Had to crank her way too long to turn over and then stumbling idle.....now dying while driving (1 Viewer)

[Francis K]

Makes me wonder if you had some kind of vapor lock in your tank if that really was the case. If you opened the gas cap when it was acting up, did you hear air rushing in or out?

I never noticed it when I took the gas cap off but when I unhooked the hoses from the charcoal cannister it definitely hissed for a really long time.......

 

[Francis K]

Yes so it's definitely not fixed, totally jinxed myself I knew it couldn't be that easy.

Funny because she teased me, she was ready to rock for a few days no issues and tonight worse than ever. It stalled out in the drive through line waiting for coffee and took a while to crank back up then headed home from work she wanted to stall out as I was driving her, the rpm's would just drop and the gas pedal was unresponsive or at least not doing much....that's new. Stopped at a light and she shut down, it took a lot of cranking multiple times to get her turned over and rolling, kept wanting to die when I put her in gear even when I got her idling.

So yea at this point I'm afraid to drive her I'm sure she'll just eventually leave me stranded. I'm thinking fuel pump, or at least hoping not head gasket, but she needs to go to a shop to see a real mechanic. Going to see if I can pop in tomorrow and at least see what he thinks.....I hate going in blind like that but I don't have a choice.

 

[desmocruiser]

If you want to pull and check the plugs, there is a video of cranking an 80 while the plugs were removed to check for a blown head gasket Ryan with Otramm posted that might be helpful.

If all those are clear and you are zeroing in on fuel related issues and it has a newish filter, I would research or have the fuel pressure regulator checked along with the pump while you are at the shop.

 

[Francis K]

Took her to my guys shop and he looked her over, unfortunately I couldn't reproduce it there but he was pretty confident it wasn't the HG. Told me I should try cleaning out the throttle body and MAF, I actually do have a spare MAF so might just throw that on.

He also noticed this sensor going to the manifold was broken, anyone know what it is?

 

[brockdeck]

EGR Temperature Sensor, your EGR valve may be stuck open

While you poke around there careful not to put your hand on the "gas filter" and break the barb like so many of us do

 

[desmocruiser]

Took her to my guys shop and he looked her over, unfortunately I couldn't reproduce it there but he was pretty confident it wasn't the HG. Told me I should try cleaning out the throttle body and MAF, I actually do have a spare MAF so might just throw that on.

He also noticed this sensor going to the manifold was broken, anyone know what it is?

View attachment 3212908View attachment 3212909

Should be easy to reconnect to see if it fixes the issue !

 

[Francis K]

Should be easy to reconnect to see if it fixes the issue !

Would that possibly be causing it though? What do you think just splice it up and slap some electrical tape on it until I get a new one?

 

[ajax1]

Yes

 

[Francis K]

I ended up splicing it lets see what happens, I tried removing it from the manifold to make it easier but that bolt wouldn't come off to save my life even though it looks completely clean, I damn near stripped it trying to wrench it off. That's going to be an issue when it comes to replace it....

 

[BloodyMGT]

Updating for future reference to help anyone else, put a new charcoal cannister in and it has stopped stalling out. Mind you this was intermittent so I'm not 100% counting my chickens but we shall see....

I'll update down the line either way.

EDIT: problem persisted....read on

The first thing I would do is install a fuel gauge pressure monitor port.
I don't know why Toyota didn't.
I put mine on the input to the fuel filter (under the intake manifold).
I used a banjo bolt adapter that has an AN-6 head on it (similar to picture with a 1/4" NPT port).
This allows an analog fuel pressure gauge to be installed in the engine bay either to troubleshoot or monitor.
I leave mine in ALL the time so I know for certain what the fuel pressure is.
I also have an analog oil pressure gauge in there.
I have had SEVERAL issues on my 1994 with the same symptoms as you report:
1) Bad (new) fuel pump. Check valve in the pump didn't work. Would bleed fuel pressure to zero 15 seconds after shutting down. Not good. Found this immediately after installing pressure gauge. Clogged (open) injectors can also do this.
2) Corroded terminals on fuel pump relay (F4). Found this by monitoring 12VDC at the fuel pump connector right at the tank. Read between 6V and 9V, depending on wind direction. Should be about 9 to 10V during normal running (going through resistor) and 12V when starting or cold.
3) Corroded factory splice in the 12V wire between the fuel pump relay and the pump (I14). The factory used "solder sleeve" type splices with blue tape (sort of) sealing it and this one got corroded after numerous stream crossings. This also caused 6V to 9V at the pump, depending on wind direction.
4) Broken/shorted wire(s) on the THW engine coolant temperature sensor. If the ECU thinks the engine is too hot, it will lean out the fuel. Too cold and it will enrich it. Both are bad. With the ECU plugged in, back-probe the pins at the ECU and measure what your engine coolant (THW) and intake air (THA) temperature sending units read.
Read pin THA to pin E2 with a multi-meter: 0.5–3.4 VOLTS WITH IGNITION SW ON AND INTAKE AIR TEMP. 20°C (68°F)
Read pin THW to pin E2 with a multi-meter: 0.2–1.0 VOLTS WITH IGNITION SW ON AND ENGINE COOLANT TEMP. 80°C (176°F)
You can also unplug the ECU and just read the resistance at the wire harness connector pins:
Read pin THA to E2 : 2.0–3.0 Kohms (INTAKE AIR TEMP. 20°C (68°F))
Read pin THW to E2 : 200–400 ohms (ENGINE COOLANT TEMP. 80°C (176°F))

Any way you go you need solid data to base your corrective actions on.
The sooner you get solid data, the sooner you'll be back to loving that Cruiser.

 

[TomH]

A simple test would be to bypass the fuel pump resistor, shown on the schematic above. Toyota limits fuel pump speed based on engine need for fuel. Bypassing the resistor would provide 12V to the fuel pump all the time.

I didn't even know that someone made a bypass connector. Maybe it's more of a 100 series issue.

fuel pump resistor bypass blank. 80s and 100s

far as I know fits 80s and 100s. I have 4 to spare. just a fancy bypass. 20$ to your door.

forum.ih8mud.com

 

[ppc]

A simple test would be to bypass the fuel pump resistor, shown on the schematic above. Toyota limits fuel pump speed based on engine need for fuel. Bypassing the resistor would provide 12V to the fuel pump all the time.

I didn't even know that someone made a bypass connector. Maybe it's more of a 100 series issue.

fuel pump resistor bypass blank. 80s and 100s

far as I know fits 80s and 100s. I have 4 to spare. just a fancy bypass. 20$ to your door.

forum.ih8mud.com

View attachment 3213569

Rather than bypassing the fuel pump resister, it better is to bypass the fuel pump relay. When bypassing the resistor only, you're still leaving the relay in the circuit which certainly is more prone to failure, degraded contacts and voltage drop.

 

[TomH]

Rather than bypassing the fuel pump resister, it better is to bypass the fuel pump relay. When bypassing the resistor only, you're still leaving the relay in the circuit which certainly is more prone to failure, degraded contacts and voltage drop.

Makes sense. So you are saying pull the relay and jump pins 3 and 5 which will provide 12V to the fuel pump and ignore the signal from the ECU.

One thing we don't know for sure is what year Land Cruiser @Francis K is driving. I think it is a 97. These circuits are different for earlier years.

 

[Francis K]

Thanks @TomH @ppc @BloodyMGT I sincerely appreciate it! It is indeed a 97.


I'm counting my chickens again over here but since I spliced that EGR sensor back into place she's been starting and running fine. Hoping that's the end of it but if not all that info is invaluable, I will update either way!

 

[ajax1]

If the egr gets in the wrong position will do exactly what happens to op. @Francis K the fsm has a test you can run to see if egr is stuck

 

[Francis K]

We're still good over here since splicing that wire together.....got a new EGR sensor on the way.

Thanks to everyone for the help! If it changes I will update....

 

[Francis K]

Alright boys so found some funky stuff going on here. I spliced that sensor and all was well but me being the jackass I am with a fruitless obsession of having everything perfect on a quarter century old truck I had to spring for a replacement sensor. Popped her on and all was well again, until a couple days later when a CEL popped on with the P0401....EGR issues.

I was thinking the "new" sensor was bad, which would have been odd as the old one didn't create a CEL even when it was cut, but I put the old one back on just to eliminate the variable. In the middle of doing that I noticed this:

So was my old sensor rigged up to not throw a code? Not really upset if that's the case it's pretty genius and the truck is running fine with no CEL on the old sensor....is that what I'm looking at here???



-No sensor or sensor cut, truck runs like crap

-Old sensor spliced, runs fine and no CEL (but is this thing even doing anything anymore, how does that make sense?)

-"New" sensor, runs fine but with CEL P0401



I've read all the endless headaches of chasing down the P0401, should I be concerned here or just keep it moving?

 

[cahill]

I am pretty sure this was to fool the ecu into receiving the correct signal to keep the EGR code from triggering. I think there was a thread on mud about it. You could probably just use that resistor in the new sensor to keep the P0401 from triggering and keep the wiring nice or you could fix the EGR problem.

 

[george_tlc]

The resistor hack is to fool the ECU into thinking that the EGR system is all good. More typically used as part of blocking of the EGR with a metal plate.

So, maybe there's a metal plate, maybe not. Obvously the PO has 'fiddled' with things.

With the new temperature sensor it is detecting that the EGR system is not working properly. So, either the EGR system is broken and the resistor hack was installed to fake out the ECU for smog testing etc, or it's got the metal plate blocking things off and with the new temp sensor the ECU is flagging a real error.

You need to delve further to see what the PO has actually done...

cheers,
george.