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2003 4.7 starting issue

4K views 25 replies 3 participants last post by  ccurrier 
#1 ·
First off I have to say this forum is full of great information, and even greater people. So far I haven't been able to figure out my starting issue, so wanted to see if anyone had some tips or ideas.

It all started last week, my jeep would not start right away when turning key directly to start position. No click, no crank, nothing. If I waiting a few seconds in run position, it would start.

A few days of this, and then waiting those few seconds maked no difference.
Initial observations:
1. battery good, plenty of power. (only 7 months old as well)
2. because battery was good, ignoring alternator is possible issue.

At this point I assumed bad starter (original equipment with 200k miles)
After replacing starter, still nothing.
Since then I have investigated several items that I will list in next post. I will also post the current condition of the issue.
Thanks in advanced for everyone's help.
 
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#2 ·
Current state:
If I disconnect the solenoid terminal wire harness and jump that to the solenoid battery terminal while the ignition is in the run position, the vehicle will start.

Tests performed:
1. I have checked the 10 Amp fuse in position 31 and it's good.
2. I have tested the Starter motor relay, and also swapped it out for a different one
3. I have verified cavity 30 is hot.
4. I have verified park/neutral position switch is working by checking continuity to ground at cavity 85. (can see changes while shifty between R/N/D as expected)
5. I DO NOT get voltage at cavity 86 when the ignition is turned to start position. (this leads me to think either ignition issue or wiring from ignition)

I read somewhere on this forum ( I think ) that if you connect positive battery terminal to 87? that the starter should engage, is that correct?
This is about where I'm at so far. Anyone with some ideas to try next?
 
#3 · (Edited)
Yes, when you put 12 V directly on point 87, the starter solenoid will be activated directly and the starter should work. The problem you have seems to be with the ignition switch.
But have also a look first at fuse 14 in the PDC, which is also in the starting relay circuit.
 

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#4 ·
That is what I'm thinking, ignition problem.

I did try applying 12v to 87 and the starter did not engage. This leads me to believe that I might also have a wiring issue between 87 and solenoid. Could be bad connection introduced while replacing starter. I will have to verify continuity between 87 and solenoid to make sure the cable is okay.

Any troubleshooting that I can do on the ignition? The repair manual I do have says that if no voltage at 86 with ignition switch to start then:

1. check for an open or short circuit to the ignition switch and repair, if required.
2. if the circuit to the ignition switch is OK, refer to Ignition Switch and Key Lock Cylinder in the Diagnosis and Testing section of Group 8D - Ignition System for testing of the ignition switch.
 
#5 · (Edited)
Just did an update on my previous post, but you where to quick.
Check fuse 14 in the PDC under the hood, its a 40 A fuse, which is in the starter relay circuit.
Strange that putting 12 V on 87 didn´t engage the starter solenoid.
 
#6 · (Edited)
If fuse 14 is ok, then you have to go to the ignition switch, remove connector C1 and jumper points 1 and 2. If it then starts, you are sure the ignition switch is faulty. Ofcourse you have to solve the problem between 87 and solenoid first:D.
 
#8 ·
Due to the previously intermittent caracter its most probably the ignition switch, but better to rule out all (cheaper to fix) possibilities first.
 
#11 ·
No luck, Fuse was good. I took the covers off the steering column last night hoping it was easier to get to the C1 connector you referred to so I could test that. It was a bit deeper in there then I thought. Do you have the key cylinder removal instructions as well? This latest doc talks about needing to do that first before removing the ignition switch.
 
#13 ·
Making progress! Retested terminal 87 to starter and it was good. So I reconnected it and tested 12V to 87 and the starter cranked. Must have just been a bad connection at the solenoid when starter was changed.

I then took dash out around steering column to get to C1 connector on back of ignition switch. I made a jumper wire and connected 1 and 2 of the C1 connector and the engine started. With that test done I put the C1 connector back in, and verified I could start still with 12V to 87 with ignition in the run position. All was good. So it definitely looks to be the ignition switch. I need to get some tamper proof torx bits to get it off.

During all this testing I ran into another problem, that I'm not sure is because of the bad ignition switch. Within the last few days the battery went dead, so I've been having to jump it to do my testing. I noticed after testing yesterday the time on the radio was still on after key was turned off for about 1 hour. Could the bad switch be leaving acc devices on and draining the battery?

Also last night once I was done testing, I let it run for about 20 minutes to get the battery charged. I figured why not take it for a spin. Didn't even make it out of the driveway. Once I put it in drive and tried to accelerate, it died. I started it again with 12V to 87, and pulled it in the garage. As soon as I let off accelerator, died again. Seems that after start it idles fine, but if you rev engine and take foot of accelerator it idles way down and stales.
 
#14 ·
Sometimes with a worn key cylinder, you can pull out the key in ACC position, this is not good. When you know this problem, you could verify it to be in off and not ACC before taking out the key, but better would be a new key cylinder.
Did you charge the battery completely before driving? I would check the battery voltage with engine off and then with engine running. In off it should be 12.7 V for a fully charged battery, when its 12.2 its almost completely discharged. With engine running it should go to 13.5-14 V.
 
#15 ·
I'm pretty sure the key didn't come out before going to off, but I could be wrong, I'll have to check that out.

I didn't charge the battery all the way before driving. I've always been able to run off alternator when battery was dead, before jumping, and not had any issues, like stalling out. Once ignition switch is replaced, we'll see if those two issues go away.
 
#16 ·
Yes, best to change the ignition switch first and then see what happens. If you have a charger, i would start with a fully charged battery and then see if all is ok.
 
#17 ·
Well, got ignition switch replaced and it seemed much better until this morning. I turned the key and it was like it wasn't hooked to anything. I took the cylinder back out, and removed the ignition switch. And there is was, the end of the rod that connects cylinder to ignition switch was broke, about 1/2 inch off the end. That would explain why it wouldn't start and why it was draining the battery with the ignition off and key removed.

So it looks like it's contained in a small box held on by 2 torx screws, has cable coming out of the back. Any idea what that box is called? Is that box or rod something that can be replaced?
 
#18 ·
Is the rod not a part of the key cylinder? No idea which box with wires you are talking about:werd:.
 
#19 ·
Looking into the manual i see that the SKIM is placed just above the ignition switch, but that one has nothing to do (mechanically at least) with the key cylinder or ignition switch.
 
#20 · (Edited)
Ignition Switch Actuator Pin. That is the name.
Here is what it looks like new.

I'll post a picture of the broken one when I get home. Basically the last 1/2" of the rod (right side of picture) was broken off. That is that part that goes into the ignition switch. Thanks for all your help Frank, couldn't have gotten it fixed without you.
 

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#22 · (Edited)
Yes, that is the part that sits between the Cylinder and the ignition switch. Here is a picture of my part to compare to the new one I posted before. As you can see the rod that goes through the middle, that connects the D shaped end of the ignition cylinder to the smaller D shaped connector on the ignition switch is broken right off.
 

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