How to Bypas Fuel Pump Relay 94 Jeep GC 4.0 - Page 3

docscomputers · 03-02-2006, 01:16 PM

Got the jeep to fire today but will not stay running. Starts then dies immediatley. Remember I said that temp sensor on the intake was open, Would it cause the stalling right away?

Tom

docscomputers · 03-02-2006, 02:55 PM

Well I tryed new IAT Sensor and it is open on the ohm reading also. So that must not be the problem unless the new 1 was bad. Any Ideas? Is there any special procedures you have to go thru in order to reset the PCM?

Tom

bringselpup · 03-02-2006, 05:05 PM

No the fact that the PCM has been disconnected from a battery for a bit will do the reset on it.

Bring us up to date here, you have a different PCM in the Jeep now that matches the numbers you had from the original one? You do a key on and hear the pump spin right away like you should? You can see the fuel pump relay close?

Is it possible all that messing around with the fuel pump there is something not connected now?

docscomputers · 03-02-2006, 05:33 PM

I got a reman from the yard that according to chrysler was the update for the 94 which is a replacement for the 94 which is 56028311, the raman is R6028311. Original Chrysler Reman and date is 11/11/03 That is suppose to work. I can hear the relay start, hear the fuel rail fill pump is really quite don't hear that very well. Any Suggestions?

Tom

dksob81 · 03-02-2006, 06:56 PM

I made a mistake earlier when posting that model # of the spare PCM I have, it is 56028112, won't really help you, but if anyone else needs one let me know.

bringselpup · 03-02-2006, 08:10 PM

Ok so the PCM is now making the fuel pump go at key on. This is good and sounds like it was the initial trouble because you said you had the extended cranking and waiting 15 sec and longer to get the fuel pump to go.

You were doing something with a second fuel pump testing stuff. I'm thinking things are ok there because you said you hear the fuel rail pressurize.

What else got touched during this whole troubleshooting of the issue?

docsplace · 03-03-2006, 02:37 AM

We pulled the CPS and tested it actually installed a new one and pulled it back out for return because that wasn't the problem. IT was stationary so I don't think it could be out of position. I'm going to double check that becase I don't trust the person who did it for me. I installed a new Pickup Coil becasue it was bad and open no ohm readings. But the jeep ran for a couple of hours after we did those things.

After it shutdown the last time I've poped the cap off the Fuel Relay and Initiated the relay manually to make sure it and the pump was working, Pulled and switched relays w/same numbers to see if maybe 1 was failing. Pulled and tested fuses. Pulled and tested that IAT Sensor on the intake and it reads no ohm at all but neither did a new 1, and played around with various wires to see if I could find a short or broken wire. Thats about it.

Do you think that trying the key on diagnostic sequence might pinpoint a problem? And is that key on off 3-times then leave it on?

dksob81 · 03-03-2006, 07:06 AM

Key ON, OFF, ON, OFF, ON - then count the # of CE lights and pauses.

Did your CPS have the spacer on it when you pulled it.

Some of the 4.0L engines have a spacer that goes between the bellhousing and the CPS and I know if it is not installed then you will have some problems.

bringselpup · 03-03-2006, 07:09 AM

You haven't said the check engine light is on so I don't think you'll find anything doing the 3X key on thing to pull the codes. If the vehicle ran for 2 hours after changing the cps and you haven't touched it since I'd think things were ok there.

Sounds to me like you need to focus on that intake sensor. That sounds like the other area that was putzed with.

docscomputers · 03-03-2006, 08:19 AM

Yes I am getting the check engine light and the Jeep is starting but shuts down right away. The new cps I got from the Auto Parts had no spacer or paper that I know of. I going to try and research that a little, It may have suppose to have 1 and when we got it someone had removed it.

Tom

docscomputers · 03-03-2006, 08:42 AM

Here are the codes, It flashes Once-2 times-5 Times-5 times. code 12 Which means that battery has been disconnected
5-5 means end of test. Nothing really reporting on that.

It shuts down asap no matter if I have gas pedel floored or opened.
Do you think that maybe the computer could have a Antitheft or security.
Would that cause this problem if the jeep does not.?
And I can barely hear the pump
Would fuel pressure shut it down and should I be able to test it and it maintain 49psi +-5?

Or maybe the jeep has it and I may not know about it, How would I find out it is suppose to have it or not, Calling chrysler w/the vin.It looked to me when I pulled the old CPS there was one of the bolts missing, it may have been replaced before I got it.

Tom

docscomputers · 03-03-2006, 05:12 PM

Well it appears that the jeep is fixed, Up and running now, Changed out the computer w/another and she fired right up and appears to be running good.

I wished I had known that they give us the wrong part to start with could have saved a lot of time. Dksob81 was right to start with If I had just figured out that we had the wrong part could of had it running a couple weeks ago.

Thanks Goes Out the Dksob81, and Bringselpup for all your great advice and patients with this long drawn out mess. I got a good education out of it and think I can now pinpoint a lot of those problems that the jeeps have now.

Thanks a Bunch for all your help, I will be around the forums on other Cars, I have a 98 Dodge Ram 1500 4x4 loaded and a Gas Econo Ford Aspire for the long halls I'm sure I will need some help on.

Thanks Again
Tom

bringselpup · 03-03-2006, 05:23 PM

Yeah!

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