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03 Solara 1MZ----P0171,P0174 Help!!!

11K views 28 replies 3 participants last post by  hardtopte72 
#1 · (Edited)
I have a 03 Solara with the 1MZ. I'am trying to figure out what i need to do to resolve codes P0171 and P0174. I have searched here and found a few thing to look at but didn't have any luck. I had a P0420 code from a high-flow cat i installed, but did the "anti-fouler" mod and it fixed it. I'am not sure if that's effecting it? Short term fuel trims look good from what i can tell. Long term trims look way off, but i really don't know? I did get freeze frame data for P0174, but not P0171.

things i tried:

Cleaned maf
Tried another maf from a donor car
Checked for vacuum leaks ( found plenum gasket was leaking and replaced)


Here's what came up on the freeze frame data:

P0174
-FREEZE FRAME DATA-

STFT B1(%) 1.5
LTFT B1(%) 28.9
STFT B2(%) 0.7
LTFT B2(%) 33.5
Eng RPM 833
Veh Speed(mph) 0
IAT (F) 152
 
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#2 ·
I would bet money one of your injectors isn't firing or wasn't firing. This caused the lean code and the way high fuel trim number.

Have you cleaned your injectors? You might want to take it to the dealer as they can individually kill injectors to see if one is acting up. Also they have a specialized service tool and cleaner to clean injectors straight from the fuel line (as opposed to the tank).

If it isn't that I would guess your fuel pump is weak, bad VSV, vacuum leak, or ECU.
 
#3 ·
That's kinda what i don't understand. It appears to run fine. If one injector was firing on and off wouldn't that only effect one bank instead of both of them? Any ideas what kind of numbers i should have for my fuel trims? When i run "live data" on my scan tool those numbers get high like that but drop drastically when you give it some gas. They only read high when it sits and idles, witch it was when it tripped the code.
 
#4 ·
So if you clear the code it reappears?

Rereading your post this does seem more MAF related. Have you done any resistance measurements at the connector?

If you go for a long drive and return to idle how are the numbers?

What led to these problems? Was work performed that triggered these codes? Are your O2 sensors and A/F sensors reading correctly? If these are not sending correct info the ECU then you can have this issue. Did you make sure to only use the anti-fouler on the sensor 2 (downstream) o2 sensor?
 
#5 · (Edited)
If those are the only codes u have I'd bet it's a vacuum leak somewhere. Spray carb cleaner or starter fluid on all vacuum lines while watching fuel trim. When it changes you've found your leak. If it had anything to do with the MAF you would likely have a p0101 which is MAF performance out of range. Along with an intake air temp code. Highly unlikely that both o2 sensors on front and rear bank will fail at both times. It's something effecting all 6 cylinders. Not just one bank.
 
#6 · (Edited)
Hardtopte72- When i clear the codes i go for a pretty good drive, probly 20-30 miles, then it pops up while idling in the driveway when i get back. I did only use the anti-foulers on the downstream O2. I bought this car with a used short block installed. Had to find all the missing parts off a salvage car (intake set up, exhaust y-pipe, etc.). So i'am just trying to figure out my last bug, lol.




BlackCamSe-Hmm, i think your right the more i think about it. I found the leak in the plenum to intake gasket by spraying carb cleaner and watching the fuel trim. It really surprised me since it was running good. I'am kinda starting to wonder if maybe it's leaking on the intake to block gasket. I'am in the process of building a smoke machine to check for vacuum leaks, hopefully i'll have it done tomorrow.
 
#7 ·
Hmm, i think your right the more i think about it. I found the leak in the plenum to intake gasket by spraying carb cleaner and watching the fuel trim. It really surprised me since it was running good. I'am kinda starting to wonder if maybe it's leaking on the intake to block gasket. I'am in the process of building a smoke machine to check for vacuum leaks, hopefully i'll have it done tomorrow.
Yeah it doesn't take much of a vacuum leak to throw those codes. Any type of air coming into the system after the MAF will trigger a lean code.
 
#9 · (Edited)
I had a corolla at work with the 1.8 with a p0171. Drove me nuts. Found 1 vacuum leak at the intake manifold gasket. Fixed that and the code came back. Ended up having another leak at the throttle body gasket too. Car ran fine. Lean codes caused by vacuum leaks are hard to diag when they're small enough to not cause a driveability problem.
 
#10 · (Edited)
So the car was a shell with a short block?

When you pulled the plenums did you reuse the gaskets? Did you take throttle body off of the plenum?

This is definitely sounding more like a smal vacuum leak.

Also check the brake booster and brake booster hose. Does it sound excessively airy when pumping the brakes? I have seen some cars throw a lean code from a faulty booster causing a vacuum leak.

Using carb cleaner recheck all the areas for a vacuum leak (hoses, TB, intake manifold, plenum, booster, etc.) while observing fuel trims and idle changes.
 
#11 ·
Here's a little update. I did manage to get my smoke machine built, but i haven't had a chance to try it. But i did go try to shoot some more carb cleaner around on the intake and check for more leaks before it got dark. I believe i found a leak around the shaft on the acis valve. Why i have no idea since that's one of the first places i checked. Guess the plenum gasket was leaking more than the other at the time. From what i can figure out from pictures it looks like i could probly take it apart and replace the seal. Has anyone replaced the seal? or have any idea what the part number would be for it?
 
#13 ·
lol, i wish i could say yes. Cars a 03, engines from a 02, parts that i pulled from a donor car are from a 99. I've checked and double checked everything i've had to find that was missing and made sure it's interchangeable between model years.
 
#16 ·
ACIS Gasket

99 Solara Auto 17127‑0A010
02 Solara Auto Same
03 Different based on NAP or JAP
NAP Same as above
JPP 17127-62030

Called Gasket Surge Tank Cover
 
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#17 ·
Awesome, that does help since i'll probly need it. That's the gasket that goes between the valve and the plenum right? I was actully trying to figure out if i can replace the one on the shaft. That's where i was shooting carb cleaner and the fuel trims where changing. I've tried to dig around but haven't found anything about changing that seal.
 
#20 ·
That part

1. Is not serviceable and is part of the valve which includes the 2nd gasket
2. Doesnt seal the ACIS. The ACIS is sealed to the plenum by the other 2 gaskets.

Worst case scenario I am wrong and you just go out and get another ACIS.

 
#21 ·
Well i got a change to work on it some this weekend. I hooked up my smoke machine and checked for vacuum leaks and came up with nothing. So i decided to replace the fuel filter and fuel pump sock to rule those out. I think i'am really just back to the acis valve. There's a tsb for the 04 solara's about these codes and spraying around the shaft of the acis and watching fuel trims. Mine defiantly changes when i do it. I hate to spend the cash on one not knowing 100% that will fix it since it's $200. Would spacing out the O2 behind the cat make it possibly think it's running lean? or does it solely rely on the A/F sensor for fuel trim?

Here's the link i found on the 04 Solara tsb for these codes:

http://www.discountconverter.com/tech-tips/news_page.cfm?Key=catalytic_converter-&News=240
 
#22 ·
04 Solara uses a 3MZFE. Completely different intake manifold and ACIS. Yours is aluminum those are plastic.

A/F sensor is to measure fuel trim for direct adjustment by the ECU second O2 is to measure how well Cats are working.

IF you can hit up a junkyard For another plenum do it. Just make sure they have a return policy.
 
#24 ·
What intake gasket are you using? OEM Metal?

Check all the vacuum hoses and make sure they arent dry rotted to death either.
 
#25 ·
The intake and plenum gaskets are metal, but the plenum one ended up leaking so i replaced it with a felpro witch fixed it. All the vacuum hoses look good, and i didn't see any smoke come out of them anywhere. This thing really has me stumped. There's got to be something i'am overlooking
 
#26 ·
Try another plenum. Even though I can't say I have ever seen an ACIS leak (at least one which threw a code) and you have 2 it's possible you are just unlucky.

If the leak is coming from that area and you are sure it's hooked up properly and no parts are leaking them try another plenum.

Did you verify your smoke machine works well by creating an obvious leak (like leaving a hose off) and seeing that smoke does in fact come out?
 
#27 ·
yeah, i think i've just messed with it so much my mind is kinda fried on it. The smoke machine i made worked pretty good. I put a rubber glove over the intake tube to plug it off and it was blowing out tons of smoke when i pulled the pcv valve or oil cap.
 
#28 · (Edited)
Here's another update-- I think i've finally got it fixed. I went out yesterday and blew some more carb cleaner all over everything again. I noticed that the fuel trims where changing when i shot it between the brake master cylinder and the booster. I've done this a few times and noticed no change. I thought the hose coming from the intake to the booster was sucking vacuum, so i cut some off the ends and reinstalled it. I then rechecked my long term fuel trims and they dropped, and the codes went away, but they didn't drop low enough. I then shot a ton of cleaner where the master cylinder bolts up to the booster and it shot the short term trims way up. What i think it ended up being is the gasket between the master cylinder and booster was shot, and was sucking air on the bottom side. When i hosed the crap out of it, cleaner ran down to the bottom and got sucked in. I made a gasket and coated both sides with sealant and reinstalled. Both long term and short term trims look good, Everything has registered in my scan tool as good except the evap hasn't read yet. I've drove it over 100 miles today, so hopefully i'll know for sure soon that it's finally gone. So far so good.
 
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