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Cruise KR, and a lot of it.

Just replaced the relay, and still no start. Im completely lost.

I jump the relay and I can hear the fuel system prime and continuously run.
 


Then there is another relay that turns it on. It seems to me that in the NC position the relay runs full speed, in the NO position it runs through the resistor. Either way would have power to the pump, so there must be another relay that sends power to the hi/Lo relay.

Jeff
 
I did that. Still nothing.

- Installed new relay, crank no start
- Bent tab out on Fuel Pump Speed Relay, crank no start.
- Jump fuel pump relay #14, Can hear fuel system turn on and run. Installed relay with jumper too and fuel system running, crank no start.
 
Relay 14 is your problem then either it isn't turning on or the contacts are bad. If it isn't turning on we recently had a guy with loose contacts in the panel. Just a thought.
 
I did just buy a brand new Relay and replaced it. Still nothing.

I only get the fuel system to turn on when I jump relay #14 with a wire.

Now I'm thinking the PCM isn't commanding the relay to open when the key is turned on.
 


Check the coil connections with your meter and 2 small pieces of wire. Hopefully you have a second hand or a good meter with a peak/hold or record function.

Jeff
 
EDIT: the one for 86 should have power on it when the ignition is turned on(+12V) the 85 is going to be the signal wire from the PCM. PCM's always switch on a device using a negative signal. The reason why is you can't induce a ground and inputs always float high when disconnected. But that's another class.
 
I think it could be the theft deterrent code. Did you get the scanner to work?

P1626 Chevrolet Description
The body control module (BCM) produces the theft deterrent fuel enable signal when ignition is ON and the proper key resistor pellet is sensed. The powertrain control module (PCM) monitors the fuel enable signal during crank. If the proper signal is present on the theft deterrent fuel enable circuit, the PCM enables fuel delivery to allow the engine to start. If the PCM detects that the fuel enable signal is not present or incorrect while the engine is running, DTC P1626 will be set. DTC P1626 can cause a no-start condition or normal operation depending on when the loss of the fuel enable signal was detected. The engine will continue to start and run if the condition that set DTC P1626 occurred after the BCM sensed the proper key resistor pellet and signaled the PCM to continue fuel delivery. The engine will start and immediately stall if the condition that set DTC P1626 occurred before the BCM sensed the proper key resistor pellet. With this condition present, the PCM will inhibit fuel delivery and the BCM will disable the starter.

Like I said I get this code every time I flash the pcm. First thing I do is clear it before starting.
 
FIXED IT.

Before I called it quits for the day, I checked every single fuse in the fuse block. Found the ECM fuse was blown. (Must have been from disconnecting the PCM without disconnecting the battery).

Never thought to check that fuse, as everything worked like it should, besides the fuel system.

Anyways, replaced the fuse and car runs. ZZP PCM is in now, and we are back to where I left off. Time to do some scanning with the other PCM installed and see what readings I get.
 


Cool! Just remember next time you can always tell a blown fuse if you don't have power on 86 when you should, like having the key on and such.

Jeff
 
Lesson learned the hard way.

Did some driving, car was still seeing upwards of 14.9* of cruise KR. My next decision, is to pull the trigger on two knock sensors now. Roughly $80 for them both, kinda expensive, but I'd assume that's the next step here.
 


Time to pull the trigger this week.

$46 a sensor from Autozone and I'll buy them both. Expensive, but gotta get this fixed.
 
J57ltr said:
Ill send you pics of how I did it if you like. Just PM me


Jerf
Click to expand...

The front looks self explanatory and easily accessible with a larger deep well socket.

I'm unsure on the back since a socket won't be able to fit getting to it, when looking directly up at it, so I'd like to know how you did it. You have a PM sir.
 
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