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1995 Geo Prizm struggles to start, stalls at low RPM


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snobordir
Novice

Aug 26, 2017, 7:12 PM

Post #1 of 11 (772 views)
1995 Geo Prizm struggles to start, stalls at low RPM Sign In

TL;DR at bottom.

A couple months back my 1995 Geo Prizm (AKA Toyota Corolla, 1.6L, ~205k miles, manual transmission) had stalled out on me a few times, but usually I wait 10 minutes and it would start back up and continue running with no problems. Then one day it started sputtering and died while driving, and wouldn't start again. Strong crank, but no start (battery is perhaps 2 years old).

I started doing my research to try to fix it. It didn't take long to realize this was likely a fuel pump issue. I did a pressure test, which isn't very good for this car since all you can really do is loosen the bolt at the end of the fuel rail and see if gas squirts out or not. I don't have a banjo fitting. Anyway, gas only dribbled out, and the fuel pump didn't have great resistance, so I replaced it and the fuel filter (which appeared to be the original!). The car didn't start.

I also did a starter fluid on the air filter test, and it still didn't start! So I started looking at the spark plugs and wires. The spark plugs looked really bad. I checked, and sure enough the gap was about twice what it should be. I went ahead and gapped them, and the car started up quickly!

I was excited and headed to Autozone where I figured I should just replace the spark plugs. My car died again right as I pulled into the Autozone parking lot. I bought new plugs, gapped them, and replaced them...and it started up again! I actually was able to drive it for a few days without issue.

Then a couple days later, super difficult start (cranking several times before starting), and at low RPMs it would die. I'd have to carefully keep the RPMs up while braking to drive it. Occasionally it wouldn't start at all without some serious time and effort...I'd do things like pull and replace the spark plug wires, short the fuel pump in the diagnostics (OBD1), etc..

I've been doing a lot of research since but struggle to know what the issue is. I've thought about potentially failing to install the fuel pump correctly, the fuel pressure regulator, the idle air control valve, spark plug wires, vacuum leaks, etc. I replaced the oil filter just in case. The car does slowly consume oil, there was some oil in the rightmost (drivers side) cylinder when I replaced the plugs. The car passed Utah safety/emissions with no failure or advise in late April (the original failure was in early June). Compression is okay at 150psi very consistent across all four cylinders. Spark appears to be good, but I only did a visual inspection pulling them out and testing them while grounded and cranking the engine, and am not a pro. Starting fluid still doesn't do the trick.

TL;DR: 1995 Geo Prizm (AKA Toyota Corolla, 1.6L, ~205k miles, manual transmission) sputtered and died on road. Cranking no start. Replaced fuel pump and filter, didn't start. Gapped spark plugs, started. Died again, got new spark plugs, started fine for a few days. Now struggles to start, may not start at all, often dies at low RPM. Replaced oil filter. Compression appears good, spark appears good, starter fluid test still fails.

Please help!! What do you think I should check next or do? I have the repair manual and have some ideas but feel like I'm shooting in the dark. Thank you so much for this forum!


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 26, 2017, 8:38 PM

Post #2 of 11 (761 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

 
All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.



Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.


2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.


3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



olliefromuk
New User

Sep 4, 2017, 6:16 PM

Post #3 of 11 (707 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

Poor response deleted


(This post was edited by Hammer Time on Sep 4, 2017, 7:22 PM)


snobordir
Novice

Oct 17, 2017, 6:29 PM

Post #4 of 11 (620 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

Hammer Time,

I have checked all of those things, and they all check out. I get spark, noid lights fire, fuel pressure is perfect. I have also already checked the compression of each cylinder, and it is within spec. So far nothing I've been able to probe/gauge has given bad results.

Since replacing the fuel pump, it became more of a start then stall condition. Then I replaced spark plugs, boots, wires, distributor cap, and rotor, and checked the ignitor. Now it's kind of a start then *might* stall sort of thing. I can occasionally coerce the car into starting and it will actually run for a while.

I suspected the idle air control valve, so I cleaned it thoroughly, no change. I did notice, however, that I can get the car to run with much more minimized problems by actually disconnecting the IAC wiring harness. When I disconnect it, the idle goes to about 1500RPM, which prevents the stalling issue. It only stalls when I shift gears too soon and let the RPMs dip with the IAC disconnected.

Any other ideas? Thank you so far.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 17, 2017, 6:34 PM

Post #5 of 11 (612 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

 


First eliminate all vacuum or air leaks in the system (very important)

. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



snobordir
Novice

Oct 17, 2017, 11:55 PM

Post #6 of 11 (600 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

Do you have any advice for finding vacuum leaks? I’ve heard spray starter fluid around vacuum hoses but I may not be doing that right. Haven’t heard the idle change yet.

I have already cleaned the throttle body quite thoroughly, and I cleaned the IAC by removing the air hose, plugging it, filling the IAC with throttle body/IAC cleaner and manually turning the IAC back and forth. Did that till the cleaner came out without black bits. I think it’s plenty clean. I peaked past the throttle body and into the intake manifold, there’s still plenty of crud all the way back in there, think that makes a difference?

Also, are my symptoms consistent with an exhaust leak? I noticed a crack on the exhaust manifold.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 18, 2017, 4:49 AM

Post #7 of 11 (589 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

Yes, that method will work but only on a real severe leak. The way we find them is using a smoke machine which is much more reliable.

Simply cleaning the IAC will not help if it has electrical weaknesses. It may need to be replaced.

The dirt in the throttle body only matters when it is in the area of the throttle plate or IAC.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



snobordir
Novice

Nov 2, 2017, 9:39 AM

Post #8 of 11 (534 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

I used a vacuum gauge on my intake, and am reasonably confident there isn’t a vacuum leak. The gauge was well within spec, but was vibrating about 1-2 lb rapidly.

I also sent some Seafoam through the intake. No smoke around any vacuum lines from what I could see. I did see a pretty good amount of smoke come from my exhaust manifold, so I pulled that off and put thermosteel on the crack. After it hardened the car ran very smooth for a few miles, but then driving on a hill the symptoms came back...hesitating on acceleration, stalling at idle. If I keep the RPMs up it will mostly stay alive and if I rev it pretty hard as I shift (manual trans) it doesn’t hesitate and churn much.

Pretty confusing issue. Any other ideas?? I’m curious if that crack reopened when I was on that hill and it is the exhaust manifold to blame. It was a significant crack.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Nov 2, 2017, 10:33 AM

Post #9 of 11 (522 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

Have you checked to make sure the EGR isn't hanging open or has vacuum on it all the time?





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Nov 2, 2017, 10:34 AM)


snobordir
Novice

Aug 23, 2018, 5:08 PM

Post #10 of 11 (163 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

I'm still working on this, in case anyone who commented is still interested. This is roughly what the issue has developed into:

Links deleted.......................not allowed

I may start a new post on this. Oh and to the person asking about my EGR, the 1995 Prizm doesn't have an EGR at all.


(This post was edited by Hammer Time on Aug 23, 2018, 5:20 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 23, 2018, 5:22 PM

Post #11 of 11 (157 views)
Re: 1995 Geo Prizm struggles to start, stalls at low RPM Sign In

Please read the forum rules

Links are not allowed here, especially to another forums


http://autoforums.carjunky.com/...ORE_POSTING_P122997/



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Aug 23, 2018, 5:22 PM)






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