The Mysterious LX450 Issue... No Power... Barely Holding Idle...

[TramCommon]

Hey guys, long, long, long, loooooooooooooooooooong time lurker. Grew up in an old diesel Land Cruiser my Dad used to drive us up and down the Alaskan highway every other weekend. I was about ten seconds away from buying a newer GLK450 and I just couldn't do it. So, logically, I did the next best thing and bought a 1997 LX450 with 400,000 kms on it.

Picked her up on Vancouver Island. She was ruining fine, some power steering whine and a few minor things, but the body was clean and the engine seemed absolutely decent. Test drove it for a good thirty mins... no issues.

Drove her back to mainland BC and up to the Okanagan Valley. Parked her for a week while I ordered a huge list of basic maintenance parts. The next time I went and fired her up she started a little rough but seemed alright until I put her in drive and started trying to get her to move. Almost immediately she lost power and started to idle incredibly low, like, barely keeping herself alive with absolutely no power... put her into neutral and tried to slowly get her to rev back up.... nothing, just bogging almost completely to the point of turning off.... finally she managed to fix herself and revved up and I managed to ease her back into her parking spot.

Same thing the next day... so, I decided to start doing the basic maintenance I had planned to anyways for a vehicle of its age and kms and hoped maybe something would fix the issue. To date I've done:

-All new oem spark plugs
-New NGK spark plug wires (oem were like $400 through my local shop)
-New distributor and distributor cap
-New o2 exhaust sensors
-New fuel pressure regulator
-New fuel filter
-New air filter
-New rear CAT (was included with the sale)

So far, no luck, I can get her driving properly for about half a block before she starts to sputter and nearly kill herself. I plan to check fuel pressure next. The previous owner (great guy by the way, been texting him and he feels awful it has issues, I don't suspect any foul play) he had the fuel pump replaced not too long ago, so I haven't checked that... I'm going to check fuel pressure and if that's alright, I was going to pull all the injectors for a servicing next.

Anyways, sorry for the novel. I just wanted to see if any of the gurus on here might have any suggestions or if anyone has had a similar issue and might possibly be able to pass along some info.

Thanks everyone. Looking forward to getting her driving properly.

Tram

PS - Checked compression... Front to Back 180, 175, 165, 175, 185, 185

 

[uscmas412]

I'd be interested to know which fuel pump the PO installed, research shows the OEM pump rarely fails but you're up there in mileage.

Bad fuel?

How does the wiring harness near the EGR valve look?

Also, check the fusible links near the battery. In fact, I'd just go ahead and replace them if you don't know the age.

 

[TramCommon]

I'd be interested to know which fuel pump the PO installed, research shows the OEM pump rarely fails but you're up there in mileage.

Bad fuel?

How does the wiring harness near the EGR valve look?

Also, check the fusible links near the battery. In fact, I'd just go ahead and replace them if you don't know the age.

Not sure which fuel pump. Are there aftermarket garbage replacements out there? Seems unlikely he replaced it, ran for a year fine and then the week after he sells the vehicle to me it goes?

Fuel is new. I'll definitely check the wiring harness near the EGR and replace the fusible links near the battery. Thanks for the suggestions.

Tram

 

[ppc]

Check the intake hose for any cracks allowing unmetered air into the motor and any other vacuum leaks.

 

[GOTLOCKED96]

Mine was a TPS, also did the IAC while I was there.

 

[TramCommon]

Mine was a TPS, also did the IAC while I was there.

I gotta believe a faulty TPS would still allow you to somewhat drive the vehicle, no? Like, she might be rough but you'll still be able to move... my situation is pretty much a total and complete loss of power... until it smartens up for a few seconds and then it's right back to no power and can't even limp itself forward.

Thank you for all the replies and suggestions. Please keep them coming!

 

[TramCommon]

Check the intake hose for any cracks allowing unmetered air into the motor and any other vacuum leaks.

Gonna check that tonight.

PS - I used to play hockey at UMich. Go Blue.

 

[musthave]

I'd guess fuel filter, fuel pump, or perhaps crack in a hose.

 

[TramCommon]

I'd guess fuel filter, fuel pump, or perhaps crack in a hose.

New fuel filter, old one was definitely pretty clogged but didn't solve the issue. Can you suggest which hoses to check that, if cracked, would cause this severe of a power loss?

Thanks guys.

Tram

 

[GOTLOCKED96]

I gotta believe a faulty TPS would still allow you to somewhat drive the vehicle, no? Like, she might be rough but you'll still be able to move... my situation is pretty much a total and complete loss of power... until it smartens up for a few seconds and then it's right back to no power and can't even limp itself forward.

Thank you for all the replies and suggestions. Please keep them coming!

My truck was loosing power, then wouldn't stay running unless throttle was applied.

 

[EvanD]

Sure sounds like fuel pump to me. Your description sounds almost exactly like how my F150 acted when it's fuel pump went out.

And it also went pretty much from running great, turned it off, it sat for a few hours and then ended up with your symptoms.

Edit - I have no idea if there's a way to test it besides just replacing it. After doing a bunch of research on f150 forums I just went for it.

 

[bulhas]

soooooo is it getting any misfires??? I had something similar there are 2 VERY common issues with fueling on the fzj80's and one a little less likely

1st check the wiring near the EGR valve VERY VERY VERY commons to melt a few wires together causing all kinds of headaches
next issue check behind the glove box, the harness going to the PCM runs parrallel to the metal bracket for the lower portion of the glove box this leads to a couple wires rubbing through grounding out causing major power loss.....

third check your fuel opening circuit is actually opening all the way, toyota runs a multi staged resistance based on throttle position which than limits or does not limit the amount of voltage going to the fuel pump



issue number 2 burned me, i legit tore apart my harness, changed fuel filter, change plugs, wires, distributor, injectors and so on until i read up about this rubbed through wiring, once i found it I did not have that issue again, well i technically never will I have 2 extra injectors and cylinders hahahahaha

 

[TramCommon]

My truck was loosing power, then wouldn't stay running unless throttle was applied.

Good to know. I think what I'm experience is much more severe. You could roll a cup faster down the street than she's moving and until I put her in neutral and press the gas pedal on and off and on and off and on and off for a good ten to twenty second until she very slightly corrects herself and starts revving again, she won't move... and then when she does move, its for maybe five seconds before she experiences that complete loss of power again and goes back to barely, barely idling enough to keep herself alive (and sometimes she just dies altogether).

... it sounds like the exact symptoms of a severely faulty fuel pump... although when I've had fuel pumps go in the past they've either died completely, or they've been fine... nothing in the middle... nonetheless, worth checking out regardless of the previous owner have replaced it not too long ago.

Sure sounds like fuel pump to me. Your description sounds almost exactly like how my F150 acted when it's fuel pump went out.

And it also went pretty much from running great, turned it off, it sat for a few hours and then ended up with your symptoms.

Edit - I have no idea if there's a way to test it besides just replacing it. After doing a bunch of research on f150 forums I just went for it.

I'm more than happy to just replace it if that's the culprit. I ordered that banjo fuel line fitting to test the fuel pressure. Wait for that to come in before I pull her out. The only other way I know to test the fuel pump involves the fuel pump being out anyways and I'm sort of of the opinion if you've gone to the hassle of removing the damn thing you might as well just replace it.

Should I be avoiding aftermarket fuel pumps if I do need to replace it? OEM best? Or is any option good?

soooooo is it getting any misfires??? I had something similar there are 2 VERY common issues with fueling on the fzj80's and one a little less likely

1st check the wiring near the EGR valve VERY VERY VERY commons to melt a few wires together causing all kinds of headaches
next issue check behind the glove box, the harness going to the PCM runs parrallel to the metal bracket for the lower portion of the glove box this leads to a couple wires rubbing through grounding out causing major power loss.....

third check your fuel opening circuit is actually opening all the way, toyota runs a multi staged resistance based on throttle position which than limits or does not limit the amount of voltage going to the fuel pump

issue number 2 burned me, i legit tore apart my harness, changed fuel filter, change plugs, wires, distributor, injectors and so on until i read up about this rubbed through wiring, once i found it I did not have that issue again, well i technically never will I have 2 extra injectors and cylinders hahahahaha

Misfiring for sure. Attached are two pictures of the wiring harness near the EGR. Although the individual coloured wires are visible, they seem fine.. I couldn't see any actual exposed wire.

I'll definitely check out the back of the glove box for any potentially exposed wires. Can you recommend the best way to check the fuel opening circuit?

Also, checked the fusible links and they seem fine. Ordered new ones and a new housing box anyways.

Thank you everyone for all your help and suggestions and support!

Tram

 

[EvanD]

I'm sure most around here will say OEM (if still available). I've never had an issue with mine in my cruiser so I never looked into it. I'm at almost 300k but have only had it for about 30 of that.

I'd have to look through the records from PO to recall if he replaced it or not. He sunk a good bit of money into baseline type stuff but he's was the original owner, truth be told I have no idea how many times my truck has changed hands so who knows.

Sounds like they have a pretty good reputation of not going bad but that doesn't mean it doesn't happen. Your symptoms just reminded me quite a bit of my experience with the pickup.

I'm sure there are some threads on it around here although I can't recall and specific links to point you to.

Edit - I also replaced the fuel filter at the same time so I honestly don't know which was the culprit. Probably a combo of them both but I didn't have time to try each by itself to decide. If I recall you've done that already though.

 

[Tedward]

Your pic of wires is not the place to check for damage that many people find damage.
The spot to check is a bit harder to get to. It's right next to the egr pipe. Almost, and sometimes is, touching the pipe.
I dont have a pic but its below the fuel rail and up again the head.

 

[TramCommon]

Your pic of wires is not the place to check for damage that many people find damage.
The spot to check is a bit harder to get to. It's right next to the egr pipe. Almost, and sometimes is, touching the pipe.
I dont have a pic but its below the fuel rail and up again the head.

Good to know. I'll check that location, as well. Thank you!

 

[bulhas]

by the looks of your picture the wire harness has new high temp loom, follow that loom towards your injectors, your egr pipe gets hot enough to melt wires together at times

the best place to look is your speaker, you pop the speaker out and youll see the metal bracket, there is susposed to be a plastic protector sleeve but they break, i couldnt even see the wear through point however once i pulled the harness off the metal the vehicle smartened up

 

[Bambusiero]

Here's an almost random idea.
My truck recently started bogging down, just for moment, at every crack in the road. WTF?
Turned out to be the positive battery terminal fusible link. Broken wire right at the connector, just due to age & movement.
Grabbing a hold of it and tugging, while idling, demonstrate the fault.

 

[TramCommon]

Well... I figured it out... god damnit guys... after all this... it was the fuel pump.

I got frustrated this past weekend and said to myself "**** it, I know the previous owner said he just replaced it, but I NEED to just check."

... pulled the fuel pump out and although it was a replacement pump and it looked like it was pretty new... a couple of the connectors were pretty loose and who knows why... but I just replaced it with some cheap aftermarket pump and she fired up and ran great.

FML.

Side note - As mentioned, the pump in the vehicle didn't look that old... I've read a few threads on here were guys have mentioned fueling issues... could this potentially be a situation where the truck is burning out fuel pumps at a faster than normal rate? Is that common... if so... what does that mean?

Thanks guys for all your help and support!

Tram

 

[slow95z]

it took me a while but i have learned to trust the advice on mud. when 5 people tell you the same thing you might want to look at it. glad you found it and glad to see i am not the only idiot with a wrench out there.