I am wondering if it would be possible to tap into the TPS wiring to rig up an adjustable throttle on the dash without interfearing with the electronics? Pot switch of some sort? When the dial is set in the off position the pedal would work but when turned on you would be able to adjust your rpm manually and no its not a substitute for a cruise control, i would like to be able to regulate rpm's that would best suite me for summer/winter operations as my truck is my office. Anyone have a schematic of this unit and what wires to tap into? I already know about doing it in the pcm but thats not adjustable.


Still no pyro hooked up but the wires are hangin in the engine bay...

Since you decieded to tap after the turbine, drill the opposite side from the WG arm on the turn down. The metal pieces won't matter, you're after the turbine.

Ummm.... I don't remember saying i was going to tap after the turbo, but thanks for the info QM. Still undecided, that broken tip thing would make anyone think twice about were to locate it. I am leaning toward the manifold though if i can do it in the truck.


BTW, i have 16 injectors from my 94 and 95... any ideas as to what i can do with them?

On my scanner, throttle position is a % readout, ie 0% at idle or 0 input. It is a comparisson of the voltage change on 3 potentometers, also shown. Tap the boss for the truest reading.

OBD-II PCM has two-speed hi- idle option, switchable.

Yes i understand that, just thought something adjustable would be better suited for my needs.

Just wanted to make sure, before I posted the other option, which is as follows -


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And that covers the modification, in it's entirety.http://www.dieselplace.com/forum/smileys/Wink.gif


Sorry, charlie - no can do.


And please do not confuse me with an expert - after seeking expert advice, people usually have to resort to these forums to find out what the problem, and the solution, is.


As an afterthought, seems like I read somewhere that the OBD-II 3500's can use Cruise to vary the high-idle rpm, within a certain limit.


But don't quote me on that - mine's OBD-I.

Nice procedure, matter of fact it was so easy to follow i've finished it already.


I had heard rumor of using the cruise a while back, not sure how its done, anyone know?


I'm sure if i had the tool i'd just do the high idle in the computer, but no gots at the moment, i was told you need a special plier to install it on the pcm.

Excellent, grasshopper - you follow devious instructions well.........


Surf on over to Kennedy Diesel, hit the Tech Ref section - connection procedure is outlined there.


Just need an on-off-on single pole double throw SPDT center-off switch, wire, and 3 PCM connector pins, from GM.


BTW, don't worry about the EGT probe breaking off in use, pre-turbo - if EGT's get hot enough to do that, the turbine blades will be the least of your worries.


The probe is in a 1/8" or 1/4" stainless steel tube, weld-sealed.


To install, drill and tap the manifold boss when engine is cold, idling.


Exhaust pressure will blow shavings out of hole.Edited by: gmctd

wire 417 dk blu to A15 on PCM (TPS sensor signal), off the C connector on th TPS.


I think the signal is reduced or increased when you increase the pedal? not sure. If yes, It seems like aditional resistance/ lower resistance would rev it up?

TPS consists of three potentiometers on one shaft, each varying a level derived from the PCM +5v Reference voltage.


On accel demand, one decreases voltage, one increases voltage, one increases voltage at different level.


And, remember - the TPS must be stable enough such that the vehicle does not lurch forward in traffic at the most inopportune times, waylaying pedestrians and small vehicles, alike.


Not a good circuit to be in there with a propane torch and acid core solder, I would think...........

Hmmm.... so the question is, do i want to run over pedestrians or not... http://www.dieselplace.com/forum/smileys/Ermm.gif

Or small vehicles with the fart-tube hanging out the back...........http://www.dieselplace.com/forum/smileys/Wink.gif


Your choice, entirely.


Edited by: gmctd

Why not forget about using electronics all together? With the way the TPS is 3 different pots it seems hard or near impossible to do.

Jusy use a cablelike us offroad guys use for a hand throttle, and attach it to the accel pedal arm, the you have a small lever on dash or shifter, which is adjustable to tension and such. Do a google search on hand throttles, it will make more sense, kind of hard for me to explain.
Brian

I know just what you mean, pedal on these things is pretty touchy though, even just trying to hold it at a steady rpm with a steady foot it wants to run away, very difficult to get a steady rpm with the electronics, or is mine just finicky? All 3 of my trucks have been like this.

CR, it should stay at the RPM that corresponds to the position of the pedal. But the pedal is very sensitive especially when idling at lower RPMs. Any slight movement will increase or decrease RPMs. That's much different from mechanical pedals.


Out of curiousity, what's the purpose of setting the engine to a certain, fixed RPM range?

CR, it should stay at the RPM that corresponds to the position of the pedal. But the pedal is very sensitive especially when idling at lower RPMs. Any slight movement will increase or decrease RPMs. That's much different from mechanical pedals.


Out of curiousity, what's the purpose of setting the engine to a certain, fixed RPM range?



My truck is my office, work out of it at least 12 hrs/day. It gets -40 here in the winter and +40C in summer. Gotta stay comfy!!

To keep the cabin warm, you could install an air heater. It burns a little fuel and makes lots of warm/hot air to heat the cabin. You should be able to get used ones off of ebay.

There are two different kinds available, one that heats the air in the cabin directly and one that heats the coolant of the engine similar to an electrical block heater. But the engine heaters usually run about half an hour only to warm up the engine before you start it, while the air heaters are designed for continuous use.

There are cooling solutions available, too ...

Check out these links:

http://www.webasto.com/products/en/3115_3422.html
http://www.eberspaecher.com/en/heiz/heiz.htm
http://www.atrn.com/newspick.cfm?id=313
http://www.webasto.us/home/en/homepage.html

If you're seriously interested in getting a (used) parking heater but have trouble to get one, I might be able to help out. They are not too hard to come by here, so I could see if I can I get one and ship it to you.


BTW, how do you deal with such low temperatures? Do you idle your truck 24/h a day at low temps? Is it hard to start at -20C?

I'm planning to make another trip to Sweden, but this time in the winter, at the end of January. It will get down to maybe -20C or even colder, and I do not have a block heater. I wonder if I should let my truck idle over night then. I don't know what's better on the engine at -20C and lower, letting it idle or not.

How's your experience with that?

... an air heater, like this one:

http://www.webasto.us/am/en/am_rv_heaters_833.html


New ones are expensive, though.
Edited by: quantum mechanic

That heater looks like it would do the job lee but i just don't think i need another gadget in the truck with all my other stuff and i already have an engine that will give me all the heat and cooling i want, i don't pay for much fuel, i'd have to say 80% of my fuel is FREE. So i'd rather use the truck engine for all my heating/cooling needs.


As to starting @ -20C that shouldn't be a problem as long as your glow plugs are good,1 dead plug and you may have some trouble especially if you have a weak battery. Maybe change the oil to a 5w30 and you should be fine. I have left my truck run in the past overnight when its gone below -40 and i couldn't plug it in somewhere but other than that she's always started, except if i left it for 2 or 3 days before starting it. Run it and warm it up every 24 hrs and you'll be fine. http://www.dieselplace.com/forum/smileys/HiHi.gif

Free fuel? That's even better than the 'there-is-no-such-thing-as-free-lunch' thing :) I want to have that, too.

The idea with the heater is that idling the engine will wear on it while using the heater instead does not.

Do you have so many gadgets installed? I'm thinking about eventually building a computer to be installed in the truck, but it would be more for fun than for anything else. And with too many gadgets, I imagine myselfe just stumpling over them or their wiring ... :)


Starting after cold nights hasn't been a problem yet, but she doesn't like it. It feels as if you're getting enormous wear until the engine has warmed up a little, and that must be worse at -20C ... And I should get new batteries for the trip. The ones I have may be too weak when it gets really cold, and that could get me into serious trouble. The heating in the camping trailer won't last forever ...

the remote starter i have will start and run 10 min. they off for 20 min. for 24 hrs at a time. maybe more wear on the starter and engine but not as much as cranking a cold dry engine.

Gadgets? Yes i have a couple... http://www.dieselplace.com/forum/smileys/Cool.gif (just took these)


http://www.dieselplace.com/forum/uploads/ZCB_Gadgets_0002.jpg


http://www.dieselplace.com/forum/uploads/545_Gadgets_0001.jpg


As i said, i work out of my truck..... all day.

ANd what exactly is it that you do ?

Oilfield consultant, i look after oil and gas well completions and workovers, supervise the daily rig work.


http://www.dieselplace.com/forum/uploads/Coolin_off.jpg


http://www.dieselplace.com/forum/uploads/DZ9_pj_ani.gif


Also owner of www.canadianrigger.com (http://www.canadianrigger.com)


Not trying to advertise to you guys, just wanted to show you what i do. The website is under re-development at the moment.

Nice pics, thx! :)

For the 10/20 idle/off cycle, I think letting it idle all the time would give less wear. And you'd have better heating and cooling.

Otherwise, with a parking heater, a 15/45 or 15/60 cycle might do it, and you'd have it nicely warm all the time.

The ideal solution would be a parking heater that heats the engine coolant and thereby the cabin continously. They go under the hood, so you won't have another gadget in the cabin. Maybe install two 200 amps batteries in the bed, and you can run all gadgets and the heater for two or three days or even longer :)


Maybe I'll relocate the batteries on mine into the cabin to get the weight off the front axle and to be able to use bigger batteris. The rear seat has been removed, so the ideal place to put them is just behind the front seats.
Edited by: 0lee