The trip this morning was better. Seems to hold speed without bucking as bad as it did. Not perfect, but an improvement. I was trying to hold speed in 2nd gear in a school zone and it started surging in a quick rhythmic count. Always worse in lower gears(torque multiplication). Makes you feel like you're driving a 1960's school bus that is out of tune. Ugh. If I had know it was this bad I would spent $1mil dollars rebuilding that AOD and put up with it instead.

 

Video of surging

 

Video is private.

You may need to hook the NSS wires up so the computer thinks the vehicle is in gear.

 

Ok, made it public. Sorry about that(I could see it, duh).

Am I going to have to put a clutch switch in it so I can start it instead of just soldering the two wires together so it always starts?

 

Have you taken your throttle body off and cleaned it really good. Make sure there are no plugged up holes.

 

Good and clean.

 

Maybe there is a different strategy in an auto EEC vs a manual EEC for load compensation so it doesn't know how to handle spinning a flywheel vs flexplate and tq converter. Is there anyone you know that has a manual EEC you can try. Its a shot in the dark.

 

What brand of pip, map, tps did you buy? Is it a motorcraft TFI? X2 on popping the lid off the computer

 

No spare ecm I know of. No 89 stick trucks in Pullapart. Hens teeth around here. Might get one from JY(any year) and then use it as core for reman. Had mine out and is perfect inside.

All parts from autozone. It does run a bit better so it is not the new parts. It has always had this issue but couldn't feel it as drastic before.

 

I had an 88 F150 4x4 with the 302/5sp combo. Mine had similar issues a few times.


One time I managed to get it to drive right by moving the distributor, but I don't remember if I advanced it or retarded it. Everybody I talked to said it wouldn't make a difference with the TFI and fuel injection, but it did.


Another thing I have heard of but did not experience is the gasket failing between the upper and lower intakes. From what I remember if it goes bad it causes strange surging. Maybe???


Good Luck,


Robert

 

I've had the timing bumped up before, like 12* or so. It would rattle its brains out going down the highway with any kind of light load(like going up a hill). Something around 10* is safe.

I've had the intake off years back and replaced gaskets. I don't remember exactly when the real issue started. It wasn't a concern then as it drove fine overall. Just got 18 mpg on a highway trip so it is not running rich. If you flat foot it in 2nd or 3rd gear it will accelerate fine so it isn't too lean. It just has a surging power feel to it in normal in town driving. On the highway it isn't really as noticeable.

That video above is hard to really hear, but if you turn it up you can hear it surge. Kinda like it pulls timing out and lugs(the motor sounds flat), then returns to normal. Then 2 seconds later it does it again and repeats.

Now that I have replaced most everything, I might pull intake and replace injectors. Why the heck not? It is about the only thing I haven't touched.

 

Just because they are new does not mean quality. And better than before doesn't mean right. I'm not trying to annoy you but I've had brand new distributors (RPT) with lifetime warranties fail a consecutive 5 times before I gave up and bought motorcraft/BWD parts to rebuild the original.

Your issue sounds timing related, the map sensor tells the engine the amount of vacuum and tells it what point in the timing curve it should be. The pip tells the computer when to send spark. This means that sub par components can result in improved but not resolved symptoms.

 

Well Saturday we unplugged the EGR, coolant temp and air temp and nothing changed(other then CEL came on).

I agree, they make $&(t parts today, but since the problem was there with OEM parts, likely the fact I changed them shows me that they were not the ROOT cause of the problem. I agree with your timing statement. It is screwing with it and causing the surge. It is very consistent about it. You can feel a very distinct shake to the engine at certain rpms. Not a miss, but a shake.

Under hard acceleration(WOT), it pulls fine. No shake or miss. That tells me that those new parts must be working as well as the original parts. I likely could put all the old stuff back in and still run it. It is to the point of just throwing parts at it til something fixes it. I'd be happy with a points distributor and a 600 Holley right now. Screw this 25 yr old computer crap.

I have a reman computer coming for it. I have multiple people telling me that an automatic computer runs different from a stick computer. Ok, well for $95 I'm going to try it. Why the hell not at this point. What's another $100?

Something will correct the issues. I just haven't changed that part yet.

 

Fixed!!!!
Reman computer showed up today. Bolted it in and what a difference. Smooth up through the rpm range(no shaking). Holds rpm where ever you put it. Checked timing and it is rock steady. It was all over the place with old computer. Took a short drive and no bucking on light engine load. Smooth acceleration/decel. Pretty excited.

 

Glad you found your problem. Those kind of problems can be very frustrating. Where did you buy the remanned computer?