what's needed to change firing order?

[bcmbcmbcm]

Hey folks,

I'm almost done with the 331 for my fullsize bronco...but I am wondering if I f&Cked up the firing order. I have been reading that truck (non HO) 5.0s have different firing orders than Mustang HOs.

Coast built me a nice 331. Jay Allen ground me a cam. I didn't specify what firing order for the cam but I assume it would be an HO firing order. And, I have converted to Mass Air using a FRPP overlay kit, with new computer.

Is the cam the only thing which determines the firing order or do I have a potential headache in front of me?

 

[Gearbanger 101]

The 351W/302 HO uses a 1-3-7-2-6-5-4-8 vs 1-5-4-2-6-3-7-8 for the standard 302W

 

[vristang]

Hey folks,

I'm almost done with the 331 for my fullsize bronco...but I am wondering if I f&Cked up the firing order. I have been reading that truck (non HO) 5.0s have different firing orders than Mustang HOs.

Coast built me a nice 331. Jay Allen ground me a cam. I didn't specify what firing order for the cam but I assume it would be an HO firing order. And, I have converted to Mass Air using a FRPP overlay kit, with new computer.

Is the cam the only thing which determines the firing order or do I have a potential headache in front of me?

Your build sheet from Jay should have the firing order on it, IIRC. Haven't looked at mine in a while....
If it isn't on the build sheet, call Jay and verify.

The firing order of the cam MUST match that of the ecu.
What ecu are you running? I'm assuming an A9L or similar from a HO Mustang?

If the cam is to the non-HO firing order, you should be able to change the firing order of the ecu (to match the cam) by using a custom tuning chip.
The quarterhorse from Moates would work well for $250...

Let me know what you find out.
jason

 

[bcmbcmbcm]

uh oh...

Build sheet is tucked away, way way away in storage....I have moved twice.

Not sure of the computer, I think it is a truck computer since it came in a discontinued FRPP Mass air conversion kit designed for Broncos and F150s.

 

[vristang]

Does the ecu have a catch code on it? Or just a Ford part number?

You may want to call Ford and see what the firing order of that ecu is...

Just checked my build sheet... Jay did specify the firing order...
Didn't you make a backup copy of the digital version?

 

[SMOKEDYA]

Most cam manurfacters grind 302/351 cams to the new HO order unless otherwise specified. peace







john

 

[Maryland Stang]

You're gonna hate this...

Later F-150 trucks with an auto tranny used the HO firing order and were Mass Air. My 95 F-150 has the HO firing order and Mass Air and came that way from the factory. The stick F-150s had the 302 firing order and SD right up until the end of production. You're going to need to find out which computer you have. You're also going to need to know the firing order that the cam was ground on. DON"T ASSUME anything at this point.

 

[Mustang5L5]

Can you not swap the injector harnesses around?

 

[vristang]

Nope.
Swapping the harness in SEFI applications will lead to Adaptive issues... as the O2's read each bank, and fuel is adjusted on each bank based on that banks O2.

Swapping Injector plugs around will move a couple of injectors to the opposite bank....

 

[SetofAces]

Can you not swap the injector harnesses around?

Ford Fuel Injection Injector Firing Order

I'm working with a non-HO motor myself, I think from a Crown Vic or something similar. Everyone says that the cam -- and the cam only -- determines firing order; I guess they know what they're talking about, but what if the motor had a different crank? different cylinders would be at TDC at different times, right? Of course this is irrelevant (I think) because last time I went to the dealership I asked if the Crown Vic had the same crank as the mustang HO 302, and it does. I'm still curious about how the crank doesn't affect firing order, though . . .

 

[bcmbcmbcm]

I just checked the computer and the cpde was A3M1

 

[Maryland Stang]

Everyone says that the cam -- and the cam only -- determines firing order; I guess they know what they're talking about, but what if the motor had a different crank? different cylinders would be at TDC at different times, right? Of course this is irrelevant (I think) because last time I went to the dealership I asked if the Crown Vic had the same crank as the mustang HO 302, and it does. I'm still curious about how the crank doesn't affect firing order, though . . .

There are at least 2 potential firing orders with any 4 stoke engine (except for single cylinders). It is like this because the cranks spins twice for every one time the cam spins. Small block Chevy's also have an alternative firing order.

 

[RYC CUKR]

The a3m is an HO computer. My 93 GT vert has an a3m in it.

 

[bcmbcmbcm]

think i am HO order

Yes Jay said he 99.9% grinds to the HO firing order unless specified, which I didn't. I did send him the build sheets and the cam tag for him to 'beat.' I attached it here

 

[bcmbcmbcm]

another attachment

attach

 

[bcmbcmbcm]

attachment

hope it attached. anyway it was an Elgin E1017-P I replaced. (which if anyone wants it, it was installed by coast but removed and never used! make me an offer!)

 

[bcmbcmbcm]

which cylinders are which?

Oh and a nother dummy question, which cylinders are which? I searched but so much comes up ...

thanks!