MSP hit boost and jerks/hiccups...

[jdwk]

I haven't found my car to be that sensitive to the gap. I just have the cheap autozone counter gap tool and they've all been close enough out of the package, right around .30 gap.

How do you know they were misfiring at 30? .28 vs .30 shouldn't make a huge difference; I don't even have a .28 on my ring.

Unfortunately, with intermittent problems like this, it's hard to say for sure it was the plugs just because you got a few clean on-ramp pulls. The gap on your old plugs is retarded but if you have the new ones down to .30 and the problem persists, it's not the plugs.

You described it as a lag this time, not jerking. Are you saying the car loses power and then kicks in abruptly? How many "jerks" do you feel all the way to redline? It sounds like you might be describing the infamous hesitation, which is a fuel problem, not a spark problem.

 

[BOOSTR]

Not only is it not the PCM, its not running plugs with a 0.040 gap. My first set of replacement stock type plugs went right out of the box in to the engine and car ran great, just like always. When I decided to ditch the OE Laser platinums for Coppers, I started gapping them within the spec range 0.028 - 0.031. I have every plug ever ran in my car. All show textbook signs of normal wear.

Do you at least know what brand of plug is in your engine. If its not NGK or Denso then get them out of there and put in one or the other.

 

[josh182]

I put ngk in, but the mechanic replaced them with ngk g power platinums and put 40 gap. you said youve always run fine between 28-31? went i pulled them out from the first owner they were all different 41-44-46-50 or something. i just want it to burn the fuel its being given, not blow it out the back hah
And yea fuel was an option i looked at, not sure where to start with that though. ill put fuel cleaner in next time i fill. what other cheap things can i do to check that? the injector orings were just replaced too.

 

[josh182]

well its fine till full boost, so at 4200 rpm or so (3rd) it lags a bit and rpms stay about the same, boost doesnt go down, car seems to like misfire or something quick, its just like a weight was added to the car for 2 seconds, then let off and it accelerates normally after. unless i shift right after the lag, then fourth lags bad until the rpms get back up.. its the strangest thing. frustrating ha

 

[jjm86m]

Having the same problems as above. I won't threadjack this but I'm interested in finding a solution for this.

 

[josh182]

Yea, sorry for threadjacking :/
It's funny how many different variations there are to the same type of issue though, the more I read into it, the more i see that could be wrong

 

[BOOSTR]

@josh 182 - the factory supplied spark plugs were NGK Laser Platinums. Those plugs are not supposed to be gapped. So when it was time for me to change the 1st set, I bought a new set of OE plugs and put them right in. The car ran fine having a gap above the specs shown in the addendum manual. All plugs used after the 2nd set have been NGK V Powers, a copper plug that can be gapped.

I'm wondering if you have a stock turbo in your car because your boost is delayed. 3500 rpm or so is the norm not 4200. Either that or your GT2554R is not within specs.

 

[jdwk]

Sounds like you have a fuel problem not spark. Throw a data logging wide band on there like an LC1 and record a few runs. I'll bet you'll be very surprised.

I don't think he has an accurate boost gauge that is telling him when he is at full boost. 4200 happens to be exactly where the MSP PCM switches from open to closed loop, so it certainly sounds like the stock tune.

 

[BOOSTR]

My car has a flashed pcm only. It never jerked under boost and has not stuggled under load or going up hills since Oct 2003 when it was flashed. That is what I meant by its not his PCM. Something else IMO and experience is causing his problem. That is typically the case with these cars. And people usually say your need this or that to fix it. Again not IMO or experience. My car runs great. Could it run even better, perhaps. But at this point I am not spending another dime on it other than routine maintenance.

Ive been having a similar problem, at full boost it jerks like crazy, sometimes struggles under a load or going up hills now.
I replaced my spark plugs and set them to 30 like has been said on the forums, when i brought it to the mechanic they found the spark plugs covered in unburned fuel, they gapped them to 40, and now i blow gas smoke out my exhaust everytime i take off.. what would you say is the best gap?

 

[josh182]

does an o2 sensor make sense, I only got a Bank 1 error code for a few hours. My friends car (non msp) was lagging similarly to mine, he replaced the o2 that his code brought up and it seems to be back to normal. If thats all it is, ill be content with the 100$ for the o2

 

[bwlknsn91]

Could it be a boost leak?

 

[pbarton14]

if it were a boost leak it would have to be a huge one, pre-maf

 

[CHIQLES]

Jdwk is right you guys need an elm reader
My moneys on coils unless you have upgraded your down pipe and intake your probably not hitting the fuel cut.
i went through 4 coils mixing and matching ones that gave me the best result and these where new the guy at the auto store thought i was trying to rip him off cause i kept returning his stuff.
My maf readings are right at the limit and im pushin close to 10psi..

 

[Sport23]

My car would bog with the flash. Disconnect the battery and turn the headlights on for a few minutes to clear the ECU. Turn off the headlights and reconnect the battery. If the car drives fine then your problem is your stock tune and a split second or unichip pretty much the only solutions.

I did have any issue with my coilpacks that caused my car to buck when I hit boost. On the two plugs under the coil packs the spark was jumping past the porcelain and causing a misfire. I've never heard of anyone else having that issue, but I wonder if some of the people who changed plugs and coils had this issue and didn't know it.

 

[jjm86m]

My car is exhibiting the exact same issues. I noticed that whenever the hiccups and jerking occurs my A/F ratio on my turbo timer jumps from 12-14.7 under acceleration to up to 18-20 whenever it occurs in the 3500-4200 range. I find this interesting because it is only occurring in a certain RPM range. I can hit 5500RPM once I get past the hiccups with no problems.

 

[jdwk]

22 AFR is pretty much open air. That means you have misfired. Many people think that a misfire means you have a bunch of unburnt fuel and you will be terribly rich (<12 AFR). What they don't understand is that an O2 sensor only measures oxygen. If fuel is unburnt then it passes right by the O2 sensor and all the oxygen is still in the mixture just like open air as if I poured a gas can out onto the driveway.

Please stop doing this. The misfires are bad for your engine. The super lean burns will raise temps to the point that you may actually pre-detonate (meaning the gas/oxygen mixture ignites before the piston reaches top dead center (TDC)) which is what causes rods to go through blocks.

We are now at the point with the MSP that all warranties are completely gone, and the only support is this forum. For anyone to have any chance of helping, you must have a couple of tools. One is a wideband O2. I know the car didn't come with it stock, but this is stupid for any FI car, and Callaway at least had the foresight to put a perfect spot for it on the J pipe. The other is an OBDII scanner and software to read it (Torque Pro is $5). Lastly, a boost gauge can be really helpful as long as you can log its output. No physical needle or human eye can accurately log the fluctuations in manifold pressure. We are all accustomed to saying our MBC or EBC is set to X psi boost, but the fact is that pressure is incredibly volatile, no matter how good your boost controller is.

I know these tools are cost prohibitive for some people, but some investment needs to be made to keep this car running. This car was never intended to be turbocharged and there are a lot of compromises made. You have to be able to deal with these compromises to own this car. If you cannot afford to, then you should consider selling it and buying something that requires less attention.

 

[StreetLimitz89]

if it were a boost leak it would have to be a huge one, pre-maf

pre maf? o.0 my MAF is on the intake side of the compressor wheel. would that make much of a difference
?