Another start up issue...sensors?

[buguhrich]

I know this is like the 58990023423rd thread on start up problems but I've searched around and can't seem to find someone with the same problems I'm having. My car, ever since I bought it about 6 months ago, has always started rough when its cold. It will fire but then idle like its only running on 3 cylinders for about 30sec-1min and then idle fine. Any ideas?

Also, just recently, it has been cutting the engine off intermittently while I'm driving it and if I try to restart it, it won't fire until I crank it for a good couple minutes. I've done some diagnosis and I have a feeling it might be a sensor going bad. Anyone know what sensor would do this? Or anything else it might be?

Thanks!

[jlevie]

You could easily have more than one problem here. The cold start problems sounds most like an intake leak or fuel delivery problem. The hot problem could be a bad timing reference sensor, fuel pump issue, faulty main/fuel relay, etc.

[buguhrich]

So far, I've replaced the FPR with an adjustable one, new fuel pump & filter, and new pump relay. The only thing I haven't checked were vacuum leaks but wouldn't that cause the car to run rough constantly?

[StereoInstaller1]

What year is the car?

Late models have a connector under the intake manifold which always gets all corroded and makes the injectors all pissed off...JLieve has the rich issue nailed, I bet it is leaky injectors or some shit.

Your car dying while just running down the road is likely the main relay. Seems to be a recurring theme in these cars.

[buguhrich]

It's a 1988. What connector is it that goes under the manifold? And how can i test the main relay?

[StereoInstaller1]

It's a 1988. What connector is it that goes under the manifold? And how can i test the main relay?

Pull your airbox and boot off of the throttle body and look, you will see it.

Pull the main relay and look at it. If you see shitty terminals, replace it.

[buguhrich]

ok thx. I'll try that out.

[StereoInstaller1]

Forgot to mention: go find a can of CRC "Electrical Cleaner". Any ground points you see bolted to anything, loosen the bolt (just enough to let the terminal slide, like 1/2 turn), give it a squirt, slide it back and forth a few times and re-tighten.

Do this to EVERY ground point on your car (for that matter, ANY 15 year old car) every few years.

Also, there is no such thing as too clean a contact. Clean every damn plug you see, your car will thank you for it!

Luke

[yert315]

I do this to every one of my cars when I first buy it: replace the spark plugs. I know this may not be the problem, but there is a large possibility that they are the original ones. When the plugs go bad, they give off weak spark, sometimes causing misfires. Also, check your wires.

Other than that, listen to the guys above^^

[buguhrich]

Thanks, I'll go over all the connections tomorrow.

I have near-new spark plugs in her. NGK's with about 1,000 miles on them. I have replaced the plug wires, plugs, coil, rotor and cap since i've had the car. I've also replaced the injectors and seals.

[buguhrich]

Just went over every connection. Cleaned them all up and made sure the grounds were clean, still cuts out randomly. Is there a cam sensor that might be going bad or something?

[nando]

no cam sensor, but the crank sensors sometimes go out (or the wires rub on the pulley and short) and it will be very cranky if it's dead. ;)

[jlevie]

That engine only has one timing reference sensor, mounted on the lower right front of the engine. it could be bad, and if it is you'll see the tach needle take a serious drop when the engine cuts out. The same thing can be caused by a bad main relay.

If you havent already done so, new main and fuel pump relays are a good idea.

[buguhrich]

Yea that sounds exactly like what is happening. The engine doesn't hiccup or stumble or anything, it just completely stops and the tach plummets.

Anyone have the part # for the main relay? I'm having trouble finding it on Pelican.

I'll see if I can posts a picture of my main relay. I'm not experienced enough with them to know whether it looks bad or just looks like an old relay.

[buguhrich]

The main relay: