Car stops pulling under boost

[ThurnisBaum]

Hi all, a couple weeks ago when I started pulling my car would do fine up until about 4000 Rpms, then it would start jerking and backfiring a little and would not go above 4500. My alternator ended up giving out so I replaced that and it fixed the problem for a little. It just started doing it again though, just wondering if anyone had experienced this and where to start. I tested the battery and it is time for a new one. 1997 GST with a 6 bolt swap and a 16g turbo, untuned

 

[gst-turbo]

Have you checked for boost leaks and how much boost are u runing might be fuel cut

 

[2GDEVIL]

My old gst did the same thing and i had a boost like in my intercooler and on top of that i changed spark plugs and wires and problem fixed.

 

[2g_ab63t]

Boost leak test or maf might be done or spark plugs.....

 

[Maes]

Just start with a boost leak test and report back

 

[2gmitsueclipse]

Not much to go on information wise.

• Have you completed a boost leak test?
• Are you using the stock boost solenoid?
• If not, what are you controlling boost with, and what are you boosting to?
• What do your AFRs look like when this occurs?
• When was the last time you changed the fuel filter?
• Any other fuel modifications?
• What spark plugs and gap size are you using? How old are they?
• How old are your spark plug wires?

 

[steve]

I'll add:
What's the electrical system voltage when it starts acting up?

 

[Dsmkauai]

Also 16g at what boost untuned? And stock injectors and fuel system?

 

[miliman13]

Can an alternator cause this type of problem ?

 

[CrackedDSM]

Can an alternator cause this type of problem ?

If you think about it, the fuel pump runs on voltage, and our fuel pumps already need a super thick gauge wire running to it to keep constant voltage. Add in a malfunctioning alternator into that equation and what happens.

 

[miliman13]

If you think about it, the fuel pump runs on voltage, and our fuel pumps already need a super thick gauge wire running to it to keep constant voltage. Add in a malfunctioning alternator into that equation and what happens.

Assuming that is so , wouldnt it run lean?. What it it runs rich? ..

 

[ThurnisBaum]

Not much to go on information wise.

• Have you completed a boost leak test?
• Are you using the stock boost solenoid?
• If not, what are you controlling boost with, and what are you boosting to?
• What do your AFRs look like when this occurs?
• When was the last time you changed the fuel filter?
• Any other fuel modifications?
• What spark plugs and gap size are you using? How old are they?
• How old are your spark plug wires?

Boosting consistently at 14psi, stock boost solenoid. When it cuts out it continues to spool at full boost it just won't move up in Rpms. Only had the car for a couple of weeks so not too sure when the fuel filter was replaced, or what spark plugs/gaps it has.

 

[2gmitsueclipse]

Boosting consistently at 14psi, stock boost solenoid. When it cuts out it continues to spool at full boost it just won't move up in Rpms. Only had the car for a couple of weeks so not too sure when the fuel filter was replaced, or what spark plugs/gaps it has.

Well, I would work your way down the list of questions. Starting with that boost leak test.

 

[ThurnisBaum]

Well, I would work your way down the list of questions. Starting with that boost leak test.

Okay, thanks guys I'll report back with results once I get my hands on the materials to make the boost leak tester.