1989 Chevy S-10

JEFF1528

MEMBER
1989 CHEVROLET S-10
4 CYL
2WD
MANUAL
97,849 MILES

I have a 2.5 4 cylinder that I can not get to run right I cant get the timing right I put #1 top dead center and tried to time it but the only way it will run half way normal is to put timing mark on 4 but it still back fires I changed all sensors and distributer so now I need to know how to run diagnostic test on it myself to see what it tells me where can I find that information out and what the codes mean, I just know im about ready to take this truck to a wrecking yard please help before it comes down to that

Thursday, July 22nd, 2010 AT 7:18 PM

3 Replies

JDL

MECHANIC
16,098 POSTS

In the left column for this forum there is a link for code definitions, or just post the code.

You turn the key to on, no crank, no start. Place a jumper wire between terminals A & B at the datalink connector. The check engine lite starts flashing, you count the flashes to get the codes. Your looking for two digit codes.

You need to check compression, without good compression it may never run right? Minimum spec is about a 100 psi, difference between cylinders no more than 30 psi.

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Friday, July 23rd, 2010 AT 11:49 AM

JEFF1528

MEMBER
2 POSTS

I checked compression its good got all new sensors the only way I get it to run good but it still backfires is to leave one of the vacuum ports on the side of throttle body disconnected but if I plug it in the truck dies so I have to let it suck air or it wont stay running so im confused it shouldnt run good at all with it disconnected.

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Friday, July 23rd, 2010 AT 10:11 PM

JDL