help with chevy truck
 

I have a very nice 1995 tahoe and I started having problems upon acceleration. I changed plugs, wires, rotor and cap also fuel filter, no help. the local garage said o2 sensor, no helpI changed fuel pump, fuel reg in TB and TPS sensor, still no help, egr valve and spark controller in distributor. no help, today i changed timing gears and chain, started up but when I went to unplug wire to set timing the engine stops . I 'm lost can anyone help?

Re: help with chevy truck
 

Jim, check the shaft in the distributor for weak magnets. To do that just hook up your timing light, unplug that tan wire, and fire it up. Someone may have to sit inside and keep it runing for you. At idle the timing should be at Zero (TDC), rev it up to 2500 RPM. By 2500 the timing should jump up ten degrees. Won't be gradual, it will jump. If it does not advance, or even retards slightly, you need a new shaft in the dist. Don't go to Autozone,O'Reiley's, etc, for a reman distributor. Go to the GM dealer to buy a shaft, and pray it is still available. I used to keep three or four of those things on the shelf. Also causes stalling at idle when shifted into Drive, or Reverse. Most did it worse going into Reverse, but don't ask me why. Watch the dimple in the gear, it is supposed to align with the rotor blade. Knock the pin out, pull the gear, turn the distributor upside down and spray Berryman's Chemtool B12 down inside the housing, around the shaft. Let it sit a while and the shaft should slide out. Going to make a mess, so don't do it anyplace clean. Knock the shaft out and you will usually break the distributor housing.
Good luck, Ed

Re: help with chevy truck
 

Jim-One thing ya might see with the magnets on the dist. shaft if ya look close ya could see cracks-they can disrupt the signal trying to be generated and can cause a couple different things to happen.While you're there maybe change the pickup coil.Lotsa reman motor guys won't warrantee their stuff if ya don't change that dist. shaft 'cause it can make for real weird timing fluctuations and raising hell in the cylinder.

Re: help with chevy truck
 

Ed , when I unplug the tan wire , the engine stops.

Re: help with chevy truck
 

Doug , I will check for cracks

Re: help with chevy truck
 

Check the timing with it hooked up. Should be some where around 14 to 20 depending on calibration. If not unplug knock sensor. I've chased my tail so much because of a bad knock sensor shorted out. Does it have a lot of miles?

Re: help with chevy truck
 

Jamie, yes very high miles, whatever it is keeps getting worse, it started perfect after timing chain installed, ran about 15 sec and wont start . then it was starting but when I went to set timing it quits when tan wire is unplugged. is knock sensor tied into this system? Almost ready to put HEI and intake with a holley.( not sure if that will affect anything else

Re: help with chevy truck
 

They usually stop when the tan wire is unplugged because the timing is too slow. A second person working the throttle can usually keep it running in that case.
Hope by Holley you don't mean you put a Holley throttle body on it. :-(

Re: help with chevy truck
 

try unpluging your mass air flow sensor

Re: help with chevy truck
 

They don't have one.