A 3 yr headache

[chevygal79]

94 Chevy Suburban, 1/2 ton 350
Changed out
TPS
Fuel injectors
Distributor, pick up coil, rotor, cap,
Spark plugs and wires
ECM
Ignition module
Fuel pump, fuel relay,
Starter
Checked all the fuses
Its getting fuel pressure, the oil pump is working.
There is more I just can't think of it right now. I have basically have put all new under the hood

When I turn the key to the on position it lights up the dash, when I turn the key over to start the lights do not come on, the truck will not start, after a few tries I will hear a ding, the lights come on and the truck will start.
It has done this for the past few year at the same time, when the weather gets hot, the truck will not start, but around October the truck will start and run fine. The June-July rolls around and its the same thing all over.
I did get it started long enough to take it to the shop, the technician put it on the machine and told me its all in my head, it didn't throw any codes.

I bought a Chilton book and checked all the wires going to the ECM, they seem to be ok, except for a suspect orange one that seems to go nowhere.

I feel like I keep going in a circle when it comes to this truck.

 

[zora]

how hot is hot? Could be a bad ignition switch, interior temperatures in hot areas of the country can easilly go past 110.

 

[Chuzz]

I have to agree with Zora on this one. It sounds like you've got a wire or a contact that is losing contact as it heats up. I could very well be in the ignition switch. I had an old Motorola two way radio that behaved the same way back when I had a delivery route in the 80's. When it got hot, it would not transmit and once it cooled off, it worked fine. Of course the shop couldn't find the problem because once they got it out and apart, it had cooled off enough to work. After they replaced it with a new unit, no more problems. I'm not saying that's what your problem is because I am in no way, shape or form a mechanic, but since you've replaced damned near everything else, there's not much more it could be. Thermal separation is occurring somewhere, and you've just about run out of places.