ok i just finished converting my 89 bronco from non-ho to HO. It runs good, idles fine, but will not make any power past 3k-3500 rpms. It just flat lines and hesitates. I tried swapping injector wires 5 for 3, and 4 for 7. But that made the idle unusually high and sounded rough so I wired it back. My bronco originally had 19lb injectors on the non-ho motor and ran fine before the swap. Im really stumped on this one. Ive heard of many people doing this swap and didn't swap in another computer and ran fine. Only thing i can think of is maybe the TFI module is bad, but it was fine last time i used it which was like around jan.

 

I believe the firing order is diffrent from a 302 to a 302HO. The 302HO uses the firing order of a 351W. I remember a posting about 8 months ago about this subject.
Al

 

what size injectors is the ho have in it? also changing injectors wont do anything on a speed density setup because its a batch fire setup not bank fire like a mustang would be

 

Yes I know about the firing order. I am not a newbie to how motors work. I've had many mustangs, and have rebuilt alot of motors. I converted the motor to HO because of the new firing order and the new power that comes with it when changing the cam, pushrods, lifters, etc.

 

Like i said before, 19lb injectors.

 

Has anyone heard of the TFI module causing this problem? The motor wont rev past 3k at all, it just stutters like there's a spark problem.

 

Then do you think a computer for standard 302 can be used for a totally diffrent firing order??? You said other people have done it and had no problems, why cause they said so? Well you said it runs great until you get above 3 grand, Many people don't run the Bronco's above 3 grand for any extended period of time. By a book a perform the system test on the TFI Module. However it sounds to me like an advance timing curve at higher RPM's with the H.O. motor and a standard 302 ECC. But you probably new that!
Al

 

you may have a clogged cat. pull codes as well. the ecu should tell ya if there is an issue.

 

the computer does't matter what firing order the cam is. Because essentially it is the same motor. Im guessing i have to figure out how to wire up the fuel injectors for a speed density setup. Im sure the swapping 5 for 3 and 4 for 7 works for the maf computer, but not the speed density. On my wiring, injectors 1, 4, 5, 8 are all connected together, so those fire at the same time. And injectors 2, 3, 6, 7 are connected to each other. Im not a electronic expert but im sure thats the key to getting this to work. If anyone has not done this swap, please dont answer, because then you have no idea without the experience. thanks!

 

if you were using your original harness it should have been left alone. your not messing with a mustang harness here which is wired totally different.

what cam is in that motor? is it the stock one.

 

Ok, for reference, I have a bone stock SD 5.0 Bronco, replaced engine with a reman HO long block. I have 19lb injectors (which are stock for most trucks and the HO's, colored yellow) and an original un-molested SD wiring setup. It runs fine, there is a barely noticeable pause when accelerating from a stop - almost like a little dead spot - when cold. I attribute that to some confusion on the part of the SD computer. It seems to make great power above 3500 rpm. It's just the ticket for merging onto the interstate. If you start fiddling with the wiring order of the gang fire injection, you will likely cause more problems than you solve. I have the parts to upgrade to a Mustang Multipoint Mass Air setup, but I have not done it yet because the SD works just fine. This would be the only wiring enhancement I recommend, but you must rewire the 60 pin connector and replace the injector harness to do it.

Knowing that the swap does work with the stock computer, you need to put some of that motor expertise to work. Pulling the EEC-IV trouble codes is a good place to start. Also, check base timing, make sure the spout connector is installed, ignition components in good order - new or very new. Exhaust unrestricted, air cleaner clean, compression good, fuel pressure good, etc.

 

Can you not read? I took my motor apart, i replaced the cam, pushrods, installed the wishbone pieces and tray that keep the new lifters in, all these parts came off a 91 mustang 5.0 ho.

 

I have wired up the stock injector wiring the way it was before I cut it and the motor still doesn't want to rev past 3k. it just stutters there. I have new plugs (gapped properly 0.44), new wires, i tested the ignition coil and TFI module, everything passed. Timing is set correctly at 10* BTDC. I am close to giving up at this point.

 

That's a great way to get help, be an a** about it.

 

My bronco originally had 19lb injectors on the non-ho motor and ran fine before the swap

So, I'm asking like Kem, What injectors do you currently have on the new motor?
Seems like you answered that with another one of your CA replies.

This site has been around quite some time, longer than most of us. Please allow folks to help you by proof reading your posts before rambling them out there for all of us to see how cluttered your thoughts are.