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2003 gmc envoy_sle
1 Posts
Discussion Starter #1
This is the craziest issue....No crank, no start. I rebuilt the engine, re-installed. No Crank and no start.

I have tested all I have thought possible. Any new suggestions would be great.

Here is what was tested:

- New battery
- Manually triggered stater via ground signal on relay - Cranks
- Relay good
- starter good
- PCM replaced / same condition new or old PCM
- Via tech 2 - crank volt detected
- voltage tested to both relay points control circuit and starter enable
- Via tech 2 - park switch in proper position and detected
- all fuses 17, 22, 34, 24 checked and good

Car was cranked via manual trigger to starter, while in run position, still wouldn't fire.

PCM not sending ground signal to the relay control circuit.

All connectors to all sensors verified connected.

Anyone have any insight to this?

Many thanks!

2005 chevy trailblazer_lt_ext
7 Posts
Bad ground? PCM? No Crank!!

I have all of the same symptoms, :bonk: but mine is the same old engine, and this issue was periodic, erratic. I would sometimes get it to start on the 3rd time rotating the key. Other times, it was 10 or 15 times. Happened to me cold mainly, but sometimes (like yesterday) it happened while hot. Now, today, no amount of cranking helps.

Problem has been going on for half a year, but I always was able to eventually start it.

I also tried shorting across the correct pins where Relay 47 plugs in. I saw the same as the OP: engine cranks, but does not run. I have heard the fuel pump I believe, but I am not positive it runs. I suspect PCM, but here is are some tidbits:

  1. I had a bad air conditioner and discovered that a mouse had chewed the two wires on the passenger side where they plug into the A/C system.
  2. My fuel gauge no longer works. One day, after a fillup, it went erratic and now reads mostly random, but always 1/8 tank or down to E.
  3. The fuel pressure "gauge" reports 0 psi while hot and at idle, but it fluctuates. It recovers when I increase rpm.
  4. The tachometer didn't work for a few days last week!

Maybe someone has an idea where I might check for bad wires or bad ground(s)?
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