Thread: 03 Top Swap running hot UP AND RUNNING

Got the heads back and started putting things back together. The shop did a good job on repairing them and cleaning them up. They even painted them black.

My brother also picked up some new valve covers from GM parts direct to replace the broken ones that we picked up at the slavage yard. Just so everyone knows they came black straight from gm parts.

We are in the process of modding the LIM. Looking to get that done on sunday and button things up.

Originally Posted by 99prixgt

No, 97 gtps heads are known for small hairline cracks in between the valves

See I didn't know that thanks for the tip is it only 97's? I had a pretty small crack between valves and we kinda patche it up but idk lol

Well got everything installed. It starts up just fine but it has a rough idle. The engine shakes as well. It also back fired a few times through the exhaust and there is a rotten egg smell. The code thrown is P0300. I used the aeroforce gauge he has and it was showing cylinder 1 having the misfire along with 5. But primarily on 1.

These are the mods on the car:

3inch catted down pipe
SLP cat back
ZZP 1.9 rocers
I forget which valve springs he is using but they are upgraded as well
Autolite plugs
PRJ plug wires
Top Swap tune which has not been touched in months

I will try a few things mentioned in the description of P0300 to figure out what is cauing the issue. Nothing was changed other than replacing the heads.


This is what the code description is.

What does that mean?Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.

A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

SymptomsSymptoms may include:
the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present
CausesA code P0300 may mean that one or more of the following has happened:

Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer
Possible SolutionsIf there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Maybe you installed the wires wrong on the coil packs for 1 and 5??

Vacuum leak may be another thing for the rough idle.

The wires are on right. I used my GP as a reference on top of a diagram. All of the vacuum lines look to be installed but it could possibly be an exhaust leak. I will have to double check everything once again.

Swapped out the plugs and the car started up just fine. I did get a P0300 code when idling and reving to about 2500-3000 rpm's with teh SES light flashing on and off. I had aeroforce monitoring misfires and it showed on cylinder 1 and 4. I replaced the 1/4 coil and it did the same thing with the replacement. I will have to double check the gap on the plug to see where it is at for both 1 and 4.

But the car is running smooth.

Perhaps swap the ICM with the one on your car quick and give it another go.

Originally Posted by Fivefingerdeathpunch

Perhaps swap the ICM with the one on your car quick and give it another go.

Yeah that's what I plan to do next and see if that fixes the issue. I'm just glad it's driveable.

The metal dust boots still on the wires?

Not using the boots. The PRJ wires are angled so the straight metal boot won't fit.

I have been driving it for a couple days and the car runs great. Took it on the highway and the temperature stays between 180ish to 195ish. It doesn't get any hotter. Seems like the repaired heads did the job. I have not looked into replacing the ICM as I have not experienced anymore P0300 random misfire. I will drive it to get the computer to relearn since it was disconnected.

awesome! cant wait to get mine started, who did you get to tune the pcm?

Originally Posted by Grimsin

awesome! cant wait to get mine started, who did you get to tune the pcm?

Got the tune done by Brian. He's a sponsor on another forum

http://www.dynotunemotorsports.com/

ah ok just wondering if it was a mail in tune, Im gonna drive over to overkill and have him do it.

Yeah there is nobody out here in the area that is familiar with the 3800. I did invest in HP tuners to learn and twaek the tune. Plus the guy is very helpful and he did say that he could tweak the tune based on scans that I provide. All in all he did a good job tuning it.