Topic: truck dies when hot

[86turboyota]

1988 toyota pickup 4x4, 22-re, 5spd, 151,xxx miles.  When cold the truck starts just fine, but then once it gets up to temperature or about 4-5 minutes idleing it just dies and wont start again until it is cold.  I changed the fuel pump and filter less than a year ago and have not run it out of gas or anything like, so i dont think it is either of those ( fuel pump and filter where what my search results brought up).  Please help.

[88wildrunner]

could be your radiator or thermastat so you should probly check that, its prolly over heating. only reason i can think of for an engine dying when hot.

[wa4x4]

There should be some form of choke on your EFI system. My guess is that your engine is flooding, but I could be wayyy off.

[toyzuk]

i remember a guy tellin me the same thing happened to his toyota and he said it was the feul pump fuse i believe. some how it would get so hot it shut the pump off(dont know how it did that but?), hed pull the fuse to cool it down and got it home.
i doubt this is the prob but might want to check.

just somthin i herd awhile back.

[86turboyota [OP]]

could be your radiator or thermastat so you should probly check that, its prolly over heating. only reason i can think of for an engine dying when hot.

i dont think it is the radiator ( my radiator has under 20,000 miles on it and i have never had overheating problems) the truck actually dies before it even gets all the way up to temperature.

There should be some form of choke on your EFI system. My guess is that your engine is flooding, but I could be wayyy off.

sounds feasable ... where would i find this and how do i adjust it?

i remember a guy tellin me the same thing happened to his toyota and he said it was the feul pump fuse i believe. some how it would get so hot it shut the pump off(dont know how it did that but?), hed pull the fuse to cool it down and got it home.
i doubt this is the prob but might want to check.

just somthin i herd awhile back.

ive checked the fuse and it dosent appear to be blown or damaged so im not sure what to make of your post....

[kneedownnate]

There should be some form of choke on your EFI system.

Negative, most efi systems "choke" by dumping in extra fuel, thereby richening the mixture.

[toyzuk]

the guy said it didnt' blow the fuse or anything it just got super hot and turned the pump off then it cooled down and worked again. he said the same thing, he could only drive it for about 5 min then it shut off... i dont know how that would shut the feul pump off but its just somthin a guy told me awhile back.

[crx-si]

Coil, ignitor.

[86turboyota [OP]]

the guy said it didnt' blow the fuse or anything it just got super hot and turned the pump off then it cooled down and worked again. he said the same thing, he could only drive it for about 5 min then it shut off... i dont know how that would shut the feul pump off but its just somthin a guy told me awhile back.

how did he fix it?

Coil, ignitor.

how do i test those?  do they stop working when hot?

[skipjack]

the guy said it didnt' blow the fuse or anything it just got super hot and turned the pump off then it cooled down and worked again. he said the same thing, he could only drive it for about 5 min then it shut off... i dont know how that would shut the feul pump off but its just somthin a guy told me awhile back.

thats the fuel pump relay, the way they wire them from the factory theres a built in saftey, its like a circuit breaker, if the pump runs to hard and heats up it could cause a real problem (kaboom) so they designed the system to shut itself off if the pump works to hard. im not real sure how to find em, but if you have a wiring diagram you can trace it all out.

[BigMike]

uhhhhhhhhhhh oh boy

I changed the fuel pump and filter less than a year ago and have not run it out of gas or anything like, so i dont think it is either of those

I don't know why so many people believe that you can damage an EFI engine by running it out of fuel. The only way to ruin anything on an EFI engine would be if you continued to crank the engine for more then 5 straight mins. This might be enough to over heat the fuel pump since there is no fluid absorbing the heat. Injectors can operate for hours without any fluid in them, etc.

could be your radiator or thermastat so you should probly check that, its prolly over heating. only reason i can think of for an engine dying when hot.

The older EFI systems will not die when they over heat. You can run an engine without any coolant, and it will continue to idle until it locks up. There is no fail-safe system onboard.

i remember a guy tellin me the same thing happened to his toyota and he said it was the feul pump fuse i believe. some how it would get so hot it shut the pump off(dont know how it did that but?), hed pull the fuse to cool it down and got it home.

thats the fuel pump relay, the way they wire them from the factory theres a built in saftey, its like a circuit breaker, if the pump runs to hard and heats up it could cause a real problem (kaboom) so they designed the system to shut itself off if the pump works to hard. im not real sure how to find em, but if you have a wiring diagram you can trace it all out.

No, this is not true. There is no such system. The fuel pump gets it's voltage through the OCR (Opening Circuit Relay)  (triggered by the AFM via the ECU) which is powered through the EFI Main Fuse (IGN ON), which is directly powered from the battery through the AM1 80A Fuse. If either fuse is blown, then the circuit is "open," otherwise, the fuel pump will always have power whenever the key is ON & there is air flowing through the AFM. Since the AFM reports the air flow to the computer, the computer is the one who controls the Fuel Pump, so it also precharges the fuel system prior to turning the key to the START position.

It does not make any since for an overheated fuse to not work. Even if it is physically hot, unless it is blown, current will still be transfering across it. I would rather think that the connection that the fuse plugs into must not be good/clean, and possibly other devices have been installed onto that circuit which are creating a higher resistance across the fuse (ie. heating it up). So if he has been replacing the fuses, then sure, its getting hot enough to blow it, but if it is just hot, then that would just mean that the amount of current is near the physical capacity of current flow across that fuse, or it's rated amperage. Bad connections typically heat up because there is less contact area for the current to flow.

There should be some form of choke on your EFI system. My guess is that your engine is flooding, but I could be wayyy off.

If the engine is flooding out only when hot, then it could be something to do with the engine temperature sensor. I am not sure if it is the gauge sensor that the computer reads from, or if it is one of the other temp sensors that are mounted on the front side of the lower intake manifold, just down stream from the theromostat. If the sensor is not reporting that the engine has warmed up, then the cold start injector could still be powered which would cause the engine to lean out the engine injectors. This would more then likely through a check code, especially if the cold start injector is moving more than 15% of the consumed fuel.

Coil, ignitor.

I have seen coils overheat and become inefficient, but I don't think just idling could cause this. I would definately check the grounds on the ignitor, but usually the ignitor will either work or not work, and if it is working, then any problems with it should be notices across a certain rpm range or engine load. I have gotten a coil soaked in water, and it the engine was able to idle just fine, but once you gave it a load, it bogged out.

86turbo, I am courious, like wa4x4, if this is a fuel related issue. Next time it dies when hot, try to crank it a couple of times making sure that it won't start, and then pull out a spark plug and check if the plug is dry or soaked in gasoline.

[chim]

I had this problem recently, and so did my cousin.. our trucks would start fine, and when they got warmed up they would just die..  after 10min or so they would start again..  we both changed our ignitors and they have been working fine since.

[86turboyota [OP]]

....86turbo, I am courious, like wa4x4, if this is a fuel related issue. Next time it dies when hot, try to crank it a couple of times making sure that it won't start, and then pull out a spark plug and check if the plug is dry or soaked in gasoline.

ok i did what you said here, ran it till it died ( 15 minutes or so) then cranked it over several times and pulled a spark plug ( plugs where very sooty and had white reisdue on them) and i cleaned and regapped them, put them back in and it still didnt start, pulled 1 plug again and looked to see if it was wet ( flooding), and it was dry as a bone.  Please give me more feedback, thanks.

[86turboyota [OP]]

I had this problem recently, and so did my cousin.. our trucks would start fine, and when they got warmed up they would just die.. after 10min or so they would start again.. we both changed our ignitors and they have been working fine since.

Is there a way to test the ignitor?  how much did your new ignitors cost?

[BigMike]

Well if the plugs are dry, then there isn't any fuel getting in there. The check engine light is not on, right?

If your igniter is bad or good, it would have no affect on the fuel delivery.

Let's tackle this problem one thing at a time. First let's find out what's wrong with your fuel system.

Next time it dies out, with the engine off and the key turned off, put a rag under the cold start injector and crack the metal line that runs to it. Gas will spray out as the pressure inside the fuel system slowly goes down. After it has stopped spraying, have someone else turn the key to the ON position. It may or may not develop fuel pressure right now. If it does, then they computer must think the engine is still cold. That could be related to what I was talking about earlier..
After the key is in the ON position, regardless if any fuel came out or not, leave the fuel line cracked open, and try to crank it. See if it is able to build fuel pressure.

If it is something related to the operation of the injectors, then you could check your injector resistors. They could have a weak ground or be bad. I do not know off hand where the injector resistors are located in the engine bay.. I would need to see a picture of a 22R-E engine bay. This would be a simple fix as the resistors are a simple aluminum component that has one plug to it. It could be found from a wrecking yard and swapped out very easily.

Let us know what you find out about the fuel pressure.

Mike

[86turboyota [OP]]

well i got the truck to run now.. or at least so far it seems to be running good.  I pulled the coil/igniter out of my 4runner and put it into my truck and the truck seems to be fine now.  Thanks everyone for your help.

[crx-si]

It made sense to me. Sounded like a fire issue.