1993 Camry V6 idle rough/won't start - Toyota Nation Forum : Toyota Car and Truck Forums

sincity2k · 07-18-2011, 03:06 AM

So I bought 93 camry used has 260,000 miles. Now it has been acting quite strange and I need some TN help. It has the 3VZ-FE motor and from what I have been told it is a pretty good motor. Well here are the problems, appreciate any help.

Symptoms:

I start the car when it is cold, starts right up and drives great. Kind of a weird idle sometimes when the A/C is off, like if I come to a stop, it acts like it wants to die, then sometimes if I give it gas, it kind of sputters like it is going to die and then it gets going again. Now here is where it gets even more weird.

After the initial cold start and the engine is warm, I go to start it maybe 30 mins later, it might start, and if it does, I have to give it a lot of gas because it sounds like it is going to die. or it won't start, it just keeps cranking, if I give it some gas, you can smell the gas after awhile but it still won't start. So it will do this for about 5 -15 mins, and then the car will start but I have to keep giving it gas. It will have a weird rough idle for awhile and still if I give it gas it hesitates and then starts going. I put some gas in it, started it up one time and after it started the engine kept revving it self up and down for like 15 seconds, then it stopped and idled fine???

Poss Solutions:
I cleaned the throttle body pretty good with a toothbrush, nasty black stuff in there. I took off the IAC and sprayed some sea foam in it, but did not take it apart all the way. I have Check engine light and i got the codes from running a jumper wire and having it flash at me. One was code 25, air/fuel ratio lean malfunction -- the other code I think was code 27 - sub oxygen sensor. So it is weird, start it on cold and it will run great, but after the initial run it is hit/miss about starting and the idle is rough when at warm.

Please help me get this thing operational. Thanks again

dc_98_cam · 07-18-2011, 06:19 AM

Did you check the electrical response of the IAC valve?
If you connect Battery voltage to the center terminal, and negative lead to each respective outer terminal of the IAC electrical connector, you should observe opening and closing of the IAC valve.
Another component to look at is the A/C Idle Up Valve. If you have the factory service manual, you might be able to determine if it is working properly. ... Just one or two simple tests.
If you don't have the factory service manual ... take it to the dealer.
https://techinfo.toyota.com/techInfo....toyota.com%2F

sincity2k · 07-18-2011, 09:10 AM

I have the manual and I did use a jumper wire to test IAC and it said it was suppose to rev up for like 5 secs and it did do that. Which indicated it was working right? Where is sub oxygen sensor? It us weird how it only does it after it is warmed up. I will try and test a/c idle up tonight. Please let me know if I should be looking anywhere else. Thanks again

hill8570 · 07-18-2011, 10:07 AM

In general, does she seem to be running rich when warmed up (not just at idle)?

If so, might be that the Engine Coolant Sensor -- if it is indicating too "cold", your mix will be too rich once your warmed up. When this problem occurs, you can try disconnecting the ECT (if the ECU can't see the ECT, it will fail-safe to "warmed up" mode) and see if she starts OK.

Off chance something's up with the cold start timer or injector. If it turns out not to be the ECT, that's something else that problem needs to be looked at.

***BMR*** · 07-18-2011, 02:05 PM

Quote:

Originally Posted by sincity2k

Where is sub oxygen sensor?

It's downstream from the cat. You must have a CA emissions-equipped car.

The idle RPM surging up & down is a classic symptom of the IAC valve sticking. Mine started doing that, so I disassembled it and cleaned it; totally fixed it. Here's a good DIY thread for that. There were places inside it that I doubt can be cleaned well enough by just spraying in some Seafoam. I'd bet that's where the problem is.

sincity2k · 07-18-2011, 04:21 PM

Quote:

Originally Posted by BMR

It's downstream from the cat. You must have a CA emissions-equipped car.

The idle RPM surging up & down is a classic symptom of the IAC valve sticking. Mine started doing that, so I disassembled it and cleaned it; totally fixed it. Here's a good DIY thread for that. There were places inside it that I doubt can be cleaned well enough by just spraying in some Seafoam. I'd bet that's where the problem is.

I will do the ECT test after work, then if not pull the IAC and do a real clean on it, maybe that is why its so hit and miss. I will keep you guys posted. Thanks for giving me a good place to start.

sincity2k · 07-19-2011, 01:28 AM

Well I removed IAC valve, took it all apart, cleaned it out, and put it back in. It started and stalled like 3/4 times, then I took it for a drive, drove great and the idle seemed great after it warmed up. I thought the problem was solved, then i went for the dreaded 2nd test drive, it started up, idled rough again, then when I would give it gas, it acted like it wanted to die before it would go. like it was a stutter in the gas, it is really crazy, why does it drive so good when started cold but then when it is warmed up and I go to start up, it drives like crap!! Then it might die and not want to start up again.

I did not pull the ECT sensor because I lost daylight and the Haynes manual is not clear on where it is at on this specific engine. (any tips??) Well I have one more day to work on it tomorrow, so please anybody HELP ME get this old ride going again. Appreciate everything

Mike Gerber · 07-19-2011, 10:27 AM

"why does it drive so good when started cold but then when it is warmed up and I go to start up, it drives like crap!!"

Three or four thoughts on this. It may be the problem with the O2 sensor. On these generation cars they are out of the loop as far as engine management until a certain operating temperature is reached. Then they come in to play. I'm not certain of this, since you don't commonly see problems like this from a rear O2 sensor, but you are going to have to replace it anyway so you might as well do it and see if it helps.

Another thought is a weak or cracked coil inside the distributor. They can cause drivablity problems like this when they heat up. That's when they have a tendancy to fail. Check the coil for being in spec. Your manual should show you the specs for this. You will need a digital volt/ohmeter to do this. Also remove the coil and inspect it carefully for hairline cracks. This is a common problem on the first 3 generations of Camrys.

A weak fuel pump also has a tendancy to cause problems when they heat up. You will need a fuel pressure tester and some fittings to tap in to the fuel rail to test the pump. Again you can refer to the specs in your manual for the proper fuel pressures.

The ECT sensor is usually on a coolant port off the cylinder head under a green plastic connector. Sorry I don't remember it's exact location on your engine. Again, you will need the DVM and the specs from the manual to test it.

Good luck.

Mike

***BMR*** · 07-19-2011, 10:32 AM

Quote:

Originally Posted by Mike Gerber

Another thought is a weak or cracked coil inside the distributor.

Minor correction: On this 3VZ-FE engine, the coil isn't inside the distributor. It's mounted on the driver's side strut tower, just behind the battery, if you're standing in front of the car. Follow the wire in the center of the distributor cap; it'll hook up to the coil.

Another possibility along the same line of thought: It could be the plugs, wires, disty cap/rotor. sincity2k - Any idea how long it's been since they were replaced?

sincity2k · 07-19-2011, 11:42 PM

Some Success! I finally did the ECT test, which I hope is the ECT it is near the top of the engine on the right side and it had a green and brown wires with a green plastic cover. So I drove it around and it warmed up, it ran really good for the most part. I waited about 40 mins and went to start it which is usually when it doesn't work, and of course, I started and it stuttered and then stalled.

So I tried and it wouldn't start!! So I pulled the ECT plug off and went to start it, and it started right up. I did it twice and it worked. Does this mean I should start by changing the ECT sensor or what? Please advise.

Thanks to everyone

P.S. I inspected the coil which appears to be in good shape but I'm not really sure what I'm looking at, it looks like a plastic box and has a wire going into it from the distributor. I unplugged the wire and it looked very clean. Well I will keep you posted.

dc_98_cam · 07-20-2011, 01:35 AM

Good job tracking down the apparent problem ...
Before you actually go out and buy a new ECT sensor, take a good look at the electrical connector and any metal tabs. Any electrical connections need to be 'bright shiny metal'.
If they are corroded or oxidized ... even the harness plug ... you could still have a problem.
So ... stop by radio shack or fry's and get a spray can of plastic safe electrical contact cleaner, and make sure the harness connector contacts are clean and free of any contamination. I always try to use a fine grit emery cloth to clean any metal surfaces that will be touching each other.
When you get a 10 or 20 year old vehicle .... a lot of miles on it .... little details like this can be important.

sincity2k · 07-20-2011, 01:48 AM

Quote:

Originally Posted by dc_98_cam

Good job tracking down the apparent problem ...
Before you actually go out and buy a new ECT sensor, take a good look at the electrical connector and any metal tabs. Any electrical connections need to be 'bright shiny metal'.
If they are corroded or oxidized ... even the harness plug ... you could still have a problem.
So ... stop by radio shack or fry's and get a spray can of plastic safe electrical contact cleaner, and make sure the harness connector contacts are clean and free of any contamination. I always try to use a fine grit emery cloth to clean any metal surfaces that will be touching each other.
When you get a 10 or 20 year old vehicle .... a lot of miles on it .... little details like this can be important.

Sounds like a plan, yeah I think this is the problem, I went out a little later, and it started right up while it was warm still with the ECT sensor unplugged. So looks like tomorrow after work, I will grab the new sensor and some of the electrical cleaner and see how everything works out.

Quick side question: What is the consequence of driving with the sensor unplugged? Does the ECU/ECM just default to a safe mode?? Bad gas mileage or what?? Anyways I will hopefully have good news tomorrow night. Thanks to everyone on TN for helping me so far and lets hope this is the end of my craigs list special

hill8570 · 07-21-2011, 12:05 AM

Quote:

Originally Posted by sincity2k

Quick side question: What is the consequence of driving with the sensor unplugged? Does the ECU/ECM just default to a safe mode?? Bad gas mileage or what?? Anyways I will hopefully have good news tomorrow night. Thanks to everyone on TN for helping me so far and lets hope this is the end of my craigs list special

Well, you'll get a "check engine" light, and the ECU will fail-safe to assuming the engine is warmed up, so you'll be running lean until the engine is really warmed up. Summertime, not so big of a deal, but you probably wouldn't be able to start the car in the winter. Hopefully you'll have 'er fixed before then

sincity2k · 07-21-2011, 12:47 AM

So I changed the ECT sensor. That thing had to be an original because it was very brittle and the plastic on top broke right off and I just unscrewed the sensor it self and it looked pretty OLD!! Anyways I put the new one in and warmed it up, drove it and it drove good. The the real test

I shut it off once it was warmed up and then waited about 40 mins which usually it wouldn't start after that pre ECT change. Now I fired it up and it started right up like it should. Continued more tests, no more idle stall crap and it seems to start up warm each time. So I'm pretty sure this was my problem and I want to say a big thanks to all of you who helped me during this almost weeklong battle with a very used 93 camry. I just hope no more big problems come at me. As usual I will end with one quick question because I made a rookie mistake and did not reinstall the washer with the new sensor.

So it drove good without it but is this something that I should wait till the engine cools and reinstall the new sensor with the washer or what??? Anyways the big thing is I'm happy that my car starts now when it is warm which it didn't this whole week. Thanks everybody!!