Lower LIM change now MISSING?? Any opinions... [Archive] - GrandAmGT.com Forum

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sugar ray
04-16-2010, 04:17 PM
Just finished doing the LIM gasket and head gaskets on my 02 3.4. Made sure ALL push rods went back in original place. Even went as far as cranking the engine over by hand a few times around making sure the rocker arms were seated properly with the rods. Got everything back together, cranked it over and it ran better then new.

Drove it around for 2 days (about 60 km's) then out of no where the SES light came on and the car felt like it was running on 5 cylinders? I don't have a OBD2 reader but hope to acquire one this weekend. Checked plugs to make sure they were tight.
I put on a pair of welders gloves and pulled the plugs one by one. They all spark when I pull 1,4,6, or 3 the engine almost completely stalls and spark is strong at those cylinders. However, when I pull 2 or 5 the spark is there but extremely weak. Its almost like the 2&5 pack is faulty. Its almost like cylinder 2 & 5 fire but extremely weakly.

I guess I am just trying to convince myself it is NOT a bent valve or something gone wrong during the rebuild process. I do NOT want to have to tear it all back down.
It runs rough at idle and misses upon acceleration but will smooth itself out at about 60kms.

If it were a misplaced rod would I have NOT noticed it when first starting the engine? I don't think a misplaced rod would allow you to drive around perfectly for 60 kms, would it?

AaronGTR
04-16-2010, 05:52 PM
No, if you put a rod in the wrong place you'd notice immediately. One would get bent, and the other would be loose and rattling around. You'd probably notice it during assembly, but it you actually put it together and started it like that you'd notice it immediately on running, so I don't think that is the problem.

I'd lean towards a bad coil pack or some other type of ignition problem. Especially since it seems to be a problem with 2 and 5, and those are on one coil together.

zukiracer19
04-16-2010, 06:16 PM
i would think you forgot to plug something in would be my guess... make sure ur wires and ur plugs are in all the way too

Malaclypse
04-16-2010, 07:09 PM
No, if you put a rod in the wrong place you'd notice immediately. One would get bent, and the other would be loose and rattling around. You'd probably notice it during assembly, but it you actually put it together and started it like that you'd notice it immediately on running, so I don't think that is the problem.

I'd lean towards a bad coil pack or some other type of ignition problem. Especially since it seems to be a problem with 2 and 5, and those are on one coil together.

Seconded. Or perhaps one of the plug wires backed off the plug. This happens sometimes. It'll cause that cylinder to miss as well as the one it shares a coil with.

Vegeta
04-16-2010, 07:46 PM
swap coil packs around and see if the bad cylinders change. Looks like the coil pack is the issue.

sugar ray
04-16-2010, 10:12 PM
Thanks guys for the suggestions!

AaronGTR your post makes me feel a little better. Like I said was running great until out of no where. I did put an ohm meter on the towers HOPING there would be a difference in the suspect coil. However, all coils seem to read equal. I will try the swap tomorrow and if need be will purchase a new coil. Just seems fishy that a coil would die now, almost right after the rebuild

sugar ray
04-17-2010, 04:02 PM
Ok..... might be getting somewhere. Got a coil pack from a wrecking yard today, put it in with SAME result so my old coil is fine. My #2 cylinder's spark plug is however, soaked with gasoline so its NOT firing. Just #2, all other plugs seem fine

hmmmmmmmmmmmmm

2000 GT Coupe
04-17-2010, 04:20 PM
Ok..... might be getting somewhere. Got a coil pack from a wrecking yard today, put it in with SAME result so my old coil is fine. My #2 cylinder's spark plug is however, soaked with gasoline so its NOT firing. Just #2, all other plugs seem fine

hmmmmmmmmmmmmm

From what I remember there are 3 electric connections to the coil packs could one of them not be fully seated?

Malaclypse
04-17-2010, 04:29 PM
From what I remember there are 3 electric connections to the coil packs could one of them not be fully seated?

If that was the case every cylinder would be misfiring or the car wouldn't run at all.

Since the #2 plug is fuel fouled, it means one of two things. Your #2 injector is sticking and flooding that cylinder or the plug became fouled shortly after the repair for some reason.

My suggestion would be to replace the affected plug and see what happens. If it fuel fouls out again you may want to consider removing the #2 injector and cleaning both the engine side and the insides of the fuel injector with carb cleaner to see if that solves the sticking issue. If it doesn't it may be time for a new injector.

AaronGTR
04-17-2010, 07:51 PM
^Exactly. The grand am runs a waste spark system and since two plugs are on one coil together, both those plugs fire at the same time even if there is no fuel mixture in that particular cylinder. If the coil wasn't working and cause #2 not to fire, #5 wouldn't be firing either.

I would also say either faulty/stuck injector, bad plug, or bad wire going to that plug.

sugar ray
04-22-2010, 12:05 AM
YAHTEEEEEE!

Malaclypse: Good Call Man:applause:

It was a DEAD or should I say a stuck open injector. What blows my mind. Up here in CANADA. the CHEAPEST injector I could find from ANY local parts store was $125 for ONE freakin injector. What am I missing here? Re-mortgage my house to replace ALL injectors? It was CHEAPER to purchase an ENTIRE fuel rail / injectors and all off a low miles pick a part GA, then it was to buy ONE injector up here. Carparts.com from the USA has them for MUCH less. like $40 each. Our FUNNY money must be funny

Anyways....replaced. Car is now firing on ALL cylinders. It NO longer reports a miss fire trouble code from my OBD2 reader. No more fuel fouled plug

However.....NEW problem.....I am SURE it has to be a vacuum leak? It idles waaaaay to high. throttle cable checks out just fine. I put it into gear and it takes off like I am at a drag race! Low RPM range and during take off runs too lean. Higher rpm range runs like a dream.
checked and replaced vacuum hoses. My upper intake gasket did take a beating cause it has been removed so many times in the past few weeks so is that feasible? Was also thinking of changing the throttle body gasket for the relatively cheap cost of both of them. After that.....I may be stuck?? I wouldn't assume any bad sensors since No codes are triggered and didn't have a vaccum issue before injector change.

any thoughts??

Grandamgtblk99
04-22-2010, 12:48 AM
Bad injector o ring possibly.

Malaclypse
04-22-2010, 08:00 PM
Bad injector o ring possibly.

That or the upper intake gaskets like you mentioned. If it were me I'd be replacing the upper intake gaskets any time I separated it from the lower manifold. Stupid paper material.

Injector O-rings like to roll sometimes during installation. Some grease will fix that. I tend towards chassis grease because its what I have on hand but white lithium may work as well. Also consider that the o-rings on the replacement injectors you bought used may have deteriorated because they've been sitting.

sugar ray
04-23-2010, 01:04 AM
I will try both suggestions when I have time tomorrow. I did learn a valuable lesson though. When they say, "its all in the heads" that is an understatement. After porting and re seating the valves that I am sure had to be leaking by now. What an amazing difference!! It freed up some horses that I didn't realize the 3.4 was capable of. ALMOST makes me want to purchase headers. just gotta get my vacuum issue under control

sugar ray
04-23-2010, 11:33 PM
Yuppers!!

Took the upper intake off today and the paper gasket was in rough shape. It was a NEW gasket when I changed the LIM gasket a week ago but had been taken on and off so many times tracking down that bad injector that it had torn.

New gasket and the 3.4 now runs BETTER then new :angel

Thank you everyone for your suggestions and knowledge on these boards :applause: