Hi All. Having the hardest time with my 84 GN. Car will absolutely not build boost without stumble and falling flat on its face. The setup is 42lb. Injectors, TT Chip, Delco CR43 gapped at .32, Walbro Pump Hotwired, 86 ECM, stock MAF (was working fine), all Powerlogger numbers look good. Pulled a spark plug and it was black with soot after less than 5 miles on them. The car was running fine with about 10 psi of boost, then I added the Walbro so I could turn up the boost. That when the problems started. I verified fuel pressure on my Bosch 237 (looks about 41, line on) and it looks good, even rose with the barely 3 psi of boost I am able to get, then that's when it bogs out. Switched ignition module and coil, checked for vacuum leaks (none), now gonna change plug wires because the may be bad. The shortest tested about 2.5-3K ohms and longers tested 1.5K? Any other suggestions? Please help!!!
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Car Won't Build Boost without Stumble
- Thread starter holmesboy
- Start date
Nope. No alky yet!alchy injection?
Hi again anyone who reads and can maybe offer any help!! Today, I verified fuel pressure, dead on 38 line on, 43 line off on Bosch 237. Taped FPG to windshield to monitor and pressure does rise smoothly up to the 3 or 4 psi of boost before bad stumble or stall (but car doesn't cut off), just no power and I have to let off throttle and ease back into. I have installed new plug wires, no change, uplugged cam sensor while running, no change, reset ECM, no change, tested all vac lines etc with carb cleaner, idle stayed the same. New I am posting two PL files on i tried to do a couple WOT pulls from a roll. While doing these pulls I noticed that I could kinda hear or feel air from turbo spool under the car dumping maybe? Again the last thing I did before this was install new Walbro FP, but it seems to be OK. I did notice that the MAF isn't near 255 ever. Please any suggestions would be greatly appreciated.
Attachments
Hotrodbuick
Member
- Joined
- Apr 17, 2012
There have been a few cars lately doing the same thing. Did you try running the car unplugging the cam sensor an driving it? Also posting a video helps out a lot.
Hotrodbuick
Member
- Joined
- Apr 17, 2012
Do you have a fuel pressure gauge you can see driving down the road or one mounted to the rail? Wonder if its losing fuel pressure or raising fuel pressure while driving. Have a wide band to watch air fuel?
Yes. Also stated above. Bosch 237 43 dead on with line off, 38ish line on at idle. Fuela was good and stready just crusing and also rises smoothly up to the 3psi of booast before the studdering starts. I did post pl and the MAF never goes above 115, even at WOT. Is that a problem?
- Joined
- Feb 18, 2006
Looks like it won't even rpm. That may be why the mass air #s not rising. Or is the rpm reading not accurate for some reason?
You should get the boost/map signal into the pl.
Do you have a log file when car is running ok?
RL
You should get the boost/map signal into the pl.
Do you have a log file when car is running ok?
RL
I do not have a PL file where it was running better. I thought the rpm reading was accurate. I do have a buffer from Dakota digital connected between the tach signal wire on the coil and a digital dash because it wouldn't show a reading before. Could that be the problem?
Hotrodbuick
Member
- Joined
- Apr 17, 2012
That's low, might not be supplying enough power to fuel pump. Should be 13 to 14 volts running.
The voltage stayed at about 11-12 for maybe 5-10 min while I drove around, still stumbling and ruuning very rich (black smoke from pipes) everytime I got into even 1 psi of boost. Then out of the blue the voltage jumped to 13.8-14? Tried WOT and it was a little better, but still stumbled pretty good and couldn't get above 5 psi of boost. Could the alt be bad and not be supplying enough power for the coil to fire the plugs properly. Also noticed that I absolutely cannot get above 2500 rpm. Any other suggestions? Thanks!
Hotrodbuick
Member
- Joined
- Apr 17, 2012
Ever figure out the problem?
Hotrodbuick
Member
- Joined
- Apr 17, 2012
My car was/is doing the same thing and I'm trying to figure it out. Right at 2400 2500 rpm it spits an sputters and won't go. I tried just about everything you have except changing ignition like u mentioned. I did change the chip in the car as a friend had a few laying around and it seemed to help the car but it was still there
Similar threads
- Replies
- 16
- Views
- 2K
- Replies
- 17
- Views
- 2K
