1994 Toyota Tercel Engine dies while slowing down then hard

Tiny
JMIHICH
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  • 1994 TOYOTA TERCEL
Engine Performance problem
1994 Toyota Tercel 4 cyl Two Wheel Drive Manual 160K miles

My sons Toyota Tercel dies as he slows down. Some times it really hard to restart.

What we have done.

New fuel pump and regulator
New Coolant Temp sensor.
Used IAT
All tune up parts.

It has very good spark when it doesn't want to start.

What we noticed this time - I had him unbolt the top bolt on the fuel regulator - no fuel came out - car off. Had him jump the fuel pump - fuel started to flow. He then then tighten the bolt and the car started. Is there a sensor/switch that would tell the ECU to stop the fuel? I think that is where our problem is.
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Thursday, June 24th, 2010 AT 1:00 PM

22 Replies

Tiny
MMPRINCE4000
  • EXPERT
Start by checking the fuel pump relay.

Look at diagnostic port, short Fp and B+, if engine runs, then relay is bad.
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Friday, June 25th, 2010 AT 7:03 AM
Tiny
JMIHICH
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I have to drive 100 miles to work on this today. So when I get there we'll try.
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Friday, June 25th, 2010 AT 9:24 AM
Tiny
JMIHICH
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Well I did as requested and it started but it did start at times so this may or may not be the solution. So what we did was swapped out two identical relays. We then drove it for about 1/2 hour around his neighborhood w/o a problem. So we are going to hope that this fixes the problem. I will get back if there's an issue or w/i a week.

Has been a very difficult problem. :)
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Friday, June 25th, 2010 AT 5:37 PM
Tiny
MMPRINCE4000
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Good news, let us know.
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Saturday, June 26th, 2010 AT 9:23 AM
Tiny
JMIHICH
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Well my son didn't drive it for a couple of days then it starting acting up again. Same hard or no starting.

Just to let you know what we have changed.
Fuel Pump - new
Fuel regulator - new
All new vacuum lines
New coolant temp sensor.
Fuel pump relay
Tune up - cap, rotor, wire, plugs.

Replaced with used.

TPS The original did test ok - grasping at straws here.
The vacuum switches attached to fuel regulator.
The IAC was removed and cleaned.

Tested -

All the sensors and switches that had test procedures in the Haynes manual we tested.
Coil - test right exactly as in the book.
TPS - tested fine through the whole range.

It will start when cold, and when it hot, but when it sits for a little after getting to op temp it either is hard to start or won't start until it's really cold. We do smell gas at that point.

We are really stumped.
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Sunday, July 4th, 2010 AT 2:48 PM
Tiny
MMPRINCE4000
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Try a used ignitor.
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Monday, July 5th, 2010 AT 9:20 AM
Tiny
JMIHICH
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We have a couple sitting around so we'll give that a try. I have another (Tercel - 92) that had similar issues so I grabbed a bunch of parts from several junked cars at our local pick and pull.

I think we have changed every part under the hood except that - probably should hve.

I'll let you know.
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Monday, July 5th, 2010 AT 12:21 PM
Tiny
MMPRINCE4000
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Let us know.
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Tuesday, July 6th, 2010 AT 9:24 AM
Tiny
JMIHICH
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Ok I think we are getting close. We changed the igniter w/o making a difference - we get good spark both when it starts and when it does not.

We can reproduce the problem.

Start the car when cold - standing an hour or so.

Run it for a period of time - two - three minutes.

Try starting after about 5 minutes - will not start. Strong smell of gas - pull plugs and they are wet. If we try right after stopping it will start.

Wait a couple of hours and it starts.

We are going to change the Fuel pressure regulator even though it's new.

We have tested the switch to the regulator and it works according to the book.

It appears that the fuel pressure remains and the fuel is leaking into the cylinders so when it tries to start it's flooded. Is there something that should be releasing the pressure when the car is shut off?
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Tuesday, July 6th, 2010 AT 2:37 PM
Tiny
MMPRINCE4000
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Fuel pressure regulator.

Remove vacuum line to it and check for gasoline, if present, then FPR is ruptured.
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+1
Wednesday, July 7th, 2010 AT 8:15 AM
Tiny
JMIHICH
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Well we switched the FPR - had a new one and 2 used ones - same symptoms.

I had him remove the gas cap (new) and try to make it fail - it would not fail. He then put the cap back on and it started - let it run for a minute - then waited 5 minutes - it would not start.

I'm sure it fuel related just not sure which component is causing the problem. We did swap out the injectors - same thing.

I guess he could ride w/o the gas cap. :) When we swapped the injectors we damaged one of the O rings so I have to get a new one - That'll have to be tomorrow.

I really think we are getting close.
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Wednesday, July 7th, 2010 AT 11:57 AM
Tiny
MMPRINCE4000
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You may have to remove tank and check the return and vent lines, they may be clogged.
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-1
Thursday, July 8th, 2010 AT 9:06 AM
Tiny
JMIHICH
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I believe great minds think alike. I was thinking yesterday that I was going to go under the car a trace the lines and see if something had hit one of them. I should be able to check them w/o removing the tank. The car is easy to access the connections to the tank and the engine. I was going to remove the connections and blow air through them. Of course it was raining this morning. I'm hoping for clearer skies this afternoon. Not enough room in the garage to move a car into it so I work outside. I have a wood working shop - priorities you know. I'll let you know.
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Thursday, July 8th, 2010 AT 12:03 PM
Tiny
MMPRINCE4000
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Hope you find the problem.
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Friday, July 9th, 2010 AT 8:27 AM
Tiny
JMIHICH
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I disconnected the vent lines and was able to blow air (low volume) through it w/o a problem. I drove it around while the gas cap was off and it started every time. Then I let my wife drive it to her school where it sat for about 1/2 hour - wouldn't start. I was able to get it started - 15 minutes later - by pressing on the gas petal when attempting to start - it did - not first try - second. She drove it home. It has lots of spunk when it does go. I'm at a loss. I also was able to blow air through the charcoal canister.

I'm going to sleep on this again. I need to jump in the pool.
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Friday, July 9th, 2010 AT 3:41 PM
Tiny
MMPRINCE4000
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Was gas cap off when it did not start?
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Saturday, July 10th, 2010 AT 8:16 AM
Tiny
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Well it doesn't start with cap on of off.

Just to recap where we are.

It will start when sitting an hour or so and over night. It will also start if I just shut it off and try to start it. I won't or is hard to start if I run the car, shut it off, and try again about 15 minutes later. I have been able to start it each time now but it doesn't want to and it idles only if I give it gas.
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Saturday, July 10th, 2010 AT 2:25 PM
Tiny
JMIHICH
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Will a bad IAC valve cause these issues? I did take it off and cleaned it really well - it did improve a lot - no more stalling. I replaced it with another used one and the problem got worse. So I'm thinking that the IAC could be the cause.

I'm thinking about ordering a new one and just try it. I know they are expensive (got a line on a 1/2 price new one) but that would eliminate another possibility.
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Monday, July 12th, 2010 AT 10:27 AM
Tiny
MMPRINCE4000
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IAC can cause stalling, if it moves too far it will cut air off to engine.
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Wednesday, July 14th, 2010 AT 7:16 AM
Tiny
JMIHICH
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I've been gone for a couple of weeks so no update. I should be getting a new IAC soon. I'll keep you updated.

John
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Friday, July 23rd, 2010 AT 8:37 PM

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