still running rough after engine install. HELP :/

[JMD Engineering]

im going to make this as short and simple to follow. I installed an RNH 347. Its crank is set for the REGULAR 5.0 firing order (1-3-7-2-6-5-4-8). my stock 93 lx 5.0 computer is running the HO firing order (1-5-4-2-6-3-7-8). So initially, it was running off of 4 cylinders due to the fact that 4 cylinders coincide (1,2,6,8) between both firing orders. After talking to a few techs at my work, they all agreed that since it is sequencial injection - I should be able to switch the pins in the injector harness so that the 4 cylinders that DIDNT match up (3,4,5,7) in the HO firing order would parallel the correct order in the REGULAR (switched 3 with 5, 4 with 7 - and so on). It seemed to run OK upon doing that.. but still rough. So for ****s and giggles, I switched the firing order (but left the injector pins how they were) and it seems to run better on the HO firing order...

all i can say is HELP. i dont know what to do from here.

 

[jrichker]

A.) You are wrong about the firing order The cam determines the firing order, not the crank. HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8

You need an A9L or A9P computer to match the firing order. Do not use a non HO computer and move the injector pins around in an attempt to correct. See http://fordfuelinjection.com/index.php?p=92 for more information.

 

[bullitstang1313]

Just curious, but what happens when you run the non H.O. firing order with an H.O. ECM? Does it matter?

 

[Rick 91GT]

J, did the new injectors show up?

That FTI custom cam is a H.O firing order, same goes for your stock EEC you need to use the 1-3-7-2-6-5-4-8 FO

 

[Rick 91GT]

Just curious, but what happens when you run the non H.O. firing order with an H.O. ECM? Does it matter?

Usually it will start and run, sound like a .600ci Pro Stocker and have no bottom end at all, but in the upper rpms it may run OK. It will also get little to no gas mileage.