1985 Stalling out at speed.
Thread Starter
Instructor
Joined: Feb 2014
Posts: 145
Likes: 5
From: Dunkirk Md
1985 Stalling out at speed.
I have a 1985 corvette stock, engine stalls at speed.
NO codes
Fuel pressure =41lbs
New Cap
New coil
New electronic module in distributer
New set of injectors from FSI
New Plugs
New wires
New O2 sensor
New connectors on injectors
removed Cold start injector
All new sensors and connectors
New EGR
New Throd Body
No vacume leaks
Removed air pump and pipes off exhaust manifold
New Cat and exaust system
The below was before changing the parts above
The way the C4 acts you will be doing around 55mph. All of a sudden the eng starts to loose power. I give it some gas and pops and stalls. I pull over to side of road and try to start. Its starts when I try to depress the gas pedal the engine pops through Throd body if I get the eng to rev up it will clear ove a few min. get up to speed and will run perfect and then stall again and I pull onerpull over.
New fuel pump and sender assy
NO codes
Fuel pressure =41lbs
New Cap
New coil
New electronic module in distributer
New set of injectors from FSI
New Plugs
New wires
New O2 sensor
New connectors on injectors
removed Cold start injector
All new sensors and connectors
New EGR
New Throd Body
No vacume leaks
Removed air pump and pipes off exhaust manifold
New Cat and exaust system
The below was before changing the parts above
The way the C4 acts you will be doing around 55mph. All of a sudden the eng starts to loose power. I give it some gas and pops and stalls. I pull over to side of road and try to start. Its starts when I try to depress the gas pedal the engine pops through Throd body if I get the eng to rev up it will clear ove a few min. get up to speed and will run perfect and then stall again and I pull onerpull over.
New fuel pump and sender assy
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
How does tach act? Pick up coil/ pole piece could be on it's way out. It won't set code. A scanner with a multi frame snap shot function. Data logger in a graph form may show sensor dropping out indicating where to look. 85 also has a unique MAF module, I am not familiar with it just it is there,
Thread Starter
Instructor
Joined: Feb 2014
Posts: 145
Likes: 5
From: Dunkirk Md
Tack seems to be ok. When increase the rpms the Tack works fine. The Pick up coil/ pole piece is the only thing I have not changed. It seems when I pull over it wants to stall. If I keep pumping the gas and attempt to rev it up it will clear for a little while and go down the road and acts up again. What gets me no codes I have the db1 interface cable and the free program and all looks normal.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
There is no code for pick up coil. Ecm thinks engine is turned off both spark and injectors quit. So you might see injector pulse ms 0 during event. MAF g/s lagging behind TPS. Codes have certain values that are met to set, but there can be soft failure that doesn't quite hit threshold to set code. Graph sometimes will show wave irregularities that numbers don't. You have replaced alot of parts codes or this problem?
Thread Starter
Instructor
Joined: Feb 2014
Posts: 145
Likes: 5
From: Dunkirk Md
Yes I had changed TPS for error code Voltage too high
IAC when not Idle smooth.
Fuel Reg, pressure was dropping to zero when ING turned off.
This Problem happened before changing parts, it was part of troubleshooting
IAC when not Idle smooth.
Fuel Reg, pressure was dropping to zero when ING turned off.
This Problem happened before changing parts, it was part of troubleshooting
Last edited by agillings; Apr 15, 2019 at 09:29 AM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
I would try to data logs looking for a drop out. I would also check for wear of distributor shaft and bushings - wobble ,oil in housing, and condition of pick up coil wires - a gentle tug and no cracks in insulation.
