Hesitation under boost

[FuryCharger]

So today I cruising around trying to get miles on my new clutch. I was in 5th gear and floored it just to get some load on the turbo and as soon as it reached boost it started like stuttering or hesitating, almost like a misfire but I cant imagine I have a misfire.

When I reach the boost zone its almost like the car has trouble making more boost because of the stuttering. Its not a fuel issue as I have 10 A/F ratio at WOT and 60 psi on the pressure gauge. Not getting spark?

Any thoughts are welcome.

I will check wires and coil packs this coming week.

[ssms5411]

Re: Hesitation under boost

10.1 A/F at WOT is way rich I'm surprised you haven't had a backfire. 11.5 is about where you want to be maybe 11.0-11.5 around there.

[Shodown]

Re: Hesitation under boost

almost like a misfire but I cant imagine I have a misfire.

Really? Why is that? These cars have more problems with random misfires than anything else.

I will check wires and coil packs this coming week.

Do this. Check your oxygen sensors as well.

10.1 A/F at WOT is way rich I'm surprised you haven't had a backfire. 11.5 is about where you want to be maybe 11.0-11.5 around there.

Not necessarily. I've been in sub 10's A/F a few times while doing some tuning and it never backfired. It stuttered a tad on the top but never once backfired.

[vr4gasm]

Re: Hesitation under boost

what plugs are you running?

[Turbo V6 Camaro]

Re: Hesitation under boost

you are to rich...... lean it out, or shorten plug gap, but save some time and lean it out

10 AFR at full boost is usally fine but when the turbo is spooling it sometimes flood the air charge with to much much fuel and it feels like a misfire

also if you have a "autozone" ICM boost is VERY iffy on those..... ask shodown :)

[FuryCharger]

Re: Hesitation under boost

Thanks for the replys.

I am running NGK TR55s? I think thats the correct spelling.

You could def be right on the to rich portion. To much fuel is causing the "misfire" feeling?

When i got home the other day I looked the hood and noticed that my radiator spill line right below the cap was draining the excess fluid right onto my piping sleeve below the turboi before it enters the intercooler. You dont think some coolant seeped by the sllev e and into the pipe and is causing a blockage somewhere?? I will check this week.

Do not have an autozone ICM boost.

Like I said, it rides fine when I am not at WOT but when I punch it, it feels like the air charge is getting blocked or I am misfiring.

[pace2006]

Re: Hesitation under boost

I am running NGK TR55s? I think thats the correct spelling.

There's part of your problem. You should be using a colder plug like TR6s and a different gap with FI or nitrous.

[Turbo V6 Camaro]

Re: Hesitation under boost

you should be running TR6 try those and see first, if still seems like a revlimiter lean it out

I run TR8 plugs

[vr4gasm]

Re: Hesitation under boost

yah wrong plugs for FI

[ssms5411]

Re: Hesitation under boost

Def. wrong plugs for FI , I hope you don't or didn't run alot of boost and log KR, also correct that A/F no need wasting gas and performance. You'll be quicker with a better A/F, I know most widebands won't read below a certain point and just say rich , mine did this with nitrous and I caught it but the next thing I knew some fuel was left in the hollowed CAT at the time and blew a crack in it.

[FuryCharger]

Re: Hesitation under boost

I cant imagine that I put the wrong plugs in there. I did a ton of research. I will double check. I know I had the NGKs a while back but I know I changed the plugs when I did the turbo.

[Shodown]

Re: Hesitation under boost

depending on how much boost he is running, 11.5 will be way lean, i would stay around 10.5-11

Huh? Who told you that?

And yes, TR55's are the wrong plugs for nitrous or FI. TR6's are what you want.

[Shodown]

Re: Hesitation under boost

I've never heard of anyone wanting to be in the 10's AFR on these cars. I wouldnt go lower than 11.0 at the very most.

I hope they werent the same people suggesting that you spray nitrous INTO your turbo....

[FuryCharger]

Re: Hesitation under boost

I will check:

type of plug in motor
any coolant in the turbo piping.

To my knowledge my car was tuned with my bad fuel feed line, which was at 30psi. I fixed the feed line and my pressure went from 30psi to 50psi instantly at idle, so I was seeing some crazy rich numbers. it is idling at 13-14 A/F.

[pace2006]

Re: Hesitation under boost

when i was tuning, I have a friend who works at a performance shop here in austin and he told me to stay 10.5-11.0, maybe you heard of them, there called "Boost Logic" they have the record for the 2 fastest supras in the work

...because what works for a track-oriented 2J is going to be exactly what a street-driven 3800 needs. :rolleyes:

Different motor designs have different preferences and tolerances, and even individual setups differ, as I'm sure you've noticed. For example, a friend of mine has a 280ZX turbo setup from an L28ET on his higher compression L28E 280Z. That car likes to stay in the high 9s to low 10s when under boost, otherwise it starts to ping. Yet there are few 3.8s seeing that AFR under boost.