Crank But No Start
- Thread starter Sputter
- Start date
So here’s my question: the continuity of each wire I test is .2 ohms or lower. So if the wiring and grounds are good and I have 12.84 volts at pin A15, what is keeping the 12.84 volts from reaching the coil and (presumably) the fuel injectors?
Your losing your ground somewhere. Put your DVOM ground test lead at G105 instead of at the battery and perform the test again.
Well you’re right. I got 0 volts when I tested voltage a15 to g105. Went back to a15 and the negative terminal and it was zero! Ok so now what?
Check the continuity of the G105 wires. There’s a bad connection or broken wire somewhere. Pull up your grounds diagram and perform the appropriate continuity tests. You can begin with pins 31 & 32 at PCM connector C1 to G105.
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I checked, cleaned and retightened the grounds. Still no joy with starting. Not enough voltage going to the coil connector. Going to pause on the electrical stuff for now. Got a lead on some used harness at a pick and pull down in Daytona so headed there next weekend to see if they have what I need.
Your missing a ground. You should have two grounds from the negative side of the battery. Unfortunately there’s no diagram in the FSM. Take a look at these pictures and see if they help.
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Agreed with Daryl. You measured 12v when you used the battery negative as your ground but when you used the block as your ground you didn't measure voltage. This means the block isn't grounded to the battery. So anything that uses the block for the ground path to the battery won't have ground.
I understand what you guys are saying. I traced out the ground wires from the battery. One goes to the firewall behind the engine. The other (g105) goes to the engine block on the drivers side. I cleaned and tightened them. Continuity is .02. 12.29 volts from a15 to g101 and a15 to g105. I think I am good here.
Well my lead on the wiring harness fell through. Was doing more research and came across this site (see picture). Question: I had previously swapped out the transmission solenoid but did not get the parking sprag back in right so it doesn’t hold in park. Could this be a problem? I’m pretty sure I was able to start it after that repair...
The part you have circled in red is just the neutral safety switch. That prevents the engine from cranking over in gear. If your engine cranks over, that’s not it.
Thanks for the quick reply. When I get back from vacation I’m going to start from the top. I think I’ve got a lot of things ruled out but I need to start with a clean slate with the multi meter and wiring. Got a spare CPS from the PO so I might swap that out too.
Started from the top. Getting low voltage coming from ASD relay to pins 12 and 3 on C3 connector. Seemed to fluctuate with connector movement. So I suspected a bad connector. I took it apart. The actual wires passed continuity tests. A closer examination looks like the pins don’t lock in place which would explain the flaky power gremlins. So I think I will replace the c3 connector - maybe the others. New connectors cost about $300. Any one have thoughts on repairing these or buying used?
Just to close this out - I bought some Jeep Liberty connectors and replaced them but still no start. I replaced the CPS and the ignition switch but no start. Retraced my steps with the wiring diagram and everything looked in spec.
I decided to send the PCM off to be checked out again. Talked to the technician from SoloPCM and he was able to find the motherboard was bad. He swapped me out with a new motherboard, added back my memory module and programmed the unit to my vin. Got it back today and it started right up.
Thanks to @Daryl who stuck with me through the electrical troubleshooting. I learned a lot!
I decided to send the PCM off to be checked out again. Talked to the technician from SoloPCM and he was able to find the motherboard was bad. He swapped me out with a new motherboard, added back my memory module and programmed the unit to my vin. Got it back today and it started right up.
Thanks to @Daryl who stuck with me through the electrical troubleshooting. I learned a lot!
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