This car was towed into my shop not running, but has been running good for years. I found the cam sensor trigger wheel loose on the shaft. I lined up the wheel to the notch in the shaft and welded it, and then went through the GM manual set up procedure. The car spits and sputters, but will not run. I have spark and fuel, but it is not at the right time to run. Any ideas?
1987 GN no start has Big Stuff
- Thread starter DMS
- Start date
EightSecV6
MDBL
- Joined
- Jul 18, 2001
turbodave231
Moderator
- Joined
- May 24, 2001
I had this happen to me at BPG a few years ago. The cam sensor ate the little timing tab off the cup. I sheared the cam key and threw off the cam/crank timing enough to make the engine run really, really bad.
If you can't find any other cause, you might want to check this.
Dave
If you can't find any other cause, you might want to check this.
Dave
darkred87T
Active Member
- Joined
- Oct 27, 2003
The 25 degree mark has to After TDC but I don't remember if your mark should be to the left or right of the notch on the damper facing the engine. Here's a link but I'm not sure if it helps with that:
Cam Sensor Information
It was definitely on #1 TDC compression. I turned the crank to 25 degrees after TDC. The window of the trigger wheel was facing the power steering pump. I then installed the cap and adjusted it counter clockwise until the voltag dropped off. I repeated the entire install process a couple of times just to be sure.
darkred87T
Active Member
- Joined
- Oct 27, 2003
It sounds like you have the cam sensor installed correctly. My guess would be the module/coil pack like WSLN6 said or perhaps the crank sensor or ECM itself has failed. If it was MAF it would probably at least start up and run for a few seconds. Did it all of the sudden not start one day or was it intermittent?
My car did something like this recently where it acted like it was running out fuel and then suddenly died all together and I had to have it towed. It had 45psi at the fuel rail and good spark. I charged the battery and went back out later to start it and it would turn over and not start. I swapped the ECM with another one and it still wouldn't start. I let the battery charge overnight, went back out in the morning to try again and wallah! It kicked over and it's been running fine ever since. I'm not sure if the swapped ecm was the cure or not but maybe it's worth a try?
Keep us posted.
My car did something like this recently where it acted like it was running out fuel and then suddenly died all together and I had to have it towed. It had 45psi at the fuel rail and good spark. I charged the battery and went back out later to start it and it would turn over and not start. I swapped the ECM with another one and it still wouldn't start. I let the battery charge overnight, went back out in the morning to try again and wallah! It kicked over and it's been running fine ever since. I'm not sure if the swapped ecm was the cure or not but maybe it's worth a try?
Keep us posted.
I have also changed the crank sensor. The engine has a stand alone Big stuff system, so it is not that easy to just swap another ecm. The car started to run rough like it needed a tune up and then just quit one day while driving. That is when I got the car on the hook. It had sheared the alignment pin on the cam sensor off. The distributor gear was also worn badly.
darkred87T
Active Member
- Joined
- Oct 27, 2003
Can't hurt.
Is this the 560hp car? Does it have a new timing chain/gears? Sounds like the timing chain might have jumped the gears. If it was an original car I'd say the plastic cam gear teeth were broken. Why is the dist gear so worn? Hmm, why did the cam sensor pin shear? New cam sensors are available from Kirban, etc.
- Joined
- May 28, 2001
???
Cam sensor gear could be eaten up due to:
** billet cam gear incompatibility.
** aftermkt ft cover sensor bore off location.
** hi volume/hi psi oil pump.
I'd also be leaning toward the t/chain failure.
Cam sensor gear could be eaten up due to:
** billet cam gear incompatibility.
** aftermkt ft cover sensor bore off location.
** hi volume/hi psi oil pump.
I'd also be leaning toward the t/chain failure.
- Joined
- Feb 18, 2006
A good possibilty here. Reomove the cam sensor and inspect the gear.
Cruzbear
Member
- Joined
- Feb 10, 2006
This is the the 560hp at the rear wheels, Below are the modifications the car has.
All the help here is very much appreciated
• 3000 MILES ON THE MOTOR
• BOTH FRONT AND REAR ENDS WERE REMOVED AND REBUILT.
• ALL NEW AXEL SEALS - NEW ETON POSI-AXELS - ALL HELD TOGETHER WITH A BILLET DIFFERENTIAL GIRDLE
• DYNOED 563 HP TO THE REAR WHEELS @ 21LBS.
• PTE 72 (GTQ) TURBO W/.85 HOUSING, 83LBS INJECTORS,
• PTE FRONT MOUNT INTERCOOLER,
• ATR 3 INCH DOWN PIPE WITH ADJUSTABLE GATE,
• ATR HEADERS,
• BLOCK IS .30 OVER,
• FULLY PORTED IRON HEADS
• ESP RACE GRIND ROLLER CAM
• EAGLE CRANK
• STAGE CORRILLO RODS (STROKED)
• BIG STUFF COMPUTER
• T&D ROLLER TAPPETS
• ROSS 8.1 PISTONS
• FULL FLOATING PINS
• KENNE BELL INTAKE
• 70MM THROTTLE BODY
• RJC POWER PLATE
• TURBO 400 WITH BRAKE, REVERSE MANUAL
• ADJUSTABLE KONI SHOCKS
• ART CARR 9" 3800 NON-LU
• LINE LOCK
• EATON POSI
• DUAL AIR BAGS
• AEROMOTIVE FUEL SYSTEM
• 10MM WIRES
• 6-POINT CHROME-MOLY
All the help here is very much appreciated
• 3000 MILES ON THE MOTOR
• BOTH FRONT AND REAR ENDS WERE REMOVED AND REBUILT.
• ALL NEW AXEL SEALS - NEW ETON POSI-AXELS - ALL HELD TOGETHER WITH A BILLET DIFFERENTIAL GIRDLE
• DYNOED 563 HP TO THE REAR WHEELS @ 21LBS.
• PTE 72 (GTQ) TURBO W/.85 HOUSING, 83LBS INJECTORS,
• PTE FRONT MOUNT INTERCOOLER,
• ATR 3 INCH DOWN PIPE WITH ADJUSTABLE GATE,
• ATR HEADERS,
• BLOCK IS .30 OVER,
• FULLY PORTED IRON HEADS
• ESP RACE GRIND ROLLER CAM
• EAGLE CRANK
• STAGE CORRILLO RODS (STROKED)
• BIG STUFF COMPUTER
• T&D ROLLER TAPPETS
• ROSS 8.1 PISTONS
• FULL FLOATING PINS
• KENNE BELL INTAKE
• 70MM THROTTLE BODY
• RJC POWER PLATE
• TURBO 400 WITH BRAKE, REVERSE MANUAL
• ADJUSTABLE KONI SHOCKS
• ART CARR 9" 3800 NON-LU
• LINE LOCK
• EATON POSI
• DUAL AIR BAGS
• AEROMOTIVE FUEL SYSTEM
• 10MM WIRES
• 6-POINT CHROME-MOLY
Cruzbear
Member
- Joined
- Feb 10, 2006
I did get the car back from the shop still not running...it has been a little too cold to get into the car up here in Canada.
So I started again. I just replaced the Module and coil pack, picked it up from NOS4GN. It definitely required replacement when I took it apart the module was gooey inside. Rechecked the plugs and connection order to the module, ensured everything inside the mod was set up as per the instruction. Installed a new battery.
As it is attempting to turn over the engine bay gets a little smoky, as it turns over it seems to for a few revolutions then pauses dies and starts over.
Picked up the sensor cap from Caspers and will review the work on set-up there. Will put on today. Based on the information above do I really need to find TDC again or simply install?
With the module looking to be fried would it have messed up the timing?
So I started again. I just replaced the Module and coil pack, picked it up from NOS4GN. It definitely required replacement when I took it apart the module was gooey inside. Rechecked the plugs and connection order to the module, ensured everything inside the mod was set up as per the instruction. Installed a new battery.
As it is attempting to turn over the engine bay gets a little smoky, as it turns over it seems to for a few revolutions then pauses dies and starts over.
Picked up the sensor cap from Caspers and will review the work on set-up there. Will put on today. Based on the information above do I really need to find TDC again or simply install?
With the module looking to be fried would it have messed up the timing?
