FJ62 Cranking over but Not Starting

[psuarez00]

Hey Everyone!

Need your assistance….My rig died on me as I was driving away from my house. Cranks over but does not start. I followed the IG-7 troubleshooting instructions from the repair manual and everything is within specs. I do the spark ️ test and no spark coming from the ignition coil when I crank it over. I tried putting the spark plug wire to different bolts and no spark. All connections to the ignition coil, distributor and igniter are good.

I already bought a new igniter and coil even though the other ones were good. I just got annoyed and wanted to verify it was not those components.

Any assistance would be greatly appreciated!

EFI, Ignnition, and Engine fuse ohm’s out good.

Fusible links ohm’s out good as well…. Does anyone have a picture of a melted or non working fusible link?

 

[TheElegantFox]

While you're working on diagnosing the ignition system, take a look at the coolant temp sensor. Mine was a faulty aftermarket one that masked a lot of other starting issues when it was the culprit. The cold start injector is also worth a look since it's a quick pull to see if it's gunked up.

 

[Devils Paw 80]

Circuit opening relay?

 

[Godwin]

Is the CEL light coming on with the ignition? If not, dead EFI relay. If the CEL will light have you run the codes? Check these before throwing parts at it.

A bad fusible link will look like a good fusible link, check the voltage at the fusible link to verify condition.

 

[OSS]

Yeah - the photo you’re showing is the “plug” for the fusible link. The links are actually thick wires farther down the cable. Examine them carefully and especially examine all the spade connectors in the link assembly. The actual links may not be burned out but the cheapo spade connectors can be toast.

 

[psuarez00]

Deleted

 

[psuarez00]

Yeah - the photo you’re showing is the “plug” for the fusible link. The links are actually thick wires farther down the cable. Examine them carefully and especially examine all the spade connectors in the link assembly. The actual links may not be burned out but the cheapo spade connectors can be toast.

Just checked the voltage across and got the same as at the battery 12.81V. I used a probe to poke each wire at about 10in below the connectors. Should I have checked further down?….. how far down do they go?

 

[psuarez00]

Is the CEL light coming on with the ignition? If not, dead EFI relay. If the CEL will light have you run the codes? Check these before throwing parts at it.

A bad fusible link will look like a good fusible link, check the voltage at the fusible link to verify condition.

EFi main relay test
No continuity between terminals 1 and 3 - Failed?.…. It actually gives me 85 ohms of resistance. The resistance of the coil within the relay is 85ohms. Does anyone know if this is within spec?

but… when I apply 12v it closes terminals 2 and 4 and they do have continuity.

Seems like I need an EFI RELAY!!!!….. I swear I tested this before and it had continuity between terminals 1 and 3.

 

[BurntToast]

EFi main relay test
No continuity between terminals 1 and 3 - Failed…. It actually gives me 85 ohms of resistance.
but… when I apply 12v it closes terminals 2 and 4 and they do have continuity.

Seems like I need an EFI RELAY!!!!….. I swear I tested this before and it had continuity between terminals 1 and 3.

View attachment 3664697

View attachment 3664698

I have one you can have for the price of shipping since I yanked it for my LS swap. But I will say I just measured 1-3 and it’s also ~85 ohms. But mine did run and drive before I yanked it so who knows. It’s likely just the coil resistance

 

[psuarez00]

I have one you can have for the price of shipping since I yanked it for my LS swap. But I will say I just measured 1-3 and it’s also ~85 ohms. But mine did run and drive before I yanked it so who knows. It’s likely just the coil resistance

I have been researching and it sounds like that resistance is within specs, to call my and your EFI relay in working condition. Unless someone else knows otherwise.

 

[psuarez00]

Just checked the Voltage to the EFI relay with the key turned over to accessories and it 11.71v vs at the battery it’s 12.5v…. Seems okay …right?

When I plug in the relay to the harness I can feel and hear the relay click closed terminals 2 and 4 in the relay.

 

[psuarez00]

Circuit opening relay?

Followed the service manual procedure to check continuity and everything turned out good, except for terminals B and FC. I got a resistance value of 111.8 ohms, not sure if this is too high.

I also applied 12v per the service manual and got continuity where I was supposed to. Here is a picture of my setup.

 

[toy_tek]

Those measurements look ok. I'd expect some higher resistance between B and FC given the diagram. Resistance = continuity.

Lets go back to your spark test. The manual says "hold the wire end 1/2 inch from the body of vehicle". Since you're following the manual pretty closely (awesome!) I'm guessing that's how you're testing spark. Honestly I'd be surprised if a known running EFI would show spark like that. Maybe. But maybe not.

Growing up I never tested spark that way, I'd shove a screwdriver in the end of the plug wire (making contact with the metal insert) and lay the metal shaft of the screwdriver within a mm or two of a ground (engine bolt, etc). Then crank the engine. I probably should disclaimer: don't hold the screwdriver while the engine is cranking. It's quite easy to see spark then. Doing it at night with the lights off is even better.

Maybe give this a try and report back. I could be wrong (often am!), but I have a hunch your ignition might be fine based on all your very good troubleshooting notes here.

If it is, move on to the AFM & Fuel.

 

[psuarez00]

Those measurements look ok. I'd expect some higher resistance between B and FC given the diagram. Resistance = continuity.

Lets go back to your spark test. The manual says "hold the wire end 1/2 inch from the body of vehicle". Since you're following the manual pretty closely (awesome!) I'm guessing that's how you're testing spark. Honestly I'd be surprised if a known running EFI would show spark like that. Maybe. But maybe not.

Growing up I never tested spark that way, I'd shove a screwdriver in the end of the plug wire (making contact with the metal insert) and lay the metal shaft of the screwdriver within a mm or two of a ground (engine bolt, etc). Then crank the engine. I probably should disclaimer: don't hold the screwdriver while the engine is cranking. It's quite easy to see spark then. Doing it at night with the lights off is even better.

Maybe give this a try and report back. I could be wrong (often am!), but I have a hunch your ignition might be fine based on all your very good troubleshooting notes here.

If it is, move on to the AFM & Fuel.

I also have a 67 Mustang and when I do a spark ️ test I can most likely weld with that spark and yes I insert a screw driver without holding the metal and bring close to the body or bolt. I will check it tonight for spark ️, expecting a smaller/weaker spark than what I get on my Mustang. Thanks for the suggestion!

 

[psuarez00]

@toy_tek …..did not check the spark but I did check the resistance values of the AFM. One thing I forgot to mention is that I accidentally took the screws off the AFM and tugged on the connector and it came out a little before it died on me. I was actually doing an oil change and then changed the air filter and was curious to see how clean the AFM was. After doing the oil change, it turned on and was able to pull it out of my driveway but then it just died.

Here are the results of the resistance test, all pictures are in the order of the test procedure.

The resistance values are not within specs and I am thinking I must of broken some of the sauter connections, like in this video. Would a messed up AFM prevent it from turning on?…..I am assuming so.

 

[Hammer45]

Did you get this figured out?