2.9 California MAF conversion - No Start

[PetroleumJunkie412]

In my recent ECU adventures, I also attempted the California EEC conversion. Hooked the MAF into positions 14 and 15 as the guide suggested. No start condition followed.

I also do not have a CEL at startup.

No other wires were moved on the 60 pin. 1988 Ranger 2.9, manual, 4wd with manual hubs, xlt, factory air con truck.

MAF sensor is F0VF-12B579-A2C AFH45-25 1A23

California computer:

 

[adsm08]

Look at it as you would any other no start. What's missing, spark, fuel?

 

[PetroleumJunkie412]

Look at it as you would any other no start. What's missing, spark, fuel?

Don't know. Have fuel pressure at the rail, have spark. Crank over has injector pulse. Sensor is seeing voltage from ECU. Chokes like its out of time when WOT at startup.

 

[PetroleumJunkie412]

Look at it as you would any other no start. What's missing, spark, fuel?

SD computer and UK Sierra computer will still start and run it. The lack of a CEL at KOEO makes me wonder if the Cali ECU is dead. Wouldn't surprise me. Rolled the dice on an EBay one.

UK and SD computer do have CEL at KOEO

 

[adsm08]

Yeah, sounds like a bad unit.

Open her up and look for obvious signs of trouble.

 

[PetroleumJunkie412]

Yeah, sounds like a bad unit.

Open her up and look for obvious signs of trouble.

Did out of frustration earlier. Unit looks pristine inside. No telling though. Case has a few deep dents in it like it was dropped into a bag of hammers a few times.

 

[RonD]

Spray gas into the intake and see if it starts, it should 2.9l spark is self contained for startup

MAF or MAP shouldn't effect startup in any case, driving yes but not startup

So yes probably no EFI because computer has failed

 

[PetroleumJunkie412]

My guess was injectors not getting pulse from the ECU after seeing normal preasure at the rail. On closer inspection, fuel pump relay isn't kicking on with MAF ECU but is kicking on with UK and SD ECUs (hard to hear the damn thing over the cooling fans on the relocated TFI). Fuel pump relay is on pin 8 on my harness.

Even with no relay, the rail is retaining pressure from the other computers which suggests to me that either I don't have an injector pulse, or a ECU signal, or both. My concern is that I'm missing some glaring generational wiring change between the 1988 and 1990 that's not allowing for the truck to start, but even with laying the ECU wiring diagrams over one another, I cannot find anything save the MAP pin and MAF pins/power/grounds.

Still searching for the under-hood wiring diagrams that are not the awful Haynes ones for both the 1988 and the 1990 California. I'm going to bug the admits to add them to the 2.9 MAF conversion page if I can source them.

What's bothering me is that for some reason, the UK and SD ones will work, but the MAF computer AND a spare 1990 SD one I have on the shelf from a parts truck will not fire it (checked the 1990 SD one late last night in a half-in-the-bag "I got this" stupor). It's extremely possible I have two dead units. The parts truck had been sitting for years.

On a side note, I called around to Ford dealers in Pittsburgh to find a break out box to assist in diagnostics. Not a single one has one. Looks like that's on the "to purchase" list once I get some more spare parts sold off.

 

[RonD]

pin 22 is the fuel pump control on the EEC-IV

Seen here: http://www.auto-diagnostics.info/ford_eec_iv

Spray some gas into the intake and see if it fires up, confirm spark and its timing is correct, with the MAF ECU connected


You can bypass ECU fuel pump relay control using the OBD1 connector in engine bay

Look at 2nd drawing here: https://therangerstation.com/tech_library/OBD_I.shtml

Fuel pump slot is IDed, if you Ground that slot fuel pump relay will close with Key On and stay closed until key is OFF

The ECUs pin 22 wire runs to that slot and so does the Fuel Pump Relays Ground wire.
If should have 12volts with key on, thats the 12volt from EEC relay closing with key on, it powers/passes thru FP relays coil to that slot and pin 22 on ECU


Pin 47 is from TPS(throttle position sensor), if that pin has 4.5v or higher volts it will cause ECU to turn off fuel injectors, its for Clear Flooded Engine mode

 

[PetroleumJunkie412]

pin 22 is the fuel pump control on the EEC-IV

Seen here: http://www.auto-diagnostics.info/ford_eec_iv

Spray some gas into the intake and see if it fires up, confirm spark and its timing is correct, with the MAF ECU connected


You can bypass ECU fuel pump relay control using the OBD1 connector in engine bay

Look at 2nd drawing here: https://therangerstation.com/tech_library/OBD_I.shtml

Fuel pump slot is IDed, if you Ground that slot fuel pump relay will close with Key On and stay closed until key is OFF

The ECUs pin 22 wire runs to that slot and so does the Fuel Pump Relays Ground wire.
If should have 12volts with key on, thats the 12volt from EEC relay closing with key on, it powers/passes thru FP relays coil to that slot and pin 22 on ECU


Pin 47 is from TPS(throttle position sensor), if that pin has 4.5v or higher volts it will cause ECU to turn off fuel injectors, its for Clear Flooded Engine mode

Maybe I misspoke. I'll have to look tonight.

Either way, return window was closing so sent it back while I could.

A reman one is on the way now... Round 2 to follow

 

[Paulos]

Pin 8 goes to the load side of the fuel pump relay, and only tells the ECU that the fuel pump circuit is energized. As Ron said (for the most part), pin 22 supplies the negative side of the coil of the fuel pump relay.

 

[PetroleumJunkie412]

Well, plugged the reman computer in. Truck is idling around 750-800 rpm, throttle is sluggish (as in non existent), and after revving to 2000 rpm or so (as high as it will Rev) idle drops to 500-600 and it dies.

Ugh. ?

Suggestions? Or places to start looking?

 

[PetroleumJunkie412]

Video of it running at startup.

Had a spare MAF sensor and housing (same part number). No change.

Pulled the SPOUT connecter after I shot this. A lot smoother, but lots of popping and it's struggling to rev. Is it possible that it's a timing issue?

Compared the harness to the 1990 diagrams. Harness is pinned out exactly as its supposed to be.

MAP vac line is disconnected and plugged, and sensor is still plugged in and reading atmosphere

 

[PetroleumJunkie412]

KOEO Codes:

57, 16, 85, 89, 86
Memory: 22, 45

 

[PetroleumJunkie412]

EDIT: Still not sure if I found the problem

Photo of ECM I was sent.

Which translates to...

So the seller is insisting that I have a 2.9 MAF computer. Homework is showing that it's for a 4.9 or 7.3... No idea at this point.

Any help is appreciated and needed.

Thank you!