Car seems to stall at WOT

[Hedge]

I have had my 87 GN for about a year. I just had the tranny rebuilt which works great but now that I can floor the gas pedal I am noticing another problem. The car seems to run fine until about 4k rpm then it seems to hit a brick wall. The RPMs don't climb and the car will not shift into 2nd. When I let out of the gas about 25% the RPMs climb a little and it shifts into 2nd. Then the same scenario repeats itself for 3rd gear. It sounds like the car is trying to go but it is not actually going anywhere. So far I have replaced the plugs, wires, air filter, and fuel filter. Any ideas on what I migth replace next? I can't tell how much boost the car is running because the stock boost gauge maxes. However the problem starts to occur at about 11 - 12 psi on average. Thanks for your suggestions.

 

[Paul Clark]

It might be a tranny problem/adjustment, but it's also possible that you are getting knock. It could be retarding the timing enough that you don't have enough "oomph" to make the shift.
Do you have a scan tool of some kind?

 

[mikestertwo]

Need more info. How many miles on the car? What mods if any? Could be valve springs if it's a high mileage car.

I have had my 87 GN for about a year. I just had the tranny rebuilt which works great but now that I can floor the gas pedal I am noticing another problem. The car seems to run fine until about 4k rpm then it seems to hit a brick wall. The RPMs don't climb and the car will not shift into 2nd. When I let out of the gas about 25% the RPMs climb a little and it shifts into 2nd. Then the same scenario repeats itself for 3rd gear. It sounds like the car is trying to go but it is not actually going anywhere. So far I have replaced the plugs, wires, air filter, and fuel filter. Any ideas on what I migth replace next? I can't tell how much boost the car is running because the stock boost gauge maxes. However the problem starts to occur at about 11 - 12 psi on average. Thanks for your suggestions.

 

[Hedge]

More Info

Car has 85k miles on it. My friend with a GN has a scan tool and when we tried to hook it up we got no power through the cigarette lighter. That's another issue though. I ordered this week two sets of gauge holders and will be ordering the boost, knock, water, and oil gauges for it soon. Sometimes I do hear a spark knock and when I do I let out of the gas but sometimes I do not hear one when it does this. No mods car is bone stock cept for the tranny rebuild. I have had two other guys with GNs drive it and they seem to think the tranny shifts fine that the problem is elsewhere. Let me know if you need any more info. Also any ideas on the cigarette lighter issue? I don't see a fuse for it and when I pulled it out is was hooked up to the orange wire. Not sure where to look next.

 

[MY3TTYPES]

Car has 85k miles on it. My friend with a GN has a scan tool and when we tried to hook it up we got no power through the cigarette lighter. That's another issue though. I ordered this week two sets of gauge holders and will be ordering the boost, knock, water, and oil gauges for it soon. Sometimes I do hear a spark knock and when I do I let out of the gas but sometimes I do not hear one when it does this. No mods car is bone stock cept for the tranny rebuild. I have had two other guys with GNs drive it and they seem to think the tranny shifts fine that the problem is elsewhere. Let me know if you need any more info. Also any ideas on the cigarette lighter issue? I don't see a fuse for it and when I pulled it out is was hooked up to the orange wire. Not sure where to look next.

I think the lighter fuse (on fuse block) is also the interior light fuse. 20 amp.

 

[fitz3820]

Get a scan tool and boost gauge ASAP!

Your wallet and your motor will be thankful. Knock is REALLY bad in a turbo car and beats the heck out of the motor.

Keep reading as much as you can, everyone here will help you once you get back to us with scan tool numbers.

 

[Hedge]

Scan tool recommendations? Leaning towards Turbo Link so far. I have XP laptop. DirectScan doesn't use the newer operation systems from what I have seen. I'm open to recommendations though.

 

[fitz3820]

I have both the scanmaster and turbolink.

Scanmaster is my favorite as you do not have to mess with a laptop and it is always on and there for you.

The laptop based scan tools may tell you more troubleshooting wise but are a pain to use daily.