Author Topic: Starting (or not)?  (Read 854 times)

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van

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Starting (or not)?
« on: October 29, 2007, 04:43:51 PM »
Over the past two or three weeks the 97 has taken up an annoying habit of not wanting to start.  Not even trying to fire (almost like a bad cps).  When it does decide to fire up, it does so perfectly normally (i.e. no clouds of smoke from unburt fuel), and continues to run fine thereafter.

Symptoms/exclusions include:

Manifests itself usually as not starting when warm, only twice when cold. 

Hot starting is fine.

Doesn't manifest itself at all if I stick to fairly long trips (i.e. commuting 40 miles each way to work, I can go a week without it happening.)  Short trips (<10 miles) and it shows up.

I have codes 41 (generator field ??? it charges fine) and 72 (catalyst) stored.

Thoughts?  Condensation?  I have cleaned out distributor cap an wd-40d it.

Offline Jeffy

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Re: Starting (or not)?
« Reply #1 on: October 29, 2007, 05:48:02 PM »
Over the past two or three weeks the 97 has taken up an annoying habit of not wanting to start.  Not even trying to fire (almost like a bad cps).  When it does decide to fire up, it does so perfectly normally (i.e. no clouds of smoke from unburt fuel), and continues to run fine thereafter.

Symptoms/exclusions include:

Manifests itself usually as not starting when warm, only twice when cold. 

Hot starting is fine.

Doesn't manifest itself at all if I stick to fairly long trips (i.e. commuting 40 miles each way to work, I can go a week without it happening.)  Short trips (<10 miles) and it shows up.

I have codes 41 (generator field ??? it charges fine) and 72 (catalyst) stored.

Thoughts?  Condensation?  I have cleaned out distributor cap an wd-40d it.


Is the fuel pump priming?  My guess is a fuel pressure issue.
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Offline aw12345

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Re: Starting (or not)?
« Reply #2 on: October 29, 2007, 06:02:02 PM »
When the no start occurs, does the fuel pump prime or cycle on doe a few seconds? If that is ok check for spark
If no spark check to see if you can either get a tach reading or if the injectors trigger ( check with a noid light or check on the negative side of the coil with a test light it should flicker while crancking if so your problem is in the coil  coil wire rotor or distrivutor cap if all of that is fine check for fuel pressure and the pump running. If no fuel pressure or no pump running check the asd relais and the fuel pump relais. That should get you closer to the problem if all that functions ok start looking at the ecm
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Offline neale_rs

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Re: Starting (or not)?
« Reply #3 on: October 29, 2007, 07:38:33 PM »
Check to see if the check engine light comes on while the fuel pump is priming with the key set to run (not cranking).  If it is not, then you need to start checking all PCM grounds and 12v connections.  I went through this recently and it ended up being the PCM.  In your case the jury is still out, it could be bad connections, a sensor, fuel issues, etc.
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

van

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Re: Starting (or not)?
« Reply #4 on: October 30, 2007, 06:04:11 PM »
Tx for the quick responses.
Replaced PCM in July (grr.)  Replaced fuel pump last year when I performed filler neck mod.  Check engine comes on as neale_rs identified.  Have spark.  Keep spare (working) coil and cps in console.  Not them.

I took the liberty of swapping the fuel pump and horn relays (until I can get to the parts store), and so far, it has been perfect, although real test will be weekend short (chauffer the wife) trips.

van

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Re: Starting (or not)?
« Reply #5 on: November 13, 2007, 05:49:34 PM »
Kudos to the fuel pump/relay tips.  That did it!  tx

Offline neale_rs

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Re: Starting (or not)?
« Reply #6 on: November 15, 2007, 12:07:51 PM »
So it was just the relays?  It sure is nice when it tuns out like that.

'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

van

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Re: Starting (or not)?
« Reply #7 on: November 29, 2007, 04:49:08 PM »
Yep.  Been perfect ever since.
I have nightmares about troubleshooting electrical ghosts.
Especially after I cooked my PCM this summer.