Anyone near Idaho Falls, ID that has a spare 3FE ECU or AFM? (1 Viewer)

[LhPickle]

I am trying to trouble shoot, my 1991 3FE and I think I have it narrowed down to either the AFM or the ECU. I don't really want to buy new/used ones, if I don't actually need to. So I am looking try swapping them out to see if that solves my problems. Iv'e gone as far as my non-electrically minded brain can go working through @jonheld diagnostic...

I have No CEL with key in the on position and it wont start. I spray starting fluid in the air filter and it acts like it wants to start, otherwise it just cranks with no starting fluid.

Replaced the following:
Fusible Link
EFI Relay Under the Hood
Spark Plugs and Wires
Distributor Rotor and Cap
Fuel Pump and Fuel Filter

 

[baldilocks]

@ginericLC may be able to help.

 

[Tools R Us]

...
I have No CEL with key in the on position and it wont start. ...

Does it have power to the ECU? If not it's not going to start, changing the ECU isn't likely to help.

 

[ginericLC]

I have a 91 3FE ECU for sale over in Mountain Home. $112 shipped to ID Falls.

 

[LhPickle]

Does it have power to the ECU? If not it's not going to start, changing the ECU isn't likely to help.

I don't have a FSM, how do I check to make sure it has power? What do I need to do to verify that?

 

[LhPickle]

I have a 91 3FE ECU for sale over in Mountain Home. $112 shipped to ID Falls.

interested if I can validate that the ECU is the problem

 

[Tools R Us]

I don't have a FSM, how do I check to make sure it has power? What do I need to do to verify that?

Need to run the voltage checks at the ECU. I'm not much of a 3FE fan, so not sure these pinouts are correct. At least need to key on power, at the yellow/black circuit, connector C, pins; 1 & 7, full time power at red/yellow C 2. There should be a meter check list in the FSM.

https://forum.ih8mud.com/threads/40...sm-for-a-hell-of-a-price.610994/#post-7851101

 

[jonheld]

I am trying to trouble shoot, my 1991 3FE and I think I have it narrowed down to either the AFM or the ECU. I don't really want to buy new/used ones, if I don't actually need to. So I am looking try swapping them out to see if that solves my problems. Iv'e gone as far as my non-electrically minded brain can go working through @jonheld diagnostic...

I have No CEL with key in the on position and it wont start. I spray starting fluid in the air filter and it acts like it wants to start, otherwise it just cranks with no starting fluid.

Replaced the following:
Fusible Link
EFI Relay Under the Hood
Spark Plugs and Wires
Distributor Rotor and Cap
Fuel Pump and Fuel Filter

No CEL=No start
Cranking the starter will do nothing but run down the battery.
Replacing plugs/wires/rotor/cap/fuel pump/fuel filter will do nothing to help the issue.

Lets back up a bit. Is this a sudden issue? Driving fine then stopped running?
Were you doing maintenance under the hood and then it wouldn't start?
Throw some history and backstory at us.

 

[Technician1985]

It has spark but no fuel?

 

[LhPickle]

No CEL=No start
Cranking the starter will do nothing but run down the battery.
Replacing plugs/wires/rotor/cap/fuel pump/fuel filter will do nothing to help the issue.

Lets back up a bit. Is this a sudden issue? Driving fine then stopped running?
Were you doing maintenance under the hood and then it wouldn't start?
Throw some history and backstory at us.

It was running fine, we were driving on some forest service roads and we stopped and idled while looking at wildfife and it died. It started right back up and made it home just fine. I parked it in the driveway to hose down dirt and mud and it hasn't started again. I thought it might be a spark issue and I might have gotten water in the distributor when I was spraying off the suspension and knuckles. I honestly just pushed it in the garage and didn't make time to look at it for a couple weeks. I already had a bunch of parts to replace as part of the baseline. So i replaced the spark plugs, wires, distributor rotator and distributor cap, Fuel Pump, Fuel Filter, and Fusible Links. After it still wouldn't start I replaced the EFI Main relay under the hood and it still wouldn't start. I have 12v+ at the relay box and also at the little terminal in the engine compartment in front of the passenger.

 

[LhPickle]

I assume it has spark because when i spray ether/starting fluid in the air filter it ignites the starting fluid.

 

[jonheld]

To clarify, you're seeing +12 on pin 8 of the diagnostic connector with the key in the ON/RUN position. Correct?

 

[TBDAZ]

Sit back and take it all in the master is speaking. I had the same problem back in October. I did what your about to do and throw parts at it. Then John to me by my stupid little monkey hand and walked me through it. After I spent over $200 on parts, it turned out to be a bad wire coming of the AFM. A $1.50 fix. It looked like it had a slice in it. Down in close proximity of the distributor. Probably something I did at some point changing the oil or who knows. Something you may want to look at. Never did thank John for his help.

 

[jonheld]

A quick test for the AFM is to simply unplug it. If the CEL comes back on with it unplugged, then you have your culprit.

 

[OGBeno]

Sit back and take it all in the master is speaking. I had the same problem back in October. I did what your about to do and throw parts at it. Then John to me by my stupid little monkey hand and walked me through it. After I spent over $200 on parts, it turned out to be a bad wire coming of the AFM. A $1.50 fix. It looked like it had a slice in it. Down in close proximity of the distributor. Probably something I did at some point changing the oil or who knows. Something you may want to look at. Never did thank John for his help.

Sensei Held's name is "Jon".

 

[LhPickle]

To clarify, you're seeing +12 on pin 8 of the diagnostic connector with the key in the ON/RUN position. Correct?

View attachment 1632699

Yes.

 

[jonheld]

Sensei Held's name is "Jon".

Change Sensei to SomeGuy.

 

[jonheld]

Yes.

Did you disconnect the AFM and check for the CEL?

 

[jonheld]

Sit back and take it all in the Master Bater is speaking.

Fixed it for you...

 

[Zeus0623]

A quick test for the AFM is to simply unplug it. If the CEL comes back on with it unplugged, then you have your culprit.

Jon,

I am having a similar issue with my '91 FJ80. I think it has something to do with the air/fuel sensor in the intake. When I have the sensor unplugged, I do get a check engine light on. Mind taking a peek at my thread?

Thank you!!!

80 Series Project!!!