Stalling issues - Will my LC ever be reliable? (1 Viewer)

ProjectsNMotion

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Sep 19, 2018
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New York
Sigh. Maybe. I like my guys a lot. Solid people. But maybe my rig is too much for them to take on at this time. Its certainly not the fun stuff like putting lift kits on.

Your guys can be good guys and bad diagnosticians, that's okay, and actually very common. They're probably very good and thorough when it comes to replacing or installing parts, and that's commendable, but what you need right now is a proper diagnosis. Best of luck.

Cheers
 
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PA
The engine will run fine with no EGR, so a clogged vacuum port or EGR port will not cause this.

I have found with my '93 that is will obey the O2 sensor. Mine was running way down on power, very uneven power, idle issues, etc. You can run it with the O2 sensors unplugged without causing harm. I've been doing so for the last couple thousand miles. My truck runs much better with them disconnected, which is pretty much proof positive one or both are not right.

Before I figured out the O2 sensors were bad, I did have a similar idle issue to what you described with the AC on. My truck would start at 800 rpm, then start to idle down, and run really rough, to 450 rpm or so. In my case turning off the AC would reset the idle so to speak. But it only did it on an offroad trip, and I disconnected the O2 sensors shortly thereafter.

I'd recommend starting there. It doesn't cost anything, and the effect is immediate if they are bad.
 
Joined
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Messages
2,370
Some good suggestions. But is ould be looking for a new mechanic or better yet start doing you own work. It will pay off in the end.

I have a 94 that ran good but kept throwing codes years ago. New O2s didnt help. Then I cleaned the harness side of the O2 plugs. Code went away 100%. So they do get water in them and you need to clean the harness end of the conector.

But the intermitant problem sounds like wiring. Dont check it, just put a new fusable link in. They go bad and are cheap. Also check the wiring near the EGR. It gets hot and brittle. Only takes one or two small cracked wires to ground out when you turn or hit a bump. You can clean all the grounds as well.

On my 94 I did new O2s, cleaned the harness plugs. Removed the air injection and put the O2 in there spot to keep them dry.

New fusable links

Upgraded to heavy gauge marine wiring
And cleaned all the grounds.

Check the harness near the egr. I eventually removed the egr system but that is involved.

New vacume lines all round.

Also I would replace cap rotor plugs and wires obviously.

Also the air idle will cause idle issues but not directly what you are having. I think mine is going bad. Mine truck idles a little low for the first few seconds when it is hot out and idles normally when it is cold. But this is only the first few seconds of running. Always starts and is always smooth. Just a little off from the normal high idle roar when it first starts.

I can't even imagine having to pay a shoe to do all the work I have done. Even if I had the money. When I break stuff on a trail there is no way get the truck out unless I fix it my self. The best way to learn how is by wrenching on it. Buy a fsm and a ratchet set and dig in.

And my 2 cents is please use oem parts as well
 
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Messages
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Los Angeles, CA
Some good suggestions. But is ould be looking for a new mechanic or better yet start doing you own work. It will pay off in the end.

I have a 94 that ran good but kept throwing codes years ago. New O2s didnt help. Then I cleaned the harness side of the O2 plugs. Code went away 100%. So they do get water in them and you need to clean the harness end of the conector.

But the intermitant problem sounds like wiring. Dont check it, just put a new fusable link in. They go bad and are cheap. Also check the wiring near the EGR. It gets hot and brittle. Only takes one or two small cracked wires to ground out when you turn or hit a bump. You can clean all the grounds as well.

On my 94 I did new O2s, cleaned the harness plugs. Removed the air injection and put the O2 in there spot to keep them dry.

New fusable links

Upgraded to heavy gauge marine wiring
And cleaned all the grounds.

Check the harness near the egr. I eventually removed the egr system but that is involved.

New vacume lines all round.

Also I would replace cap rotor plugs and wires obviously.

Also the air idle will cause idle issues but not directly what you are having. I think mine is going bad. Mine truck idles a little low for the first few seconds when it is hot out and idles normally when it is cold. But this is only the first few seconds of running. Always starts and is always smooth. Just a little off from the normal high idle roar when it first starts.

I can't even imagine having to pay a shoe to do all the work I have done. Even if I had the money. When I break stuff on a trail there is no way get the truck out unless I fix it my self. The best way to learn how is by wrenching on it. Buy a fsm and a ratchet set and dig in.

And my 2 cents is please use oem parts as well

I agree. Ordered up 2 fusible links and junction box from Wits End.
Also gonna check the o2's and see if they need cleaning. Might even just replace them.
Figure these are relatively easy things to do.

I'm doing more research on plugs, wires and cap replacement.

Thanks for the encouragement everyone. Curious where I end up. Hopefully not lighting this thing on fire in the middle of the desert.
 
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Since nobody brought it up - there was a recall or service campaign for 93/94 O2 sensors, I thought. Check with the dealer - you might get them to replace them for free.

If not, Denso is the only really OEM part. Some people run NGK sensors in 93/94 and had said they failed within a year or two. I don't know if that's still an issue. I shelled out for Denso myself (not cheap!) before i knew that there was a possibility they could be replaced for free.

I also had wiring issues at both of my o2 sensor harnesses. One of them just had some pins completely corroded out, the other one had been replaced by a mechanic that clearly did not know what they were doing and they had shorted some things out.

The difficulty with diagnosing the 93/94 is that the OBD1 ecm is too stupid to tell you what is really going on, and faulty readings from sensors will cause it to misbehave. It requires some unfortunately rare diagnostic skill.

It's not a bad idea to check every electrical connector for corrosion. They should all be silicone packed so "clean" might not be the right thing to look for, but corrosion can cause real problems. It's not very hard to replace individual contacts on these connectors if you need to.

I don't know that the vacuum lines are going to be a probable cause for your issue but there are an awful lot of them on this engine. Don't forget the ones that are under the throttle body either. Some people have discovered that some of their hard vacuum lines were clogged with some kind of powdery substance - you can use a steel guitar string to clean them out.

I do agree that it could be an electrical issue that may be due to poor grounding and/or bad fusible links at the battery. So change out the fusible links if you haven't already, and if that doesn't solve the problem, tuck the old ones away somewhere in your rig as spares.
 
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Oh i forgot to say. If your charcoal canister isn't working properly, that will cause the thing where the gas tank is pressurized and wheezes out a bunch of fumes when you remove the cap. In extreme cases people have boiling gas or burst tanks. It's not a good scene.

But don't replace the canister. You can disassemble it by filing down the outer edge where it is crimped together at the top, open it up, dump the charcoal, clean the check valves, re-fill it with activated charcoal and maybe replace the pads that are supposed to keep charcoal out of the valves, and then epoxy it back together.
 
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Georgia
Since nobody brought it up - there was a recall or service campaign for 93/94 O2 sensors, I thought. Check with the dealer - you might get them to replace them for free.

If not, Denso is the only really OEM part. Some people run NGK sensors in 93/94 and had said they failed within a year or two. I don't know if that's still an issue. I shelled out for Denso myself (not cheap!) before i knew that there was a possibility they could be replaced for free.

I also had wiring issues at both of my o2 sensor harnesses. One of them just had some pins completely corroded out, the other one had been replaced by a mechanic that clearly did not know what they were doing and they had shorted some things out.

The difficulty with diagnosing the 93/94 is that the OBD1 ecm is too stupid to tell you what is really going on, and faulty readings from sensors will cause it to misbehave. It requires some unfortunately rare diagnostic skill.

It's not a bad idea to check every electrical connector for corrosion. They should all be silicone packed so "clean" might not be the right thing to look for, but corrosion can cause real problems. It's not very hard to replace individual contacts on these connectors if you need to.

I don't know that the vacuum lines are going to be a probable cause for your issue but there are an awful lot of them on this engine. Don't forget the ones that are under the throttle body either. Some people have discovered that some of their hard vacuum lines were clogged with some kind of powdery substance - you can use a steel guitar string to clean them out.

I do agree that it could be an electrical issue that may be due to poor grounding and/or bad fusible links at the battery. So change out the fusible links if you haven't already, and if that doesn't solve the problem, tuck the old ones away somewhere in your rig as spares.
Some good info here. I didn't know about the o2 sensor recall. I will try that at my dealer next time.
 
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2,454
Since nobody brought it up - there was a recall or service campaign for 93/94 O2 sensors, I thought. Check with the dealer - you might get them to replace them for free.
Below is a link to that Toyota service campaign for free replacement of 93/94 O2 sensors. The problem with trying to use that campaign, the O2 sensor kit P/N 89465-60110 are now NLA from Toyota.
 
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... Someone who can/will do more diagnostics than 'guessing' and parts replacement.

A 'good' mechanic will spend his time testing and narrowing down the possibilities as long as testing time is not exceeding the cost of replacing a suspected part/component.
This hits the nail on the head. While you may like your mechanic, maybe they need a little more encouragement from you as to details like this. You'll be doing each other a favor.
 

early91fj80

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Hello masterminds of Mud,

So I’ve had my 94 LC for about a year. The whole time, its been in an out of the shop. It’s always had a rough idle / stalling issue and after multiple trips to my mechanic, nothing seems to fix the darn issue. Sometimes, I’ll get a rough low idle and the engine fights to stay running. I’ll give it gas and it’ll run very jerky until i shut it off. Other times, I’ll come to a stop to make a turn and when I do, it just shuts off immediately. I have to then put it in P and start it back up. Which it then runs rough until I shut it off for 5 minutes then it kicks on and turns fine. Lately, after doing all new fuel system work, its been taking a bit of time to turn over. Ill turn the key and the car will crank for a bit longer than normal before firing up.

So far, I’ve done:
• New MAF sensor.
• New Intake hose (previous was very old and brittle)
• Engine harness re-wrap
• Tightened all connections
• New radiator
• New fuel regulator
• New fuel pump
• New fuel injectors

I just want to enjoy this damn truck. Ive been wanting one for so long. I’m willing to put in the work but my goodness, I’m stumped. I search Mud constantly. Even tried a few things I found but nothing to solve the issue yet. The only other major issue i have is some serious clunking in the drive shaft. Or I think its that at least.

Anyone got any other suggestions? As always, appreciate you guys and this forum.
My ‘97 recently started stalling/cutting out randomly while never throwing a check engine light. After some research, I replaced the fuel pump resistor , EFI relay, and circuit opening relay. It’s been about two months and it hasn’t stalled or cut out. It might be worth checking. Joe
 
Joined
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Below is a link to that Toyota service campaign for free replacement of 93/94 O2 sensors. The problem with trying to use that campaign, the O2 sensor kit P/N 89465-60110 are now NLA from Toyota.

There are people who got their replacement cost reimbursed by toyota, so you might be able to get the cost of some denso sensors and labor out of them.

Worth a shot anyway.
 
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Messages
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Texas
I had another thread last week with my 94. Same symptoms. I cleaned the corrosion in my O2 sensor connector and replaced the TPS. Neither one of them helped, although the TPS did need to be replaced.

Someone mentioned checking the ECT sensor, and said that if that sensor is malfunctioning the truck won’t run the way it should. I’ll change that out in a couple weeks and report back.
 
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Israel
Since nobody brought it up - there was a recall or service campaign for 93/94 O2 sensors, I thought. Check with the dealer - you might get them to replace them for free.

If not, Denso is the only really OEM part. Some people run NGK sensors in 93/94 and had said they failed within a year or two. I don't know if that's still an issue. I shelled out for Denso myself (not cheap!) before i knew that there was a possibility they could be replaced for free.

I also had wiring issues at both of my o2 sensor harnesses. One of them just had some pins completely corroded out, the other one had been replaced by a mechanic that clearly did not know what they were doing and they had shorted some things out.

The difficulty with diagnosing the 93/94 is that the OBD1 ecm is too stupid to tell you what is really going on, and faulty readings from sensors will cause it to misbehave. It requires some unfortunately rare diagnostic skill.

It's not a bad idea to check every electrical connector for corrosion. They should all be silicone packed so "clean" might not be the right thing to look for, but corrosion can cause real problems. It's not very hard to replace individual contacts on these connectors if you need to.

I don't know that the vacuum lines are going to be a probable cause for your issue but there are an awful lot of them on this engine. Don't forget the ones that are under the throttle body either. Some people have discovered that some of their hard vacuum lines were clogged with some kind of powdery substance - you can use a steel guitar string to clean them out.

I do agree that it could be an electrical issue that may be due to poor grounding and/or bad fusible links at the battery. So change out the fusible links if you haven't already, and if that doesn't solve the problem, tuck the old ones away somewhere in your rig as spares.


I got the recall in 2017 free of charge, although all was rusted and they had to cut bolts


One correction DENSO is not OEM for 93/94 they are OEM for 95+

OEM for 93/94 is NTK That is what Toyota sent fro Japan and that's what was on the original on the rig
 
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Messages
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I had another thread last week with my 94. Same symptoms. I cleaned the corrosion in my O2 sensor connector and replaced the TPS. Neither one of them helped, although the TPS did need to be replaced.

Someone mentioned checking the ECT sensor, and said that if that sensor is malfunctioning the truck won’t run the way it should. I’ll change that out in a couple weeks and report back.

It might be worth disassembling the connector on the harness to be sure that the corrosion didn't go all the way to the crimp, unless you have already done that.
 
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It might be worth disassembling the connector on the harness to be sure that the corrosion didn't go all the way to the crimp, unless you have already done that.

I couldn’t figure out how to remove the female connector on the wire harness side without destroying it so I left it alone for the time being.
 
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Ok. I FINALLY got my fusible link and replacement junction block. Took a closer look this morning at everything and good christ, if the fusible link doesn't end up being my problem, I should've replaced and cleaned everything a while ago either way.

Is it just me or did the previous owner do some weird stuff. Everything looks straight forward in regards to replacement but that red wire doesn't have a male connector piece to go into the female end on my fusible link replacement I got from Wit's End. I'm not very knowledgable with my 80 but I'm trying to learn. What should I do here? Is there a male connector I can buy and put together? Can I just cut the red female connector from the link and connect it straight up?

Thanks a bunch.

FusibleLinkBatteryShot.png
WitsEndFusibleLink.png
 

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