1986 GN bogs out at 8 psi why?

GNbythebay

Member
Joined
Jul 28, 2016
when i am driving i can get the car right around 8 psi before it starts to act up. Once i hit that 8 psi it stutters(makes a small popping noise) and doesn't want to go past 8 psi. Im pretty sure I dont have a boost leak anywhere and I just replace the whole ign system so what could be causing this? i would like to figure this out by this weekend because i plan on taking my GN to cruisen weekend in OCMD.
 
If you're in Maryland look up the MAGNA guys i'm sure someone can help you up there. Was it doing it before you worked on the ign system?

Is it setting a code? What MAF do you have on the car?
 
If you're in Maryland look up the MAGNA guys i'm sure someone can help you up there. Was it doing it before you worked on the ign system?

Is it setting a code? What MAF do you have on the car?
I don't live in Maryland I will just be up there next weekend. The MAF is stock and I don't believe it was doing it before I installed the new plug,wires, coil pack and ignition module.
 
Was it doing that before you changed your ignition system?
 
I don't believe so. It started after I out the new stuff in
Then that's where I'd look to first. Just because the parts are new doesn't mean they are correct for our cars. What new module and coil pack did you put in? Many threads on here with people having problems with parts store modules and coil packs. At best they are hit and miss. Do you have someone nearby with a known good coil pack and module to swap and see?
 
Then that's where I'd look to first. Just because the parts are new doesn't mean they are correct for our cars. What new module and coil pack did you put in? Many threads on here with people having problems with parts store modules and coil packs. At best they are hit and miss. Do you have someone nearby with a known good coil pack and module to swap and see?
I can try to find someone to swap with but I bought my coil pack and module at advanced auto
 
I can try to find someone to swap with but I bought my coil pack and module at advanced auto
If you're short on cash I'd see if you can find someone with a known good module and coil pack to avoid throwing parts at it. If money is not an issue buy a module and coil pack from one of our vendors (HighwayStars or Kirbans). Even if it ends up not being the problem this is one of those parts you should have a spare of anyway. FWIW, many times stuttering/popping under boost ends up being ignition related and I don't have a high degree of confidence in that Advanced Auto stuff but I could be wrong.

The stock MAF could also be suspect but I'd start with the ignition and go from there.
 
Sorry, I ASSumed the old ignition parts were taken off because there was a problem with them. Lol.
 
Sorry, I ASSumed the old ignition parts were taken off because there was a problem with them. Lol.
That a bad coil pack or ignition module will cause popping under the pressure? It sounds like a coupler trying to blow off
 
That a bad coil pack or ignition module will cause popping under the pressure? It sounds like a coupler trying to blow off

True, but the only changes you say you made were to the ignition system. Why not rule out those changes being the problem before chasing another rabbit down a different hole?

That's one of the main causes guys new to these cars get into trouble.
 
True, but the only changes you say you made were to the ignition system. Why not rule out those changes being the problem before chasing another rabbit down a different hole?
I also installed the hot wire kit, 42lbs injectors with the turbo tweak CAI and the throttle body plate
 
I also installed the hot wire kit, 42lbs injectors with the turbo tweak CAI and the throttle body plate


Well, with the exception of the hot wire kit and RJC power plate,(I'm assuming that's what you mean by t body plate) I would still reverse each change you made one at a time until you figure out what it is or that none of the changes is causing your issue.

Doing wholesale changes to these cars all at one time isn't a good idea unless your pretty experienced with them.

Is the chip seated properly? You're sure the wiring is correct on the hit wire kit?

Did you install or does the car already have a Scanmaster? Any codes?
 
Do you have a scan master ? If not borrow one if you can. Set it to read what the maf is reading. If it doesn't hit 255 then the maf is starting to go out. The symptoms you describe are exactly what happened to me a few years back. Car would run strong to about 8 psi and then start to stutter misfire and try to stall
 
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