Injection Pump component ID

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Apr 24, 2023 | 08:17 PM

mikekozak

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Injection Pump component ID

Can you please identify the solenoid circled in the picture that is disconnected? I believe this is the fast idle solenoid. Truck came with it disconnected.

Apr 24, 2023 | 08:29 PM

tecgod13

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From: Western Mass

Yes that is the fast idle solenoid.

Apr 24, 2023 | 09:02 PM

mikekozak

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Thanks. Does appear to be busted which is probably why it was disconnected.

When connected, there's no difference in starting or rpm. If any throttle is applied, it revs high and sticks.

Apr 25, 2023 | 01:09 AM

Prototypemech

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Mine broke years ago. I don't miss it. If I find another one, I'll replace it but it causes zero problems being disconnected.

Apr 25, 2023 | 09:21 AM

tecgod13

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From: Western Mass

Quote:

Originally Posted by mikekozak

Thanks. Does appear to be busted which is probably why it was disconnected.

When connected, there's no difference in starting or rpm. If any throttle is applied, it revs high and sticks.

You might be mistaken on how the fast idle solenoid works. It doesn't have enough ummph to move the throttle, just hold it at a higher position if the pedal is pushed.
So if you hook it up with ignition on, nothing will happen. If you push the throttle lever back towards the firewall, the little plunger in the solenoid should move out to hold the throttle. When the engine warms up (I think above 140 F?) it should shut off and let the idle drop back down.
If you read the starting directions, it mentions to turn key on, then depress pedal halfway (engages the cold start idle) then crank.
The plunger can be turned in and out with a wrench to adjust the high idle position.

Apr 25, 2023 | 11:40 AM

mikekozak

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Quote:

Originally Posted by tecgod13

HAHAHAH! tecgod13! I actually spent many hours last night learning exactly how it works, how to test it and how to tune it up.

I said specifically to my wife "thank god for this post from tecgod13 at 3:13AM in 2015 and a post off-site from a guy named OkieGringo in 2006" for the detailed explanations of the operation, testing, and the description in the manual.

So you helped me understand before replying here. Incredible wealth of information on the internet about these trucks with the golden nuggets scattered into tiny little pockets of comments.

My running theory is that it does work, probably, but that it's just very poorly calibrated and has the idle set too high. I'm waiting for a tach gun in the mail so I can get it properly configured.

Apr 26, 2023 | 12:17 PM

tecgod13

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From: Western Mass

LOL... not sure why I was posting at 3:13am... think I was still single and unemployed then, hmm...
Its certainly possible the previous owner didn't want the idle to jump as high as it does when turned on. Depending on the climate where he was, it may not have been needed as well.
There sure is a whole lot of info about these trucks out there. Its also possible that the sensor that turns the high idle on and off could be stuck in the on position, keeping it on high idle the entire time its running which is not helpful once warmed up.