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95 Z28 LT1 will start and die continuously for 20 times then idle and then once shut off will do the same thing. It has a new fuel pump, fuel filter, fuel pressure regulator, idle air control valve, opti spark harness plug, ignition control module and ignition coil. I’m lost at this point, fuel pump was bad when I got vehicle hints why it was replaced. But I can’t seem to find out why it won’t just idle. Please help, I just tested the injectors and they are all reading a resistance of 10.2-10.5 ohms. After Closer Inspection my wires are cut in multiple spots, exposed wires etc. Could this be my issue?
Is this a problem on a car you just bought, and has never started correctly? Or is it a problem that just developed on a vehicle that has started and operated normally previously?
Have you checked the fuel pressure? What is the pressure when the pump primes for 2 seconds and shuts off? Should be at least 40 PSI. How fast does the pressure drop after the pump shuts off. Shouldn't drop more than a few PSI in 5-10 minutes.
Have you scanned for codes?
The minimum acceptable resistance for the injectors is 11.6 ohms. GM considers them "faulty" below that resistance, and recommends replacement. Would be odd for all 8 injectors to read that low, unless they are not the correct injectors. Or maybe your meter is inaccurate?.
The single gray wire near the PCM, with the black connector is the fuel pump prime connector. Normally not connected to anything. Only used to test the fuel pump operation. Make sure it isn't shorting to ground by taping it up.
The rest of the wires are virtually impossible to identify without knowing the exact location. And even then there can be multiple wires of the same color in large bundles. The nylon tie that appears to be holding a bunch of wires to an A/C line is not stock, so impossible to identify the wires.
Stock 95 engine wiring harness (courtesy of Shoebox):
Thanks for the reply so I bought the car like this and the previous owner had the same issue and couldn’t fix it. He did say the fuel injectors were replaced so maybe he did the wrong ones. And I have not had a chance to do the fuel pressure test yet. Where would I go to find the right fuel injectors? For a good reliable part, non ebay. no codes
You want 24 #/HR injectors, GM Multec or Bosch 3. Do not buy the cheap (less than $100 per set) Chinese “Bosch style” counterfeit injectors on eBay or Amazon. They are junk.
I replaced the injectors and the pcm and now it starts up everytime. Although my engine is over heating and I don’t know why. It has a new radiator, thermostat, coolant and a water pump. And my temperature sensor on the drivers side head keeps melting. What can I do to figure this out.
What temperature thermostat? Is it the correct t’stat required by the LT1? You can’t use the standard t’stat for a small block Chevy, but many parts store personnel don’t know that.
When does it overheat - at idle, at moderate driving speeds, at freeway speeds, all of the above?
Are the radiator fans working? Both fans should turn on at low speed when A/C is working, or when coolant temp reaches 226°F. Both fans should switch to high speed when the coolant temp reaches 235°F. Some people add a manual switch to operate the fans, and that may explain some of the cut/damaged wires, if the switch was removed.
Are you using the dash gauge to determine the temperature? Is it in the red? The PCM gets the coolant temp from a sensor in the water pump housing. That is the reading used to determine when to operate the fans. If air is not removed from the coolant, it’s possible for the sensor in the driver side head to not be immersed in coolant and read higher than the sensor in the water pump. To get an accurate reading on coolant temperature, it can be read from the PCM using an OBD-1 scan tool.
As far as melting the sensor (first time I've heard that one in the 25 years I've been helping on this site) does the engine have headers? Does the sensor look like this?
