engine cutting out in boost

[faulkner576]

my setup is a f22a1, forged bottom end, 550cc injectors, 1.2 bisimoto turbo cam, 50 trim garrett on 12 psi. made 297 whp/288 ft lbs. also im kinda new to the forums.

after i got my car tuned it ran great. smooth, healthy and powerful. randomly it started running completely different. in boost it cuts out, and afr is all over the place running dangerously lean in boost. car runs fine at idle and cruising on the hwy.

my question is...
has anyone had this problem? or have a clue what would cause this?

ive tried a different ecu, new spark plugs, new burnt chip, and it didnt change a thing.

here are some pics of my car...

[Sordz]

Id check to see if the fuel filter is clogged/dirty, also check the fuel pressure regulator. What fuel pump is in the car?

[evil_demon_01]

my setup is a f22a1, forged bottom end, 550cc injectors, 1.2 bisimoto turbo cam, 50 trim garrett on 12 psi. made 297 whp/288 ft lbs. also im kinda new to the forums.

after i got my car tuned it ran great. smooth, healthy and powerful. randomly it started running completely different. in boost it cuts out, and afr is all over the place running dangerously lean in boost. car runs fine at idle and cruising on the hwy.

my question is...
has anyone had this problem? or have a clue what would cause this?

ive tried a different ecu, new spark plugs, new burnt chip, and it didnt change a thing.

The cutting out will most likely be due to the lean AFR's as a protection.
What is it tuned with?

I'd say there is a faulty sensor.

[faulkner576]

Id check to see if the fuel filter is clogged/dirty, also check the fuel pressure regulator. What fuel pump is in the car?

the filter is new, also im running a walbro 255, the regulator i havent checked thanks for the input.

[faulkner576]

The cutting out will most likely be due to the lean AFR's as a protection.
What is it tuned with?

I'd say there is a faulty sensor.

its tuned with ECtune. today i took apart the MAP sensor ($30 ebay 3 bar) and it looked like someone put it together with super glue. very cheaply make. after i put it back together the car wouldnt even start.

im hoping thats the problem. im ordering a new one tonight and ill let you know if that fixes the issue.

i appreciate the input.

[GhostAccord]

You found it before I could suggest it. That sounds like a boost vs MAP sensor issue. I remember tuning a guys car and he swore it had a 3 bar map sensor installed. Well as soon as we got tuning @ about 11-12psi...bang she would hit a brick wall and drop like a fly. Right away I knew he had been scammed and it was running a 1bar MAP sensor. I could see it in the datalog. Every time I hit 11.5-11.7lbs of boost it would fuel cut.

[faulkner576]

You found it before I could suggest it. That sounds like a boost vs MAP sensor issue. I remember tuning a guys car and he swore it had a 3 bar map sensor installed. Well as soon as we got tuning @ about 11-12psi...bang she would hit a brick wall and drop like a fly. Right away I knew he had been scammed and it was running a 1bar MAP sensor. I could see it in the datalog. Every time I hit 11.5-11.7lbs of boost it would fuel cut.

the map sensor is one of the things i cheaped out on and i guess im paying for it now haha.

does anyone suggest a good 3 bar map sensor? i was looking at the msd gm style for like $85

[KeeleDesign]

I ran 36 psi on a gm 3bar with no issues.

Something I also had issues with was spark blow out. I had to close my plugs to a .017 gap, it took me 6 months to find that perfect gap. otherwise at higher boost it would spit and feel like fuel cut, due to blowing out the spark.

[GhostAccord]

I have installed the GM MAP sensor from Xenocron without any issues.

http://www.xenocron.com/3-bar-map-se...-gm-p-195.html

$65 and it comes with the 3 wire weatherpack connecter.

[g22paul1]

I have a gm 3 bar for about a year and a half no problems ive found them cheaper on ebay than $85

[faulkner576]

Thanks guys for the input. My map sensor should arrive tomorrow I'll let y'all know if that's the fix.

[faulkner576]

hooked up new map sensor today and the car starts but wont idle. ive heard that you can have 2 different 3 bars and they will read a little differently causing the afr and timing to be off.

i guess i will have to contact the tuner and see if he can brush up my tune to match the new map sensor

[GhostAccord]

Yes that is correct, they have different voltage scales. It would be a good idea to see of your tuner will switch that up for you.

[faulkner576]

just wanted to give everyone an update...

i took my car to the tuner and like we thought the map sensor was the problem. suprisingly that small change made a big differance in the tune. my car now runs great.