Another Q: High-idle needed on 7.3?

[msm618]

Another noobie Q: on every Ford diesel ambulance I've ever worked in (6.9 to 7.3), there is an electric high-idle switch as part of the Upfitter package (there to boost amps to run our Circus Lights, as well). Are these 7.3's prone to cylinder wash-down (fuel) when idling for more than say, 10 minutes?

I remember the 2-cycle Detroits in the coaches and transit buses I drove as a yung'un all had high-idle switches for this reason. Just curious.

Mike
Up waaay 2 late!

[Frank 93L]

Originally Posted by msm618

Another noobie Q: on every Ford diesel ambulance I've ever worked in (6.9 to 7.3), there is an electric high-idle switch as part of the Upfitter package (there to boost amps to run our Circus Lights, as well). Are these 7.3's prone to cylinder wash-down (fuel) when idling for more than say, 10 minutes?

I remember the 2-cycle Detroits in the coaches and transit buses I drove as a yung'un all had high-idle switches for this reason. Just curious.

Mike
Up waaay 2 late!

I don't know if they're prone to wash-down, but I can tell you my truck has idled at 650rpm for upwards of 4 or 5 hours more times than I can count while recovering vehicle wrecks (tow truck). No known problems thus far.

The reason I only let it idle at 650 is the Auxiliary Idle Control unit doesn't work in my truck!!! It reads out as if it's functioning correctly, but the truck never idles up. I've asked for help around here and I've talked to some Ford techs, but nobody seems to be able to help me.

So if you know anything about that unit please let me know.

[stewy]

for the idle control to work the parking brake must be ingagedand the park brake warning light must be glowing in your dash area.

[redstroker_2002]

you can buy a tony wildman custome chip. and on the shift on the fly chip you can have him put a idle position on there so if you turn it to say postion 3 it will idle up to what ever rpm u want it to. the five postion chip is 450 and thats cheaper than an real idle kit. plus you get the benefit of the idle high

[Frank 93L]

Originally Posted by stewy

for the idle control to work the parking brake must be ingagedand the park brake warning light must be glowing in your dash area.

THANK YOU VERY MUCH!!

My light doesn't work, and I suspected it to be the problem. I found the wire unplugged, and plugged it back in and it STILL didn't work. I couldn't confirm whether or not the light had to work so I wasn't going to chase down the problem for nothing. So now I need to know why it doesn't work. I suspect maybe the bulb (which would open the circuit).

Any ideas?

[redstroker_2002]

i think your on the right track you would have a open circuit. and if that doesnt fix it you still got your light to work

[Frank 93L]

Well I've spent the last couple hours tinkering around with the truck. I wanted to try to avoid tearing into the dash and such. A few diagrams and a PCM pinout later, I decided I would go directly to the PCM to give it the signal that the brake was on.

Pin number 4 (purple & white wire) is the 'Brake Warning Indicator' input. I had high hopes when I began splicing into the wire at the PCM to ground it directly to the battery (rather than tracing the problem all the way down through the brake bulb then to the switch). I thought for sure this would have it taken care of. I was disappointed when I found myself in the same boat I was in to start with.

With the brake applied, truck neutral and clutch depressed, I'm pressing "RPM Control"...then selecting a pre-programmed RPM of 1300....the pressing the "FORD" button. I sit and wait and as the RPM readout changes from my current RPM to what I programmed it to, I still don't have the truck idling up.

Anymore ideas anyone? This truck is really getting under my skin.


PS...sorry I'm so long-winded.

[fordnut85]

I don't know a whole lot about the ICM but it seems really odd that it reads the RPM coming up but not doing anything. It would seem to me that the ICM needs a signal from the PCM for engine speed and that it should read the same as the tach on the dash. I have to say I'm stumped man!!

[Frank 93L]

Originally Posted by fordnut85

I don't know a whole lot about the ICM but it seems really odd that it reads the RPM coming up but not doing anything. It would seem to me that the ICM needs a signal from the PCM for engine speed and that it should read the same as the tach on the dash. I have to say I'm stumped man!!

Well thanks for the help anyway. I wonder if the unit itself may be the problem? If only I knew somebody I could swap with for testing purposes....

[fordnut85]

I wouldn't think it would be the unit itself, it would be my guess it is getting a false input from the pcm regarding engine RPM. But that would just be a guess.