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Engine suddenly runs like hell


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dharma
Novice

Feb 10, 2008, 4:02 AM

Post #1 of 4 (1980 views)
Engine suddenly runs like hell Sign In

My 1994 Saturn SL1(1.9L I4 SOHC) has been running a little on the rough side lately, but I chalked it up to the extreme cold the last couple weeks(-30'sC, -20'sF).


Anyways, I fired it up today after sitting overnight, and immediately I noticed something was really off... even in -24C -9F temps once I got it started it generally used to idle normally and run fine, once I let it warm up to operating temperature.

...But this time it stalled, and kept stalling unless I gave it a little bit of throttle just as it was about to stall... it would rev up to 1,500rpm or so and it sounded fine, naturally slowing to about 1,000rpm at which point it would suddenly drop in revs and stall, unless I gave it a blip of throttle at which point it would purr up to 1,500 or so, repeating the process... I thought it was on account of it being cold, but even after a lengthy warm-up period it still had some serious probs.. it ran, but if I gave it too much gas it would bog until I let off the gas.. I had to gingerly baby the throttle until I got home.



I was hoping it was something like a bad sensor, but would that burn out suddenly? Keep in mind my baby has some 438k KM(270k+ miles) on it, so it could possibly be a stretched timing chain jumped a cog or something, but I've taken good care of it, and it has run like a top till last night..... So, Oxygen sensor, MAP sensor, fecked injector, or something mechanical?

...Thanks for any replies!.. I'll use the advice to check it out this week, and I'll post the results if I can get my poor car running smooth again.. Wink


(This post was edited by dharma on Feb 10, 2008, 4:11 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 10, 2008, 4:50 AM

Post #2 of 4 (1975 views)
Re: Engine suddenly runs like hell Sign In

That's a lot of clicks on the counter! Guess: With that kind of cold it's probably struggling for fuel and for extremes like that I do suggest additives. I like SeaFoam - sparingly, Isopropyl formula dry gas/moiture remover. I'd put a new fuel filter in this if it's been a while. The cold would just make it that much harder for fuel to get around already trapped junk in it.

If it's still that cold the reaction time for additives may be slow, so getting the whole vehicle - body and all warmed up a bit would help,

T



Double J
Veteran / Moderator
Double J profile image

Feb 10, 2008, 3:32 PM

Post #3 of 4 (1967 views)
Re: Engine suddenly runs like hell Sign In

Just to add...

They do sometimes develop a vacuum leak at the gasket on the plastic TBI tube module on the TBI assembly,....and/or the connectors of the vacuum harnesses from the vacuum tube module to the MAP sensor, EGR solenoids/valve and the EVAP canister purge solenoid may be damaged,causing a vacuum leak as well.
Inspect the gasket of the plastic TBI tube module and the vacuum harness connections...

Don't know if this will help or not....just a thought.....

Here is a picture...




dharma
Novice

Feb 11, 2008, 2:49 AM

Post #4 of 4 (1961 views)
Re: Engine suddenly runs like hell Sign In

 
Thanks for the replies Tom and Jim N!! Smile


..It was warmer today, but I threw in the emergency bottle of IPA I kept in my glovebox... I'm not sure if it was the warmer weather, the isopropyl alcohol, or what, but it seemed to run worlds better today!


Thanks for the suggestions guys.. I'm gonna chenge the fuel filter(hasn't been changed for at least the 4 years I've owned the car), and ALSO check all my vacuum hoses/connections.. couldn't hurt anyways.Tongue


I appreciate the help.. this is a great site.. may have to check it out more often. ;)



P.S.: Thanks JIM for the vacuum diagram.. I have a chiltons manual, but that's a much better pic than the one in the book. :)








 
 
 






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