wont boost over 4500rpm

[jason901]

i have a 95 gsx that im having a problem with any help would be great so i bought this car this way and thought was just a simple boost leak it had many so i fixed the leaks so no more boost leak still same problem so figurd needed plugs so i bought plugs wires and coil packs still nothing someone told me maybe the maf so i got another one same problem nothing seems to work ..... it runs and drives fine however it wont boost over 4500rpm she run nice seems to pick up fine till you hit 4500 then she boggs and spits does this in all gears im only pushing 10psi what could the problem be

 

[Seamus]

What ecu do you have?

 

[jason901]

Im not to sure guess the stock one that came in the car

 

[Seamus]

Could be lots of different things. Does this happen at exactly 4500 rpm or just round about. Does it just stop making power and bog out or does it start backfiring and stuff. Does the turbo spool up normally? It would help if you post up a a log from one of the cheap obd loggers. Check fuel filter make sure the do is in good shape, is the fuel plp wiring and ground in good shape. I don't know anything about the 2g cas, butane sure timing is correct if it can be adjusted. That's a few of the real wast things before you start getting into real diagnostics. Also, was the car sitting a long time? Fill her up with fresh gas.

 

[jason901]

i got the car on empty so she has fresh gas ... i would say right at 4500 you can get it up higher but it starts to bog spit pop. you can hear the turbo spool sounds good hear the bov as long as you stay under 4500. 16g turbo has no play no smoke even when it bogs i haven't tried fuel filter i guess ill try a new one, im not sure what you mean by post a log? also timing is on point

 

[bw2277]

Did you check knock sensor too? Had a 1g had same problem and it was a knock sensor. Might not be it but something to check.

 

[Lou98GSX]

it could be a fuel problem . check your fuel filter

 

[codym]

How much boost are you seeing at 4500? How much throttle are you giving her ? You said you did a boost leak & if your confident you eliminated them all I'd look around at the wastegate. Check the flapper and the spring.

 

[jason901]

it holds it at 10psi it doesnt matter how much gas i give it does the same half or full what would i be looking for on the wastegate?

 

[Kdouglas89]

it holds it at 10psi it doesnt matter how much gas i give it does the same half or full what would i be looking for on the wastegate?

My car did the same thing. Double check boost leaks. Solved it for me.

 

[Spoolingaround]

What plugs did you get? I had misfire problems on single grounded plugs over 14lbs on my 14b. Switched to NGK BR7ES I believe and no more misfire.

There is a thread for selecting the right plugs for our cars. Search for it.

 

[jason901]

plugs are ngk bp6ey ... i check for boost leak i didnt have one but i did hear small amount either from my tester or the thing under it which is the Actuator

 

[Spoolingaround]

What pressure are you pressurizing to? Spray some soapy water on joints, connections and suspected boost leak areas and look for bubbles in the soap which will indicate leaks.

 

[Phantom DSM]

plugs are ngk bp6ey ... i check for boost leak i didnt have one but i did hear small amount either from my tester or the thing under it which is the Actuator

Damn, what happened to your first thread where we discussed this issue?
Bp6ey? Is that a typo. Put in NGK BPR6ES.. like 2 bucks a piece. Gap at .028. Check your fuel filter as suggested above. Let us know if it changes.

 

[jason901]

OK im getting closer... so i put on a new fuel filter still the same so i tried redoing the vac lines on the tb i had the a and e port just looped together so i plugged them by there self seemed to work better. she spits at 5000rpm now but shell pull throw and boost nicely after it spits this does this in all gears some times it will boost harder then others then soon found out that the #2 plug was fill of oil so i put a new valve cover gasket on after cleaning the oil up she still is running the same she spits at 5000 then will boost why is it spitting at 5000 then pick up boost and why is it harder then others

 

[Boosted90TSIAWD]

Definitely swap them plugs out for the factory bpr6es which is part # 7131 at most auto parts stores. If you are running 14psi or more try the step colder bpr7es part number 5534. Im pretty sure the bp6ey plugs are meant for a different aspiration/displacement. If the plugs and fuel filter dont help, my 93 gsx had the same problem even after trying a spare coil, fixing a minor vaccum leak, adjusting fuel pressure and verifying no boost leaks. It would hit a wall pop and carry on right about 4500 rpm every time it hit 5psi or more up to that rpm and it ended up being a fried capacitor in the ecm per ecmtuning. After reinstalling the ecm car goes to redline like it should.

 

[jason901]

i took out bpr6es to put the new bp6ey v-power in which run alot better im thinking maybe the 255 fuel pump is to strong or need injectors? maybe vac lines aren't right what is a ecm?

 

[jason901]

ok so now the clutch went so pulled trans to put a new clutch in ended up looking over a few things so I found out I have very small amount of shaft play in the turbo (up and down) which I don't think it will do any harm because it has very little play could this be a problem? im gonna swap the plugs again also... just trying to figure this car out any help? update be4 the clutch went she wouldn't boost over 4500rpm couldn't drive it over 4500 at all,,, then after replacing few new parts coil plug wires fuel filter maf seem to be a lot better but still not right she get up to 5000rpm but still will spit and sputter right at 5000 but shell pull threw and boost nicely will do this threw all gears what can this be? ??

 

[fonzgst98]

Bump!
Hey have you fixed your problem?
I recently swapped my t25 for the big 16g and I'm getting the same thing as you. My car was running faster with the t25 wth!

 

[mercaholik]

There are so many things to check, and of course it would help me to drive it but what about your cat, of you have one. It could be clogged, or partially melted from rich a/f ? Those are not likely though, you really should do all basic checks then maybe even verify valve timing is correct.