dash/under dash fuse and fire-wall junction box harness compatibility

[99xcss4]

I hope this is the right spot for this. I am getting ready to pull the under dash harness from what I think is a 90 or 91 k1500 5.7 5 speed. before i do I would like to know if it will be compatible with with a 94 454 4l80e truck was born 6.5. I know the gas diesel harness/fuse boxes/junction boxes are not the same. I this is a big part of why the fuel pump relay coil and dizy have no power and no injector pule with noid light but it will crank. just to be more clear when I say junction box I mean where the engine harness and cab harness plug into the fire-wall.

 

[someotherguy]

Family-size can of worms. Not only do you have differences based on engine and transmission combos, almost each year introduces differences as well.

For your dash harness you want to stick with a donor much closer to your year model - for a 94, that would be a range of 92-94 only. 88-91 have very different electronics especially in regards to the gauge cluster. Then 95 of course is the whole dash/interior redesign and is very different.

When you start talking under hood harness for the PCM, the very general groups are 88-90, 91-92, 93-94... 91 is when the shape of the opening in the firewall changed, so that's an issue for anyone doing swaps that may not want to get heavily involved in harness modification. Obviously the firewall hole is just one of many more variations but that's the obvious one.

Richard

 

[99xcss4]

thanks for the info how hard would it be to diesel harness in the cab to work with the 454 tbi engine trans t-case harness and pcm as I said in first post it cranks but has fuel and no spark and no power to fuel system and coil and dizy no injector pulse. a better question is has any one ever successfully ever done a diesel to tbi swap and is there a wright-up on it any where? I am unable to find any info any where online for this problem. with the exception of this problem every thing else on the truck work all lights power windows the dash responds radio works brake lights headlight tun signals park light horn wipers hvac controls power door locks even if i conect the coil and fuel pump directly to the battery it will not start and will not pulse the injectors if I dump gas down the throttle body it will run till the cup of gas has run out and will do the same with starting fluid. will changing the dash harness even fix what ever the problem is?

 

[99xcss4]

you say a year range between 92-94 dose it have to come from a 454 4l80e and be a 4x4 and or can it be any thing as long as it is gas?

 

[someotherguy]

All depends on how much work you want to put into modifying the harness. As I said each engine/trans combo brings in its own variations. I would suspect the harness between the PCM and engine is what's giving you trouble but I doubt it's something anyone can diagnose long distance instead of laying hands on the truck.

A whole lot of people have replaced blown-up 6.5td's with a TBI engine.. most likely they got the computer, harness, and engine all from the same donor truck, as that's the easiest path. I replaced one with a Vortec 7.4 because that's what I wanted (and had) and man I'll tell you it was some work! LOL

Richard

 

[99xcss4]

okay starting at the beginning I had a 1992 k2500 suburban that was born with a 350 at some point in its life it got a 454 4l80e swaped in it did not run very well. I needed a pick-up and got a killer de on a 94 c2500 me and my step dad pulled the whole drive train from the suburban meaning engine trans and t-ace pcm and engine trans and t-case harness and put it all in the pick-up we did not but should have pulled the dash harness. next we cut the front halve of both frame of and grafted the suburban front end to the back half of the pick-up and that is where I am now we do not know what to do or if the dash harness is the answer to the problem