Hi, I'm a newbe posting here but I've been reading and using the info I've found here for a long time. Be easy on me. I bought my truck new in 89. Had the head gasket replaced when they had the recall. The head gasket did let go about 2 years ago. My current problem is the truck dies and won't start after about an hour of idling or when it gets to a certain temp. I've replaced a lot of parts, fuel pump and fuel pump relay included. Yesterday when it wouldn't start, I jumped the two terminals that makes the pump run and it wouldn't run. Can anyone suggest what might also be bad? It will start right up when it's cold. Thanks!!!!

 

Hello, I literally bought my 89 with the v6 yesterday. But I can offer some general auto knowledge. In my experience there are two types of fuel pump activating systems. One that primes when the key in cycled on and a type that requires a cranking signal of some sort to activate. I'd figure that out first by researching on Google. This isn't really on going to do much for diagnosing other than help you know if you should hear your pump after you turn your key on or not.

Now to me this doesn't sound like a fuel pump issue. It sounds more like a bad coil to me. In my experience fuel pumps either work or don't. Coils on the other hand will start to fail when they get warm and function normally again when cold. I've successfully diagnosed this by keeping the coil cool and seeing if the problem stops. You can do this by using upside down airbduster cans or a fan and the hood popped.

 

Fuel filter clogged? Start simple, especially if you've never changed it.

 

Thanks for the replys. The fuel filter was changed a few years ago for the first time. The coil and ignition modual was changed a few weeks ago along with the dist cap, new plugs and wires. Do you think the coolant sensor would have anything to do with the problem, it's cheap and that's what I thought I'd try next. I know, I need to get an olm meter and learn how to work it.

 

Once again...I don't know about these engines but I've had a coolant temp switch cause a similar issue on a Turbo Eclipse before. It would hit a certain temp and then send out an infinite cold signal and run so rich the engine would die and not start.

 

Thanks Rule So Hard. I'll try that. Oh, I've also replaced the Fuel Pressure Modulator and the Throttle Position Monitor. I'm just about out of parts to replace. But being so old, I figure they needed replacing anyway ha.

 

If the sensor dosen't fix it you'll need to start looking at wiring. A short could cause intermittent issues like this too.

 

Well, the Coolant Temp Sensor didn't fix the problem. I'm check for shorts and buy an ohm meter and learn how to use that. I'll try to check the ECU. It's throwing codes 42 and 52 at me. 52 is the knock sensor but and it's been showing for a few years after I had the head gasket replaced and heads shaved.At that time I went ahead and bought a new knock sensor, later went back and replaced the short harness going into the sensor and the check engine has stayed on. It never effected how the truck drove though. 42 I'm not sure what that means, going now to find my shop book.

 

Don't be like that. You'll run out of money long before you figure out the problem

Yes, and a timing light ($20). Just the process of checking the timing will (first) tell you if the plugs are firing.

Making a truck start is, in the end, very simple. Fuel, spark, air. Use the timing light to confirm you've got spark (and in the right time). Pull the plugs to see if they are wet with fuel; if not, you have a fuel problem.

And DON'T replace parts just because, well, you've got nothing else to do.

Code 42 is the speed sensor, which will not affect starting. http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf Code 52, on the other hand, causes the ECU to dramatically retard timing; the truck should run like crap. (But won't affect starting either.)

Spend a few minute looking around this site. You'll quickly learn that we have easy access to the manual (for all the codes). And you don't need to spend much time on "general auto knowledge" guessing what type of fuel system Toyota trucks have.