Correct 88 ECM for 1986 RWD auto with EGR delete?


Kellogg

New member
Joined
Feb 6, 2019
Messages
14
Reaction score
1
Points
3
Location
West Chester PA
Vehicle Year
1986
Make / Model
Ford
Transmission
Automatic
I did an egr delete on my 86 2.9 auto RWD due to a leaky egr tube. I know after deleting my egr system I would need an 88+ ecm. I coworker gave me a ecm for a 88 2.9 bronco ii auto 4x4 and its runs worse than with my original ecm reinstalled. Getting code 95 (has been since diagnosed) and code 86 along with high rough idle and bad hesitation/gasping when the throttle is cracked.

See original thread here:
https://www.therangerstation.com/forums/index.php?threads/2-9-egr-removal.106270/page-2#post-1672927

I want to try a newly refurbished 88 ecm to rule out the possibility of a faulty ecm. Rockauto carries two versions of an 88 2.9, auto, RWD, both with standard emissions: I am curious what is "standard emissions"? and what is the difference between the two ecms listed below? Would either work for me? When I look up ecms for an 86 or 87 (both having egr systems) those ecms also come with "stanard emmsions"

CARDONE 784478 {#E8TF12A650SA, E8TZ12A650SA} Remanufactured Info
RWD; Automatic trans.; with Federal Emissions; I.D. #(s) E8TF-SA

Rockauto link:
https://www.rockauto.com/en/catalog/ford,1988,ranger,2.9l+177cid+v6,1137608,electrical,engine+control+module+(ecm+computer),2896
 


Rock Auto 5% Discount Code: 173A8B749AB83C Expires: January 1, 2020

Nez'sRanger

Active member
Joined
Oct 6, 2018
Messages
160
Reaction score
43
Points
28
Location
Los Angeles, CA
Vehicle Year
1989
Make / Model
Ford
Engine Size
2.9L V6
Transmission
Manual
That would be Standard (or Federal) emissions vs California emissions. I'm not sure what differences they would have on that year, but, for example, in 1990 the CA emissions had a maf sensor vs the speed density of the federal emissions.
I'd make sure the ECU you get has all the features your truck has. Especially auto/manual trans and standard/California emissions. I'm sure there's a reason they sell different ones for 4x4, so I'd make sure that matches too.
 

Paulos

Active member
Joined
May 7, 2018
Messages
254
Reaction score
91
Points
28
Location
North Carolina
Vehicle Year
1987 STX
Make / Model
Ford
Engine Type
2.9 V6
Engine Size
2.9L
Transmission
Manual
2WD / 4WD
4WD
The "SA" is the correct ECM if you're going with an '88 ECM. There are Federal emissions and California emissions ECM's. The code 86 is probably being caused by the EGR position sensor that you have connected. On the '86, pin 52 is used for the EGR position sensor to the ECM. On the '88, pin 52 is used for the A4LD auto trans (3rd to 4th gear shift).

Like I said earlier, disconnect the knock sensor, the EGR position sensor (EVP, EVR, etc.), and the EGR solenoid (near the starter solenoid). The vacuum reservoir is also unneeded without the EGR system, so disconnect it and plug the vacuum port to avoid any potential vacuum leaks. After disconnecting the sensors and solenoid, disconnect the battery for 20 minutes or more, then test the system again and pull codes.

Pin 23 is for the knock sensor. So if you are not going to go back to an EGR system you can pull pin 23 from the ECM harness connector, plug it in where pin 8 should be, cut the wire, and extend the pin 8/ECM side to the line/input side of the inertia switch to get rid of code 95.

The '88 and '89 schematic shows another solenoid on pin 52 for the A4LD transmission (3-4 shift solenoid) that the '86 and '87 schematic does not show. Pin 53 is used for the A4LD shift solenoid in all these year models. Will the lack of wiring for the 3-4 shift solenoid on your '86 harness cause any issues with the '88 ECM that provides for it? I don't know. Maybe someone else in the forum knows, like @adsm08 or @RonD.

In the schematics the '87 is like the '86, and the '89 is like the '88.
 

Attachments

Kellogg

New member
Joined
Feb 6, 2019
Messages
14
Reaction score
1
Points
3
Location
West Chester PA
Vehicle Year
1986
Make / Model
Ford
Transmission
Automatic
Thanks for the additional info Paulos. It is strange that the 86/87 schematics only show the torque converter solenoid and not the overdrive/3-4 shift solenoid like the 88+ does. I always assumed all A4LDs had these two solenoids. I did notice that my original ECM has about 10 or so fewer pins then the 88, which has all of its pins.

When I did the egr delete I unplugged the egr purge solenoid and the egr valve vacuum sensor and conducted several "ECM resets" by disconnecting the battery for 20-30 mins. As of now those two plus are just laying unplugged and tapped up since both are still receiving voltage. I have not yet unplugged the knock sensor. Will do that tonight.

As for my question about the RockAuto refurb ECM listed above (784478), I was thinking that the program codes listed {#E8TF12A650SA, E8TZ12A650SA} were two different ECMs both for the RWD 1986 2.9 auto and that I needed to choose one, "F" or "Z", when I realize now that they are one in the same. Sorry for that.

So it seems if I go with a 88 or 89 ECM, I should rob pin 23 and install it in pin 8 on the ECM harness plug and wire it to the hot side of the inertia switch to deal with code 95, and also possibly deal with some additional repining for code 86.
 

Paulos

Active member
Joined
May 7, 2018
Messages
254
Reaction score
91
Points
28
Location
North Carolina
Vehicle Year
1987 STX
Make / Model
Ford
Engine Type
2.9 V6
Engine Size
2.9L
Transmission
Manual
2WD / 4WD
4WD
I just read that the '88 (and most likely later) A4LD has two solenoids and a 3-wire connector. Which makes sense, that the '86-87 would have one solenoid and a 2-wire connector. So the '86-87 ECM is clearly designed to work with the single solenoid, but the '88+ ECM's are made to work with two (that's the way I'm seeing it). All year models with the A4LD have the "lockup" solenoid which uses pin 53 in all cases. So I have to wonder if your trans will function correctly using the '88+ ECM's on your '86. I looked in the tech section at the Ranger Station, and it did not show different types of A4LD's. You might want to research the A4LD before getting the '88 ECM.

A few interesting things I found right away are:

And here :)
 

Paulos

Active member
Joined
May 7, 2018
Messages
254
Reaction score
91
Points
28
Location
North Carolina
Vehicle Year
1987 STX
Make / Model
Ford
Engine Type
2.9 V6
Engine Size
2.9L
Transmission
Manual
2WD / 4WD
4WD
I suppose it's possible that the '88 ECM would work in regards to the missing 3-4 shift solenoid; but you would probably have that code 86 all the time.
 

Kellogg

New member
Joined
Feb 6, 2019
Messages
14
Reaction score
1
Points
3
Location
West Chester PA
Vehicle Year
1986
Make / Model
Ford
Transmission
Automatic
Last night I disconnected the knock sensor with no difference so I went ahead and ordered the 88 ECM from rockauto. Should be here sometime tomorrow hopefully. I'll throw it in and scan for codes again, I will most likey still need to repin to deal with code 95 and I'm sure I'll see code 86 which I think I'll just have to live with. If it still runs rough I'll start looking again for possible air leaks and check for a gummed up IAC valve or bad grounds. I'll keep the thread updated on what happens. I also checked the fuel pressure last night and at KOEO it was at 35psi and with KOER it was at around 28psi, a little low for KOEO (book says 40psi) so I might check out the filter too.
 

Kellogg

New member
Joined
Feb 6, 2019
Messages
14
Reaction score
1
Points
3
Location
West Chester PA
Vehicle Year
1986
Make / Model
Ford
Transmission
Automatic
Ok, well after a week of messing with it, the truck ultimately runs better with the new 88 ECM but still has a lot of gasping/hesitation when throttle is cracked and the exhaust smells just awful. Possibly a lean mix as I didn't smell gas. Engine seems to lack power as well. Fuel filter seemed fine along with air filter. Both pumps and regulator were replaced just over a year ago. Is 35psi on the fuel rail is too low?

I also noticed that my truck is still making a rattling noise when I hit the gas... Not as bad as with the loose egr tube but now I am wondering if my cats are falling apart. They came with the truck and have definitely seem some miles. Could this be an issue? I am not burning oil but they could possibly still have some restrictions at this point.
 

alwaysFlOoReD

Forum Staff Member
Forum Moderator
TRS Banner 2012-2015
TRS 20th Anniversary
Joined
Apr 13, 2009
Messages
9,642
Reaction score
761
Points
113
Location
Red Deer, Canada
Vehicle Year
'91, '94, '80
Make / Model
Ford, GMC
Engine Size
4.0,4.0,350
Transmission
Manual
35 psi is good. Under 30 is not.
 


Top