When my truck gets up to normal oper. temp., and I shut it off, it doesn't want to start back up until it cools down quite a bit. If I go on a short ride and it doesn't heat up it usually fires right back up. And sometimes even after long rides it starts but usually not and when it does its verrryyy sluggish to crank over.

So far I've replaced all the basics.... The starter solenoid, negative battery cable, I ran a double positive to the solenoid, both the negative and positive cables to the starter, I swapped in a different battery, and still have the same results. Even when jumping the positive and switch posts on the solenoid, so it's not the ignition switch either.

Here's my ideas now. I was thinking maybe the alternator has an issue and once it gets hot it gets weak, the truck puts strain on the battery, then it doesn't have the juice to crank over when I go to start it. But that doesn't explain why it still starts when it's cooled down..... The other thought is maybe the starter itself, but again, when it isn't warmed up, the starter has plenty of power... The starter is only about 3 years old, it was replaced right before I bought the truck, but that doesn't mean it can't be bad. Anybody have any ideas????

I needed the cables replaced anyways I suppose, but I don't want to blindly throw money at this issue.

 

And its the straight six with a 5 speed. So if I pop the clutch I can get it to start at least, but the truck is too heavy to be pushing around all summer.

 

Ok good start on things to try but why not try looking at your cooling system? Thermometer, and there is a sensor that is linked to the computer that tells it to start if it is cool enough. I don't remember the name but my buddy has a tbird an that was his issue and we did everything u did. Cost him $20. I'll see if I can find out what its called and post again

 

Normal op temp is when the ECU goes into closed loop. Run error code scans. Start w/ KOEO's.

 

It's actually called a coolant temperature sensor

 

Your probably referring to the ECT sensor (Coolant temp). The ACT sensor (incoming air temp) is also important for proper fuel trim & ECU modification of timing curve, based on temperature.

You want to pre-warm the engine to normal op, then do the KOEO scan. That's all we're interested in initially, so it doesn't matter if it doesn't restart at that time.

See link:https://www.f150forum.com/f10/heads-...05/#post623219

 

For those following, it's an 89'.

ECT = http://www.fordfuelinjection.com/?p=28

ACT = http://www.fordfuelinjection.com/?p=29

 

I just did a lot of cooling system work recently and pulled codes the other day. No codes pertaining to this, just an egr code and smog codes because I do not have either, and an ac compressor code because I took the compressor off. The thermostat and coolant are new. The radiator is new-ish, and it runs just right at normal op temp and never has a problem shutting down or overheating while its running, only after I shut it down. I had the engine temp sensor go bad before, and it threw a code, but there is no code now. Could it be bad without a code and with the gauge still reading normal?

 

Also, as ymeski and some others may remember, I have done the timing bump on this truck and am currently at 12.5 to 13 degrees advanced. I know this can make starting a bit more difficult, but it hasn't really been an issue, it only seems to do this around the summer time, as it did this same thing last year. I can put it back down to stock timing, but I'd rather leave it where it's at, as I don't want to lose gas mileage.

 

Were you experiencing this before you bumped?

You can't just do the test w/ engine not pre-warmed. Result's may not be accurate regarding those two sensors You want to pre-warm the engine to normal op, then do the KOEO scan. That's all we're interested in initially, so it doesn't matter if it doesn't restart at that time.