First and foremost - thanks Ken, to you and your staff, for giving my application a shot. I really wish we could get something tuned for it, and hope there's a chance, yet.

For all...... I need some help and any input, including EEC-IV swaps or similar experiences.

Over the last winter, I rebuilt the 302EFI in my '85 Bronco ('85 was a half year for EFI and the 302, with '86 being the first full year for EFI.) I was very careful to keep "smog legal" and to go mild with my modifications, as I wanted to retain the ability to pass emissions and retain the speed density setup. Details are as follows:

block bored 0.030" over, Keith Black hypereutectic pistons w/ Total Seal rings, E7TE heads (from an '88 F150) rebuilt to stock specs / given three-angle valve job / installed, stock fuel system / lower & upper intakes, reconditioned stock 19 lb./hr. fuel injectors installed, Crane Compucam 364112 installed, Ford Racing 1.6 ratio aluminum roller rockers, Bassani ceramic-coated shorty headers into high-flow Y-pipe and cat installed, all new sensors and emissions valves replaced.

In February, when I broke the engine in, it ran great. It did seem to take a while to warm up (even with the stock 195F t-stat), but no issues. Gradually, as the weather warmed into spring / summer, I have encountered driveability problems after warm up. Specifically, the idle "hunts" and I have a part-throttle surge and stutter. I'm getting two KOER codes - a 41 (no O2 sensor switching) and a 13 (unable to control idle rpm). Both the O2 sensor and IAC valve have been changed to no avail.

I disconnected the O2 sensor and corrected the surge, but now the truck is down on power as it always runs rich. The local Ford dealer advised that another customer recently rebuilt an '86 F150 and changed the cam to have the same problems (EEC did not like the mods). Reportedly, he left his O2 sensor connected, but disconnected his EGR valve and solved his driveability problem.

My '85 computer cannot be chipped (per Ken). Does anyone else have any suggestions, short of rigging in mass air, or putting on another intake and carburetor? Would the EEC from a manual tranny (as mine is) '87 or '88 Bronco be closer to the ballpark, given that they used the same heads and were speed density? I really don't want to drive my truck around with half of the emissions and / or sensors disconnected, and even if I did, I can't believe that it would be even halfway efficient. If the '87 or '88 EEC would run the truck, could it be mapped and chipped, where my '85 EEC could not?

Any insight, including what I would be facing (besides $600 plus labor) to try mass air would be appreciated. Also, what have I missed in the way of options for retaining speed density? Thanks in advance!

 

why could it not be chipped? I as far as using a later model the only thing i could possibly suggest is maybe using an 86 model. they have the same set up as far EGR, O2, MAP, etc. that would be sending the same signal to the same parts, however when ever you go to a parts store it will usually list 5 to 7 different computers for that same year. maybe there is a computer that has a certain number that can be chipped? now that you have this problem I need to see if my truck can be chipped, mine is an 86 f150. Ive got edelbrock heads, cam, headers, no cats and I have the same problem, seems as ifsome time it runs great has a ton power, and some times it runs like crap! idle goes up and down ect!

 

It cannot be chipped because the computer is not readable. It dumped mostly hex 7Fs instead of executable code.

Superchips doesn't have a read on this code either which means they haven't been successful. Success rate plungs on any EEC-IV before 1987.

Any compatible computer should would but I don't have a cross-reference for GR PCMs.

 

Update: I spoke with a tech at Ford Racing Performance Products this afternoon. We both have an idea that I could probably take an '87 or '88 Bronco EEC-IV processor (around $100.00 remanufactured), get the pin placement diagrams for my '85 and the '87 or '88, and jockey the pins around to match up properly. From there, I could probably get the truck to crank and run, possibly the same and possibly slightly better, but likely still to have some driveability problems. From this, if Ken could get a read on a slightly later model EEC versus the first generation dinosaur I shipped him, we could possibly burn a chip for it. All of this said, I'm probably looking at 2/3 of the cost of buying a mass air conversion kit. The FRPP M9000-T50 kit (for '87 and up) would reportedly work. I have read that these require a distributor with an excitor ring, which pings the #1 firing position, and tells the EEC where it's at so that the sequential EFI can squirt in time with valve openings. The tech advised that, while this will give slightly less emissions (and slightly improved efficiency), it isn't totally necessary. The alternative has the charge shooting out (at approximately 25 per second) of an injector, and hanging out in the runner until the next valve opens. I'm still weighing everything out, but the "chanciness" of trying out later model EEC's and hoping everything will work, as well as the alternative of swapping in a carb and intake, and very possibly purchasing a new fuel pump, and/or regulator, and EGR valve along with an air cleaner assembly while disabling all of the EFI is all pointing me toward doing the conversion and calling it good. I appreciate everyone's help.... this has certainly been educational!

 

It Sounds like you have a very similer problem that I currently have with my '90 Bronco with 5.8L(351W) and the E4OD Trans. I have replaced just about everything (but the kitchen sink) and the computer. Last year I just had the engine rebuilt with .30 over pistons, mild cam, new 19lbs enjectors, Edelbrock upper & lower intake manifolds, Edelbrock 56mm Throttle body, & K&N fipk kit, and possibly more that I forget at this time. Everything I mounted & installed are all emission legal. The rig ran great for about six months then the problems started to happen. Right nowafter the engine warms up, I can't get it above 3k rpm without it hunting to keep the rpms right. Granted I could cruise at about 80 or 85 mph as long as I'm in over drive and rpm's are below 3,000 rpms.
Unfortunately the speed density, bank firing system has a hard time dealing with even some of the mildest modifications. So, I recently just purchased a mass air flow conversion kit last month. The mass airflow system is run on sequenstial injection I will be installing it with in the next few weeks and will let you know how it works. The kit comes with every thing you would need; new computer, mass air meter atatched to an air filter, 2 bungs to be welded into the ehaust for two O2 sensors, one new O2 sensor, an adapter to mount onto twin throttle body to single tube, tube to go between adapter on throttle body and mass air meter and new wireing that plugs into the computer and into the injectors and a few other items. The instructions seem to be pretty thourough. The requires the rewireing of wiring harness that plugs into the computer in the engine compartment.

The company that has this conversion kit is 'PRO-FLOW-PRO-M Racing' = http://pro-flow.com/

By the way the new computer is A9L, If I remember correctly.

Also, one of the things that I too was concerned about was being able to pass smog with all the things I've done to my rig, and with the problems that I'm having. Well, I just had my rig smoged and passed, barely.

Hope this helps

 

I appreciate the reply..... let me know how your conversion goes. If you passed smog in CA without your truck fully tweaked, I've got to believe that the mass air conversion (especially if you time the sequential injectors properly) is only going to help. I may have my idle code (13) figured out..... some months ago, I was monkeying with the throttle stop screw w/o fully knowing what I was doing. I've since read how to adjust this (and minimum air), and am thinking this may correct my problem. Also planning to tweak (adjust by voltage) the TPS while I'm at it, for good measure. As for code 41..... I'm thinking this may be related to my driveability problem / EEC not recognizing my parts changes. I'm on my second O2 sensor, I did not use any sealer on the rebuild that wasn't labeled "sensor safe" (so silicone fumes shouldn't be contaminating anything), and my Autometer Air/Fuel Ratio gauge has been as happy as can be with the readings it's gotten from both sensors. I took a lot of time in putting everything together, and I can't see the possibility of it leaking vacuum (especially given that it runs okay with the O2 disconnected), but I may look even harder for a leak with an unlit propane torch and, perhaps, try one more O2 sensor before ordering the kit. I'm not glad that you're having the same type of trouble, but I am glad to see the consistency, which is making me more confident that the EEC / need for mass air is, in fact, my problem.