1996 ZJ start issue - JeepForum.com
 
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post #1 of 10 Old 01-12-2017, 02:20 PM Thread Starter
constantine0913
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Lately my jeep has begun to start for a second, and then die immediately. After this the car won't start. The fuel pump turns on, lights and radio come on when the engine turns as well. Last night we were able to get it to start right up using jumper cables. Today it did it again, only this time we couldn't jump it anymore. It had been working fine these past 2 weeks, but the day it started doing this was the day I tested to see if the cruise control worked. Lost at what the issue could be as it also has a new ignition coil, new spark plugs, and a new fuel pump. Any form of help or advice is greatly appreciated!
I should note that we have looked and done the 12 Jeep stall fixes, as that used to be what it was doing. The only thing on the list of 12 that hasn't been worked with or replaced is the pcm.

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post #2 of 10 Old 01-12-2017, 04:02 PM
trol1374
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I think your last sentence answered your own question. Check with junk yard to find a comparable jeep to pull the PCM. Or if handy with a solder iron and circuit boards, then do the fix. Or Rockauto sells the box for $200 ish and then return the old PCM and get $60 back.
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post #3 of 10 Old 01-12-2017, 07:59 PM
Uniblurb
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What year/engine and how exactly did you test the cruise control to see if it's working?

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #4 of 10 Old 01-13-2017, 11:46 AM Thread Starter
constantine0913
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It is a 1996 with the 4.0 6 cylinder engine. For the cruise control, I just got on the highway home, turned cruise control on, got to the speed I wanted and set it. After that it did what it should, maintaining the set speed and disengaging when I used the brakes.
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post #5 of 10 Old 01-13-2017, 03:37 PM
Uniblurb
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Ok, I thought maybe you did some type of electronic testing on the cruise control. In just checking it's operation then then it shouldn't have anything to do with your no-start problems.

When you went through the dirty dozen did you check/clean the grounds? This would include the one next to the battery, making sure the battery terminal connections are good, and the PCM ground on one of the coil studs in particular. This PCM ground also supplies ground to all the engine compartment sensors via this coil stud ground.

Do you have an alarm system which may be disabling the system? Have you checked for spark/fuel when it won't start? Curious what brand of fuel pump you installed? Answer these questions and we can go on from there.

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #6 of 10 Old 01-13-2017, 03:48 PM Thread Starter
constantine0913
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The grounds have been checked and cleaned. It's getting fuel, can't guarantee it was sparking. Not sure about the alarm system, and I will have to check the reciept for the fuel pump.
It started today but something strange happened. Clear liquid was coming out of the exhaust. I included a picture, maybe there's something getting mixed in with the fuel?
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post #7 of 10 Old 01-13-2017, 04:09 PM
Uniblurb
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It's not uncommon for water to condense in the exhaust, especially with the huge temp swings we've been having. If you get liquid blowing out of the exhaust after warming up a while then you could have a problem.

Just like water condensing in the exhaust it also condenses in the fuel tank. And the less fuel the more room for water to condense in there. You may want to try dumping a bottle of "HEET" in your tank to help disperse any water in the tank.

I only mention the fuel pump brands since we've seen many problems with ones like Airtex and some Eherko ones.

You should pull your coil or plug wire to see if you have spark when it's cranking and near the engine block. Best to use a rubber handled pair of pliers and/or rubber glove so you don't get zapped. Bad coil or bad crankshaft position sensor can cause no spark.

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #8 of 10 Old 01-15-2017, 03:40 PM Thread Starter
constantine0913
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Sorry I haven't replied, I've been helping with a friends eagle scout project these last few days. Anyway I checked on the fuel pump and it was an airtex. My dad keeps saying that the way the vehicle is acting is if it has a fuel leak, but that since there wasn't any smell of gas he didn't understand what was up so perhaps our airtex was bad as well. We checked for spark, and can now confirm its sparking. Haven't tried the HEET just yet. Thanks for the advice!
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post #9 of 10 Old 01-15-2017, 08:52 PM
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Understand, you have the same 96 4.0 I do, and you're welcome.

Your dad could be right about the fuel leak but it could be on the pump outlet check valve, pressure regulator, etc, all which are internal in your Airtex fuel pump module. If you don't have a problem with the pumping system itself often the fuel sending unit connected to the float on the Airtex go bad where you won't know how much fuel you have in the tank by the fuel gauge.

It could be pumping some fuel but how much? You need to get a fuel pressure tester for Chrysler and connect it to the shrader valve on your fuel rail. There's a cap on the drivers side of the rail you remove and the shrader valve is like a tire air valve. Often parts stores like Advance or Autozone have loaner fuel pressure testers which should work.

Fuel pressure spec is 49psi +/- 5 psi and since it's electronic it's should stay constant at idle or higher rpm's. The pressure shouldn't drop below 24psi after 10-20 min or the check valve in the pump is bad.

If you do find your fuel pump is bad you won't beat this deal of a brand new Mopar 5003867AC fuel pump module for your 96 for $78 with a new tank seal and free shipping. Eherko is a reputable ebay vendor others here have used and the dealer charges 3x-4x this price.

http://www.ebay.com/itm/OEM-Mopar-Fu...item540724539d

I have nothing to gain on you buying this and just like to pass on the best deals to members.

Another thing you could try first is make sure the horn works then flip the horn relay with the fuel pump relay in the PDC (power distribution center). This is the black relay/fuse box on the passenger inner fender in the engine compartment. Look inside the lid for a diagram of the relays/fuses. Flipping these relays will rule out a possible bad fuel pump relay. Good luck.

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #10 of 10 Old 01-16-2017, 09:27 AM
ihbinder
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I just went through this goat rope with my 96, I installed NEW(er) relays in the fuel pump and ASD ports which solved the problem.
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