Back Fire at Full Boost

[gsx219]

hello community haven't posted here in a while as of my dsm running without issue for a few years now. As of recently i haven't been about to push full boost without the car feeling its hit a brick wall and backfireing. I've checked most of what i can with my current knowledge of the car and everything seems to be fine. So my question to you is does anyone have an idea on what the issue could be cause im stumped if you need any info to help pinpoint the problem easier please ask ill be checking back regularly.

again thanks in advance!!!

 

[cody92talon]

do you have your boost turned up a little on a completely stock car?

 

[gsx219]

moderate build with internals 22psi havn't had issues till recently

 

[mrbill86]

Do you have a eprom ecu? What kind of mods exactly? Tell us everything that you have in the car that's aftermarket and we can get a better idea as to what it is. It definitely sounds like boost cut if you feel like you're hitting a brick wall, but if it's stuttering, then that's a completely different issue. Let us know.

 

[96awd]

Could be misfire... check your plugs.. what plugs and gap?

 

[gsx219]

no eprom 97 ecu with old version safc hks cams 264/272 wiseco pistons 9.0:1, fp3052 turbo, hans intercooler custom piping, aem fuel rail, 660 greddy injec, littly tipsy atm can't think tho as said engine is a 1st gen with a moderate internal build

i run NGK v-power and don't change the gap on em, also there maybe just a few months old

 

[96awd]

no eprom 97 ecu with old version safc hks cams 264/272 wiseco pistons 9.0:1, fp3052 turbo, hans intercooler custom piping, aem fuel rail, 660 greddy injec, littly tipsy atm can't think tho as said engine is a 1st gen with a moderate internal build

i run NGK v-power and don't change the gap on em, also there maybe just a few months old

as to plugs, I would get the brp7es and gap to 18. I had a 57 trim PTE turbo at 27psi and at full boost I would get random backfires.. turned out to misfires. I changed the plugs and gapped them to what I said above and no more random back fires or anything. Just a suggestion.

 

[gsx219]

where can i find those plugs?

 

[spoolin ddub]

Bent valves. Have you misshifted recently?

 

[gsx219]

no mis shifts car runs smooth as can be other than at full boost

 

[mrbill86]

It's possible that not having the eprom could be the issue because from what I understand, eprom overrides fuel cut. Also, I was told to have the plugs gapped at .28 Try turning your psi down to 14-17 and see what it does then. If you still have the same issue, could be other things. I.e.; ptu, coil, timing, etc. Also, you said that it's a 1g engine with a 2g ecu. That could be a possible issue if not set up right.

 

[96awd]

You can get them from a vendor. A local auto parts store usually don't have them.

And not having an eprom Ecu isn't gonna cause that... as long as he has some type of tuning system which can't remember if you do, then you're fine. I doubt its bent valves as well it wouldnt just happen in full boost. He would know just on the start up and easy, daily driving. Yes, it would be better if you had dsmlink but anything works....almost.

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[gsx219]

i know for a fact it isn't anything with not having a eprom as this car runs just fine running 22psi all day long and thats the minimum setup as thats as low as the wastegate will go so car was built for boost.
i guess ill give those plugs a try next week since i don't believe dealers will be open on a sunday and thanks for all the quick responses. again thanks in advance to anymore ideas that could be my issue

 

[spoolin ddub]

no mis shifts car runs smooth as can be other than at full boost

It running smooth while driving means nothing. I'm just saying i had the same exact problem when I ran BC springs and bent four valves for a month and the car drove normal enough where no one could tell the valves were bent but car missed so bad on boost it felt like it was hitting a brick wall. I just happen to get a leak done test for shits and giggles and surprise. Only 400 miles and head had to go back to machine shop. If it's not the plugs do a leak down test.

 

[jed344]

sounds to me like boost cut aswell.