure on your 2000 Avalon if you need to go into diagnostic mode to get a correct ignition timing indication or not. I don't have a service manual for your car.

 

I will check my Chiltons manual and see if it has a procedure for that. I doubt I have the tools to do it, but if it just a timing light, I may be able to borrow one from Autozone. I also have a neighbor down the street that use to work on old cars. He may have one and might offer to help me do it.

 

What were your individual compression pressures (for each cylinder)?

If you are off a tooth, the engine will run fairly smooth, just will be sluggish. Two teeth or more and you would really know something is wrong. Not so much being off just a single tooth. And yes, your compression pressures would be affected if your timing belt is off a tooth or more - worse the more teeth off the mechanical timing.

 

The spec for my car is 218 psi compression. The range I saw was 200-220 psi. I think 145 psi was considered a problem. Back in 2012, I had a shop do the timing belt. They were off one tooth and I was able to drive the car to work and back. It ran rough, but it ran. So, i know what it feels like when off one tooth. If I have good compression, does it even make sense to check the timing?

 

Your compression pressures are fine. 145 psi was a pressure which you would not want to run the engine at. I'm thinking the minimum acceptable pressure for yours would have been around 175-180 psi. So I don't think your mechanical timing could be off.

Yes, all Toyota EFI engines had ignition timing controlled by the ECU, including those that had distributors. Early distributor models wanted the ECU to be put into diagnostic mode, where the ECU would have a zero advance on ignition timing, so the ignition timing could be set at +10 deg BTDC. Most likely your distributorless engine doesn't have a need for this ignition timing setting, as there is no variable (like distributor possition) to affect ignition timing.

 

I think I am back to the MAF sensor. I just got off the phone with a local salvage yard. They have a few MAF sensors for my car. He wants $50 for one. He also said if the one I get does not work, I can return it for one of the others. I thought the price was a little high, given that I saw new Denso OEM MAFs for less than $100.

 

A few thoughts:

1. If you are considering getting a salvage MAF (or two), I'd also get salvage oil control valves
   • Cleaning your originals should have at least gotten the oil inlet screen clean, but you don't know if the internals are bound by sludge or have broken
     • If broken, yes, they will have an effect on cold starts and cold running engine - not dependent on closed loop control
2. With a MAF-based control system, any unintentional air leak between the MAF and the intake connection to the head is critical
   • You have a PCV valve and a secondary ventilation valve feeding unmetered air into the intake - make sure the PCV valve is not stuck open and the secondary ventilation hose is not overdoing valve cover ventilation just ahead of the throttle bodies
   • You have an intake air control valve assembly on the opposite end of your intake surge tank where your throttle bodies are attached (see attached diagram)
     • Make sure this intake air control valve assembly is not letting unmetered air into the intake when it should not be
   • Make sure your intake surge tank gasket at the intake manifold, and the two gaskets at the bottom of the intake manifold (where it attaches to both heads) are not leaking air into the head
   • Make sure there is absolutely zero leaks on any hose connections downstream of the MAF, and that no connections to the large air intake hose downstream of the MAF are not connected, or have hoses attached that are not connected, or any hoses are cracked or broken
     • For MAF-based engines, can't emphasize this enough

There may be more thoughts, but maybe after doing these, something will make an effect - hopefully a positive one. If so, you know what new part you should get (if you don't trust a salvage part long term).

 

Thanks.
I went ahead and bought a used MAF from Ebay : 2000-10 Toyota 22204-21010 MAF Sensor OEM Denso Corolla Camry Lexus Scion Prius | eBay. It was only $27.71 after tax. If it is bad, I am just out the shipping cost to send it back.
My understanding is that a MAF that is over reporting the g/s can cause a rich condition. At an rpm of 1300, I show a MAF reading of 13 g/s. My 3.0 L car should have about 3 g/s at idle which is around 800 rpm. So at 1300 rpm, I would expect about 5 g/s on the MAF, not 13 g/s. I could be wrong on this, but this logic is why I am replacing the MAF.
Short term fuel trims on both banks are around -18% indicating a rich condition. I don't think I have any vacuum leaks because that would cause a lean condition. I also measured the intake vacuum and got 17.5 in-hg which is within spec for my car. I also smoked the system and found no leaks.
If I pull the trigger on the oil control valves, I will most likely go new. Probably the ones on Ebay I mentioned earlier. My concern with used valves is that if I see no improvement, I would be second guessing the used valves. I did clean the filter screen on bank 2 as it was easy to get to. It was clean to start with, so I did not bother doing the bank 1 screen. If I replace the valves, I will clean bank 1 screen then.
Also, I plan to jack up the car this weekend and take a good look underneath and make sure nothing is damaged that could cause some weird results. I was under there when I did the charcoal canister, but that was only at the rear of the car. The mechanic was under there and did not mention seeing anything strange, so I don't expect to find anything. Won't hurt to check it again.

 

There is a table on the 1MZ-FE on the internet that has engine operating condition values. Of course, it does not say the year or if the engine had VVTi on it, so don't know. But it should be approximately right for you. Here is the interesting data that would be seen on a typical scanner's live data screen:

• Normal Idle Speed: 700 +/- 50 RPM
• Test Hi-Speed w/o Load: 2,500 RPM
  • System Control: OPEN (air:fuel ratio data not present or not valid)
  • CLOSED (air: fuel ratio data present & valid): NOTE: Does not involve coolant temperature threshold
  • CALC LOAD: Idle: 12.9 - 25.2%
  • Hi-Speed: 11.7 - 23.9%
  • Coolant Temp: 176 - 203 deg. F
  • STFT Bank 1: 0 +/- 20%
  • LTFT Bank 1: 0 +/- 20%
  • STFT Bank 2: 0 +/- 20%
  • LTFT Bank 2: 0 +/- 20%
  • IGN Advance: Idle: 12 +/-5 deg BTDC #1 Cyl
  • Intake Air Temp: Equivalent to Ambient Temp
  • MAF: Idle: 2.4 - 4.8 gm/sec
  • Hi-Speed: 7.9 - 16.2 gm/sec

Not sure if this helps. Advise what happens when you try out the replacment used MAF.

 

Thanks, very helpful. Using the numbers above with my actual values: 1300/700 x 4.8 =8.91 g/s is what I should be seeing at 1300 rpm. I am actually seeing 13 g/s at 1300 rpm which is 1.5 times what it should be.
I am surprised that there is a +/- 20% on the fuel trims. Not sure I understand what this means. Are they saying it is normal to have as much as a 20% fuel trim? Or if the fuel trim exceeds 20% it will shut your engine off. Maybe that is what is happening. I doubt it.
I won't receive the MAF sensor until Mon-Tue. Will let you know the results for sure.
I did order the new VVT valves from Ebay. I did not want to miss out, as it appeared to be the last one they had. Plus at this point I need to do what it takes to get this car fixed. The wife is on me pretty hard about using her car and wants to get a new car bad. I told her I only had 290,000 miles on the Avalon and in about 5 years I might finally have it broken in. She did not buy it.

 

It is always a possibility for both LTFT & STFT to be very high or very low, depending upon the situation. Towing a camper or large boat would suggest a large LTFT & STFT. Would be nice to know how long of a period of time LTFT covers, and how long of a period of time STFT covers, and maybe there is such a time factor out there, but I haven't seen it nor heard of it. If you are driving with the wind, or driving down a mountain, I'm sure both LTFT & STFT values would be in the negative. So that is why the range is large, to ensure people don't panic due to a particular driving situation that they don't remember anymore, but they see these values. And there is now level, plus or minus, that the ECU will shut down an engine on.

Like I said before, your wife is pretty amazing, helping you when you need it and correcting you when you need it too!

 

It is always a possibility for both LTFT & STFT to be very high or very low, depending upon the situation. Towing a camper or large boat would suggest a large LTFT & STFT. Would be nice to know how long of a period of time LTFT covers, and how long of a period of time STFT covers, and maybe there is such a time factor out there, but I haven't seen it nor heard of it. If you are driving with the wind, or driving down a mountain, I'm sure both LTFT & STFT values would be in the negative. So that is why the range is large, to ensure people don't panic due to a particular driving situation that they don't remember anymore, but they see these values. And there is now level, plus or minus, that the ECU will shut down an engine on.

Like I said before, your wife is pretty amazing, helping you when you need it and correcting you when you need it too!

The new MAF and VVT solenoids made no difference. Put the old ones back on. I did check under the car and did not see anything of concern. Back to the drawing board.

 

Take a good close look at post #51, and the diagram. Looks for areas of air getting into the large surge chamber that you maybe haven't yet dug into.

 

I did a vacuum check at the air intake a while back and it was 17.5 in-hg. This puts it at the low end of the spec. I also smoked the intake and showed no leaks. I think I may introduce some propane gas around the intake and see if the engine surges. This assumes I can keep the car running long enough for this test. The pcv valve is newish. I still have the previous pcv that was working before I replaced it. I have cleaned both and tried them on the car and it made no difference. Does not appear to be a pcv issue. I also made sure the line from the pcv and intake manifold was actually connected. Is this what you called the "secondary ventilation hose"? Or is that something else? As I mentioned earlier, I have negative fuel trims, which indicates a rich condition. If I had extra air leaking in, I would expect a lean condition. I will take your advice though, just in case I am misinterpreting the fuel trim info from my scanner. Let me know if you think the propane test is the right test. Thanks again.

 

The only thing I saw from you regarding fuel trim was in post #52, when you said your STFT on both banks was -18%. To be honest, STFT is important, but means little by itself. What is far more important is LTFT, followed by LTFT + STFT. STFT is instantaneous adjustments made by information obtained at the moment by your air:fuel ratio sensors. STFT are not stored in ECU memory. LTFT, on the other hand, are calculations made by the ECU over a long period of time, and account for gradual changes going on with the engine. LTFT values are stored in ECU memory. Total fuel trim is the combination of STFT + LTFT. So an instantaneous -18% STFT means little if your LTFT is +20% (so total fuel trim is +2%). So let's get your LTFT values on both banks to see what the long term adjustments look like on your engine first, before determining if you have air leaks or other items going on.

 

I will try to get the LTFT, but I am not sure the care runs long enough to get it.

 

The car does not need to run to get LTFT. Remember, these values (for Bank 1 & Bank 2) are stored in the ECU memory. All you need to do is turn the key to ON, plug in the scanner and go to live data. The STFT will be 0, but the LTFT values will be there.

 

For some reason, I have to crank the engine. All the fuel trims are 0. When the car cranks, the LTFT shows a non zero value. If the car does not start and I return the key to on, the LTFT goes to 0 again. If the car starts, I get a non zero LTFT. Weird!