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Re: Stranded...1st Gen LWB V6 Won't Start [Re: mrray] #1037713 10/16/12 03:47 AM
Joined: Feb 2010
Posts: 117
mrray Offline OP
Wheeler
Some new developments...

Got deep into the wiring last night. Unfurled, cleaned, checked all connectors I could get to, and replaced Throttle Position Sensor (TPS), as that was the code I was getting.

Now, no code. ECU is giving A-OK signal again. But no starty and no sparky.

In exasperation (and maybe a subconscious desire to end it all for both of us), I tried another shot of ether. After that didn't help I tried it on the Montero.

By God, a couple times I SWEAR I heard / felt a little life out of her. Just a short chug-a-lug.

Is it possible that the fuel pump is KINDA working, and occasionally it is sending enough fuel pressure to motivate the lazy-ass ECU to order spark? Am I hallucinating? Will enough ether (administered to the vehicle, not the driver) lower point of combustion to the point that I'm getting diesel ignitions w/out spark?

Another thing...if the TPS is now ok, shouldn't I have had to d/c battery neg to reset the ECU??? It spontaneously did so. I never d/c'd batt neg.

My next parts swap might have to be to swap in another Montero and see if that helps...

Should I just buy a new fuel pump and see?


1991 Montero LS (LWB) 3.0L V6 Stock 205K Miles
Re: Stranded...1st Gen LWB V6 Won't Start [Re: mrray] #1037714 10/16/12 04:53 PM
Joined: May 2007
Posts: 4,628
hazy_daze Offline
Roll Me Over
*****
Disco the battery for a few minutes and try again.

Have you applied 12v to the fuel pump test plug in the PS footwell to verify the pump is coming on?


Fasteddy's advice is occasionally sound...
Re: Stranded...1st Gen LWB V6 Won't Start [Re: hazy_daze] #1037715 10/16/12 05:52 PM
Joined: Feb 2000
Posts: 3,269
justice Offline
Roll Me Over
*****
I could be wrong, but I dont think low fuel pressure will shut off spark...If that were the case all the many times I ran out of gas, it would have shut the ignition off and I'd never get it to fire again untill I refilled..not the case.

I'd concentrate on the no spark. Sorry comming in late here. Did you test the coil and inspect connections to it?


99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..
Re: Stranded...1st Gen LWB V6 Won't Start [Re: justice] #1037716 10/16/12 06:01 PM
Joined: Sep 2001
Posts: 8,557
LandRaider Offline
Forum Moderator
*****
Fuel pressure is not monitored. Will have no effect on spark, or lack of spark.


87 Raider 4D56td v5MT1
31's..Basically Stock
Re: Stranded...1st Gen LWB V6 Won't Start [Re: LandRaider] #1037717 10/16/12 07:51 PM
Joined: Feb 2010
Posts: 117
mrray Offline OP
Wheeler
Thanks guys.

Bummer on fuel pump idea. I was hoping that was it.

I have done the jumper test and the pump comes right on and sounds strong and steady. Also pulled it out and watched it pump from one bucket to another out of the vehicle. Further, when I connect the test jumper and squeeze the fuel line going into the rail I can feel the pressure in the hose increase.

I did go through testing coil, control module, main wire to dizzy cap. All tested good. I visually inspected (in light and in dark) wiring and connectors and tested for continuity where I could. Also replaced TPS, dizzy and ecu with new or known good ones. I visually inspected the fuel/control relay and can hear it clicking on and off when I turn the ignition.

Hazy, I'll d/c the batt(-) when I get home and report back. This morning the ecu was still saying "all is well". Liar...


1991 Montero LS (LWB) 3.0L V6 Stock 205K Miles
Re: Stranded...1st Gen LWB V6 Won't Start [Re: LandRaider] #1037718 10/16/12 08:02 PM
Joined: Jan 2001
Posts: 13,649
fasteddy Offline
Web Wheeler
*****
He is not seeing any movement of the tach needle when cranking. Therefore, no tach signal from the coil, and if no tach signal, no fuel injected. The ground path from coil - goes to a branch. One branch goes to LC filter and then to tach. Other branch goes to power transistor, which is switched by ecu to a ground point. Wire from coil - is white/blue to PT, and path to ground from PT is a black wire.

If I've read his posts right, he's tested the PT, TDC and crank position sensors in dizzy, coil, and sees no spark. The ecu has been rebuilt. I'm wondering if the ecu is really good after the rebuild. I'm also wondering if the ecu just needs a reset.

Try:
1. disco the battery - cable for 30 sec and reconnect. Try to crank it.
2. Check the wiring from coil to LC filter (little square thingy under the coil bracket - note if wires are brittle) to power transistor - the white/blue stripe wire.
3. redo the power transistor test and also test the following - see if the white wire to the PT has a pulsing 5v signal when the engine is cranking. Do this test with the connector attached. This will test if the ecu is controlling the PT.


Not responsible for advice not taken...
Re: Stranded...1st Gen LWB V6 Won't Start [Re: fasteddy] #1037719 10/16/12 08:32 PM
Joined: Feb 2010
Posts: 117
mrray Offline OP
Wheeler
Thanks Eddy. Will try the suggestions tonight.

Regarding the ECU. I had my original one rebuilt by AV-Pro, but I also have Hazy's ECU on loan. They both respond the same.

Is there a test for the fuel/control relay? All I've done there is visually inspected (it was immaculate inside) and observed clicking when I turned the key.


1991 Montero LS (LWB) 3.0L V6 Stock 205K Miles
Re: Stranded...1st Gen LWB V6 Won't Start [Re: mrray] #1037720 10/17/12 02:49 AM
Joined: Jan 2001
Posts: 13,649
fasteddy Offline
Web Wheeler
*****
FSM has a test for the control relay. I'm not positive, and too lazy to look it up now, but the relay may feed one side of the ecu, too, with key on power. I may be mixing this up with the starquest ecu/control relay configuration.


Not responsible for advice not taken...
Re: Stranded...1st Gen LWB V6 Won't Start [Re: fasteddy] #1037721 10/17/12 03:07 PM
Joined: May 2007
Posts: 4,628
hazy_daze Offline
Roll Me Over
*****
I don't have a spare ECU control relay to send him. Anybody got one? I want to see this fella ridin. Eddy, if it ain't running by 11/17, you up for a road trip?


Fasteddy's advice is occasionally sound...
Re: Stranded...1st Gen LWB V6 Won't Start [Re: hazy_daze] #1037722 10/19/12 07:44 PM
Joined: Feb 2010
Posts: 117
mrray Offline OP
Wheeler
I'll say it again...you guys are amazing. I appreciate you sticking with me on this.

Unfortunately I haven't been able to do much since my last post as I'm out of town for a wedding.

All I had time to do was disconnect the battery (-), wait a few minutes, then reconnect and try cranking. No change.

I'm looking into the FSM procedure for checking the relay.

How difficult expensive is it to just replace the entire ignition part of the wiring harness? Might be educational.

Beyond that, when I get home again I will repeat (threepeat?) all the tests I've done thus far just to be sure before any rescue teams are dispatched <img src="/forums/images/graemlins/baby.gif" alt="" /> .

Until next time...

(In case anyone has any other ideas, I will still be watching the thread)

Thx again.


1991 Montero LS (LWB) 3.0L V6 Stock 205K Miles
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