1991 Camry Intermittent No Start

[Hildy]

Hey guys, first post here so hello all! Well here goes.

It is a 1991 Camry 4cyl, electronic auto tranny, 131k. Car had been towed into our shop a couple times for an intermittent no start (couple months apart), and started everytime it got to our shop. I finally snapped a waveform view of the fuel pump, and it was nasty, so we replaced the pump on a recommendation. Car was fine for about 6 - 7 months and then it came back, again, this time as an intermittent stall when running then no restart, of course starting every time we seen it. Only recently did it get to the point where it died completely. I went to the customers house to diagnose it, as i love diagnosing no starts, and didn't want anything to jiggle around on the tow truck. It had solid spark, jumping my 30kv gap, and beautiful injector pulse, as well the tach was fluttering and great fuel pressure. It did not, (and never has had) any codes, and the car was turning over like a champ. So i got it towed back to the shop.

(I am going to apologize right now for such a long post, but U have more hours into this car than i care to admin, and i don't like to get beat)

So of course it starts when i get back to the shop, runs great, several test drives, and nothing. After about a week, no start, so right away i double verify spark and injector pulse, both there, both great. Car sounds great when it turns over, but then i notice it wants to try to run backwards, only when you turn the key back from crank to run. I can turn it over for 2 min, or 2 secs, but only when i let the key come back from crank to run does it do this. So im thinking great! Easy! Timing!. So i check: Timing belt marks, Verify TDC with 0 on crank pulley, and verify rotor movement in distributor. All Great ( I did double check timing when running as well and it was in spec). Then it starts again so i have to wait another week before it no-starts.

SOOOO it no starts again and i scratch my head, kind of repeating all my previous steps, as it had been a week, and my memory was a little vague. I decide, what the hell, lets take a sample of the fuel and put it in a bowl. Did this and, waddya know, WATER in the fuel (lots), so now i am excited! Drain tank by pulling backseat and sucking dry, change fuel filter (which was almost plugged with dirt, yet tank was spotless), add some new gas and methyl hydrate for good measure, and cross my fingers, runs for another couple days, no start in the morning again. It seems to be getting worse. When it does fire and run, it seems to have a lean stumble when you accelerate the motor quickly, but fine if you load it slowly.

So here is a list of things i have checked and verified as good/working

1. TPS checked and Adjusted (IDL s/w was mis-adjusted)
2. ECT checked and verified as same voltage and resistance as IAT in MAF
on a cold morning
3. IAT - mentioned above
4. VAF, checked for smooth movement as well as no drop outs or glitches,
voltage at KOEO was around .6v IIRC
5. CKP, CMP, IGT, and IGF signals at both ECM and Igniter
-Note, i was getting 5v flatline on IGF at one point and no spark, but i am not sure if i induced this somehow, as i have had spark the rest of the time it has not started.

6. Timing (Belt and Distributor)
7. Fuel pressure - a tad on the high side by about 3-5 psi, but seemed ok
8. Spark and injector pulse, at the same time
9. All power and grounds at ECM and sensors. Voltage drops at grounds are about .07v, goes up to .12v when cranking, back to .07 when running.
10. I even watched my o2 signal during a drive, and it seemed to function quite normal
11. Wiggle tested every wire in the car about a billion times
12. Compression test - 180 across the board
13. Pulse width on injectors - 15 ms during crank, 65 fahrenheit, cold no start, about 8-10 ms during crank on warm start, 2 ms at idle

I am sure there is more, but i have forgotten at this point. So I am stuck right now. I am assuming that because i have good IGT signal to my igniter that my CKP CMP and ECM are functioning OK. Since i have injector pulse and Fuel pressure, i am assuming i have fuel at the cylinders. I dont think that 15ms pulse width during crank is enough to flood it (?) And dont tell anyone, but i even pulled a vacuum cap and sprayed some staring fluid into the car, to see if it was a lack of fuel, which did nothing as well.

One last thing, it only seems to up the pulse width to 6 ms when i snap the throttle quickly, no matter if i snap to 1/4 throttle, or snap to full throttle - this seems odd to me, but then again i have never actually checked pulse width on a camry

So tomorrow morning i am getting up a couple hours early to hopefully catch the car no starting again, and try to narrow this down once and for all. I will let you guys know how it goes, and if you have any ideas, any at all, feel free to let me know,

very much appreciated,
one very frustrated,
-Jason

[Tech1984]

Jason, sorry I only scanned your post, but the first thing I used to go after on these back then for this concern was the thermo time switch.
P#89462-20050 (brown sq connector, i think)
It wouldn't allow the cold start injector to squirt (at times).
As the weather gets cooler it gets worse.
A little test I did was to pull the connector and apply 12v to one side. (the other pin contacts starter)
With the cold start injector pulled but still connected I could test the wiring and spray pattern all in one shot.
Course you need fuel pressure, so I jumped b+ and FP at the check connector with koeo.

tech1984
Toyota MDT

[hairball]

I'd put MY money on the ignition switch!

I've seen other cars, both foreign and domestic (oh, sorry Canada!, I meant Japanses and American!) do this and it turned out to be the ignition switch.

It only makes sense, too. If the car only starts when you let off the key into the Run position, it has to be something in the ignition switch. I know that you won't get spark if it's not in the Run position, so if the switch is faulty, it could be why you're not getting spark all the time and it's not starting all the time.

Just a hunch. Plus I noticed it wasn't in your list of things checked. And there are only so many things that could cause an engine to not start. Sure, there could be a ton of things to stop it from RUNNING, but if they start, then they might die or run like crap or something. But if an engine doesn't start (an then only sometimes), it HAS to be something related to the starting circuit. Again, I'm betting on the ignition switch.

Good Luck!

[Darwin686]

Originally Posted by hairball

I'd put MY money on the ignition switch!

I've seen other cars, both foreign and domestic (oh, sorry Canada!, I meant Japanses and American!) do this and it turned out to be the ignition switch.

It only makes sense, too. If the car only starts when you let off the key into the Run position, it has to be something in the ignition switch. I know that you won't get spark if it's not in the Run position, so if the switch is faulty, it could be why you're not getting spark all the time and it's not starting all the time.

Just a hunch. Plus I noticed it wasn't in your list of things checked. And there are only so many things that could cause an engine to not start. Sure, there could be a ton of things to stop it from RUNNING, but if they start, then they might die or run like crap or something. But if an engine doesn't start (an then only sometimes), it HAS to be something related to the starting circuit. Again, I'm betting on the ignition switch.

Good Luck!

I'm with haitball on this one with one more part that overlooked can be very problematic. Take a look at your ignition coil. Its part of the distributor but easy to check. Pull the distributor cap, spinner, and dust cover on the dizzy. Feel around for cracks if you can't find any cracks check the ignition coil. It could be failing.

[white90dx]

Originally Posted by Hildy

Hey guys, first post here so hello all! Well here goes.

When it does fire and run, it seems to have a lean stumble when you accelerate the motor quickly, but fine if you load it slowly.

Have you noticed a difference with weather - namely, humidity? The stumble on hard accelleration and ok on light accelleration points to ignition (namely, ignition coil - they go out often on this car). When dry it works, when wet it doesn't (and it may work worse when hot too...). I think that explains the stalling...

As for the starting, the ignition switch is an interesting option, but I'm not so sure that's the case.

Another thing that popped into my head is the signals from the cam sensors in the distributor might be messed up - this may be where the totally mis-timed spark comes from. That would probably only show the error on the cold start condition. It might be worth a full inspection of the distributor and cam sensors.

-Charlie

[Hildy]

Well guys thanks for all your replys, gave me a couple things to try. I had a little time on friday to have another quick peek.

Darwin-
I physically checked the distributor/coil, and did notice what looked like possible arcing through the coil itself, to the rotor shaft. So i went for a test drive to get things warmed up, and it started falling on its face like crazy, anytime that I hit the gas quickly from a stop, it would just cut out, or pop through the intake once or twice and die, but if i get the motor to around 2000 rpm, then gun it, no problem. I got it back to the shop, hooked the scope up to it, to see if i could catch any funny stuff going on, and of course by the time i get back, the car has cured itself again!. I haven't been able to scope it while it is acting up yet

So really this has to be either a spark/spark timing, or lean issue. I checked the injectors again, and noticed to weird things. 1) When the car revs fine, (by snapping the throttle) the injectors are commanded to about 9-12ms peak, but when it does decide to bog, the injectors are never commanded at any more than 6 ms, no matter if i snap to 10% throttle, or 100% throttle. 2) I then checked waveform and noticed that during saturation, the injectors don't fall under 1 volt. If there is resistance in the circuits, or the drivers in the ECM, that could cause commanded injector time to fall short of actual injector time?

White90dx-
It does seem to be getting worse as the weather turns bad. I seem to have power everywhere i need it when cranking, so i am assuming the ign. s/w to be OK. Also, I am going to check injector firing versus ckp/cmp, and make sure they are timed, and rythmic, thanks for that thought

Tech1984-
I have checked the thermo-time switch, and it was functioning great, actually it was one of the earlier tests i did do, lost of tips in alldata and the modis pointed to it, all seemed to check out great at that time.

Hairball-
I have checked for power everywhere when it wasnt starting. ECM igniter etc. all checked good, also this problem seems to have shifted to a KOER condition as well, so for now i am assuming that portion of the system is working good.

Again, thanks guys for the interest, i think i may wonder in today (saturday, my day off) and throw in some non time-stressed hours at it, see if i can get anywhere, ill keep you all informed!

[Darwin686]

Originally Posted by Hildy

Well guys thanks for all your replys, gave me a couple things to try. I had a little time on friday to have another quick peek.

Darwin-
I physically checked the distributor/coil, and did notice what looked like possible arcing through the coil itself, to the rotor shaft. So i went for a test drive to get things warmed up, and it started falling on its face like crazy, anytime that I hit the gas quickly from a stop, it would just cut out, or pop through the intake once or twice and die, but if i get the motor to around 2000 rpm, then gun it, no problem. I got it back to the shop, hooked the scope up to it, to see if i could catch any funny stuff going on, and of course by the time i get back, the car has cured itself again!. I haven't been able to scope it while it is acting up yet

So really this has to be either a spark/spark timing, or lean issue. I checked the injectors again, and noticed to weird things. 1) When the car revs fine, (by snapping the throttle) the injectors are commanded to about 9-12ms peak, but when it does decide to bog, the injectors are never commanded at any more than 6 ms, no matter if i snap to 10% throttle, or 100% throttle. 2) I then checked waveform and noticed that during saturation, the injectors don't fall under 1 volt. If there is resistance in the circuits, or the drivers in the ECM, that could cause commanded injector time to fall short of actual injector time?

White90dx-
It does seem to be getting worse as the weather turns bad. I seem to have power everywhere i need it when cranking, so i am assuming the ign. s/w to be OK. Also, I am going to check injector firing versus ckp/cmp, and make sure they are timed, and rythmic, thanks for that thought

Tech1984-
I have checked the thermo-time switch, and it was functioning great, actually it was one of the earlier tests i did do, lost of tips in alldata and the modis pointed to it, all seemed to check out great at that time.

Hairball-
I have checked for power everywhere when it wasnt starting. ECM igniter etc. all checked good, also this problem seems to have shifted to a KOER condition as well, so for now i am assuming that portion of the system is working good.

Again, thanks guys for the interest, i think i may wonder in today (saturday, my day off) and throw in some non time-stressed hours at it, see if i can get anywhere, ill keep you all informed!

Ok so you have actually identified your problem without realizing it.

I want you to try this. Replace the coil. Get the car hot and runnig and let it fail if it does at all. pop the hood an get a can of compressed air and spray the metal housing on the distributor. After rapidly cooling it down it should crank right up.

Here is what is going on. Its actually a combination of two things. I dealt with this recently myself. What you should be feeling when the car stalls or dies is a kinda high RPM from the motor and a an uneasiness from the engine that would feel like the timing is slightly off before it dies.

You have two things that are potentially failing.

First your ignition coil is toast. the Coils are failing. Replace the coil. How do i know this? Well in your reply you said it is perceptually bad when mosit or humid. Dead indication of a failing coil plus the ARCHS. BAD BAD! Don't JUST be looking for ARCHs on the coil. Pull the distributor from the engine and remove the coil. I'm willing to bet everything you have a crack in the housing of the coil somewhere. The only way to properly inspect is to pull the distributor and completely remove the coil. When the coil is removed you can see al sides of it. I know you have a crack in it somewhere and it only take one as small as a hairline to case major problems. half of the time the cracks in these develop on the backside facing the engine.

secondly if this continues the distributor is going there is a component of the distributor that if it go to infinity resistance will kill the motor. Be rapidly cooling it with compressed air it will return to a normal state. With ARCHS in the distributor from the bad coil it could have potentailly killed the distributor!!!!

When you pulled your distributor cap off did you notice any oil in the distributor? These distributors are bad for an internal seal to ffail and cause oil to be pulled thorugh the distributor. This can cause what your experiencing.

Also inspect the condition of the rotor while your in there. It could be in need of replacement. A worn rotor will cause similar problems. however I doubt that is it in your case. But always good to check while your in there.


If I were in your shoes, and i was two weeks ago. Replace the entire distributor with a re-manufactured one. The damage has been done. I would not trust this distributor as far as I can throw it! Sorry i can't remember what the part is called in the distributor that goes to infinity and kills it, i just know that it is there.

Good Luck!

[sayers74]

Sorry i can't remember what the part is called in the distributor that goes to infinity and kills it, i just know that it is there.


its the pick up coil. its not available separately, but i have got 1 from a j/y dist. and installed. Very simple to diagnose & replace.