1998 Lx470 Stalling Out

[whitec13]

After reading your FB post, have you thought of removing your Viper setup? I’ve read quite a few times of those systems causing electrical issues on vehicles if not professionally installed. I also remember reading somewhere that Toyota’s in general don’t get along with aftermarket remote start/security systems. Could be totally wrong, but if you’re exhausting other efforts, why not? I did have a similar issue, but found it was related to water intrusion from a rusty windshield surround.

 

[tpham18nm]

With the vehicle turned on, cold start, the voltage on the battery reads about 14-14.2 volts. My first test when I got home it read 14.2v. Then later in the evening, it read 14.1. Underload it dropped to 13.7 (first test), 13.9 second test. After the truck was shut down, the battery reads 12.8. Now it reads 12.6 sitting. It seems like the battery and alternator are in good shape. So I am going to rule that out.

When I bought the truck the fuse box was replaced, which is making me think that they original owners been chasing this gremlin for a long time. Thats probably why they replaced the fuse box, fuel pump, and other related items. Not good....

I'm going to give Bill from Bill Toy Shop a call to see if he can give me some advice. I live about 3 hours from him. Waiting for a friend to work with me on the tech stream. Other then that, it seems like I am stumped... Any other ideas would be awesome.

So lets recap:
MAF sensor- Good
Battery/alternator- Good
Grounds - Seem good from visual inspection- but need data to confirm.
Vacumme leaks- going to test tomorrow by spraying carb cleaner around (is this a good idea?) visual inspection, good.
Serpentine belt- Installed correctly
TB- cleaned
Swapped battery with new battery- Good

Things to check:
Viper alarm system. I have no idea how to disable this unit. I'll do some research...

Anyone got any other ideas, i'll gladly listen. Gotta work on the possible vacume leaks tomorrow.

 

[tpham18nm]

Update on the problem. It was not the TPS. But when I changed out the TPS, I noticed that there was a wire very close to the serpentine belt. This wire was frayed and I think the wires are touching. I am going to take the wires out (I think there are 3) and rewrap them with electrical tape and see if that helps.

I also noticed that many of the wires are not attached to the wire holders, which is why the wire touched the serpentine belt in the first place.

The original owner had their son-in-law redo the timing belt with a "mechanic friend". Could the timing be possibly off? I mean, if they didn't even replace the wires back properly, this could be the culprit.

Can I please have your opinions?

I guess the only way is to check timing by pulling the cover.

 

[Mike NXP]

Update on the problem. It was not the TPS. But when I changed out the TPS, I noticed that there was a wire very close to the serpentine belt. This wire was frayed and I think the wires are touching. I am going to take the wires out (I think there are 3) and rewrap them with electrical tape and see if that helps.

I also noticed that many of the wires are not attached to the wire holders, which is why the wire touched the serpentine belt in the first place.

The original owner had their son-in-law redo the timing belt with a "mechanic friend". Could the timing be possibly off? I mean, if they didn't even replace the wires back properly, this could be the culprit.

Can I please have your opinions?

I guess the only way is to check timing by pulling the cover.

Timing is OK , I'd think you would know by now but maybe someone else will tell you otherwise.

The wires not being secured there has been documented a handful of times, seems like many folks forget to re-secure it.

Don't just bunch the wires together and tape them, maybe for testing, but if possible try to fix it properly

 

[tpham18nm]

Timing is OK , I'd think you would know by now but maybe someone else will tell you otherwise.

The wires not being secured there has been documented a handful of times, seems like many folks forget to re-secure it.

Don't just bunch the wires together and tape them, maybe for testing, but if possible try to fix it properly

Yes, will do. The wires are not severed through, but the white wire is exposed and was touching the wire sheathing around it. The red wire was also partly exposed. I will repair it and see if that solves the issue. I've seen this wire before, but I didn't think to cut it open and I didn't know that the white wire was exposed. Hopefully this will fix the issue.

 

[Mike NXP]

Yes, will do. The wires are not severed through, but the white wire is exposed and was touching the wire sheathing around it. The red wire was also partly exposed. I will repair it and see if that solves the issue. I've seen this wire before, but I didn't think to cut it open and I didn't know that the white wire was exposed. Hopefully this will fix the issue.

This thread may be relevant for you
And these wires go to...........? - https://forum.ih8mud.com/threads/and-these-wires-go-to.1136581/


Is it these wires maybe? Hopefully you can get it mended up without having to dive in any deeper. A bandaid fix may be appropriate for now.

 

[tpham18nm]

Correct. Those are the wires. The white and red one are frayed. I do not have a black wire connected actually. There are only two wires on mine, and two prongs at the end of the connector. Mine is a 1998. Is that normal?

 

[Mike NXP]

Correct. Those are the wires. The white and red one are frayed. I do not have a black wire connected actually. There are only two wires on mine, and two prongs at the end of the connector. Mine is a 1998. Is that normal?

I'm not knowledgeable enough in this area to say yes or no. I assume normal but the only way to know for sure is if someone with experience chimes in or finding your electrical diagrams and figuring out what's what.

Perhaps if you have enough room to work just separate and repair the exposed wires the best you can and see if your symptoms change. Removing skid plate and coming from below may help

 

[Import Driver]

I think you're probably on the right track.

A couple weeks ago mine cut out and stalled several hours from home. It would intermittently run for 15 or 20 seconds. Crank position sensor code. Long story short, whoever did the timing belt last did not route the (driver's side) wire harness where they should have and the crank position sensor wires were rubbing on a pulley. I ended up pulling the radiator to access everything, find problem, and fix it.

I hope it works out for you!

 

[KrOswalt]

Had a Nissan Xterra that would randomly shut down when coming to a stop about once every 2 months. The Nissan tech and his fancy computer couldn’t even find the issue because it wouldn’t throw a code. The sensor was over the passenger side fender built into a crevasse that would hold road debris and water and was later known to be a common issue.
I removed a long travel lift, roof cage with lights, rear suspension, one off custom front bumper, and a TON of other upgrades getting ready to sell the cursed thing to someone for cheap due to the issue but decided to try a new mechanic one last time. Turned out to be that dang $50 sensor. By that time I had sold all my parts and was to pissed to keep the vehicle and rebuild it.

Anywho, it’s worth a shot to rebuild that harness or try a crank sensor if they’re cheap

 

[tpham18nm]

Damn, really wish that it was the crank or the cam sensor. No luck. So I rewired the cam sensor and reinstalled it; the truck still stalled. I swapped the cam sensor in case it was fried and did not throw a code. No luck. I saw that the wires on the crank sensor was also frayed. I rewrapped it and checked for shorts. Nothing. I cleaned the crank sensor and reinstalled it. Nothing.

I hooked it up to data. No misfires on any of the cylinders, injectors are firing normally, fuel pump seems okay.

I have no idea.

 

[kerrye]

If you posted the video on Facebook today, it seemed pretty clear to me that your torque converter is locked up and that's why its stalling when you come to a stop. You need to figure out why it's locked up, and unlock it. It seems obvious that as soon as the truck goes into gear and the truck isn't moving the engine stalls exactly like what would happen on a manual transmission truck if you didn't engage the clutch.

 

[tpham18nm]

If you posted the video on Facebook today, it seemed pretty clear to me that your torque converter is locked up and that's why its stalling when you come to a stop. You need to figure out why it's locked up, and unlock it. It seems obvious that as soon as the truck goes into gear and the truck isn't moving the engine stalls exactly like what would happen on a manual transmission truck if you didn't engage the clutch.

I thought it had something to do with the transmission as well. But the truck also stalls in park or neutral.



This is the video

 

[kerrye]

I thought it had something to do with the transmission as well. But the truck also stalls in park or neutral.

In the video it appeared to be running in neutral and immediately stalled when you put it in gear. edit--I can't find your Facebook post to rewatch it but I wasn't the only one who thought the torque converter was locked up. edit again--the video you posted above is not the same video I saw on Facebook so unless you posted a different video on Facebook, ignore my comments

 

[rexington14]

I thought it had something to do with the transmission as well. But the truck also stalls in park or neutral.



This is the video

But it doesn't stall if you are giving it any throttle?

And to summarize, is it correct that you put on 2000 miles without any stalling issues, but then one day on the highway your engine made a "thud" and from that point on you have been having stall issues? Any more info on what this "thud" felt like?

 

[tpham18nm]

It does not stall when I'm on the throttle. If my foot is light on the throttle (going 20mph in the neighborhood) the engine will stumble. Kind of like it's going to die and surge back to life. It stumbles and quickly recovers.

The thud that I felt on the highway felt like I hit a hole or object in the road, but there was nothing there. I think I can remember that I felt a thud like that at least 3 times over the course of a week or 2, before the stalling issue.

 

[kevgentile]

I'll repeat once more, you need live data. It's all a guessing game until then.
You don't need a registered fault to observe what all the signals and sensors are doing.
The workshop manuals are free to download from Mud. Familiarize yourself with them, all the specs/requirements are listed throughout.
It'll save lots of long term aggravation and you'll learn a lot about the 100 and how to chase problems later on.

 

[tpham18nm]

I have hooked it up to live data. There are no misfires and injectors are firing at normal rates. I'll hook it up again to see if anything is out of the ordinary. My mechanic friend was looking at it as well, he said he didn't see anything weird. But we might be inexperienced. Thank you for your feedback. I'll look again. But you're right. I need to look at the specs to be able to figure it out.

Where do I find the workshop manuals?

 

[kevgentile]

I have hooked it up to live data. There are no misfires and injectors are firing at normal rates. I'll hook it up again to see if anything is out of the ordinary. My mechanic friend was looking at it as well, he said he didn't see anything weird. But we might be inexperienced. Thank you for your feedback. I'll look again. But you're right. I need to look at the specs to be able to figure it out.

Where do I find the workshop manuals?

Need to have one person drive while another observes all the sensors. Basic items like spark and fuel are a good start but are just a small piece of the puzzle when there's so much more info available. There will be a few dozen signals to look for any inconsistencies in. I haven't used Techstream much since we have similar machines in the shop, someone else might be able to confirm whether or not TS can record data so you can match the parameters while running and then when stalls.

I spent a lot of time in motorsports using data acquisition. No "check engine" lights so we rely on data to diagnose problems, so it's what I tend to go straight for when I have no MIL and a drive-ability issue. That and the trusty smoke machine.

Find the WSM in resources in the above menu bar.

 

[Cafetero]

Keep an eye out for your TPS/APPS - mine started stalling as well, got better by cleaning the throttle body, and it finally lost all power after a few months. I ended up getting a whole new throttle body assembly and it runs great now with no stalling issues.