Idle speed. temperature and brakes

[BigRigTech]

What should the idle speed be set at for my 91 F250, 7.3IDI with an automatic tranny? Mine idles about 750-800rpm...Kinda high to me. I usually like to see diesels idling around 650-700 at work. The temp gauge is running around between the M and L in the normal range all the time. I checked my top rad hose, about 70C* so it''s not running hot. Maybe this is normal or I have a bad sending unit?

Would a 96 F350 and my 91 F250 have the same rear brakes? They both have 10.25 axles, single wheel. I noticed today will taking stuff off my 96parts truck that the rear brakes, shoes, W/C's and drums are like new on it, mine are worn out on the 91. I had a 1-1/8" M/C on my 91 that was going bad, I took the 1-1/4" M/C off the 96 and put it on my truck tonight. What a difference, stops on a dime now.

I hauled my first load with the F250 today, had 1340KG (2950lbs) of gravel in the bed, no sweat for the IDI I must say. ...I used to haul that much with my F150 but the F250 feels much safer at the same loaded weight.

 

[FordGuy100]

Is that what it idles at all of the time, or just when you first start it up when its still cold? If its idleing that high all of the time, even when the motors warmed up, I would say thats a little high.

As far as the gauges go, you cant really rely on the factory ford gauges as they are not accurate. Like the temp gauge will say its up to temp at anything from 130*-something like 230*F.

I cant say if the rear brakes are the same between the two truck.

 

[subway]

yea these factory gages are more like a glorified idiot light. i would put a real gage in there to see whats going on.

i also agree that sounds like a high idle speed, solenoid isent stuck is it?

sorry cant help on the axles more than they should be the same lug pattern.

 

[BigRigTech]

No, that's the regular idle speed. It goes to about 900rpm on the high idle solenoid. I plan on installing some gauges in the next little bit - I hate hi/low type gauges - I need numbers!!

 

[payableondeath6]

Mine idles about the same (750-800 rpm) and high idles around 1000 rpm but I'm sure that's high.

 

[Dsl_Dog_Treat]

Watching Mel do his annual timing clinic at the rally this year, on a neighboring camper at the grounds who also had an auto, the idle speed IIRC should be checked while in gear with someone standing on the brakes.
That's prolly bout right where you're at.

 

[OkieGringo]

To check the connections to the IP, here's what you need to do. Turn on key to 'run' position. Check the main wire that comes from the loom to the IP (injection pump), does it have juice. The wire runs to the FSS (fuel shutoff switch) connector first, then to one side of the Cold Engine Switch(two-prong sensor, located in hole behind the upper radiator hose connection). When the engine is cold 'juice' will pass thru the sensor, if the sensor is good, and go to either the FIS (fast idle solenoid) or the CTA (cold timing advance), then to the other. If the engine is cold and sensor is good it will be 'closed' and allow 'juice' to get to the FIS plunger which holds the idle speed up. If FIS plunger is working, but not pushing up far enough, use a 1/4" wrench to turn/extend it until the idle speed is ~1000 rpm. The CTA (cold timing advance) near the spider/distribution end of the IP 'advances the timing' to make engine run smoother/run cleaner/less smoke. The Cold Engine Switch opens/shuts off the electricity to the FIS and CTA after engine reaches 112 degrees, and engine speed/rpm will/should drop to ~650 rpm. If these three items are working correctly, when you go to start engine, hold the throttle pedal at least 1/2 way to floor to allow the FIS plunger to 'set' itself. Use a test light to check for electricity/juice at each of the solenoids, FSS, FIS and CTA. Let me know if this helps. Good luck, OkieGringo

 

[Agnem]

Yup. 650 is the spec, give or take 25 rpm. As Ron said, on an auto it is supposed to be set in drive, but the reality is you can do it in Park, and it won't drop below 625 which is still in spec. All manuals sit at 650. When you go to adjust it, keep in mind that sometimes the high idle solenoid can hold up the throttle lever. If that happens, you have two options. Either A), using a 1/4" open end wrench, screw in the solenoid plunger to retract it. or B), loosen the two 7/16 bolts that hold the high idle solenoid bracket on, and move the bracket (there is often enough slop in the bolt holes to move the solenoid a reasonable amount). If the idle doens't seem to want to come down for you, there are two possibilities. Either the metering valve is worn, or the mid/max govenor is out of whack.

 

[BigRigTech]

So 650rpm is the spec for sure eh..... Mine is idling about 750rpm, wasting fuel it is....Blasphamy!!....