I've been running into some issues with my car and it eventually the led me to the optispark. The car's been idling low, getting bad gas mileage, rough start, backfire sometimes, and now not wanting to shift. I changed the opti with a remanufactured GM opti from Rockauto and the car ran worse. I also spliced in a new connector to the opti but double checked it and the spark plug wires and everything seems to check out good. Tried taking the opti out and putting it back in and nothing changed. I then proceeded with another opti I bought from summit. This time I started the vehicle without the water pump attached (all sensors plugged in though) and it seems to start up much quicker and reaches normal idle but it only stays running for 1 or 2 seconds after. Is it possible the car wouldn't stay running with the water pump off? I know it normally should. The car is tuned and cammed so don't know if that makes a difference. I doubt i have 2 bad optis but I dont want to put the water pump back on only to find out the car won't run. Should i try the icm and ignition coil?

 

Also if I have the key in the on position a lot of the time the fuel pump will reengage 3 or 4 times in a row. I'm not sure if that means any thing.

 

Well I attempted starting the car with the original opti installed and waterpump off and it still doesn't run. I did notice that the fuel pump doesnt keep repriming itself though like before which is strange. Anyhow, im going to put the opti from summit on and put everything back together and see what happens. If im still having issues ill go ahead and try the icm, coil and wire. I'm open to any advice and suggestions.

 

Hook up your air intake including the MAF and see if it stays running. I know it should with it off, but some don't like to.

 

I put everything together and ran the car. It still doesn't want to shift out of first gear and the speedometer isn't working I'm guessing that's the VSS which I'll be changing today. The idling is also still off. Idle gets up to normal idle faster but I notice misfires sometimes. The idle goes way down with A/C on as well. Is this possibly the ICM? I've had this problem for a while and changed so many other parts already.

 

Something sounds seriously wrong here if the trans isn't wanting to shift out of 1st. Is there enough trans fluid? Do you have a Cable to data log what the car is doing? When I had a issue with my T/A I bought a ALDL Cable and asked some people on here for help. It's better than just throwing parts at a car anyway.
[never mind the VSS controls shift points so i would assume it controls the speedometer as well ]

 

Yeah it was shifting fine before and then all of a sudden it would have a really tough time shifting out of first while the speedometer would kick in and out. And now the speedometer doesn't work at all unless I unplug the ecm fuse and then it sometimes works for a little bit shifting normal and then goes out of wack again. I'm assuming the VSS and now I'm trying to figure out this idle issue I've been dealing with forever.