rough
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rough
help, my 89 started running rough like a one bad plug miss.when i brought the rpm up driveing it smoothed out .back to idle it missed.now its very hard to start and keep running at all.it is very rough now. changed plugs and no difference.fuel pressure checked out at 46 psi.help i want my wheels back............
Le Mans Master
Joined: Aug 2007
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From: WV
I would suggest checking your fuel injectors, the 89 Vettes had Multec injectors and they have known problems.. Check the resistence on the injectors by using an Ohm meter...You saying rough idle, plus hard to start sure sounds like injectors.The injectors should be near 16 ohm ...WW
Le Mans Master
Joined: Aug 2007
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From: WV
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
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Le Mans Master
Joined: Aug 2007
Posts: 8,735
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From: WV
You don't need to start the car to check them cold..The car needs to be turned off to check them hot or cold,you only run the car to get them hot....Just pull the injector cap off by squeezing the metel clip on top , then set your ohm meter to read that range..Put one probe on each of the prongs ( doesn't matter if neg or pos) they should read about 16 ohms if there good..WW
Last edited by WW7; Jul 10, 2010 at 11:39 AM.
Instructor
Joined: Aug 2009
Posts: 146
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From: Broadway Virginia
Could maybe be a plug wire going or gone bad, but still could be one or more bad injectors even if they do OHM correctly.
Last edited by walter schweigert; Jul 10, 2010 at 11:20 PM. Reason: spelling correction
Race Director
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From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
Lets start with the simple stuff first. could be a plug wire got against a header.. or something you were doing moved them or pulled one loose.. when you changed plugs did you do it one at a time? be sure you didnt mess up the plug wires and firing order. it could also be a severe vacuum leak (like the brake booster hose pulled loose.) check the simple easy stuff first.. it isnt always a catastrophic failure.
Is it smoking black smoke? does it run like crap all the time? or just warm or cold?
Is it smoking black smoke? does it run like crap all the time? or just warm or cold?
Burning Brakes
Joined: Oct 2009
Posts: 773
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From: Minneapolis MN
Lets start with the simple stuff first. could be a plug wire got against a header.. or something you were doing moved them or pulled one loose.. when you changed plugs did you do it one at a time? be sure you didnt mess up the plug wires and firing order. it could also be a severe vacuum leak (like the brake booster hose pulled loose.) check the simple easy stuff first.. it isnt always a catastrophic failure.
Is it smoking black smoke? does it run like crap all the time? or just warm or cold?
Is it smoking black smoke? does it run like crap all the time? or just warm or cold?
Check fuel pressure regulator as well.Check cap & rotor as well.Do a full tune-up if its not been done in awhile(wires,cap & rotor,fuel filter,& air filter).If your car has a Mass Airflow Sensor check the wires on it for debris or dust on it & clean wires gently with a Q-tip wet with MAF cleaner.Do you smell gas at the tailpipes when car is idling?
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i think that if the maf was acting up it would set a code. my next step is a cap and rottor. yes it does run very bad all the time.i think it has gotten worse.i cant hardly start it now. it wont idle at all.