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1993 Corolla


mthomas84's Avatar
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01-03-04, 08:01 AM   #1  
mthomas84
1993 Corolla

My daughter has a '93 Corolla, 1.8L that runs and drives great when the engine is cold, but once it warms up, it sputters and hesitates when given the gas. It still idles okay, but driveability is poor. I have replaced the plugs, wires, distributor cap and rotor. It doesn't seem to have any vacuum or compression leaks. Ideas?

NEW INFO:
The problem appears to be related to the Throttle Valve cable to the transaxle. I've tried adjusting the cable and have gone from one extreme to the other. The problem only gets worse, never better. Is there a way to prove the cable bad without replacing it ad hoc?


Last edited by mthomas84; 01-03-04 at 09:48 AM.
 
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01-03-04, 11:06 AM   #2  
First thing to do is check for trouble codes. Jump out "T" & "E1" in the Diagnostic connector under the hood, read the blinks and post back.

I really can't see what the trans cable could have to do with it.

What brand cap and wires did you use? Were they replaced before the problem or after. Exact service history very important.

 
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01-04-04, 05:31 AM   #3  
mthomas84
Wires,cap & rotor replaced after the problem. Cap and rotor are Wells and wireset is Double-Silicone. No error codes reported.
I recently bought the car from a guy that had a problem with the fuel pump and didn't want to bother. I replaced the pump and got the car running to this point. I've tried tweeking the distributor (b4&after parts) and the motor seems to run best with the adjustment fully clockwise(?). Today I will look at TDC and check timing.

 
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01-04-04, 06:17 AM   #4  
Have you checked your timing belt for being a tooth off? That would show up when you put the timing light on it.

You might change the fuel filter also if it hasn't already been done.

 
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01-04-04, 07:41 AM   #5  
You have to cover the basics first.

Check fuel pressure when problem occurs.

Guessing at the timing is not going to work.

The Wells cap will cause problems. The only cap and wires is OEM, not uncommon to last over 100,000 miles or more.

Some of the aftermarket wires will induce high voltage into the air temp sensor wires, they are sometimes to close to it because of poor fit. Will cause all kinds of weird problems. The computer dosen't fair well by high voltage spikes.

Mileage would help?

 
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01-04-04, 08:16 AM   #6  
mthomas84
Mileage is 215k.
Since the problem didn't change after replacing wires, cap & rotor, wouldn't that rule those components out? What's confusing is that the problem doesn't show up until after the engine is warmed up. It seems to point to a sensor output that is involved after the warmup.

 
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01-04-04, 08:34 AM   #7  
Check the O2 sensor, Check with DVOM in check connector. Should switch between .2- .8 almost every sec or two. That would fit you conditions.

Another basic check:

Check the water thermo sensor, back probe with a DVOM. Should start around 2 volts or so depending how cold it is and go down to .25-.50 volts warm.

The cap maybe good today but won't last 1/10th a OEM.

 
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01-05-04, 04:35 PM   #8  
mthomas84
Note: I removed the heat shield over the exhaust manifold to get a little more room to work and found that there is a spot where someone has attempted to weld a break in the manifold right between the 2nd and 3rd tubes (MS Word text drawing attached). Of course the weld didn't hold. Can that cause a problem like this? It's very close to the O2 sensor. I'll check the suggested outputs and post result tomorrow.

 
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01-05-04, 05:54 PM   #9  
Any kind of leaks upstream of the O2 sensor will make it get poor readings and give poor information to the ECU.

 
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01-13-04, 10:21 PM   #10  
Hi guys;
I may be off the mark here, but I did have the same problem with a 1985 Mazda. Great when cold, but lousy when warm. It turned out to be the fuel pump.
The original was bad, and I replaced it with a non OEM. BIG MISTAKE!!!!! Non OEM specs were too general and they tried to make one size fits all. As it turned out the pressure was too low when it ran awhile and overheated. Did a lot of walking home with that car.
Was the replacement fuel pump you used a OEM or generic (NAPA, or some other)? Check there it may be some of your problem.
I found it by letting the car run and when it ran bad felt the pump. If hot thats the problem, as the gas from the tank usually keeps them cool and avoids lock. Replaced with a OEM and it ran with no problems!!!!!

As Rod Sterling used to say" submitted for your consideration"

 
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