#3 cylinder problem

[93_240_sx]

I'm in need of some help with my 93, here is the problem and what I've done so far

When I start my car I have to give it some gas or it bogs, after that the idle is fairly stable at about 900rpm but the engine and car shakes. We've traced it to cylinder 3, with the car running we removed the plug for each injector, and the rpm dropped for each cylinder except #3. So here what we've done so far

New cap and rotornew spark plugsnew injectorcompression test (140-148-140-148)we have spark, fuel and the injector is getting power

The car still bogs down at start up and shakes

Any ideas what to look for/try next?

[S13 240SX]

ughhh... 1.. your compression results suck balls. ... Can you get the car started without having to give it gas?... Timing could be off

[93_240_sx]

it will start but the rpms drop to around 200 then bounce around between 200 and 1000. After a couple seconds it will sit at around 900 pretty steady. What should my compression be?

I though as long as all the cylinders are with in 10 psi of each other the actual number didn't matter?

[S13 240SX]

seems like you can't find an idle... check your idle air control valve... clean it out with carb cleaner or replace it.

[93_240_sx]

That was the first thing I replaced, forgot to mention that. I cleaned it out, didn't help any so I bought a new one still didn't help.

[S13 240SX]

check your ecu for codes?

[TheOne]

it will start but the rpms drop to around 200 then bounce around between 200 and 1000. After a couple seconds it will sit at around 900 pretty steady. What should my compression be?

I though as long as all the cylinders are with in 10 psi of each other the actual number didn't matter?

that'd be 14 psi between each:P, also compression should be ~170, with a lowest of 150, did you do the compression test with WOT and a good battery?.

but this sounds like something with timing, or really bad gas, or clogged fuel filter, but since you say it bogs and idles @ 900rpm, it could be your timing, check it.

also check for corrosion around the coolant temp sensor.(the 1 around the top radiator hose on the intake manifold, its the red 1)

[93_240_sx]

Alright, pulled codes

34 Knock sensor13 coolant temp sensor circuit14 vehicle speed sensor signal circuit is open

ok, I didn't press the gas at all when testing the compression so I'll do it again tomorrow with wot, hopefully that should help my numbers.

I'll also check the temp sensor when I get off work tomorrow

appreciate the help guys, I'll let you know how everything goes

[93_240_sx]

notied another thing, apparently I replaced the Idle Air Adjustment unit, not the Idle Air Control Valve. I'm gonna have to order that one while I'm at it.

[pr240sx]

check fuel injector #3could be clogged

[93_240_sx]

already bought and installed new injector for #3, didn't help

[93_240_sx]

Looks like my problem was I put some seafoam in my car and then ran the car low on fuel and it appears it clogged my fuel filter and injectors, once I fixed that she runs great, thanks for eveyone help