03 7.3 will not start unless plugged in.

[GODZILL]

I have a 03 7.3L with new starter, batteries, glow plugs, and have replaced glow plug relay. (solid state type).
Truck still has to be plugged in to start.
Any suggestions?

[Chile]

Does your truck have a chip with custom tunes???? I put a chip in my truck that had custom tunes and it was written for a 48 state truck. They didn't know it was a Cali truck and something in the tunes does not tell the glow plugs to turn on. As soon as they wrote a new tune..... fires right up.

[GODZILL]

I had the 4 inch exhaust and non programmable chip installed in CA. It is a manual 4 way switch. 0, 35, 75, 100HP.
I will try disconnecting it and removing battery cable to deprogram the truck to see if it that.
Thanks.

[Dobbelaar]

Check your Glow plug relay if not then perhaps your starter is going bad .... needs the warm oil to help it turn over fast enough

[GODZILL]

Replaced Glow plug relay 3 times because first 2 were not in package from parts place. still no go.

[ianstew]

what kind of temps are you trying to start in?

[GODZILL]

This year being so warm anywhere from 26 up to 70 and it acts the same way, just a little harder as it gets colder. But must be plugged in to start.
Could the relay still be bad?
I helped on an older 99 7.3 with relay and 2 were bad from parts place.
I have had 3 on this and still no change.

[ianstew]

did this statrt all of the sudden or gradually get worse

[ianstew]

ive never worked on a cali truck, but it should start at 70 degrees unaided by GP's, my truck will satrt in the 40's unaided, even as low as 35 degrees or so. takes a long crank, maybe even two, but itll start. im not familiar with cali trucks at all though, so i dont know if starting is prevented if the gp's do not come on.

[GODZILL]

It started last year and we first had it checked and the #8 injector was replaced. It improved but was not 100%. It then got back to plugging in so I had it taken to dealer who replaced the starter, glow plugs, harness, and sensor?.
It came back and still had to plug in. I did some research thru here and relay seemed to be culprit. but then I got 2 bad ones for sure thru parts and 3rd one is in question.
The CA 7.3L for some reason did not come with a catalytic converter? (surprised me).
So some of the parts are the same just different outputs. they look the same.

One of the relays changed it for just one start up and then when the next day rolled around it did not start. Could the relay be bad for a 3rd time from parts?