New Engine - No Crank How to tell if it's the Computer?

[JeepJerk]

So I spent months building a stroker for my '98 TJ. Got it in, hooked everything up- won't turn over. When I was pulling the motor I forgot to disconnect the battery (duh) and grounded something out that melted the fusible link. I replaced that and have tried the following:

Checked every connection
Checked grounds
Jumped 'S' terminal to power (it turns over, no spark with ignition on)
Attempted to diagnose with OBDII tool- will not connect to ECU

I have a feeling that I fried the computer. When I turn the key on the fuel pump runs, which I don't think it should unless the engine is cranking or running.

How can I tell? If it's bad can I get a recommendation on where to get a replacement? I don't want to wait a long time. There are lots of places online that you can send the ECU to, they repair it and send it back. I hate to do that if I'm not sure that's the problem.

Thanks!!!

 

[User Namespec25440@mypack]

I doubt it is the PCM, thats way down on list.
Does the CEL come on @ 3seconds every start?


1998 wrangler Auto or manual trans?

 

[JeepJerk]

I don't see the CEL come on at all- it won't crank, so it won't start.

It's a manual trans.

I happened to have a computer out of a 2000 Grand Cherokee, threw that in there to see what would happen. Same thing...no crank, fuel pump running with key on. Lights come on, everything else works. It's for an auto trans so maybe there's something in there that's supposed to sync up with the neutral safety switch but I'm not sure about that.

 

[JPNinPA]

Check ARES technologies for PCM and help.

Any codes?

Fuel pump turns on for 5 sec when key is turned on. That is normal.

Cranksensor. Ckp

Grounds?

Be sure all sensors are oem as many fail out of box.



Never look down on anyone unless you are helping them up - Jesse Jackson

 

[JeepJerk]

So here's my latest- I jumped the BR/LB wire to ground (terminal 13 from the starter relay in the PDC), according to the wiring diagrams it splices with the PCM and goes to ground. I've been unable to trace it all the way down but if there's a break between it and the PCM then the PCM isn't grounded like it's supposed to be and maybe that's the source of the whole problem.

With the jumper to ground the starter will now get power to the solenoid and turn over. However, I do not have spark and the PCM will not communicate with my code scanner, and the fuel pump runs continuously. I also noticed that some of my gauges don't seem to be working, such as the fuel gauge.

Any ideas on tracing this down?

 

[JeepJerk]

Also, the CEL never comes on. I believe it would normally come on when the key is turned to the 'on' position and then go off after the engine starts.

 

[JPNinPA]

Have you checked the ignition switch and start relay?


Never look down on anyone unless you are helping them up - Jesse Jackson

 

[JPNinPA]

You mention the NSS
Does it turn in park with a slight push or pull on the shifter or in neutral?



Never look down on anyone unless you are helping them up - Jesse Jackson

 

[JeepJerk]

Thanks for the help, I went back and checked the connections again and that's what it was. Idiot that I bought it from busted the tabs that hold the connectors together rather than take them off right so I had to go back and zip tie them all together. Pffft.