Thanks for the info, that helps.

Unrelated:
I got my breakout box in, this thing is great. Shoulda done it ages ago.
So I check voltage across pins 29 and 49 (O2 + and O2 ground) I get full rich, around .9 steady. It does switch on/off when I give it some gas.

Now here's the weird thing. Maybe I don't understand how this works. But when I check voltage across pins 29 and 60 (O2 + and vehicle ground) I get around .5-.6v, which is more what I'd expect according to the manual.

Why the difference in voltage?

 

Nice piece of gear. I'm jealous!

The difference using pin 60 vs. pin 49 for a ground reference really looks like the ground jumper I mentioned earlier, (orange wire to the LR corner of the intake manifold), is missing.

Can you measure continunuity from pin 49 to engine ground?

 

Here is a scan of the dreaded Haynes manual schematic. Not EVTM for sure, but you can clearly see what they are trying to do with pin 49.

 

Got that bad boy for $70 shipped! So worth it.

Wow, I'm surprised the Haynes is that good. My EVTM diagram is almost useless and skips all sorts of stuff, frustratingly enough. I'm really not a fan despite all the time I spent hunting down one for an 86. My Ford shop diagnostics manual is about a thousand times better.

Measuring across 49 to engine (used headers and IAC body) I get less than 1 ohm, so pass. Also tried at the breakout across 49 to 60 and get 0 ohms. I checked the actual connection of the orange wire to the block and it was indeed one that I had reterminated nicely.

 

Seeing as 49 and 60 both return to chassis, it would be interesting to see what happens if you connect them together at the breakout box. Can't see anything high current in the circuit, so I would consider it safe. Of course, trying to see if that O2 sensor voltage can hit that midpoint when measured across 49 and 29.

 

Think I figured it out. Both pin 40 and pin 60 had a stray .1v or so, pin 49 was fine. Checked the ground by the battery (I think g203, can't remember, but it's the B/LG one) and found it had been ****ty crimped and such. Reterminated it and the stray voltage is gone!
I'll watch the O2 voltage again tomorrow to confirm it's good.

Now the TPS reads 1.05v at closed throttle so I gotta go and redo that I think, and check anything else that might have been configured wrong due to the stray voltage.
I'm also going to check into the AOD throttle valve and make sure it's good. Went down to ace and built a little 0-100psi gauge to check the pressure on it and make sure shift points are okay.

Drove it and it's slightly improved I think. Still no power on hills, at all. Getting closer.

 

Incremental steps. Nice find! That ground by the battery sure is important.

I was thinking about those grounds and why there would be a difference. I don't have an unmolested 86 to check and the layout changed substantially in 87, but I recall that the ECM grounds break out of the harness near the oval firewall plug and ground to the firewall somewhere near the wiper motor. In the later trucks there also is a pair of ground straps by the R hood hinge. One bonds the firewall to the hood and the other bonds the firewall to the intake plenum. If they are present on the 86 as well, pin 49 and pin 60 must be at the same potential voltage. Just a bit of speculation on my part. May not be relevant in this case.

Not sure about adjusting TPS voltage. Had a discussion on it elsewhere and the consensus was that the TPS is not really adjustable anyways and the ECU measures TPS voltage at startup, so the baseline is a dynamic value. Just an opinion and food for thought.

 

My 86 ranger fuel injected v6 seems very similiar with the early efi larger trucks. I was playing around with it the other day, and when I pulled that small ground apart over near the battery, it kills the engine right now. That ground is pretty important.

 

Goddammit, just wrote a long reply and lost it. Here's the short of it, next steps. Agreed, TPS is ok - acceptable is between .78v and 1.22 on a 1990.

-Confirm correct timing marks with cyl 1 and TDC.
-Re-run o2 test - ACT unplugged, rev 2000 rpm, expect around .5v
-Check voltage out of MAP, compare against shop manual to confirm correct
-Add extra grounds (~4-6 awg) between manifold, firewall, body, and frame
-Re-run o2 test - ACT unplugged, rev 2000 rpm, expect around .5v
-Fix Code 44 - passed pinpoint tests so on to air pump and valves. Routing confirmed correct including diverter valve direction.
-Swap new plug into cyl 5 to gauge AFR
-Check throttle valve adjustment to AOD w/pressure gauge. Some slack in line at TB at idle. (Strange High Idle - Ford Bronco Forum)

 

Just reviewing your initial post.

Have you ever tried your spare ECU? Any change? Does the catch code on your ECU match the original on the door post?

You mention a new TFI module. Gray module?

Have you checked to see if you are getting advance with the SPOUT plug back in?

Probably redundant. Your checklist is pretty complete.

 

I don't have a spare but may end up buying a rebuilt one if all else fails.
Yep, grey. I don't really have the typical TFI symptoms, hot engine cutting off, etc., but might end up relocating to the firewall in the future.
I'll check Thursday on the timing. I'm pretty sure it's good since I seem to remember forgetting to pull the spout one time and seeing my timing way higher than expected.
Hell I appreciate any input, redundant or otherwise

 

Andrew,

Don't know if you have made any progress, but I was wondering if you can confirm that your ECU is the original 1986 piece?

Reason I ask is because there were a few quirks with the early EECIV systems that are peculiar to the 85/86 trucks. I think a later ECU would work as long as you stay away from those that controlled the electronic transmissions. If 85lebaront2 is watching, Bill, this guy could use your help! He really knows his stuff.

You may also consider a MAF swap. Not that modifying the truck will solve your woes, but such a swap opens up a lot of performance mod and diagnostic potential. If you are really ambitious, maybe an OBDII swap using 95 and up pieces? Gary Lewis is doing one right now. He was active on this forum, but has started his own page.

???Gary's Garagemahal - Bullnose Forum

 

Hey Ray, I appreciate the input. I have thought about MAF swap with the fiveology kit, and I think it's pretty likely actually in the somewhat near future.

As far as the computer, I think it's original 1986:


I'll order a new ECU just for giggles. Found a reman from summit on a I think 87 AOD (E7TF-ATA, ATB) so I'll give it a shot. Hell, I can afford to do a MAF swap now... maybe I should just go for it instead of getting an 87 ECU??

Update:
-Add extra grounds (~4-6 awg) between manifold, firewall, body, and frame
Done. Dash, firewall, block (at o2 ground location), frame, battery, body all done up with nice 8awg cables.

-Confirm correct timing marks with cyl 1 and TDC.
PASS, on the dot.

-Re-run o2 test - ACT unplugged, rev 2000 rpm, expect around .5v
Around .88v with ACT, but switches to 0v just fine with throttle. Pegged at .95v with ACT unplugged and smells extremely rich

-Swap new plug into cyl 5 to gauge AFR
Done, Pulled cyl 1. It WAS sooty from testing last week but looks perfect now so that's a good sign.

-Found some slack in the throttle cable, which meant the pedal bottomed out before WOT. Fixed it. This doesn't solve all my problems but might help with lack of WOT power.

Next steps:

-Fix Code 44 - passed pinpoint tests so on to air pump and valves. Routing confirmed correct including diverter valve direction.

-Check throttle valve adjustment to AOD w/pressure gauge. Some slack in line at TB at idle. (Strange High Idle - Ford Bronco Forum)-Confirm correct timing marks with cyl 1 and TDC.

-Doublecheck that timing is advancing with spout in.

 

Alright, I ordered the MAF kit.
So much for having extra money!

 

After a very exhausting week of double shifts at work followed by a few hours of Bronco work, my MAF swap is mostly done! Just gotta do tidy up stuff and make some tweaks to the airbox.
I'll have a full update in my build thread. 86 Bronco Log - phobos2deimos - Page 17 - Ford Bronco Forum

Only drove it to work so far, but *seems* much better, and I think that incredibly annoying cold start rev to 2300 is gone.

I also adjusted the AOD throttle cable per the lazy shoe video. It had about a 3/8" of slack in it.

I'll drive a bunch more the next few days to see if it's fixed.