overboosting issue

[SHAGwagn]

having an overboosting problem in 4th-6th gear. Ive pulled down the intake system twice and re tightened. Problem still persists. Problem started after installing new plugs 5 months ago when I was home. Been out of town for 4 months, came home and its still happening. its pretty annoying. Any ideas of what i should do to pinpoint the problem? I am assuming its a leak but cant be certain. maybe a boost control solenoid problem? Any help would be appreciated.

nikko

 

[matsuda]

having an overboosting problem in 4th-6th gear. Ive pulled down the intake system twice and re tightened. Problem still persists. Problem started after installing new plugs 5 months ago when I was home. Been out of town for 4 months, came home and its still happening. its pretty annoying. Any ideas of what i should do to pinpoint the problem? I am assuming its a leak but cant be certain. maybe a boost control solenoid problem? Any help would be appreciated.

nikko

Do you have a boost gauge?

If you disconnect the boost control solenoid, boost should max out at ~10 PSI on a stock motor.

 

[SHAGwagn]

Yes i have a boost gauge. the motor is not totally stock. I have a few intake bolt ons. Will that make a difference?

Just plug it out? will that throw a CEL? Just curious what to expect. Thanks for the quick reply.

nikko

 

[coyfish]

I have a similar boost creep issue. Mine only creeps up in the sweet spot of the power curve though. Right around 5300-5500. Usually I hold about 17.5-18 and it jumps to 20-21 for a split second until I shift.

Is yours the same way or is it all the way through the powerband ?

 

[SHAGwagn]

exactly the same way and jumps exactly to 21-22. really annoying and dangerous to say the least. I've been getting 320 mile tanks granny shifting since I've been back stateside because it just isn't fun to worry about popping a perfectly mint motor.

 

[MSMS3]

Yes i have a boost gauge. the motor is not totally stock. I have a few intake bolt ons. Will that make a difference?

Just plug it out? will that throw a CEL? Just curious what to expect. Thanks for the quick reply.

nikko

If no exhaust mods, I don't know why you are having this jump up in boost right before your shift point. This is more likely to occur with mods that open up the exhaust side so that it flows at a higher rate than the wastegate can bleed off excess boost. An intake leak either before or after the intercooler should not produce an overboost, I would think.

I see the quick transient spike, sometimes to 21 right after shift when it comes back up on boost, with an almost instantaneous settling back to 17 psi +/- 1 psi. through the power band up to 5,500. Once past 5,800 boost gets dialed back. But I have exhaust mods too (see sig).

I'm assuming OP has stock ECU tune. Do you have an aftermarket BPV? What is outside temp? Are you getting fuel/load cut too?

 

[matsuda]

Yes i have a boost gauge. the motor is not totally stock. I have a few intake bolt ons. Will that make a difference?

Just plug it out? will that throw a CEL? Just curious what to expect. Thanks for the quick reply.

nikko

You won't get a CEL from disconnecting the boost control solenoid.

It's usually exhaust mods (downpipe and/or testpipe) that raises the minimum (~10 PSI) boost pressure.

 

[SHAGwagn]

I have a forge bpv. I live in FLA. Its hot all the time. Any ideas?

 

[rmgedon69]

you won't get a cel from disconnecting the boost control solenoid.

it's usually exhaust mods (downpipe and/or testpipe) that raises the minimum (~10 psi) boost pressure.

+1

 

[coyfish]

I have a forge bpv. I live in FLA. Its hot all the time. Any ideas?

I also live in FL and you said we had similar problems. Sometimes its worse than others. My guess is that the fluctuating "winter" temps have some effect.

 

[SHAGwagn]

nah man this s*** started happening in august when i was home for a month. ive been granny driving my car for 2 months since ive been back state side.....i guess the upside is MPG....ive been getting a steady 26.7MPG average gas mileage. Any other ideas????

 

[MSMS3]

I'm at a loss as to how intake mod would, alone, result in overboost, (except perhaps with a larger and more efficient intercooler) unless the ECU is perhaps misreading something.

OP: what kind of intake do you have installed and does it have an air straightener? Turbulence in the air flow could cause the MAF sensor to misread air mass and miscalculate density and lead to AFR error. I do not know if this could cause an overboost problem. Maybe I'm stretching here. Just looking for possible solutions.

Only other reported change was the spark plugs. I can't see how that would cause an overboost problem in our engine, but it's easy and cheap to check to make sure they are the right application and are gapped correctly - .032 inches.

I know from experience in another platform (three turbo Saabs) that having a plug gap too wide was a known cause of overboost in their 2.0L turbo engine. Not sure why. Just a thought.

 

[Romo89]

Same here it all started when i installed the cp-e turbo inlet

any ides??!!?

 

[BoostisLove]

I'm at a loss as to how intake mod would, alone, result in overboost, (except perhaps with a larger and more efficient intercooler) unless the ECU is perhaps misreading something.

OP: what kind of intake do you have installed and does it have an air straightener? Turbulence in the air flow could cause the MAF sensor to misread air mass and miscalculate density and lead to AFR error. I do not know if this could cause an overboost problem. Maybe I'm stretching here. Just looking for possible solutions.

Only other reported change was the spark plugs. I can't see how that would cause an overboost problem in our engine, but it's easy and cheap to check to make sure they are the right application and are gapped correctly - .032 inches.

I know from experience in another platform (three turbo Saabs) that having a plug gap too wide was a known cause of overboost in their 2.0L turbo engine. Not sure why. Just a thought.

A larger intercooler would DECREASE total psi not increase.

 

[matsuda]

Same here it all started when i installed the cp-e turbo inlet

any ides??!!?

First, carefully check the hoses from the wastegate to the boost control solenoid and from the boost control solenoid to the turbo inlet.

For troubleshooting purposes, you can disconnect the boost control solenoid.

 

[SHAGwagn]

update...seems to have miraculously went away...weird. ill keep an eye on it

 

[tony275]

I have a ms6 with a front mount intercooler and straight pipe exhaust and I'm over boosting alot, around 26psi or more and then it fuel cuts. this started to happen when i repaired the hose that goes from the wastegate to the boost control sensor or w/e its called. It starts to over boost at 4500 rpm. how can i fix this?

 

[cpolly69]

I have a ms6 with a front mount intercooler and straight pipe exhaust and I'm over boosting alot, around 26psi or more and then it fuel cuts. this started to happen when i repaired the hose that goes from the wastegate to the boost control sensor or w/e its called. It starts to over boost at 4500 rpm. how can i fix this?

get better boost control -
ie - get a tuning device with better versions of the tables that control boost or
switch to a manual or electronic boost controller -
sooner or later the level of bolt ons you have will put you into a position where this happens