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Forum namePerformance/Engine
Topic subjectFresh rebuilt 95 having problems, Need help diagnosing.
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=125129
125129, Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Hellfire903, Apr-10-09 12:37 PM
So, I've recently rebuilt a 95 rs that's been sitting in my folks garage for a few years, car originally blew a head gasket and was laid up afterward.
Anyway, After getting all my machine work done, and replacing all the gaskets and getting the engine back in the car with everything hooked up I'm having a few problems.

1) Oil on the cyl. # 3 plug, looks like a leak into the cylinder from somewhere. This cylinder's also making next to no power.

2) Loping idle, sounds like street cams almost, feels like it too when driving. Almost no power below 2.5k, and a sudden jump and hard pull all the way to around 5.5k.

3) Plugs 1,2, and 4 all look white like they're running lean.

4) CEL codes for a pulsed sec. air injection system, and the removed EGR valve.

5) Car experiences fuel cut or something when it's warmed up and being driven at anything past 1/8th throttle. It's more prevalent the less fuel that's in the tank and the warmer the car is. I'm possibly guessing something fuel pump related there.

Now I'm no car expert by any means, so I'm open to any suggestions and I'd greatly appreciate any help offered.
125131, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by eclipserstturbo, Apr-10-09 01:39 PM
start off with a compression test on all four cylinders. then check the timing. if the timing is off by a half of a tooth, it can make it lope at idle. mine does the exact same thing, and its definately the timing. also, wouldnt hurt to clean out the iac to see if that will smooth it out a bit if you already havent done so.
125133, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Hellfire903, Apr-10-09 03:40 PM
Originally posted by eclipserstturbo
start off with a compression test on all four cylinders. then check the timing. if the timing is off by a half of a tooth, it can make it lope at idle. mine does the exact same thing, and its definately the timing. also, wouldnt hurt to clean out the iac to see if that will smooth it out a bit if you already havent done so.


Is a compression test necessary? I can't feel any blow by from the dipstick, so I'm assuming it's not coming from a failed piston ring.
I'll go ahead with the compression test for shits and giggles anyway though, since I've got a friend with a tester...
125135, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Mopar McNeer, Apr-10-09 03:42 PM
Oil on Plug 3 is probably due to a bad spark plug tube seal.

Lack of power and choppy idle is likely due to the timing being off

125136, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Hellfire903, Apr-10-09 03:46 PM
bad tube seal?
Like the seal between the valve cover and the head?
Isn't that still outside the combustion chamber though? Wouldn't it have to somehow make it around the crush ring on the plug to get into the chamber?
125137, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by barza21, Apr-10-09 04:02 PM
Originally posted by Hellfire903
bad tube seal? Like the seal between the valve cover and the head? Isn't that still outside the combustion chamber though? Wouldn't it have to somehow make it around the crush ring on the plug to get into the chamber?


I think he is referring to the ones that go in between the valve cover and the cylinder head for each spark plug holes. When I replaced my head the first time one of the seals fell off somehow when putting the cover back on and I didn't notice until when I pulled out the spark plug wire and it was completely covered in oil. Check that out.

Fix the timing and do a compression test afterwards. If cylinder 3 is still not building high enough compression do a wet test, and go from there; could be the rings.

125138, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by 420agreenvilleSC, Apr-10-09 05:00 PM
1. timing
2. valve cover spark o rings
3. torqued in the wrong sequence headbolts and/or not torqued enough.
4. check for hydrocarbons

you may have to get in there once again.
125209, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Hellfire903, Apr-15-09 10:34 PM
Haven't had much time to work on this lately but I did go ahead and do a bit of looking.
The head-valve cover spark plug seal isn't leaking. It's got to be a bad valve guide or stem seal. I'd be hard pressed to believe it's a ring that's failed in only 1,000 miles. I'll be doing a compression test when I get the time though, just to be safe.
125225, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by RoninEclipse2G, Apr-17-09 03:57 PM
Wait... is the oil on the plug and wire outside the combustion chamber? or is it building up on the electrodes inside the combustion chamber?

if you've got oil on the topside of the plug it has to be coming from the valve cover O-ring. the loss of power is because the spark is arcing through the oil to the head instead of going through the plug into the combustion chamber.

if the oil is inside then you've probably got rings that aren't clocked or gapped properly
125230, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Hellfire903, Apr-17-09 08:32 PM
Excuse me for my lack of description.
It's building up on the electrode inside the combustion chamber.

And the compression test today revealed: 215:210:140:210
Wet test for cylinder #3 gave back 185.

Looks like that cylinder's rings have failed somehow in the past 1500 miles since the rebuild.
125240, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by bullettdsm, Apr-18-09 04:07 AM
Originally posted by Hellfire903
Excuse me for my lack of description. It's building up on the electrode inside the combustion chamber.

Well that would have helped immensely, lol.

Regardless, you now know what you have to do.

125242, RE: Fresh rebuilt 95 having problems, Need help diagnosing.
Posted by Star Turbo Talon, Apr-18-09 08:42 AM
The reason you are lean on the remaining cylinder is becuase cylinder 3 is pumping out raw fuel. The o2 is picking that up and the ECU is trying to lean out abnd correct the mixture.