Power to fuel pump cutting out
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Junior Member
Joined: Jun 2024
Posts: 10
From: SE Wisconsin
No, it did NOT run or have spark after I replaced the CKP with an AC Delco sensor and replaced the connector using solder/heat shrink connectors. After the no start, I disconnected the battery, removed the 80 pin connector to the PCM and checked for continuity between the CKP connector and the 80 pin connector. I found the 2 pins by trying them one at a time. The resistance between the connector and the pin was 0.1 Ohms at each of them which is probably due to the jumper wire and alligator clips.
After I reconnected everything, I tried it again and it started. I went inside to tell my daughter figuring I must have reset the computer by disconnecting the battery. By the time I came out, it was not running. It started right back up and ran normal for about a minute and then died again. Then it wouldn’t restart and I checked and again, NO spark. BTW I confirmed my spark test or works on another vehicle.
I disconnected the battery again for a few minutes but this time there was no change when I reconnected everything.
This morning I checked the resistance of the CKP at the PCM connector 924 ohms and then to jumped to 1124 as I turned the engine manually at the crankshaft pulley.
The PCM is definitely cutting off the spark and fuel but am I really throwing another CKP at it???
As far as other things I may have bumped, there is a single wire sensor and the oil pressure sensor in close proximity but I was careful around those and with the wiring harness.
After I reconnected everything, I tried it again and it started. I went inside to tell my daughter figuring I must have reset the computer by disconnecting the battery. By the time I came out, it was not running. It started right back up and ran normal for about a minute and then died again. Then it wouldn’t restart and I checked and again, NO spark. BTW I confirmed my spark test or works on another vehicle.
I disconnected the battery again for a few minutes but this time there was no change when I reconnected everything.
This morning I checked the resistance of the CKP at the PCM connector 924 ohms and then to jumped to 1124 as I turned the engine manually at the crankshaft pulley.
The PCM is definitely cutting off the spark and fuel but am I really throwing another CKP at it???
As far as other things I may have bumped, there is a single wire sensor and the oil pressure sensor in close proximity but I was careful around those and with the wiring harness.
OK, so you replaced the crank sensor, it worked.
Then it stopped working.
Replaced it again and the pigtail.
1 new sensor
2 new wire connections
Did you use butt splice connectors?
Did you solder and shrink wrap?
If you increase the resistance of that circuit enough, the voltage level at the PCM may be too low for the PCM's liking which is equivalent to no CKP signal detected.
Same issue with the ECTS circuit. When cold, only about 2500 ohms. when approaching overheating, 300 ohms. Corrosion on the connectors or a partial nick in the wires can be the difference between correct and incorrect info derived by the PCM.
What is the resistance measured between
the 2 CKP pins with the pigtail connected?
the 2 CKP pins with the pigtail disconnected?
Also, what else did you touch/knock into/lean on when you replaced the CKP the first time? Move a wiring harness?, etc.?
I'm not accusing you of anything. Merely pointing out that sometimes we disrupt things that are actually part of the problem without realizing it until much later.
Do you smell fuel in the cyls after a crank session? Can't remember.
Then it stopped working.
Replaced it again and the pigtail.
1 new sensor
2 new wire connections
Did you use butt splice connectors?
Did you solder and shrink wrap?
If you increase the resistance of that circuit enough, the voltage level at the PCM may be too low for the PCM's liking which is equivalent to no CKP signal detected.
Same issue with the ECTS circuit. When cold, only about 2500 ohms. when approaching overheating, 300 ohms. Corrosion on the connectors or a partial nick in the wires can be the difference between correct and incorrect info derived by the PCM.
What is the resistance measured between
the 2 CKP pins with the pigtail connected?
the 2 CKP pins with the pigtail disconnected?
Also, what else did you touch/knock into/lean on when you replaced the CKP the first time? Move a wiring harness?, etc.?
I'm not accusing you of anything. Merely pointing out that sometimes we disrupt things that are actually part of the problem without realizing it until much later.
Do you smell fuel in the cyls after a crank session? Can't remember.
Senior Member
Joined: Jul 2011
Posts: 5,544
From: Anniston, AL
I'm not a mechanic, but it sounds to me like you should the fit on the 80 pin connector. Sometimes after years of being fine, the female connector piece can become slightly loose on the male connector. It doesn't take much for it to start causing problems. I wouldn't check all 80 of them to begin with, just the ones that go to the CKP.
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