Wild, Scary Ride......

[Joel Russo]

Alright Steve and gang, put your thinking caps on...
 
Temps were in the mid 60*'s yesterday, so I parked the John Deere and hopped in the GN.  Got out on my favorite stretch of highway and cut her loose.  And that's where it got ugly!
 
I stabbed it to the floor and boost went to 19lbs, I glanced at the Scanmaster at the top of third gear and it read 800 w/2.5* kr.  Thought life was good.. I lifted and nothing.... boost stayed at 19 lbs with my foot off the accellerator.  Life was not good..  0ver 100 mph and the pucker factor building.  I was belted in to a run away GN.  First reaction was to hit the brakes, which only locked the fronts and created major tire smoke.  Second reaction was to stab the pedal trying to get it to release, no go.  Passing other cars like they were standing still and keeping a lookout of where I could crash this thing and not kill anyone but myself...  Kept trying to kick down the pedal and then threw it in neutral to get it out of gear.  Somehow it shut off, and I coasted to a safe place off the road.  After I changed my shorts , I tried to start it to get it off the shoulder.  It started normal and drove normal for about 100 yards.  I got out and took a look under the hood.  Could not see anything out of place. 
WTF I thought.  So I sat there for a bit to clear my head, then turned it around to head back home.  I drove for a few miles at 45-50 mph while monitoring oil pressure and listening for anything suspect.  Oil pressure was 40 lbs plus, and no audible noises.  I figured it had something to do with boost, so to prove myself right, I put some boost back in and it came un-glued again.  Same ordeal, foot off the pedal and it maintained boost.  Runaway GN again.  Tried the same sequence as before and it "un-boosted", but did not shut off. 
That's it, I thought, and milked it home with no boost and put it in the garage.  Went inside and poured my a Crown straight up to calm my nerves.  I'm getting too old for this shit.
To help you diagnose this problem, I'll tell you what recent mods I made.  A few miles before this incident, I did a few healthy burnouts without issue.
New Walbro 255 with Hotwire kit and in tank wiring.
New RJC 3" DP utilizing stock wastegate accumulator.
New Accufab fuel pressure regulator put on the same day this happened.     
 
This is an '87 GN with 13K on the clock.
 
Your expertise please, because common sense and reason will keep me from driving it.
 
 
 
     

[Steve Wood]

should we assume the gas pedal was stuck to the floor?  One of mine used to some how get stuck in the floor mat and I would have to kick it to make it pop back up

[Joel Russo]

should we assume the gas pedal was stuck to the floor?  One of mine used to some how get stuck in the floor mat and I would have to kick it to make it pop back up

I wish it was that easy Steve, but the floor mat does not interfere with the pedal.  I can post a pic of it to confirm if you like.

[PacecarTA]

i know in a panic you can loose sight of whats easy


sliding to neutral may save your life but you could grenade the engine and still be going warp speed only with oil on the wheels

easy is turn off the ignition key back enough to kill the ignition but keep the steering wheel free


i had it happen to a buddy at the track but he managed to get it to drop back
 wasn't the floor mat,
checked and everything seemed normal
not wanting a repeat ,  replaced the TB (stocker) and throttle cable
as i recall it was the cable that had a broken strand inside the casing

check the throttle cable also check the area above the pedal for any wires that may have been added to the car through the speedometer grommet that may have caught the top end of the accelerator rod

[Joel Russo]

Turn the key off.... what a brilliant idea.  Wish I'de thought of that when I was in panic mode.  Thanks for the tip.
Looking at it when I got it home, I initially thought it had something to do with the throttle cable.  Couldn't find anything wrong with the exterior, but didn't think about the interior of it. 
How do I check the inside of it? 
 
 

[Joel Russo]

Forget I even asked... Call me a horse's ass, please.
 
I just found the problem.  I run a VDO fuel pressure gauge off the fuel rail, and apparently when I replaced my old fp regulator with the Accufab, I did'nt have the gauge positioned properly, and the metal piece that the throttle cable is connected to hit it.  When I pushed the pedal to the floor, there was enough force to push it past the gauge, and lodge it there.  It held the throttle open.  It would not go past unless you really forced it.  That explains why I was able to do a few part throttle burnouts without incident. 
 
     

[Steve Wood]

LOL

I knew those rail mounted gauges were useless but I did not know they were dangerous!

Glad it was an easy fix and you don't need a new cable yet

[Joel Russo]

I need new front tires because they have major flat spots.LOL
 
I'm happy to buy them as this really could have been ugly.

[TURBOPOWERED68]

1-that sucks dude good luck fixing it.
2-You did what again?? why not check while parked on the side of the road???
3-Good job getting it fixed.

[Steve Wood]

It happened to me once when the pedal got hung up....was on a freeway and had punched it because the guy next lane over wanted to race...turned the key off and then the powermaster brakes and steering got really hard but better than the alternative...

[Joel Russo]

It happened to me once when the pedal got hung up....was on a freeway and had punched it because the guy next lane over wanted to race...turned the key off and then the powermaster brakes and steering got really hard but better than the alternative...

Ahh yes, turn the key off.. What a brilliant F-ing idea..  Too bad I didn't hink of that under pressure..  Pacecar TA was friendly when he said "i know in a panic you can loose sight of whats easy"

[motorhead]

Looks like something I would do.

[PacecarTA]

 oh and

WTF is with the rue goldberg throttle bracket contraption 

looks like aftermarket cruise control  which is kinda stupid since the factory parts to do cruise arent too hard to come by

[Joel Russo]

oh and

WTF is with the rue goldberg throttle bracket contraption 

looks like aftermarket cruise control  which is kinda stupid since the factory parts to do cruise arent too hard to come by

This car has a NOS kit installed back in the late 80's, and all that came with the system.  Never filled the bottle, but I kept it on the car.   Went for the Kool factor..
The cruise control is all factory.


Me rethinking keeping that shit on the throttle bracket...    Going to clean it up a bit.

[motorhead]

Yeah, you should use the nitrous.