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87GT with a 347 problems

SpeedDman360

New Member
Spring I decided to buy a 347 Stroker SB from TRE Performance. I built the block up a tad (Budget build) had it installed by a local Mechanic it ran with the speed Density pcm but barely Cause you all know that speed Density don't play nice with mods. I ended up buying a MAF Conversion kit from fiveology racing (A9P PCM, MAF harness, meter calibrated to my throttle body & injectors, directions on how to rewire the stock harness. ) followed directions Correctly. When I go to turn the key, I don't hear my fuel pump prime and out of Curiosity, I tried to Crank my car and nothing. I have dash Lights (Check Engine &Brights indicator ) but nothing else
Thought I messed up somewhere I decided to get an 89 Harness and run that, same issue
So... I thought the PCM was the issue, I sent that back to Fiveology and got a replacement. We tested it in my friends 90 GT and it worked without issue. Tried to install it in my 87 and same problem: No pump or Crank but all dash lights. The Mechanic put his Scan Tool to it and he said he can't read the PCM...

I'm at a loss for what to do. An ASE certified Mechanic is "Confused as F*ck " And the Local Ford Dealership Service department won't touch it. Any help would be appreciated. What should have been a easy swap is costing me a butt ton of cash...
 
I wish I could help but I know nothing about the computer controlled cars.
I am a hillbilly though, have tried to jumper the fuel pump just to confirm it works? I know it could be a huge coincidence on the timing of a pump failure but you never know. Also have you been able to confirm you have ignition/spark? Obviously if the pump is not working it won't matter but if you get the pump working by jumping it, it will need spark to run. If the computer system is confused it might not have spark either... IDK.
Good luck
 
Yeah, I straight wired the fuel pump (battery is in the hatch) and it kicks on. It has +/- 50 miles on it as well as the the whole drive train.
I can go back to the stock Speed Density and my car starts and runs (badly though)
 
Not straight to the MAF but the battery. I don't think the maf contains a "Power" wire since its just a sensor. I could be wrong though
 
I was wondering if with the MAF hooked up as would be normal and then jumper the pump, will it run?
 
No pump, no crank, no spark. It's like the PCM (ECU) isn't even there. We pulled that and installed it in another Foxbody and it worked fine.

Edit: I have power to all the relays, fuseable links, & solenoid
 
well, this is where I am not so strong. I do not know what signal the MAF is looking for. If the PCM and harness work in another car and the Speed Density system works in your car I see the reason for confusion. What trans do you have? Could it be something with neutral safety switch?
 
The neutral switch could be part of the no crank issue (haven't tested that) but that leaves the fuel pump and no spark.
I'll dig back into the car after work and replace that neutral switch. (I've replaced everything else do far)
I'm running a rebuilt T-5 (manual ) transmission
 
well don't replace stuff on my suggestion! I'm only guessing. Seems like something is keeping the starter and pump and PCM from getting power. If the harness and PCM and pump all work (in other car or by jumper) then it would seem to be somehow in the ignition switch... but you have dash lights and the speed density work with the switch so it's not the switch itself. Weird
 
The neutral switch could be part of the no crank issue (haven't tested that) but that leaves the fuel pump and no spark.
I'll dig back into the car after work and replace that neutral switch. (I've replaced everything else do far)
I'm running a rebuilt T-5 (manual ) transmission
With a manual transmission, you need to jumper the two NSS pins. However, that doesn't explain why the car ran in the past, unless that jumper took a hike.
 
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