Let go of the key, engine stops

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brtb

NAXJA Forum User

Location

Orlando, FL

• Jul 11, 2004

• #1

And I thought I was doing so well, too. Went out a few minutes ago to try and track down the elusive high-idle problem (which I probably caused somehow when I checked the TPS, that'll teach me to mess with old wiring again) and it almost starts... further testing reveals that it'll stay on as long as I have the key in Start, once I let go it shuts right off.

What died now, the ignition switch? Before anybody says ballast resistor, it's 1.1 ohms.

 

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PaulJ

NAXJA Forum User

Location

Lynnwood, WA

• Jul 11, 2004

• #2

It's probably the fuel pump relay. One of the ones under the plastic shield under the hood on the passenger side. You can swap them around to test.

 

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brtb

NAXJA Forum User

Location

Orlando, FL

• Jul 11, 2004

• #3

will check it, but wouldn't a bad fuel pump relay prevent it from turning on _at all_? it fires up, and runs as long as I keep the key turned to start... tried it for 2-3 seconds, don't want to burn out my starter on top of things.

 

Last edited: Jul 11, 2004

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BUCKYXJ

NAXJA Forum User

Location

Tulsa, OK

• Jul 11, 2004

• #4

I would guess its the ignition switch on the bottom of the column. kinda hard to get too but it might fix the problem. Mine had two big burn spots in it and wouldn't go to the start position. I think they only cost like $10 but not sure.
And I am not talking about the key cylinder the ignition switch, some people call them both ignition switches

 

Eagle

Lifetime NAXJA Member

NAXJA Member

Location

Terra Firma

• Jul 11, 2004

• #5

Don't know what the ballast resistor should read for resistance, but it's an easy test to just jumper it and see if that solves the problem. I would try that before crawling under the dashboard.

 

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brtb

NAXJA Forum User

Location

Orlando, FL

• Jul 11, 2004

• #6

Jumpered ballast resistor, no help. Switched around the relays - no change. Guess it's the ignition switch next.... gotta just be a weird coincidence, not related to my recent overheating adventures, right?

 

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hackedxj

NAXJA Member #1090

Location

East Tn.

• Jul 11, 2004

• #7

My bet is with Buckyxj, I've seen it before ,it may just need adjusted ,let us know how it turns out for ya.

 

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brtb

NAXJA Forum User

Location

Orlando, FL

• Jul 11, 2004

• #8

So I replace the ignition switch, since the old one did look a little singed around the brown wire... and it's still doing the same thing. Runs in Start, let go and it shuts off. any ideas while I dive into the circuit diagrams?

 

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Mich88XJ

NAXJA Forum User

Location

Houghton, Michigan

• Jul 11, 2004

• #9

I was looking at my diagrams today, and from what you were saying, my best bet is to replace the ignition switch in the column. If you look at page 12-20 in a haynes manual, you can see that the hot that goes out of the switch runs through "run" and then "start" so if something got screwed up in that switch between run and start, it would shut off when returning the key to the run position. Following that line down, it runs to the fuel pump relay, and also to the ECU, Diagnostic Connector No. 2, O2 sensor relay, and the Ignition Control Module which you already replaced. This is what my best bet is, let me know if you do it and it works. Good Luck! Christian

 

JeepinAudiophile

NAXJA Forum User

Location

Northborough, Massachusetts

• Jul 11, 2004

• #10

for present and future information... I'm not sure if you need these, they're easy enough to find... but just in case.

this is for the 88 cherokee
12V: Red @ column
Starter: Green @ column
Ignition: Yellow @ column
Accessory:Brown @ column

 

JeepinAudiophile

NAXJA Forum User

Location

Northborough, Massachusetts

• Jul 11, 2004

• #11

arty: Oh and by the way brtb... Happy Birthday! arty:

 

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brtb

NAXJA Forum User

Location

Orlando, FL

• Jul 12, 2004

• #12

JeepinAudiophile said:

arty: Oh and by the way brtb... Happy Birthday! arty:

Click to expand...

Thanks!

Got the thing to run... combination of the fuel pump relay harness clogged with junk (probably caused by the hot bath it just received) and an intermittent disconnect at the fuel pump power connector down next to the fuel filter.

 

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brtb

NAXJA Forum User

Location

Orlando, FL

• Jul 14, 2004

• #13

Actually it turned out to be more than that...

Hidden in the wire loom right below the pressure bottle are 2 important splices - always-on power (red wires) and ignition-controlled power (yellow wires). On mine, the split in the plastic wire covering was directly upwards, which made it catch a lot of water. Water + antifreeze + copper = corrosion. Corroded copper isn't a very good electrical conductor.

So, lots of soldering and electrical tape later, it's back in business.