• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

Will this work? EFI question

oldiron

Bronco Guru
Joined
Jul 21, 2005
Messages
1,032
O.k. heres the layout... '74 302 runs great but I want EFI. I have a '92 5.0 mustang upper and lower with 19 lb injectors/ harness A9L from same car. I don't want to change cam in the bronco to get the correct firing order, nor do I want to leave it as is and deal with a ragged idle.
Could I.....use the mustang harness/upper/lower, but use the 14 lb injectors and ecu from a standard firing order non-HO car ( crown vic/marquis/etc.)
What I'm looking for is smooth operation, with a little better mpg(14 lb vs. 19 lb.)
What do ya think about this plan? Am I way off base with this idea?
All ideas are welcome.
Greg
 

bronko69er

EB Addict
Joined
Oct 16, 2006
Messages
4,599
Loc.
Renton, WA
I have the same setup, use it as is, it will idle better than it did with a carb, the firing order issue is so subtle, most can't even tell.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
Just curious, but in all this, with the work you will be doing anyway, why don't you want to change the cam? Just another level of hassle and you want to get done as quick as possible maybe?
Even though I'd probably try to make the change while I was at it, I'd agree with bronko69er to not lose too much sleep over the firing order. Even though it's not perfect, or by-the-book, from all reports it's not that big of a deal.
That's probably more indicative of the engines not running at optimal values to begin with, than that it doesn't make "any" difference, but not sure. If you're hoping for max power though, or the most precise idle, your needs may change.

May be nothing wrong with your thought of using the items from the other car (SD too maybe?), but I'd use the stuff you already have, rather than trying to source another computer, injectors AND (most likely) a new harness too.

Unless someone who's done it says otherwise, I'd go with what you have, and when you eventually change the cam down the road, go for the new firing order at that time.
Not sure, but I don't think merely changing to the 14lb injectors is an automatic fuel savings either. It's all in how it all works together. I think they're sized for maximum potential power output, but the computer only gives the engine what it needs. The smaller injectors would just be working longer duty-cycles for a given output, but not allow the same max potential output.
That's the way I see it, but if I'm wrong there are plenty here who would know.

Paul
 

Terkish

Sr. Member
Joined
Feb 22, 2008
Messages
414
Not sure, but I don't think merely changing to the 14lb injectors is an automatic fuel savings either. It's all in how it all works together. I think they're sized for maximum potential power output, but the computer only gives the engine what it needs. The smaller injectors would just be working longer duty-cycles for a given output, but not allow the same max potential output.
That's the way I see it, but if I'm wrong there are plenty here who would know.

Paul

x2

If you run the mustang setup with 14lb injectors you will get a lean miss fire at higher rpms and while under load. This in turn actually makes you get worse fuel mileage.

the firing order of the injectors dose not make enough difference to even notice. it will still run smother then it dose with a carb.
 

jw0747

Contributor
Bronco Guru
Joined
Nov 22, 2006
Messages
2,434
Loc.
San Antonio, TX
x3 My engine is bone stock '73 302 w/ old firing order. Added efi and was concerned about firing order. That was four yrs ago. Idles perfect. You do not need to change cam.
 
OP
OP
oldiron

oldiron

Bronco Guru
Joined
Jul 21, 2005
Messages
1,032
O.K then.... I'm going to take the advice and proceed with a straightforward EFI swap. Thanks for the input guys.
Greg
 

needabronco

Bronco Guru
Joined
Jul 2, 2004
Messages
6,411
Loc.
Prescott/Farmington
The eec, MAF, and the injectors need to match in order for the engine to run at the right air/fuel ratio. Running 14lb injectors IMO is a no go. I run efi with the wrong firing order and honestly it runs great! I don't have any idle issues or any real issues. My last trip I got 14.9 MPG's on one tank and the rest were around 12.5, running 35"s with 4.88 gears and an AOD. With a carb I managed around 11.
 
Top