No-start (does crank) 1989 FJ62 - need input [SOLVED] (1 Viewer)

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Hey mudders, trying to diagnose a no start, no CEL, does crank issue.

At first I thought it was fuel delivery related but now I’m stumped.

I am able to get it running if I force the fuel pump to run via the diagnostic port (FSM calls it the check connector) by jumping the FP and B+ terminals. This makes me think the issue is with the Circuit Opening Relay but… when I try to start is normally without forcing the connection to the fuel pump as described above I DO hear the relay click on / off so I think it is actually working. I can’t find my multimeter but I’ll go out and repurchase if need be - pretty broke right now.

Does it sound like it’s the COR even though I can hear it (and feel it, I held the relay in my hand while a partner tried to start it) engage upon trying to start and stopping?

Could it in any way be related to the Air Flow Meter? The connection seems secure on the AFM and I think it wouldn’t be the issue because it seems to be working fine once I get it running by forcing the fuel pump to run. If it was the AFM I imagine the engine wouldn’t start or stay running with the fuel pump connection forced since there wouldn’t be air to allow the engine to keep working.

I can order a new COR from rockauto if I have to but I don’t want to without knowing for sure it’s bad. I can’t afford to throw parts at the problem so I’m trying to be methodical in my diagnosis.

Any ideas?

CBFC4518-59F2-4E2F-865D-FFA2BEA35D0E.png
 
I probably have a "Spare " circuit opening relay in Simi Valley. you are welcome to borrow it to see if it fixes the problem.
 
I have one here. Let me know if you want to try it.
COR.jpg
 
I absolutely do want to try it….unfortunately I’m stuck in Burbank with no running vehicle.
 
If it isn’t the COR or the fuel pump is it possible there is a break in the wire connecting the COR to the FP Connector? Or a break in the wire connecting the COR the AFM connector?

Damn, I really need to pick up a new multimeter.
 
Hey mudders, trying to diagnose a no start, no CEL, does crank issue.

At first I thought it was fuel delivery related but now I’m stumped.

I am able to get it running if I force the fuel pump to run via the diagnostic port (FSM calls it the check connector) by jumping the FP and B+ terminals. This makes me think the issue is with the Circuit Opening Relay but… when I try to start is normally without forcing the connection to the fuel pump as described above I DO hear the relay click on / off so I think it is actually working. I can’t find my multimeter but I’ll go out and repurchase if need be - pretty broke right now.

Does it sound like it’s the COR even though I can hear it (and feel it, I held the relay in my hand while a partner tried to start it) engage upon trying to start and stopping?

Could it in any way be related to the Air Flow Meter? The connection seems secure on the AFM and I think it wouldn’t be the issue because it seems to be working fine once I get it running by forcing the fuel pump to run. If it was the AFM I imagine the engine wouldn’t start or stay running with the fuel pump connection forced since there wouldn’t be air to allow the engine to keep working.

I can order a new COR from rockauto if I have to but I don’t want to without knowing for sure it’s bad. I can’t afford to throw parts at the problem so I’m trying to be methodical in my diagnosis.

Any ideas?

View attachment 3062651


this is a real possibility ,,,,,,,,,

confirm and verify there all still good and making solid current flow


if your LINKS are faulty , i can and will USPS Express mail EMS you a new fresh set

let me know if i can help


matt


 
this is a real possibility ,,,,,,,,,

confirm and verify there all still good and making solid current flow


if your LINKS are faulty , i can and will USPS Express mail EMS you a new fresh set

let me know if i can help


matt




Hi Matt, why do you think it’s the fusible links?
 
Hi Matt, why do you think it’s the fusible links?


- simply because
, 91% + of the time , based on your VERY WELL defined symptoms it actually is the fusible links and or the related CONNECTOR Plugs housings

are melted and 1 or more of the brass terminals are shorted out , &no longer make any current flow




- lastly , and maybe even more importantly here in your particular situation , confirming and verifying all 5 Fusible Links / Leads are in solid good working order

condition , DOES NOT cost a dime , only your careful time spent doing the said tasks and step by steps per the FSM .......



- all the tools required are a basic digital multi meter and a reliable hand held TEST LIGHT .......

- if there good then now you will know , if you do not start there , the main B+ power incoming source, then your cheating your self .......


- i am in no way saying purchase any parts till you do have a solid and concrete diagnoses here


- parts are a BIG expense , and throwing them at a issue like this based ONLY on speculation is a poor choice to be clear



i hope this helps :)


kindly

matt


2FFFD7A2-0C1E-4D0F-A774-7B938803144B.jpg
 
have you checked the connector in the driver rear quarter panel, below the jack mount?
 
Unfortunately without a meter, I think you'll just be shotgunning parts.

Re: fusible links... I'm fairly certain when the check connector is jumped, the fuel pump is still getting power through the main fusible link. It's true there could be some melt-down and current loss at a plug, so definitely worth investigating.



Have you checked and reseated your EFI relay? The COR could be closing correctly but if the EFI relay isn't closing then there will still be no power to the pump. The jumper is providing voltage to the pump by bypassing this portion of the circuit.

need to check for voltage on the yel/red wire at the EFI relay and COR relay when ignition is on. (jumper removed) and conversely on the red-green wire at the COR.

Also I believe you'll need to check for 12v at pin 3 of the COR when the starter is cranking.

I'm not 100% sure, but I believe the operation is something like this: COR gets pull close signal on pin 3 during starter operation, then during engine operation it gets pull down signal on pin 4 via a ground from the AFM switch. However when the jumper is installed, the fuel pump is getting power regardless of the EFI, COR or AFM status. Someone please correct me if I'm wrong.


1658237913478.png


this may help
 
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I haven’t checked the rear drivers side quarter panel under the jack mount yet - I’ll do that today.

Interesting to hear about the fire order. I didn’t know the forced fuel pump operation at the check connector bypassed the EFI relay as well as the COR and the AFM.

When I get the engine to fire while the fuel pump is forced to run, doesn’t that indicate proper AFM operation? Wouldn’t the engine just sputter out after a second or two of no air? I have successfully let the engine run for about thirty seconds in the forced fuel pump run state just to make sure it didn’t starve itself of air.

I’ll pick up another multimeter today. Was really hoping to find mine but it seems to have grown legs…sigh.

I’ll keep everyone posted.
 
I haven’t checked the rear drivers side quarter panel under the jack mount yet - I’ll do that today.

Interesting to hear about the fire order. I didn’t know the forced fuel pump operation at the check connector bypassed the EFI relay as well as the COR and the AFM.

When I get the engine to fire while the fuel pump is forced to run, doesn’t that indicate proper AFM operation? Wouldn’t the engine just sputter out after a second or two of no air? I have successfully let the engine run for about thirty seconds in the forced fuel pump run state just to make sure it didn’t starve itself of air.

I’ll pick up another multimeter today. Was really hoping to find mine but it seems to have grown legs…sigh.

I’ll keep everyone posted.
try to force fuel with the AFM unplugged and see what happens. Maybe it still trys? Idk
 
When I get the engine to fire while the fuel pump is forced to run, doesn’t that indicate proper AFM operation? Wouldn’t the engine just sputter out after a second or two of no air? I have successfully let the engine run for about thirty seconds in the forced fuel pump run state just to make sure it didn’t starve itself of air.
two thoughts on that...

1- it's entirely possible the switch portion (or it's wiring, or the plug, or the...) of the AFM is not operating correctly, independent of the metering portion. They're two different parts of one system, but that doesn't mean both parts are automatically failed because one of them isn't working. It could be as simple as one pin on the connector that is bent, broken, pushed back or corroded, for example (similar to what @ChaserFJ60 experienced)

2- I know some AFM systems have a "limp mode" where they'll operate to some degree when failed... like it might idle ok, or work to a certain RPM, but perhaps not operate efficiently through the normal RPM range. Again, it might not be an all-or-nothing affair. Although I don't really have enough experience with this style AFM to say if that's true or not on the 3FE.

Curious to see your findings.


EDIT -
just pulled out my manual... where you're at right now is pointing to the AFM or it's connections.

See the attached PDF for testing the AFM
 

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  • 3FE AFM.pdf
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Just started going through this again today. Picked up a multimeter yesterday.

findings so far - if I unplug the AFM connector (properly! Not via screws but by removing the retaining clip) the truck will not start even with the forced fuel pump via the check connector. It still starts up if I force the fuel pump to run AND AFM is connected.

I’m going to test the connector and AFM and circuit opening relay via the FSM now. It’s hot as hades out there so taking lots of breaks.
 
Going slow slow slow because it’s hot hot hot. and I’m terrified of breaking anything I can’t afford to replace. Having trouble getting the EFI and the COR relays off. Is there a trick to getting them off without too much force?

I tested the AFM and all the terminals are within the proper resistance levels. Trying to figure out how to test the actual AFM connector for proper function.
 
I tested the AFM and all the terminals are within the proper resistance levels. Trying to figure out how to test the actual AFM connector for proper function.
I'm in Phoenix building a roof rack outside...100% with you on hot hot hot.

so you got E1-FC to go from zero to infinity resistance when moving the plate inside? that's the AFM switch referenced in the earlier posts.
 
I'm in Phoenix building a roof rack outside...100% with you on hot hot hot.

so you got E1-FC to go from zero to infinity resistance when moving the plate inside? that's the AFM switch referenced in the earlier posts.
Oof. Probably hotter in Phoenix…stay hydrated.

I haven’t checked while moving plates yet, just checked the pins and their resistance as seen here:

69C564A7-2573-4641-AE81-664109E75D24.png
 
Tested circuit opening relay resistance and operation according to FSM. All good. It’s not the relay. Damn.

7F34E01D-C3CE-4895-B636-C76EA23AEB8C.png
 
Tested circuit opening relay resistance and operation according to FSM. All good. It’s not the relay. Damn.

View attachment 3064671
Have you checked the fusible link?

I would start checking continuity from this wire diagram and work my way down. theres probably a cleaner version of this diagram online lol
wiredia.jpg
 

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