77south

Replacing EGR valve tomorrow and repairing small fuel line leak near filter. I will also get a better Fuel Pressure Gage to check pressure. Still starts like crap, stumbles along like crap, engine rocking due to improper ignition but still can't say why. Don't see or hear any vacuum leaks. Any ideas? Thanks in advance. Phil

Rednucleus

Have you double and triple checked that your plug wires are in the right order?

77south

Thanks for the suggestion, I'll check again. Trouble code still will not display and I don't see any code scan tools with their own display for less than $300 for 1995 Chevys. Everyone I ask says they never saw a vehicle that refused to display codes. Still working on EGR replacement and fuel line repair. Thanks again. Phil

77south

I made sure that the spark plug wires are in the correct order and I set the timing line at top-dead-center and checked that the rotor was pointed at the #1 spark plug terminal in the distributor cap. I'm picking up the new EGR valve today but I really don't think it will make a difference. After I repaired the fuel line drip near the fuel filter under the rear of the van it seemed to improve the situation a little. Now the engine will start and run poorly with the gas pedal floored but when it's running it will die if you give it any throttle too quick. I see Black Smoke out the tailpipe when I do give it some gas. It will sit and idle and I searched carefully for vacuum leaks but found none. All the wiring around the top of the engine looks healthy, nothing burned or damaged. Spark plugs are black and sooty. I unscrewed the IAC (idle air control) unit from the side of the carburetor and looked it over and my only option is to replace it too but the manual doesn't point to it as a problem. I'm planning to buy a more expensive Fuel Pressure tool since my cheap one won't get the job done. The trouble codes still refuse to display and some say that means the computer is bad but it's a brand new computer. I changed the oil since gas drained into it when I was cranking with no result weeks ago. I've replaced about everything and even had AutoZone check the new Ignition Module but I'm suspicious of the MAP Sensor since it is supposed to control air/fuel mix. Thanks for any help. Phil

Rednucleus

Maybe time to bite the bullet and spend the $$ with a competent mechanic vs continuing to throw parts at it?? (I hate doing that too but sometimes needed)

77south

Thanks again for your help. I was thinking the same thing yesterday BUT...I replaced the Engine Coolant Temperature Sensor and the problem is solved ! Two weeks of work and over $1000 spent and one little sensor was the problem. An expensive lesson but one I won't forget. The van is ready for the next 250,000 miles. Now I can get back to installing the TH350 in the 1972 Blazer so we can have some convertible fun. Thanks again to everyone. Phil

kevinkpk

It's never going to be an emissions issue with not running right. This is an obd1 system 95 and earlier. Jumper a-b on the diagnostic port, then count the times the check engine light flashes. That will tell you what dtc it is. This is for future, glad you got it running.

77south

Here is an update on the 1995 Chevy van. We drove about 300 miles, went camping with no problems at all but when we came home it wouldn't start but the same as earlier if I kept pedal floored it would start rough and stumble along like the fuel mix was way off. I unplugged the Engine Coolant Temperature Sensor and plugged it back in but no improvement. I disconnected the positive battery connection and then re-connected it and it started right up and ran fine. What is up with that? Thanks as always for any suggestions. Phil

77south

Here is the final summary six months after replacing the engine coolant temperature sensor on the top of the engine. The van runs great with no problems of any kind and I've used it all summer and fall and it is pushing almost 250,000 miles now. To anyone with starting problems on these type of Chevy Vans, replace that engine coolant temperature sensor before you spend a ton of cash like I did. I even went ahead and replaced the sensor on my 1991 van before it became a problem. Thanks again for the help. Phil