Erratic idle and stalling at stops

Nay

 
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I remembered that I have a hand throttle. Lock in about 400 additional RPM and it's driving perfectly.

New TPS goes in this week.
 
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Hey Y'all

Well, for 2 months "OSO" has been running better than at any time since we owned her. The major issue with stalling seemed to be resolved with the TPS replacement (after 4 months of replacing everything else), the new O2's relocated in the new custom '96/'93 cat-exhaust system resolved other drive-ability bugs and other than the EGR code (which I have given up on) all was wonderful. Guess no good thing lasts forever.

New symptom - Starts fine, idles high as usual for short time then once it drops off and would normally go into the 600 rpm idle it acts like it is confused. It will almost stall, then run up to 8-900 rpm then drop and almost stall. If you add driver input it will run and drive fine until you come to a stop or slow significantly then it will start the whole "chase the rpm needle" game and stall.

I have checked for bad/disconnected/open vacuum lines and found none. I pulled and cleaned the PCV valve with carb clean (also ordered a replacement) and this had no effect. It's not throwing any new CEL's so I have no direction indicated there.

My wife says she (the 'cruiser) is just jealous that I have started spending more attention on the '71 Lincoln and is acting out. Oh if that were just true :)

Any thoughts on what direction to take with this would be appreciated.
Pull the fusible link and replace. Did the trick for me. Even if that's not it, you'll be glad you did. $10 or less.
 

Traakon

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Pull the fusible link and replace. Did the trick for me. Even if that's not it, you'll be glad you did. $10 or less.
Thanks for the thought but been there, done that.

Currently 'OSO' is running well. I have to pull the OLS this weekend and clean it and replace the seal to see if that fixes the random light making an appearance. When I picked up the new seal I had "Tom and Larry" locate a replacement sensor but at $460 bucks if cleaning doesn't help I will live with the occasional light blinking on/off.
 

Nay

 
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I remembered that I have a hand throttle. Lock in about 400 additional RPM and it's driving perfectly.

New TPS goes in this week.
New TPS in, no change. Everything is dead normal under driving conditions by locking in the hand throttle for idle at 650. Put it in park and it rises to just under 1K, which suggests to me the throttle electronics are functioning.

I have a new temp sensor so that's next. Or maybe the fuel pump relay I just ordered is next, because that makes more sense.
 
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Nay

 
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So did the fuel pump relay and resistor and the ECT temp sensor to no avail, although it seemed like it was running nicer.

Then realized I'd been horribly neglectful of plugs and wires as miles piled up over the last few years. Like 140K neglectful. Ahem. New NGK wires and iridium plugs.

Yup. I should have taken pics of the old plugs :hillbilly:.
 

Traakon

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Well...it's been two months and OSO has been running without complaint. It seems she really REALLY liked the replacement of the ECU Temp Sensor. Almost straight away she ran better, no issues and all aspects of driving have been smooth and normal.

I even have not had a re-occurrence of the CEL for the EGR. Damned if I did not first check to see if the bulb in the dash was burnt out but it works when you go to start and then goes out "like a normal 80".

Now maybe I can work on rebushing the rig and installing the OME lift springs that have been gathering dust.
 
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what does ECU Temp Sensor control? My 91 runs like it was designed to run. tore out all the smog crap, put in 4 port injectors and the torque is great and the fuel consumption is significantly improved. it is so smooth like it is a different engine entirely.
 

Traakon

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what does ECU Temp Sensor control? My 91 runs like it was designed to run. tore out all the smog crap, put in 4 port injectors and the torque is great and the fuel consumption is significantly improved. it is so smooth like it is a different engine entirely.
I don't know exactly what the ECU temp sensor has to do with the issues I had but is was the last thing, on the very long list of things, that I had found could have contributed to the idle/stalling problem. Since it is a separate sensor from the one that runs the temp gauge and just provides engine temp info to the ECU I assume it translates that info into determinations on air/fuel and idle speed.
 
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Traakon

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:bang::bang::bang:

Well so much for the good news.
Took the "OSO" to dinner last night and 30' out of the drive it just stopped running. Slid it to neutral and it started right up and carried on. 1.5 miles down the road, came to a light, slowed and the idle crashed, caught, recovered, and then fell off again before stabilizing at normal. Made it to dinner and it chased the idle around again a couple times but stabilized. Coming home it ran fine. No codes thrown and no re-occurrence of even the EGR code.

I am looking for a Shaman to do a sage smudge to set the demons this thing has free, beyond that I am at a loss. :meh:

Anyone have experience doing the full replacement of the engine electrical harness? At this point that may be all I have left as an option so insight on the process would be a boon.
 
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try fuel pressure regulator, or fuel filter or fuel pump or the vac line coming off the canister. if you do find that shaman or psychic auto mechanic let us all know ASAP.
 
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Jesus there is an entire community of Land Cruiser owners who suffer from screwed up idle. I am eternally grateful for this support group. Although I'm the only guy who cant move his brake pedal so I've got that going for me. And I'm learning so much! Yay! Good times.
 

Traakon

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Check your throttle position sensor as per the FSM if these things get out of adjustment nothing works right
TPS is new and was set per FSM. IAC is new as well. I have chased this as a data issue, a vacuum issue, a fuel supply issue a fuel delivery issue, a sensor/monitor issue, an electrical issue, an exhaust issue.

I am beginning to wonder if there is a gremlin in the engine wiring harness that only presents under specific circumstances. I would have given in and taken it to Toyota if I could be certain it would present symptoms while they had it and could reproduce them. It acted up over the weekend but then ran really well. It could run great for another month or go crazy rolling down the street 100 yards from the house.
 

Traakon

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have you checked the wires under the intake manifold, sometimes they get cooked
Indeed I have. I went through all the wiring while chasing the EGR code.

There in is an oddity. "OSO" had an EGR code when we bought her and spent a lot of time trying to resolve it to no avail. Since changing out the ECU temp sensor the EGR code has not reoccurred. I have found nothing in my reading that shows a link between the ECU temp sensor and the EGR code but there ya go.
 
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hahaha those codes can be wrong on the 3fe. they are not always accurate. more of a starting place. I assume you tried back probing from the ECU?
 

Traakon

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Well it looks like I need to throw in the towel and take "OSO" to some new eyes.

The problem still is unresolved. She will run great for a couple weeks, falter suddenly for a day then get better for two and then just run like crap for several days then run great for a couple weeks again.

When all else fails seek professional help...I have been hesitant because there is no certainty that when I take her in it will be a period when she is acting up. Key that with finding a dealer that actually has people that really know these old rigs and not just OBD2 babies.

She was originally purchased at Camelback Toyota in '93 (still has the dealer sticker on her) Might have to see about taking her back to her roots,
 
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Well it looks like I need to throw in the towel and take "OSO" to some new eyes.

The problem still is unresolved. She will run great for a couple weeks, falter suddenly for a day then get better for two and then just run like crap for several days then run great for a couple weeks again.

When all else fails seek professional help...I have been hesitant because there is no certainty that when I take her in it will be a period when she is acting up. Key that with finding a dealer that actually has people that really know these old rigs and not just OBD2 babies.

She was originally purchased at Camelback Toyota in '93 (still has the dealer sticker on her) Might have to see about taking her back to her roots,
I know your frustrated as hell, but I would love to hear about a dealer experience. I was told by a very seasoned Toyota mechanic the new guys dont know anything about the older models let alone an 80. Heres what i did, but Im still holding out until I put a new MAF in.... I buy lots of stuff from the main Carquest hub close to me, and the guys have always been great. So I strolled in one day and asked them, in their opinion, who are the best non dealer Toyota mechanics in town that operate privately. Immediately he scribbled a note with a guys shop name and number. Maybe you have a similar resource? In the mean time I got my 90 Trooper running and plated and dear old Toyota is very sad sitting in a barn, all by her lonesome.
 
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