Check engine light comes on and no spedo works

WITTE1919

MEMBER
CHEVROLET

1988 Chevy Celebrity - 130,000:

after about 2 mins of idling on a cold start. My car will throw a check engine light and at that very moment my car will go from running very smooth and good, to very rough erratic idling.

wile this check engine light is on and my cars speedo doesnt not work and the odometer does not roll and calculate the miles I travel.

sometimes when car is at normal operating temperature it will not keep an idle and will stall, once stalls it wont start, it is just cranking, and when this happens I am still getting all spark to all pistons.

sometimes wile driving I would have to keep my foot on the gas for it to start running and sometimes it will stall at a idle when the check engine light comes on.
also at times when driving wile the check engine light is on and my car is running bad out of no where in the blink of an eye my check engine light will go off and all at once the car will like it would normally and my speedo would shoot up to the speed I was traveling at and my odometer would start to roll again. This has been going on for weeks.

I have a brand new ignition module, coils, plugs, wires, air filter, fuel filter " old fuel filter had no build up", also replaced the engine coolant sensor

can you please help me!

4 Replies

INDYUKE

MECHANIC
416 POSTS

Are you able to scan the computer for the fault codes the check engine indicates are there? In this case, those codes would give you a major clue as to what's happening. Let us know.

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Thursday, January 25th, 2007 AT 10:33 AM

WITTE1919

MEMBER
3 POSTS

At first I jumped the the top right pins and read it my self and a code 14 came up.
It was a coolant temperature sensor. I replaced that and it still ran bad. Then jumped the pins again and the same code 14 came up. Also following Electronic Spark Timing Code.
A friend is coming to my house to scan my car with his scanner so hopefully I will find out.
Thanks for your input

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Friday, January 26th, 2007 AT 9:44 PM

INDYUKE

MECHANIC
416 POSTS

Good luck!

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Tuesday, January 30th, 2007 AT 10:34 PM

BENGA

MEMBER
4 POSTS

Am not sure how much this will help but it may be worth a try without burning big holes in your pocket. Pls keep in mind that am not knowledgeable on Chevys.
But I do know that for most cars, a problem with the speedo reading can cause all kinds of problems with the engine fuel/air mixing, including surging, stuttering, stalling, loss of power during acceleration, and of course check engine light comes on when fuel/air mixing gets jumbled.
Some cars (newer models) have an electronic speed sensor while others (older models) have a mechanical speed sensing system via the speedometer cable. Either way, it won't cost you a pretty penny to replace these, i.E. Speed sensor or speedometer cable (sometimes the problem is not the cable itself but the connector where it connects into the tranny). I'd definitely give that a try before I scratch my scalp bald. Like I said, am not that familiar with Chevys so you may wanna check with an auto shop or mechanic for the cost but am sure it's cheap, $50 - $100, maybe less if you buy the part and install it yourself.
Whatever you do, MAKE SURE your speed sensing system is working fine before you proceed.
This was just a thought which may or may not help (especially given the fact that you say the check engine light will come on while the engine is in idle).
Good Luck.

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Wednesday, January 31st, 2007 AT 1:24 AM