Lugging at speed/No power at WOT

[Gary Lewis]

Yep, I'd swap back.  But, I didn't think the feedback made much difference at idle, so it may not help.  However, it was the last thing changed so needs to be the first thing put back.

[85lebaront2]

Gary, the feedback system affects both idle and main, it works on the air bleeds of both systems. The other thing, if it is bad, the system may be going into limp mode.

[Gary Lewis]

Good to know, Bill.  And you are right about limp mode.  

[ratdude747]

Swapped... still no idle.

Ended up having to go 3.5 turns or so past bottom on the idle fuel to make it stable/smooth. Granted, that was on a cold engine though. Perhaps that's a symptom?

[85lebaront2]

Make sure that there are no air leaks at the carburetor and EGR spacer. Pull the vacuum hose off the EGR valve, if it goes rich when you do that, you have a vacuum valve leaking or something is plumbed wrong in the vacuum hoses. If it makes no difference, with it idling carefully (use a wet rag) check the valve and tube near the valve, if they are real hot, exhaust gas hot, then the valve is leaking or stuck partially open. This will make it exceedingly lean. If yours does not have the external EGR tube, then the gasket between the adapter and intake may be bad.

Ford actually used to recommend cleaning them of carbon deposits periodically due to wanting to stick partially open.

[ratdude747]

Redid the adjustment when warm (after work), ended up pulling all but 3/4 turn out (at 2 1/4 turn from bottom).

EGR valve was recently replaced (old one leaking vacuum).\

checked the tranny fluid level, was very low... looked underneath, leaking quite a bit of fluid. Grabbed 3 gallons of fluid on my way home, in the middle of a fluid/filter change (had a gasket and filter kit sitting).

gasket is very old and probably original; the plastic dipstick plug was still in there! Based on the fluid condition, I'm thinking it was flushed sometime in the last decade... just no filter change.

[ratdude747]

No change... but the EGR valve isn't getting vacuum to open either. Plumbing is good (colors backwards from chart, but the connections are right)... but only ~1VDC across the control solenoid.

This is a connector I repaired when the engine was out... I'll recheck the wiring, but I'm pretty sure all is well. If there isn't a wiring issue at the connector repair splice, any good reason why it wouldn't be calling for EGR at idle?

[ArdWrknTrk]

There should never be EGR at idle or when cold.

Only under 'cruise' conditions.

[ratdude747]

Duh... misread lebaron's post.

[ArdWrknTrk]

Bill is a tremendous wealth of information here on the forum.  

I'm sure you'll get this sorted out, you've certainly made a lot of progress so far!

[ratdude747]

Reviving this old hulk of a thread due to the final MPG (and performance at speed) issues never really getting resolved... and such coming up in the context of another thread.

Today I won a best offer on another ECU to try. This is a NOS Ford Reman unit, which the calibration lists show as being for a 1984-85 Manual application (E4FZ-12A650-NB). Not quite the exact module, but something to try and see if helps at all.

Since it's a Ford Reman (not A1 cardone),  I have a bit more faith that it will be a better unit. We shall see. Worst case, I have an ECU to resell... I got a decent price on it, so why not?

[ratdude747]

Installed the new ECU. So far, no real change in performance. MPG, we shall see (driving it to MO tomorrow!)

[Gary Lewis]

Have a good trip!  But don't forget to check codes at some point.

[ratdude747]

Got back, checked codes... stored code 21 (Temp sensor out of range), and engine is running in limp mode (timing retarded to 6 degrees, verified that the base 10 degree timing with SPOUT disconnected is still good).

Also got a fault 41 after self test completed (O2 always lean), but the engine was stone cold, not long enough for the heater to activate. So I'm ignoring this for now.

The temp sensor is the only "original" sensor left... previously checked to be good. As much as I hate tossing parts at things, it's suspect... and under $30, so not a huge loss if it's not the problem.  Edit- Not under $30 if I get a good one  locally (BWD or Duralast). Cheaper ones exist locally, but from what I've read the BWD ones of these are worth the extra $$$. Edit #2- Less than $30, thanks to a 25% promo code I found. I'm cheap...

[Gary Lewis]

I'm actually glad you found codes and that the ignition timing is locked.  That's because I think the engine is going to act like it has been supercharged when you get things fixed and you won't need to re-gear.  

So I hope the temp sensor fixes things.  

[85lebaront2]

You do not have a heated oxygen sensor on that engine unless someone added it. Yours will be in the exhaust manifold just above the exhaust pipe flange. If your truck has the air pump and it was delivering air to the exhaust, then it probably would show lean.

On sensors, I have had some (along with my son) bad experiences with aftermarket sensors on Fords, I will bite the bullet and buy Motorcraft sensors. I also am somewhat picky regarding spark plugs in Fords, had a few cases of Bosch platinum plugs running poorly in EFI 302s and one friend who inherited a 1994 F150 with a 302 that the PO had put AC plugs in, it got terrible gas mileage, he took my suggestion and put Motorcraft plugs in, called me on his cell phone on his way up I-64 to his retirement home he was building, started singing "I'm a believer", truck hadn't even use 1/2 of one tank by then.

[ratdude747]

It's a retrofitted heated O2.

http://forum.garysgaragemahal.com/Lugging-at-speed-No-power-at-WOT-tp37190p63446.html

Uses a mid/late 90's Ranger/Explorer pigtail and sensor (in this case, from a 2001 explorer sport). Did this to relocate the O2-specific block ground to the sensor itself, improve performance, and utilize a more readily available part. The heater is powered from the EEC relay, and O2 sensor ground and heater ground are tied together at the harness plug (due to technical reasons discovered while reverse-engineering the ECU later in this thread). The sensor is a used (but tested and confirmed) Bosch/Ford (Bosch was the OEM).

Plugs are Motorcraft. The exact part No. is listed in here somewhere.

---

Replaced the temp sensor and cleared codes. Idle is a lot smoother and better... apparently the limp mode idle was unnoticed by me on this weekends trip but is back to normal now. At stop lights it was silky smooth. Will daily drive the rest of the week (and take on some short trips when time allows) to see if things improve at all.

[Gary Lewis]

I'm thinking you are going to be happy!

[ratdude747]

Don't Jinx me

Had a weird idle this morning... timing lighted it, 6 degrees again

Went to pull codes... fat fingered and accidentally reset them, as when I redid the test, no stored codes, and passed KOEO with no faults (confirming my prior cold O2 suspicion). I did run it briefly with the Temp sensor unplugged before last night's test drive (in error), but I doubt that's what set the code.

Will keep an eye on it. Have the checker and timing light in the cab so I can retest over lunch break.

Thanks,

Larry

[Gary Lewis]

Oh no!  Hope it was a fluke.