Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

idle adjustment screw

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Old 08-17-2011, 12:13 PM
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idle adjustment screw

I'm still having TPS problems even after a new TPS. I can't get it to adjust to with in range. To get it to 4 volts at WOT, it has to be up around 1.8 at idle throttle. I read that the idle rpms need to be correct for the TPS to be able to be adjusted right. Mine appears to be idling at around 850 or so. I adjusted what I think to be the idle screw but it doesn't seem to change anything. It is the screw that's on the IP just under and to the right of the throttle lever isn't it?

Here's my truck idling with it in drive.
 
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Old 08-17-2011, 05:16 PM
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You may have to adjust the cold idle solenoid to get a lower idle speed. If the throttle is touching the cold idle solenoid when the key is off, it won't go any slower no matter how you adjust the idle screw. Use a small wrench to turn the plunger on the solenoid.
I noticed this on my truck this spring when I swapped injection pumps. The cold idle solenoid was set at 1400 when engaged, and it would idle around 800. After adjusting the solenoid down to 1000, I could decrease the idle speed.
 
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Old 08-17-2011, 05:35 PM
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You are right, it is touching the plunger when the truck is off. I'll adjust it what I get home. I home getting the idle right helps with my TPS adjustment cause its about to push me over the edge!
 
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Old 08-17-2011, 05:42 PM
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I never adjust for WOT only adjust for idle and set that to 1.0 volt.
 
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Old 08-17-2011, 06:20 PM
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Originally Posted by ford390gashog
I never adjust for WOT only adjust for idle and set that to 1.0 volt.
Good to know cause that's what I just did. I attempted to adjust the plunger on the cold idle solenoid but it wouldn't turn in or out so I just removed the plunger. This let the throttle lever actually come forward to where it should be at idle. Now my truck is idling at around 700. When I checked the TPS after letting the throttle lever come down to where it should be I got a reading of .72 volts! I adjusted it to 1.00 volts at idle and left it. It still will only go up to 3.66 volts at WOT but hopefully that won't matter! My constant wire on my TPS only has 4.95 volts, is this a concern? The constant wire on the TPS on my other idi has 6 volts.
 
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Old 08-17-2011, 07:25 PM
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read these two links. it is what i went through. trust me on having to have the idle at min 750 rpm.

Idle Speed? - Oilburners.net

TPS help needed quick - Oilburners.net
 
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Old 08-17-2011, 10:48 PM
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Thanks 94IDI, I actually read your two threads on oilburners last night. My problem was that my cold idle solenoid was stuck and wasn't letting my throttle lever go all the way down and it was keeping the idle at about 900 all the time. I had to remove the plunger from the solenoid so I guess I'll have to get another cold idle solenoid this winter but it's running good for now. I can't tell exactly what the RPM's are by looking at the tach but I would guess 650 to 750. Now that I adjusted the TPS with the throttle actually in the idle position, the transmission shifts the best that it has since I've had the truck!
 
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Old 08-18-2011, 09:19 AM
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Sweet man ^^^^.

Isn't the truck much nicer to drive now?
 
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Old 08-18-2011, 10:27 AM
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Yes, much nicer!!!
 
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Old 08-18-2011, 10:36 AM
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Originally Posted by LSO1123
Yes, much nicer!!!
 
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Old 12-22-2015, 01:29 AM
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Truck revs on its own at idle

i was reading a post about removing the plunger from the solenoid or disconnecting two wires, I want to know how to do that and the names to those wires thank you.


I have a 86 f250 6.9
 
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