FIS Fast Idle Solenoid R&R

[harrietnorth]

I’ve diagnosed my issue down to what appears to be a failed FIS. On cold start, the circuit that powers the FIS is getting a solid 12v, but the solenoid isn’t popping out, nor is it staying out when I know it’s energized.

Has anyone had any luck taking this animal apart, cleaning it and getting life back into it?

If it truly is dead, anyone know a good source for a be one?

It was -20 here and I’d rather have the FIS working VS a 2x2 jammed between the seat and the gas pedal.


1988 7.3idi NA - C6 - BW1356 4x4.


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[Mammoth73]

E8tz9e939a is the part number. Couldn't find it anywhere I looked until I finally found it on another forum. It's like 50 bucks vs the 140 I saw it goin for on eBay.

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[Koch13351]

I have a couple of spare fast idle solenoids in working order and I’m willing to part with one if you’re fine with a used one.


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[icanfixall]

You may want to check the sender that controls this and the cold advance solenoid. Its very expensive "if" you can find it new. Mine failed and burned down some wiring. My post is back a few months called Electrical Issues. This sender is forund back behind the thermostat housing way down low on the block too. It normally is closed so power feeds both the fast idle solenoid and the cold advance solenoid in the top of the injection pump cover.Sometimes they get unplugged and wont work the system. When the coolant reaches about 120 degrees the sender "opens" stopping the power feed to those solenoids..

 

[IDIBRONCO]

In the first post, he says that he knows that it's energized. That part is easy to check with a 12V test light. So is the switch. Harrietnorth, try wiggling the plug around on the fats idle solenoid. Maybe there's not a good contact. You could also unplug and then plug it back on the spade a few times. This may not fix your problem, but at least it's free.

 

[Mammoth73]

I have a couple of spare fast idle solenoids in working order and I’m willing to part with one if you’re fine with a used one.


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If it'll fit a 7.3 with a turbo I'll take it, save myself $50

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[Mammoth73]

I have a couple of spare fast idle solenoids in working order and I’m willing to part with one if you’re fine with a used one.


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If it'll fit a 7.3 with a turbo I'll take it, save myself $50

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[Mammoth73]

I have a couple of spare fast idle solenoids in working order and I’m willing to part with one if you’re fine with a used one.


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If it'll fit a 7.3 with a turbo I'll take it, save myself $50

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[IDIBRONCO]

They're all the same as far as I know. It should fit.

 

[Mammoth73]

Dang pixies in my phone again. Then hellyea I'll take it. More money towards pyro

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[Koch13351]

I PM’d you

 

[harrietnorth]

In the first post, he says that he knows that it's energized. That part is easy to check with a 12V test light. So is the switch. Harrietnorth, try wiggling the plug around on the fats idle solenoid. Maybe there's not a good contact. You could also unplug and then plug it back on the spade a few times. This may not fix your problem, but at least it's free.

I got in there and sanded the contact and then hard wired straight to the battery. No joy. It sounds like there is no chance for taking apart the solenoid, futzing with the innards and bringing it back to life. Gonna need a ‘new one’.

BTW - I’ve been a lurker here for awhile and I really appreciate the thoughtfulness to my first post.

I have 2 idi’s.

An 88 NA, we call ‘Frank the Tank’. 4x4 dump truck.

My ‘new’ one we call the ‘DT’ for ‘Donor Truck’. 94 Idi with factory turbo, 4x4, ZF5-42, 3.55. The DT frame is getting a body swap from a ‘75 dentside. This is a project I’ve had in my bucket list for 25 years.

I’m excited to finally start.


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[79jasper]

Try taking it apart. What are you gonna do, break it?

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[icanfixall]

Another great way of "testing" these solenoids is to remove the power feed wire. then run a jumper wire from the passenger side battery positive side. Just touch the solenoid exposed spade terminal. Watch for the plunger to move in or out. BTW that plunger is adjustable too. The hex on the end is 1/4 inch socket size. The plunger has a very fine thread so adjusting it can take plenty of turns. another possible adjustment is the actual bracket. You loosen the 2 mounting bolts and move the bracket towards to throttle or away from it. Usually a little goes along ways.

 

[IDIBRONCO]

He already "hard wired straight to the battery".