Hot Starting Problems

[ntk]

I have been trouble starting my truck when the engine is hot. Here are the details:
Year: 1999 Toyota Land Cruiser
Location: Colorado (~6-7000ft)
Mileage: 203k

Here is what's happening:
I drive the car until the engine is hot, then shut it off. If started again immediately after turning it off, there are no issues starting. If I wait about 30 minutes, I have trouble starting. I turn the key, and it cranks for 5-10 seconds. Sometimes it will rev up to about 500 rpm, but then stall out. Sometimes I will continue cranking for 10+ seconds and the only way to start at this point is to hold my foot on the gas pedal. It will start, rev up, and then idle normal, drive normal, and be perfectly fine. I have had several cases where the car has stalled after idling for a long period of time (like in a drive thru), and then has trouble starting after it stalls. Once the engine is cool, it starts perfectly fine. Starting it first thing in the morning is never an issue. I have gotten several evap system codes (P0440 if I remember correctly) that go away for months at a time after being cleared.

I also checked the vacuum switching valve today, but was not able to blow air through the ports as the FSM specifies it should be able to do if functioning properly. I ordered this and plan to replace it next week, but I'm not 100% confident that it's the cause of this problem.

Here's the recent maintenance that I've done over the last year and a half or so (most in the last few weeks) trying to solve this problem:
- Replaced fuel pump
- Replaced fuel filter
- Replaced fuel injectors (as well as o-rings, grommets, spacers)
- Replaced fuel pressure damper
- Replaced fuel pressure regulator
- Replaced engine coolant temp sensor
- Replaced engine room junction box
- Replaced PCV valve and hoses
- Cleaned Throttle Body
- Cleaned MAF sensor
- Replaced gas cap
- Checked EFI relay resistance
- Checked camshaft position sensor resistance
- New spark plugs
- Checked VSV functionality (could not blow air through ports and will replace soon)
- Tried running premium fuel for a month

I'm running out of ideas for what to try, check, or replace. Some of the stuff I've done has been good regular maintenance since the mileage is getting up there, but it's starting to feel like I've been throwing money at it with no results. What things should I look at next?

 

[nissanh]

May be too much gas vapor from the canister is flooding the cylinders?

 

[AlpineAccess]

The foot on the gas sounds indicates this is a fuel related issue.

First thought is fuel temp, or essentially vapor lock which is constantly discussed issue. Putting your foot down forces high fuel demand and would push vapor through. Premium fuel would have no effect, but non-ethanol could.

A starting point would be to syphon what fuel you have out and get some non-ethanol in as a test. Worst case you just burn through the fuel.

Plug in your OBD2 and monitor engine and ambient temps, and check out the "fuel cap gas spilling" threads for more recent updates from people on heat shielding their hard gas lines by the cats.

If you're fed up trying to figure it out Paul might be your guy. @2001LC

 

[nissanh]

The foot on the gas sounds indicates this is a fuel related issue.

First thought is fuel temp, or essentially vapor lock which is constantly discussed issue. Putting your foot down forces high fuel demand and would push vapor through. Premium fuel would have no effect, but non-ethanol could.

A starting point would be to syphon what fuel you have out and get some non-ethanol in as a test. Worst case you just burn through the fuel.

Plug in your OBD2 and monitor engine and ambient temps, and check out the "fuel cap gas spilling" threads for more recent updates from people on heat shielding their hard gas lines by the cats.

If you're fed up trying to figure it out Paul might be your guy. @2001LC

By the way... Where is Paul? Haven't seen him for a while. Hope he is safe...

 

[AlpineAccess]

By the way... Where is Paul? Haven't seen him for a while. Hope he is safe...

I think he made a note on taking a vacation or starting a big project about a week ago.

 

[abuck99]

APPS/TPS?

TPS/APPS problems

Thottle Position Sensor/Accelerator Pedal Position Sensor problems A Readers Digest on the TPS/APPS issues with links to the relevant threads. Send me any feedback/corrections/recommendations in a PM and I'll make changes. TPS = Throttle Position Sensor APPS = Accelerator Pedal Position...

forum.ih8mud.com

 

[BnvS]

I had this problem with my Toyota T100 truck. It would not start after the engine is warm. I replaced the Fuel pump, fuel filter and that fixed the issue. Your issue looks weird. Sorry could not offer to much help here...

 

[ntk]

May be too much gas vapor from the canister is flooding the cylinders?

So would this be a charcoal canister thing? I've been hesitant to replace it due to the cost, but maybe that would align with the evap system codes?

The foot on the gas sounds indicates this is a fuel related issue.

First thought is fuel temp, or essentially vapor lock which is constantly discussed issue. Putting your foot down forces high fuel demand and would push vapor through. Premium fuel would have no effect, but non-ethanol could.

A starting point would be to syphon what fuel you have out and get some non-ethanol in as a test. Worst case you just burn through the fuel.

Plug in your OBD2 and monitor engine and ambient temps, and check out the "fuel cap gas spilling" threads for more recent updates from people on heat shielding their hard gas lines by the cats.

If you're fed up trying to figure it out Paul might be your guy. @2001LC

Cool, I'll try some ethanol free fuel. There's a place by my house that sells it so that's definitely worth a test. I'll look into the heat shielding as well. I've read about it, but haven't had any fuel spilling out of the gas cap so didn't think much more about it. Probably another thing that wouldn't hurt to add.

APPS/TPS?

TPS/APPS problems

Thottle Position Sensor/Accelerator Pedal Position Sensor problems A Readers Digest on the TPS/APPS issues with links to the relevant threads. Send me any feedback/corrections/recommendations in a PM and I'll make changes. TPS = Throttle Position Sensor APPS = Accelerator Pedal Position...

forum.ih8mud.com

Thanks! I'll read up on this thread.

Thanks everyone for the help so far!

 

[OwnerCS]

I have been trouble starting my truck when the engine is hot. Here are the details:
Year: 1999 Toyota Land Cruiser
Location: Colorado (~6-7000ft)
Mileage: 203k

Here is what's happening:
I drive the car until the engine is hot, then shut it off. If started again immediately after turning it off, there are no issues starting. If I wait about 30 minutes, I have trouble starting. I turn the key, and it cranks for 5-10 seconds. Sometimes it will rev up to about 500 rpm, but then stall out. Sometimes I will continue cranking for 10+ seconds and the only way to start at this point is to hold my foot on the gas pedal. It will start, rev up, and then idle normal, drive normal, and be perfectly fine. I have had several cases where the car has stalled after idling for a long period of time (like in a drive thru), and then has trouble starting after it stalls. Once the engine is cool, it starts perfectly fine. Starting it first thing in the morning is never an issue. I have gotten several evap system codes (P0440 if I remember correctly) that go away for months at a time after being cleared.

I also checked the vacuum switching valve today, but was not able to blow air through the ports as the FSM specifies it should be able to do if functioning properly. I ordered this and plan to replace it next week, but I'm not 100% confident that it's the cause of this problem.

Here's the recent maintenance that I've done over the last year and a half or so (most in the last few weeks) trying to solve this problem:
- Replaced fuel pump
- Replaced fuel filter
- Replaced fuel injectors (as well as o-rings, grommets, spacers)
- Replaced fuel pressure damper
- Replaced fuel pressure regulator
- Replaced engine coolant temp sensor
- Replaced engine room junction box
- Replaced PCV valve and hoses
- Cleaned Throttle Body
- Cleaned MAF sensor
- Replaced gas cap
- Checked EFI relay resistance
- Checked camshaft position sensor resistance
- New spark plugs
- Checked VSV functionality (could not blow air through ports and will replace soon)
- Tried running premium fuel for a month

I'm running out of ideas for what to try, check, or replace. Some of the stuff I've done has been good regular maintenance since the mileage is getting up there, but it's starting to feel like I've been throwing money at it with no results. What things should I look at next?

Was the engine coolant temp sensor the one with two plug wires or one?

 

[ntk]

Was the engine coolant temp sensor the one with two plug wires or one?

It was the one with two wires. I believe the other one is just for the gauge

 

[OwnerCS]

It was the one with two wires. I believe the other one is just for the gauge

That's it. Wish I had more to offer.

 

[ntk]

Reviving this thread to finally write that this problem has been solved. I replaced the charcoal canister a few months back and have not had a single issue since. The old canister was hard and swollen. This came after I nearly got rid of the LC out of frustration from this problem. 3 shops in my area tried to fix the problem over the past year (one even had it for 2 months) and I finally decided to throw some money at the charcoal canister as one final attempt.

 

[SteveH]

Here's my story like this from yesterday:

I parked the truck hot for 5 minutes, and when I started it, it ran but sputtered for 20 seconds at ~200 RPM (literally) and stalled. Would not restart - just crank and sputter. I checked all fuses, sprayed Ether starting fluid in it, and it roared to life, then died. When cranked, it would occasionally sputter, but clearly a no-fuel situation. Checked all fuses.

I pulled the fuel filter outlet hose off (pinch with fingers and slide off) and high-pressure gas sprayed out from the fuel rail hose end. I called my wife and had her crank the engine with this line disconnected, and it shot out a great quantity of gas that I caught with paper towels, indicating the fuel filter was not plugged and the in-tank pump was working (it has been replaced). I reconnected the fuel line, and she cranked it again, and it fired up and ran perfectly. I drove it home and it ran great. No MIL or latent codes.

When I got home, I replaced the fuel filter (because I had a free one from the PO). Fired right up and ran great.

With no codes, etc. I think that all I can do is drive it until it happens again. Ideas? @ntk - I will study the charcoal canister - never gave that much thought.

 

[ntk]

The charcoal canister is an easy thing to check. Takes 5 minutes to pull it out, just make sure you take a picture of where all the hoses go before you disconnect them. My faulty charcoal canister had a slight bulge on the side, and the charcoal inside was solid as a rock. On the new one, I could hear the loose charcoal inside upon giving it a gentle shake. There is still something in the back of my mind wondering what caused the charcoal canister to go bad. It could be a bad purge valve on top of the charcoal canister… my plan is to see if the new one (technically used from a part out) goes bad over time and then start replacing the surrounding components if needed.

 

[nissanh]

Here's my story like this from yesterday:

I parked the truck hot for 5 minutes, and when I started it, it ran but sputtered for 20 seconds at ~200 RPM (literally) and stalled. Would not restart - just crank and sputter. I checked all fuses, sprayed Ether starting fluid in it, and it roared to life, then died. When cranked, it would occasionally sputter, but clearly a no-fuel situation. Checked all fuses.

I pulled the fuel filter outlet hose off (pinch with fingers and slide off) and high-pressure gas sprayed out from the fuel rail hose end. I called my wife and had her crank the engine with this line disconnected, and it shot out a great quantity of gas that I caught with paper towels, indicating the fuel filter was not plugged and the in-tank pump was working (it has been replaced). I reconnected the fuel line, and she cranked it again, and it fired up and ran perfectly. I drove it home and it ran great. No MIL or latent codes.

When I got home, I replaced the fuel filter (because I had a free one from the PO). Fired right up and ran great.

With no codes, etc. I think that all I can do is drive it until it happens again. Ideas? @ntk - I will study the charcoal canister - never gave that much thought.

You could have burned the car with fuel getting on to the exhaust manifold. Try not to do it again on a hot engine.

 

[SteveH]

Mine died again yesterday while driving. Lost power at 20 mph on a side street, and was sputtering as before. I got the truck to the curb, where it idled at 200-300 RPM for a few seconds, then died. Outside temp was 90F. When it sputters, no amount of throttle changes anything.

This time, it promptly restarted and ran fine, so I started it, and parked it in a parking lot, and 2 hours later, started it and drove home. No codes. Since I have no evidence that the fuel pump has ever been replaced (in 314K), I plan to buy and install one.

 

[Les Summer]

I have been trouble starting my truck when the engine is hot. Here are the details:
Year: 1999 Toyota Land Cruiser
Location: Colorado (~6-7000ft)
Mileage: 203k

Here is what's happening:
I drive the car until the engine is hot, then shut it off. If started again immediately after turning it off, there are no issues starting. If I wait about 30 minutes, I have trouble starting. I turn the key, and it cranks for 5-10 seconds. Sometimes it will rev up to about 500 rpm, but then stall out. Sometimes I will continue cranking for 10+ seconds and the only way to start at this point is to hold my foot on the gas pedal. It will start, rev up, and then idle normal, drive normal, and be perfectly fine. I have had several cases where the car has stalled after idling for a long period of time (like in a drive thru), and then has trouble starting after it stalls. Once the engine is cool, it starts perfectly fine. Starting it first thing in the morning is never an issue. I have gotten several evap system codes (P0440 if I remember correctly) that go away for months at a time after being cleared.

I also checked the vacuum switching valve today, but was not able to blow air through the ports as the FSM specifies it should be able to do if functioning properly. I ordered this and plan to replace it next week, but I'm not 100% confident that it's the cause of this problem.

Here's the recent maintenance that I've done over the last year and a half or so (most in the last few weeks) trying to solve this problem:
- Replaced fuel pump
- Replaced fuel filter
- Replaced fuel injectors (as well as o-rings, grommets, spacers)
- Replaced fuel pressure damper
- Replaced fuel pressure regulator
- Replaced engine coolant temp sensor
- Replaced engine room junction box
- Replaced PCV valve and hoses
- Cleaned Throttle Body
- Cleaned MAF sensor
- Replaced gas cap
- Checked EFI relay resistance
- Checked camshaft position sensor resistance
- New spark plugs
- Checked VSV functionality (could not blow air through ports and will replace soon)
- Tried running premium fuel for a month

I'm running out of ideas for what to try, check, or replace. Some of the stuff I've done has been good regular maintenance since the mileage is getting up there, but it's starting to feel like I've been throwing money at it with no results. What things should I look at next?

glad you fixed it. I was going to ask when you last did the ignition coils..

 

[ntk]

Actually had an ignition coil go bad about 2 weeks ago and replaced all 8 of them, but it appeared to be unrelated to the hot starting problem

 

[SteveH]

To close the loop on this thread, I installed an OEM fuel pump a month ago, and my stalling and stumbling problems (with no codes) are completely gone. I have driven it enough by now that if they were going to show, they would have by now.