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I'm stumped, CEL on, hard start when hot, high idle when cold


krugford

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I've got a 1994 Ford Escort with the 1.9L and the 4EAT auto tranny. It's my beater daily driver that gets good mileage (~33 mpg give or take).

I've got a couple problems with it that I can't track down any further without a breakout box....

When the vehicle is cold:
-Starts fine
-Runs fine
-Idles around 1,500 - 2,000 rpm

When the vehicle is warmed up:
-Idles fine if you've been driving and come to a stop (~750 rpm)
-Runs fine (No misses, burps, hiccups, etc)
-If you shut the engine off, it will restart VERY hard
-Engine turns over fine, it just won't go. It'll stumble and hesitate until it either dies or finally catches and goes, then it'll idle around 2,500 - 3,000 rpm!
-Drive for awhile and come to a stop, it idles fine and runs fine.

I've been working through the pinpoint tests in the PC/ED manaul as far as I can without a breakout box. CKP is good, CMP is good, IAT is good, ECT is good, IAC is new..., have not tested EGR system yet. Cannot find any vacuum leaks, intake gasket is new.

Here's the kicker. I can't get it to spit out any codes when I do the KOEO test. I don't even think the PCM is performing the check. I'm using a jumper and a test light. When engine is warmed up, I shut it off, let it sit for 10-20 seconds, connect jumper and test light (test light comes on dim..), turn key on without starting engine, test light stays on. It won't blink, flicker, or do anything. I know I'm doing the test right because I went over to my 92 Ranger and performed the same test and got Code 11 (System OK). I haven't stopped in anywhere to have anyone scan it yet either.

I'd love to scream HELP ME NOW!, but the car functions fine for a DD right now. I never have to start it hot because it's either in the morning to go to work, or in the afternoon to come home, EXCEPT when I have to get gas. Then you shut it off hot and have to restart the effin thing. You end up flooring it while it's cranking over to get it to start.

Anybody have any idea what this could be?? Could this be a bad PCM?

Anything obvious I've missed?
 


Jspafford

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Sounds to me like your running extremely rich. That would explain the high idle when cold and the hard starting when shutoff warm (flooded on shutdown)

I can think of two issues that will cause this and NOT throw a CEL. The fuel pressure regulator. Pull the vacuum line and check for raw fuel.

On my B2 I also have the coolant temperature sensor go out and caused it to dump massive amount of fuel. The only signs I had was a slightly higher idle and a longer than normal crank....that was until one day it just wouldn't fire at all unless I let it sit for a few hours. This issue did show up with a code scan though.

I would suspect the FPR.
 

krugford

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Fuel pressure is in spec and there's no fuel in the vacuum line.

The coolant temp sensor (ECT) is reading the proper resistances both hot and cold according to the chart in the manual.

I haven't looked into the EGR system or the evaporative emissions stuff yet, but I'll probably be doing to tonight for lack of other options.
 

rusty ol ranger

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A legend to the old man, a hero to the child...
Intake manifold gasket.

My 94 i had did the same thing.

On the back of the engine, those aluminum looking pipe things, theres a gasket on those and ill about bet ya thats whats bad,

later,
Dustin
 

krugford

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Failed ECU: Quite possibly the most frustrating thing to track down.

Rant on: I ran through every single pinpoint test they had in the book, checked every sensor, probed pins, traced wires, unwrapped a large portion of my harness looking for chaffed areas, rubs, cracks, anything, rewrapped said portion of harness. Heck, I even drove to work for a few days with a multimeter taped to the dash watching various sensor voltages as I drove just to see if I could see something weird when I was driving. Nothing. The ONLY thing that was in the back of my mind was the fact that I couldn't talk to the ECU with the scan tool or other simpler self tests. Got tired of it, said f*ck it, and started searching the junkyards for an ECU. Finally found one within reasonable driving distance, pop it in, and it works. Car started right up, didn't high idle, runs great, ran self tests with scan tool, came up all 111, ran through all the tests in the scan tool for fun, no problems found. Car seems to be fixed. [crosses fingers]. Rant off.

So, long story short, the thing that's supposed to tell you when something is broken...was broken. And it only cost me $35 for a junkyard ECU.
 

HndMeDnBroncoII

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I've got a 1994 Ford Escort with the 1.9L and the 4EAT auto tranny. It's my beater daily driver that gets good mileage (~33 mpg give or take).

I've got a couple problems with it that I can't track down any further without a breakout box....

When the vehicle is cold:
-Starts fine
-Runs fine
-Idles around 1,500 - 2,000 rpm

When the vehicle is warmed up:
-Idles fine if you've been driving and come to a stop (~750 rpm)
-Runs fine (No misses, burps, hiccups, etc)
-If you shut the engine off, it will restart VERY hard
-Engine turns over fine, it just won't go. It'll stumble and hesitate until it either dies or finally catches and goes, then it'll idle around 2,500 - 3,000 rpm!
-Drive for awhile and come to a stop, it idles fine and runs fine.

I've been working through the pinpoint tests in the PC/ED manaul as far as I can without a breakout box. CKP is good, CMP is good, IAT is good, ECT is good, IAC is new..., have not tested EGR system yet. Cannot find any vacuum leaks, intake gasket is new.

Here's the kicker. I can't get it to spit out any codes when I do the KOEO test. I don't even think the PCM is performing the check. I'm using a jumper and a test light. When engine is warmed up, I shut it off, let it sit for 10-20 seconds, connect jumper and test light (test light comes on dim..), turn key on without starting engine, test light stays on. It won't blink, flicker, or do anything. I know I'm doing the test right because I went over to my 92 Ranger and performed the same test and got Code 11 (System OK). I haven't stopped in anywhere to have anyone scan it yet either.

I'd love to scream HELP ME NOW!, but the car functions fine for a DD right now. I never have to start it hot because it's either in the morning to go to work, or in the afternoon to come home, EXCEPT when I have to get gas. Then you shut it off hot and have to restart the effin thing. You end up flooring it while it's cranking over to get it to start.

Anybody have any idea what this could be?? Could this be a bad PCM?

Anything obvious I've missed?
i would go to the o2 sesnor in most computer systems the tps and o2 and temp are interconected to the ecu eg if the temp sensor tells the ecu the engine is running to hot the ecu will lean the mixture then the o2 will say its running to lean also the ecu controls engine operation till it registers as warm then the ecu will start to read the o2 input
 

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