Stuck in the jungle: Low speed shut off (1 Viewer)

[notathomie]

Quick background: I recently bought a 1997 FZJ80 in Costa Rica. It is a 40th anniversary edition brought into Costa Rica in 2010 with roughly 200k miles on it. It now has 208k miles. In other words, it sat around for awhile. It has a safari turbo, dual batteries, reserve tank and other extras.

This car purred like a kitten when I checked it out and had incredible punch (thank you safari) so I bought it.
The car drove fine on several two hour return trips from the jungle to town and dozens of smaller forays in the backwoods near our farm. Now I am experiencing low speed shut downs. It seems to only happen when my foot is not on the gas. It eventually starts back up but can take as many as 40 attempts.

Sequence of events:
It generally starts just fine. But yesterday after a 20 minute climb from our supply town (1500ft) to a little store at 3000feet , it didn't. We stopped for drinks, I let it idle to cool down for a bit, then cut it off. When we came out with our Cokes it took 20 attempts and five minutes to get it started again. From the store to our house is another ten miles of bad gravel roads (fifty minutes total), and on that run it cut off three times. One of these cut offs was when I had rolled to a stop but the car was still in "D". The other two were while going downhill (ie, without the accelerator depressed). When I arrived home last night, I put it in park and let it idle in the driveway for ten minutes. It never kicked off.

More background:
My trip to town yesterday was to pick this car up from the shop she limped into five weeks ago. Long story short, five weeks ago I had the same problem of low speed shut off. Only it had just started to manifest itself. Another problem that cropped up - literally as I was coasting into the shop five weeks ago- was surging RPMs. The car was in the shop for five weeks because i was waiting for a friend to mule down a new IAC from the US. I assumed a new IAC would eliminate all of these problems - low speed shut off and surging RPM. Having driven it for an hour following install of the new IAC, I now see these two problems are separate issues. Or there is an electrical issue in the ECM or elsewhere that is crippling my IAC. (The IAC is a new Aisan part from Partsgeek. US$165).

When I put the new IAC in, it purred like a kitten and drove fine around town.

While the car was sitting around, I had the following done:

Injectors cleaned
A new TPS put in (it could be a new used part. A common scam here.)
The ECM has been visually inspected and looks fine.
Brand new Optima batteries
Rebuilt starter

I have not replaced the fuel filter. It was the first thing I tried to do along with an oil change after buying it but could not locate the part. I finally found one but have not put it in. (The shop was supposed to but they didn't. They only had five weeks...)

I have not changed spark plugs or cables.

I am using premium gas.

Any ideas? I will change the fuel filter out and hope it is that simple.

Thanks to everyone for all the work you put into the forum. It has been an incredible resource.

 

[flintknapper]

Definitely get that fuel filter changed. Cut open the old one and you'll probably be surprised at the 'gunk' that is in it....if its anything like mine was.

Also, check (or have checked) your fuel pressure.

TPS and IAC would have been my first guess and were good things to try. Do you have any 'Codes' (trouble codes). Best to always scan for codes first.

 

[Wayne]

It sounds like the problem is heat related. You said it starts fine when cold and the problem begins to occur when the engine is up to operating temperature. Right off, it does sound electrical. The main engine wiring harness runs right beside the EGR valve and many Mud members have experience engine problems due to the harness melting in that area causing wires to break/short out. I would check that area out thoroughly and repair as necessary. As a PM, put some heat insulation around the wiring harness in that area.

 

[Marine7]

Both are good suggestions.... I tend to lean towards Wayne's diagnosis. It is happening after it warms up, and at low speeds. It sounds like the problem is steadily getting worse, which leads me to believe that somewhere you have a wire that has started to lose its insulation from the heat, as the engine warms up the heat affects the wire (which now has less insulation from slowly melting) causing your issues. I would go after the wiring harness where it runs next to EGR, and check your o2 leads, make sure one didn't come out of its clip, causing it to hang on exhaust.
But, without a doubt.... service that fuel system! I'm guessing the fuel there isn't nearly as "clean" as it is in the states.......GOOD LUCK!

 

[notathomie]

Thank you for the replies.

I left out two pieces of information. But I suspect they are more "noise" than "signal" when it comes to figuring out this riddle of low speed shut off.

1) I did get a CEL yesterday. But I suspect it is related to something else.

The low speed shut off did not trigger a CEL when it showed up in the past.

In sixty odd hours of driving since purchasing this vehicle, I have only had one other CEL. I cannot remember the code number now but it was related to the transmission. On that occasion the CEL came on when I was climbing and got the A/T overheat light. (Another issue I am battling).

Yesterday my CEL came on just before my A/T overheat light came on during another brutal climb. So I assume it was the same code.

I have not yet set up my recently muled BAFX scanner. I will do so and update as soon as I have the code.

2) Wayne, I have been wondering about electrical too. The other key thing I left out from my comment was I got a flickering battery light on the dash as I drove in on our "roads". (The light I am referring to is the rectangular red light to the left of the "18volt" mark on the dash voltmeter) This light flickered on the back roads as I drove home. I do not remember this light flickering on pavement. But the flickering last night while coming in on the trails seemed related to the bumps in the road. So I assume I have a worn or loose wiring harness somewhere.

Heat on the wiring harness could be the culprit. The first time I got a low speed shut off five weeks ago was after a four hour drive from San Jose. And as you noted Wayne, the car did fine running errands around town following install of the new IAC. The problem cropped up following a climb.

I have an extra temp gauge on the dash and i don't think it went above 195f yesterday.

 

[notathomie]

Rereading all this, the flickering "battery" light on the dash voltmeter is probably telling me I have a worn wiring harness. So signal not noise. Never noticed this light flicker before. But it could be a wiring harness getting slowly rubbed raw. Going out to check now.

 

[ppc]

I think you have multiple issues for sure. The very first thing that should be replaced are the fusible links at the battery. They are cheap and should be considered a wear item. The fusible links have been a source of electrical problems for many mud mrmbers.

 

[LandCruisinMy93]

Crankshaft position sensor or wiring maybe? Or have you checked the wiring that runs behind the glove box? I and other people have had issues with the metal rail under the box cutting into that harness and causing issues. Also, what about O2 sensors? I'd start at the glove box wiring and then move onto looking at the engine wiring harness near the EGR and then the crankshaft sensor wiring. If all of that looks okay then I'd start by testing the Crank sensor, the oxygen sensors and then the MAF. Essentially I'm saying do all the inspecting and testing yourself to save money. I don't like throwing parts at cars to fix them like most shops do. I like To find the one or two parts that need replaced and be done. Anyway, have you considered also, that since your transmission is getting overly hot that maybe you have a failing torque converter? This could cause it to die if it's locking up as you're coming to a stop just like pushing in the brake without taking a manual out of gear. And it could explain your excessive temps. Either way, you should put an external transmission cooler on it to save your transmission.

 

[retrofive]

Agree, i would check
fusible links (well just replace, they are cheap)
EFI relay (maybe getting to hot?)
Main harness by the EGR (inside engine bay) and inside the cabin around the glove box area.

 

[notathomie]

Thanks for all the ideas.

I checked the wiring from the IAC and TPS into the harness. Turns out a previous owner had spliced in six inch extensions. (Not sure why they did this).

It was actually very well done (had that shrink wrap hair dryer stuff on the connections) and passed a visual inspection.

A few pairs of wires in each cable assembly had stuck together at the shrink wrapped spot due to the heat. Almost like they were spooning. They peeled apart easily and there was no obvious sign of copper-on-copper contact.

But when I checked everything with a magnifying glass I found two spots where a single strand of a single wire had just barely poked into its neighbor.

This might be why the shop missed it. It also would explain why the problem is intermittent and related to heat (expansion).

I am taping everything up now and will update once I have some results.

I realize this is stuff I should have checked earlier - so apologies on that one.

Thanks again

 

[retrofive]

Sounds like a good direction

 

[The Proton]

Sounds like a good direction

I had a very similar issue with low speed shut off. Usually but not always preceeded by a rough idle, sometimes very sudden and out of the blue. Took a while to figure out but it was the large rubber intake hose after the MAF sensor. There was a tear/crack in the hose on the bottom where it was invisible, and during certain conditions it would open up and let in too much air after the sensor, killing the engine. Oddly it ran well after startup, and the problem seemed very random. Possibly heating up in the engine softened the rubber, or movement of the engine? At any rate a patch immediately fixed it, followed by a new and $$ hose. When I removed the old hose it was very stiff and brittle compared to its replacement.

Since you have a turbo probably a different intake setup and this may be irrelevant, but I would do a quick check for an intake leak as well.

Annoyingly I drove that way though a very dusty desert trip, who knows what sand and dust went though the engine, the old intake hose was VERY dusty, on the inside.... :-(

The Proton

 

[retrofive]

I had a very similar issue with low speed shut off. Usually but not always preceeded by a rough idle, sometimes very sudden and out of the blue. Took a while to figure out but it was the large rubber intake hose after the MAF sensor. There was a tear/crack in the hose on the bottom where it was invisible, and during certain conditions it would open up and let in too much air after the sensor, killing the engine. Oddly it ran well after startup, and the problem seemed very random. Possibly heating up in the engine softened the rubber, or movement of the engine? At any rate a patch immediately fixed it, followed by a new and $$ hose. When I removed the old hose it was very stiff and brittle compared to its replacement.

Since you have a turbo probably a different intake setup and this may be irrelevant, but I would do a quick check for an intake leak as well.

Annoyingly I drove that way though a very dusty desert trip, who knows what sand and dust went though the engine, the old intake hose was VERY dusty, on the inside.... :-(

The Proton

That old brittle intake will get you as well. Good thought.

 

[notathomie]

My car is still cutting out. Usually it happens at low speed with no gas applied, but I had two shut downs yesterday while I was applying some gas. It always starts up again. But I usually have to wait ten minutes.

When I started the car this morning, it started right up. But it had an unusually high idle. I think 1500 rpm. It drove fine for thirty minutes and the idle seemed to go back to normal. When I got back home I let it idle for a few minutes then cut it off. It would not start up again but I only tried it a few times. (The IAC is a brand new Aisan part)

Here is everything I replaced since I last wrote:

New fusible links
New EFI relay
New fuel filter
I taped up and reinsulated all the wires from the IAC and TPS into the main wire harness.

It seems to me I have wires that are heating up and expanding and making contact with metal. Or I have a fuel delivery issue that only occasionally manifests itself. (The next part I will change is the fuel pump relay)

Two questions I have based on the comments I received on this thread:

1) Where exactly does wire failure typically occur behind the glove box? I checked here but did not see anything obvious.

2) Where exactly should I look behind the EGR for melted wires in the wire harness? THe horizontal run along the valve cover under the EGR? Or the short vertical run? or the run under the plastic covering that runs parallel to the windshield? Again, I checked here but did not see anything obvious.

Any pictures would be helpful.

I have yet to check the O2 sensors nor the crankshaft position sensor. What exactly should I look for here? And given my issues, does this sound like a possibility.

Thanks again!

 

[Tools R Us]

...
When I started the car this morning, it started right up. But it had an unusually high idle. I think 1500 rpm. It drove fine for thirty minutes and the idle seemed to go back to normal.

This can be an indacator that power has been lost at the ecu, it has to relearn.

When I got back home I let it idle for a few minutes then cut it off. It would not start up again but I only tried it a few times. ...

When it does this, with the key turned to run, is the CEL on?

 

[notathomie]

I had just installed the fusible links before starting it up and experiencing the high idle. I obviously disconnected the old fusible links. And I disconnected the other cable that the fusible links sandwich on the battery post. So maybe it did need to relearn. (Although I would think the ECU would have stored routines in flash memory, which does not need a power source to save code) .

I will recheck in a moment but I am 99% sure the CEL light comes on when the key is in "run"

 

[ChaseTruck]

Have you tried re-setting the IAC?

 

[ppc]

More details required. When you say it didn't start, did the starter crank the engine and never fire or was there no sound? No sound most likely the contacts inside the starter need to be replaced.

 

[LINUS]

If you have really SCOWERED that engine harness & confirmed the wires are all excellent (you do have ~some miles, but more importantly is the underhood heat) then I'm going with a bad actor like:

Fuel filter (did both sock & filter get swapped?)
Fuse links are new(good)

Then to wipe the motor (do you still have all power to vehicle, or dead period?)
If you go flat dead, common ground.

I'm personally going to look at common grounds including motor (esp motor)

Also, the firewall side of the harness - Kevin / Rick would know best if that is a 'total fail' of the motor when the wires chafe or if it runs poorly.

The ignition switch itself (are there any scotchlocks or BS connectors in the system?)
I would jumper the leads & run around like that (still need to twist the key, use the column lock in town)

And unless I missed it already mentioned --- the EFI RELAY ---

Beyond that, I'd want to confirm constant fuel delivery both the pump itself & the floor harness power to it.

I bet you have a short somewhere - IDK the Safari engine management, but a total loss of the motor doesn't seem a hot/cold run thing, it's a larger issue where some wire is shorting real intermittently (Just playing the percentages, that would seem intuitive - again, not sure if Safari has a piggyback or some such)
If it was a hot run thing, I'd expect the motor would ping & detonate yet run if wires and fuel delivery were all a constant.

Edit - just reread your posts, saw EFI relay done, at least that's covered.
Phone screens

 

[notathomie]

Chase truck, I did not reset the IAC, but I just cranked it up this morning and it is idling fine now. So maybe it had something to do with the fusible link install.

PPC, here is more info on the shutdowns: When she cuts off mid ride, the lights on the dash are the CEL and the rectangular red battery light next to the battery voltmeter. In other words, all the lights come on that normally come on when the key is turned to the "On" position, but one has not yet cranked the key.

The batteries are brand new and the starter was just rebuilt. So when I try to start it after a hot shut down, the battery and starter perform fine. After a hot shut down the starter cranks, but usually elicits no engine firing. If I make twenty attempts to restart following a hot shut down, 17 of those attempts sound like the starter is working fine but the engine is not turning over (ie, no fuel getting to combustion chamber). Perhaps one or two attempts to start get some type of weak firing of the cylinders. And when it finally works it just roars to life. So it is almost binary. Around twenty tries seems to be the ticket.

Again, it only seems to happen after I have been driving for 30 minutes or more. Short trips around the farm are fine.

It was only cutting out when I was giving it no gas (ie, on downhills or coasting through a lower speed zone). But I just recently got two hot shut downs with gas applied.

I have done a fair amount of driving with this problem. I will run the numbers, but off the top of my head I have had ten or twelve shut downs in 20 hours of driving.

Fuel:

I just changed the fuel filter. I have not checked the rest of the fuel system. Is the fuel sock the filter inside the tank? I will check that, replace the fuel pump relay, and test the fuel pump.

Could a PCV problem cause these symptoms? I have not tested the vacuum system properly but I do not think I am getting good vacuum for the fuel regulator on the fuel rail. In fact, I wonder if my fuel regulator is defective. I will check the FSM for a way to test/ clean it.

Electrical

Linus, I will check the ignition circuit. Since I have dashlights after the shut down, wouldn't that suggest my ignition circuit has continuity? I will look for anything unusual on the ignition circuit.

I will check all grounds and go over the wiring harness again.

Thanks everyone