bucking, stalling

[COliveira95]

bucking, stalling (UPDATED)

Hey all,

having an issue with the car bucking violently under 2000 RPM's... smooths out when revved up. Now it's gotten worse and intermittently goes from running smooth as silk to bucking and misfiring and backfiring. It sounds like a timing/ignition issue. The CE light comes and goes. I couldn't get around to pulling the codes until yesterday. KOEO got 111 and stored I got 126, 157. 211, 214.

I put a new Cam sensor in it, cleared the codes and drove it, car got up to temp and started acting up with the same symptoms, at times worse. Got it to where I needed to go, let it cool and then as I left late last night, I couldn't even get it to run without a bunch of throttle. Pulled the codes KOEO and got the same list as above. I try running the KOER but the car won't run long enough, it stalls out.

By the way, I have a Pro-M 80mm MAF in the car as well... what stumps me is I get the PIP code and the CID code after replacing the sensor and clearing the stored codes... maybe I didn't clear the stored codes? (pulled the jumper out while it was reading the codes back to me)

 

[luigisho]

Try resetting the computer. Have you tried running it with the MAF unplugged? That's an easy check although I wouldn't think that would be enough to stall it.. Might be crank sensor or maybe the dis or pcm is on the fritz. Inspect and eliminate one at a time.

 

[Bizzy]

Also try putting a 55mm MAF back on and see if it does the same thing. If you need a stock MAF or DIS let me know, I've got both. I'm sure you can get one to try out where you are a lot easier though.

 

[AutoSHO]

It sounds like you've got a ground problem with the DIS. Is your intake powdercoated/painted? Is the ground strap on the back corner of the intake hooked up?

You need to make sure you have some heat sink compound between the DIS and intake. The DIS mount needs to be completely clean and free of paint/powdercoating, etc. All 4 screws need to be in the DIS and snug. The 2 bolts that stick through the crossover tube, the bottom of those mounts and the brackets that mount to the intake need to be clean and free of paint/powdercoat. Same with the intake where those brackets mounts.

It could also be a computer ground issue.

 

[COliveira95]

You've got a ground problem with the DIS. Is your intake powdercoated/painted? Is the ground strap on the back corner of the intake hooked up?

You need to make sure you have some heat sink compound between the DIS and intake. The DIS mount needs to be completely clean and free of paint/powdercoating, etc. All 4 screws need to be in the DIS and snug. The 2 bolts that stick through the crossover tube, the bottom of those mounts and the brackets that mount to the intake need to be clean and free of paint/powdercoat. Same with the intake where those brackets mounts.

Good point Chris. I haven't had any issues with it for the two months and 5,000 miles I've put on it after the powdercoating, but I will try and run taps through all the bolt holes and clean up the powdercoating a bit. I cleared all the codes once again and made sure they were clear. I ran the car and it ran really good and then it sporadically runs rough again, and back to normal so the ground issue does sound right.

Just as an update, when the car ran rough again, it gave me the same codes as I mentioned above...

 

[Mike Kopstain]

Good point Chris. I haven't had any issues with it for the two months and 5,000 miles I've put on it after the powdercoating, but I will try and run taps through all the bolt holes and clean up the powdercoating a bit. I cleared all the codes once again and made sure they were clear. I ran the car and it ran really good and then it sporadically runs rough again, and back to normal so the ground issue does sound right.

Just as an update, when the car ran rough again, it gave me the same codes as I mentioned above...

Chris, Make sure the following is clean, not only the bolt holes, but the flat mating surfaces:

- Two 12mm bolts connecting the crossover tube to the intake
- Area behind the DIS - Make sure there is white lithium grease here and make sure all 4 screws are in
- Ground strap going to the RH intake support - make sure the entire surface the strap contacts is clean, not just the bolt. Don't depend solely on the bolt for the ground.

 

[AutoSHO]

- Area behind the DIS - Make sure there is white lithium grease here and make sure all 4 screws are in

That needs to be Heat Sink Compound (Thermal Paste). The DIS uses the manifold as a heat sink and needs a medium to transfer the heat across. Lithium grease won't do it.

 

[masho95]

Well my input on the subject, as you already know Chris, would be... Like others said check your grounds well. Check your IRCM connection, as well as the connection going to the computer. And the MAF isn't going to give you codes for the CKP and CMP sensor even if it's completely failing. I'd leave that out as a possible failing point for now. Also check the power connections coming off the positive post on the battery.

I already told this to Chris but I thought I'd share this story with the rest of you. My buddy had the exact same problems that Chris is describing with his car. Turns out the computer also threw out the CKP and CMP codes. We swapped out the CKP sensor, put a new timing belt on and it was still doing the same thing. So I started checking the battery connections and was looking at the small positive wire coming off the postive battery terminal. As I started tugging slightly on the wire it just snapped and pulled free in my hands. Turns out some one had spliced the wire (and VERY poorly at that) before. We respliced the wire (correctly) and he hasn't had any issues like that since.

 

[Mike Kopstain]

That needs to be Heat Sink Compound (Thermal Paste). The DIS uses the manifold as a heat sink and needs a medium to transfer the heat across. Lithium grease won't do it.

I knew that when I typed it... I just always mix the names. Someone yelled at me for that a month ago too.

 

[COliveira95]

update, I sanded off the mating area for the DIS, and all the bolt mating surfaces... put it back together and the car seems to be running fine now. Put about 5 miles on it so far, no problems yet. Looks like this must have been my problem! Thanks for the help everyone!

 

[n8rsk8r]

glad to

see you rippin it up again, at least your sho is runnin! LOL take a couple rices down for me will ya!?

n8rsk8r

 

[Bizzy]

Well Chris, looks like you win the race in who's car gets running again first. Glad you got it all worked out. Did you ever post on what the color codes are for the wires that used to be in your test connector that's not there anymore? You may need to run your codes one day ya know.

 

[COliveira95]

Well Chris, looks like you win the race in who's car gets running again first. Glad you got it all worked out. Did you ever post on what the color codes are for the wires that used to be in your test connector that's not there anymore? You may need to run your codes one day ya know.

Beth, I found the STI wire, which is how I got the codes I listed above. It was a brown wire, as you had stated. :thumbs_u:

 

[COliveira95]

Well, I knew it was too good to be true... after I cleaned up the mating surface to the DIS and the powdercoating around the bolts, the car ran better until two days and 10 miles later. Same issues, same codes... Still think it's a ground issue Chris? I'm going to recheck all the grounds and the ground strap and if the problem persists, I'm going to try another intake manifold...

This also might explain my overheating problem. After paying closer attention to the temp gauge, the car runs in normal temp (especially after I cleaned the powdercoating). Minutes later, I saw the temp gauge spike to just under HOT and that's when the CE light came and the car started popping, bucking, etc. It did not stall this time around though, I kept it running. So I'm thinking if this is a ground issue, it could be making my temp gauge go wacky too... sound about right?

Just for a recap on the codes again:

These are the stored codes on KOEO (111),
157 - (MAF signal voltage too low)
211 - (PIP Sensor circuit failure)
214 - (CID Signal circuit failure) - replaced this sensor, still get the code.
528 - (Clutch switch circuit failure) - didn't get this one before...

Again, these codes came back after resetting and verifying they were cleared.

 

[COliveira95]

Just another update... I removed the intake manifold and spent a lot of time cleaning up the powdercoating again. I ran taps through the bolt holes, cleaned up down to the alluminum on the crossover tube (for the DIS mount) as well as the rear face of the DIS. Seemed to be some corrosion there so I sanded that down really well. I put a thin coat of heat sink on the DIS and tightened the bolts and wiped off the excess. I also removed and sanded the ground strap and I saw that there was a lot of powdercoating still where the strap contacts the manifold. I also sanded this down to alluminum and tapped the bolt hole there as well.

Results:
this has seemed to have cured my high temp readings I was getting (another post). The gauge must have been reading wrong due to a bad ground. The car still feels a little funny, but I'm yet to put quite a few miles on it to see if the symptoms are still occurring, I will keep you all posted and would like to thank everyone again for all the input/advice.