1991 FJ80 Starting Woes (Cranks, won’t start, CEL is ON) (1 Viewer)

[ColoradoBoy]

Hello, all- it has been a while since I've been around; life gets pretty busy as you all know. Looking for some help (again!)

Background: Washed the engine compartment, as it was truly filthy. Tried to be careful, as I know I have an issue with something getting wet under the hood that has caused it to die until things dry out in the past, and know that water in general is not good for electrical components. I thought I could use this opportunity to try to track it down by slowly moving around the engine bay., as I have not found the culprit/area of issue yet. To add insult to injury this time, I was rinsing with a garden hose (motor running); got done and thought, “oh good, still running.” Cough, cough, sputter- done. This was 3 weeks ago, and still can’t get her to run again. Was thinking about possibly needing to check wire harness conditions more- I did some checking & re-wrapping while de-smogging & replacing the push rod cover gasket this spring, but have not explored more since then. I'm trying to piece together in my mind what got completely ruined this time to where once things dried out, still won't start. I thought I fried something electrical, but have yet to discover the issue. I can crank all day long, but not get so much as a sputter...

CEL is ON when key is turned.

No codes stored

Fuses checked OK, both under hood and in cab.

EFI relay checked OK

Fusible links OK


I have followed the flow chart in the FSM @ FI-10 (EFI- no start, engine cranks)

ISC tested OK.

Vacuum lines OK – all new rubber parts in the last year, incl. air intake.

Ignition checks OK (?) – coil tested good, visual spark from coil while cranking, but maybe a bit weak? FSM says I should have a spark that jumps ½” or so- not the case here.

New spark plugs, wires, cap, rotor (OEM) this spring. Distributor was removed a while back & cleaned/adjusted properly. (was running fine before this)

Cold Start Time switch & Cold Start Injector switch test OK.

AFM tests OK.

TPS tests OK (new OEM in 2022).


I have followed the flow chart in the FSM @IG-5

Connections for wires all secure.

Plug wires resistance tests OK.

Power to ignition coil tests OK.

Resistance of coil check OK.

Distributor pickup coil resistance & air gaps checks OK. New spark plugs, wires, cap, rotor (OEM). Distributor was removed a while back & cleaned/adjusted properly.


Moving on to fuel related (not sure it is a reasonable path, given the water-related issues)

Fuel pump working and fuel moving thru return line to tank.

New FPR installed 7/2020 – pressure tests completed while chasing the “hard-to-start-when-hot” condition.

Fuel pump and filter replaced around the same time.

Cold Start injector cleaned & tested 6/2020.

Fuel injectors recently rebuilt last winter (2022).

De-smogged this spring.


So, if anyone has some ideas or sees something I have missed, I would greatly appreciate some help.

Cheers!

 

[jonheld]

You claim to have weak spark. I would start there.
Did you inspect the inside of the cap for water?
Is the igniter/coil secure in it's mount and fastened tightly to the fender? It is grounded through the bracket to the body.

 

[ColoradoBoy]

Thanks for checking in, Jon! I really appreciate it.

Cap is dry & clean, igniter/coil is secure. However, I re-checked the spark coming from the coil today once the shade set in, so I could see better, and there is barely a spark if I'm touching metal while cranking. Bad ground, or bad igniter? I'll go out an check the grounds & re-check the coil & see what I find there, but I'm beginning to suspect the igniter has failed. I can't find info so far on how to test in the FSM, which seems odd to me. Any thoughts there?

Thanks!

 

[Somebodyelse5]

Thanks for checking in, Jon! I really appreciate it.

Cap is dry & clean, igniter/coil is secure. However, I re-checked the spark coming from the coil today once the shade set in, so I could see better, and there is barely a spark if I'm touching metal while cranking. Bad ground, or bad igniter? I'll go out an check the grounds & re-check the coil & see what I find there, but I'm beginning to suspect the igniter has failed. I can't find info so far on how to test in the FSM, which seems odd to me. Any thoughts there?

Thanks!

Igniter failure isn't particularly common on the 80, so I would go poking around further before dropping the coin to replace that.

I would check power circuits that feed it. My first check would be the fusible links at the battery, common problem that would cause your problem. The ignition igniter has proven to be very reliable.

Where can I test my ignition ignitor?

A mechanic stopped by...no power to the distributor. He suspects the ignition ignitor. Where can I have it tested? 818 area code.

forum.ih8mud.com

 

[ColoradoBoy]

Fusable links are good. Thanks for the link, I'll read through it now.

 

[jonheld]

Igniter failure isn't particularly common on the 80, so I would go poking around further before dropping the coin to replace that.

Not common, but not unheard of either. I went through 2 OEM igniters on my 91, so it is a strong possibility if everything else checks out.
I would try used/known good before going down any other rabbit hole, as new OEM is long discontinued.
NOTE: There is a difference between the coil/igniter combo from the FJ62 3FE to the FJ80 3FE. I'm not certain they are compatible.
There is no test in the FSM for an igniter.

 

[ColoradoBoy]

Not common, but not unheard of either. I went through 2 OEM igniters on my 91, so it is a strong possibility if everything else checks out.
I would try used/known good before going down any other rabbit hole, as new OEM is long discontinued.
NOTE: There is a difference between the coil/igniter combo from the FJ62 3FE to the FJ80 3FE. I'm not certain they are compatible.
There is no test in the FSM for an igniter.

Thanks, Jon- I found several on Ebay- 89621-12010. Can't hurt to have an extra, and the one currently installed is not OEM. If this does indeed fix things, I will get another as a spare. I'll have to buckle down to chase the ECU wires/system... not looking forward to it, as I am not very electrically inclined... Not to mention short on time to do this. I'll post back as I make progress.

Cheers!

 

[ColoradoBoy]

OK, I have dug the ECM out of the glove box area, but am confused on how to check wires still plugged in to the ECM, as stated on FI-28. Do I need a sharp pin to penetrate the wire cover & get a reading off of that? The probes on my multimeter won't do it (file to a sharper point?). Should I be finding each end of the wiring harness to check for continuity of each wire (end-to-end) first? I also have a copy of the EWD manual (color printed), but it gives me nothing that helps me understand this foreign (to me) language & procedures. Frusterating knowing that the information to find the answers are here, but I can't decipher it. A bit of guidance would be appreciated.
Thanks in advance...

 

[ColoradoBoy]

Still slogging away at testing circuits; starting to wonder if I need to switch my attention to the wiring going to the fuel pump. I can hear fuel running thru the return hose, but beginning to wonder if I'm not getting fuel. Would surprise me as I did so much work to the fuel components not so long ago, but dang, I'm feeling like I'm spinning my wheels.
I'll keep updating....

 

[jonheld]

OK, I have dug the ECM out of the glove box area, but am confused on how to check wires still plugged in to the ECM, as stated on FI-28. Do I need a sharp pin to penetrate the wire cover & get a reading off of that? The probes on my multimeter won't do it (file to a sharper point?). Should I be finding each end of the wiring harness to check for continuity of each wire (end-to-end) first? I also have a copy of the EWD manual (color printed), but it gives me nothing that helps me understand this foreign (to me) language & procedures. Frusterating knowing that the information to find the answers are here, but I can't decipher it. A bit of guidance would be appreciated.
Thanks in advance...

If your probes are too thick to get to the pins of the connectors, strip back a short piece of solid strand wire. Ethernet cable is great for this. Solder it onto the probe and use the wire to get to the terminals.
Or use alligator clips with one on the probe and the other side on the wire, but that's not as stable.

 

[jonheld]

Still slogging away at testing circuits; starting to wonder if I need to switch my attention to the wiring going to the fuel pump. I can hear fuel running thru the return hose, but beginning to wonder if I'm not getting fuel. Would surprise me as I did so much work to the fuel components not so long ago, but dang, I'm feeling like I'm spinning my wheels.
I'll keep updating....

Are you seeing fuel spray from the banjo bolt on the cold start injector with the pump running?

 

[ColoradoBoy]

Are you seeing fuel spray from the banjo bolt on the cold start injector with the pump running?

I will have to check. Thank you for the prompt, Jon. Just frustrating to know something got fried, but can’t find it.

 

[ColoradoBoy]

If your probes are too thick to get to the pins of the connectors, strip back a short piece of solid strand wire. Ethernet cable is great for this. Solder it onto the probe and use the wire to get to the terminals.
Or use alligator clips with one on the probe and the other side on the wire, but that's not as stable.

I ended up sliding sewing pins down into the connector pins & probed those. I like your idea better, though.

 

[ColoradoBoy]

Are you seeing fuel spray from the banjo bolt on the cold start injector with the pump running?

+B and Fp jumpered, ignition switch on, fuel running in return line to tank, fuel pressure at the banjo fitting when loosened. Looks like I'm back to chasing electrical gremlins...

 

[ColoradoBoy]

So, back to this after a long pause...

...and going back to the distributor. I pulled it early on in this process to clean up the crap on and around the pickups, re-gapped per FSM, and re-installed. THEN I have had the persistent no start issue (verified that TDC is correct). I am seeing spark from the coil to the distributor cap while cranking, but no spark coming out of the distributor to the plugs. Can I safely assume that the pickup(s) failed while I had them out for cleaning, due to being old parts/corroded wires, etc? I'm trying to remember where I found the info on how to test pickup coil resistance from my first distributor pull- any direction on where to find this info? My google skills have hit the wall today.
Thanks, all!

 

[jonheld]

So, back to this after a long pause...

...and going back to the distributor. I pulled it early on in this process to clean up the crap on and around the pickups, re-gapped per FSM, and re-installed. THEN I have had the persistent no start issue (verified that TDC is correct). I am seeing spark from the coil to the distributor cap while cranking, but no spark coming out of the distributor to the plugs. Can I safely assume that the pickup(s) failed while I had them out for cleaning, due to being old parts/corroded wires, etc? I'm trying to remember where I found the info on how to test pickup coil resistance from my first distributor pull- any direction on where to find this info? My google skills have hit the wall today.
Thanks, all!

If the pick up coils in the distributor were faulty there would be no spark.
The distributor coils generate both spark and crank position pulses that are fed to the ECU. The ECU then corrects timing of the pulses depending on sensor feedback and feeds them to the igniter, which in turn feeds them to the ignition coil which feeds the distributor rotor.

If you're getting spark from the coil, then the distributor rotor is faulty or the center spring loaded button in the cap is faulty or the coil wire is faulty.

 

[ColoradoBoy]

If the pick up coils in the distributor were faulty there would be no spark.
The distributor coils generate both spark and crank position pulses that are fed to the ECU. The ECU then corrects timing of the pulses depending on sensor feedback and feeds them to the igniter, which in turn feeds them to the ignition coil which feeds the distributor rotor.

If you're getting spark from the coil, then the distributor rotor is faulty or the center spring loaded button in the cap is faulty or the coil wire is faulty.

Thanks, Jon! The detailed description is very helpful and appreciated. I do have spark from the coil thru the wire, so I'll plug in a new rotor & cap & see what happens. Both of those parts are less than a year old and OEM, but you never know. For once, I have those (extra) parts sitting on the shelf.

 

[ColoradoBoy]

Thanks, Jon! The detailed description is very helpful and appreciated. I do have spark from the coil thru the wire, so I'll plug in a new rotor & cap & see what happens. Both of those parts are less than a year old and OEM, but you never know. For once, I have those (extra) parts sitting on the shelf.

Ugh. New cap & rotor, no change (or spark after the cap). Based on Jon's description, I think I have to dive into the wiring diagram and test a few more ECU wires going back to the ignition parts.

 

[ColoradoBoy]

Long time, no posts. I procured an OEM set of ignitor/coil pack. Fired right up.