Any truck sparkies on here ??

[colr6]

I need to tap into the idle control to vary the revs when stationary, it's on a 66plate Daf 75. Any body know how ? I've tried but can't work it out its on throttle fly by wire. Cheers Col

[eeb43]

if its a cambus system you probably cant

[sebspeed]

i thought you could set the idle using the cruise control

[DT36]

I would say it's OEM software controlled, Col. Idle speed and throttle calibration will be controlled via the CANbus software.

This has been the case on all Perkins, Cummins, Scania and MTU kit I've worked with. 

[colr6]

5 hours ago, sebspeed said:

i thought you could set the idle using the cruise control

You can, I need to put a second switch into it to lift the revs up from the back of the truck. Maybe a visit to the Daf dealers as there's loads of wires of the same colour and a bit reluctant to go in with a test light in case I do any damage to sensitive systems.

[Vista]

................... 

 

 

[DT36]

Col, will there be a PTO engaged at this time? Current system I work on engages the PTO Electronic Clutch via a switch (digital signal). This also automatically sets the engine RPM to a high Idle position to prevent the engine stalling when the Hydraulics are used.

This is all programmed via CAN software though. 

 

[colr6]

PTO is permanent (engine driven) the way I understand it is to take revs up and down like the cruise control is to reverse polarity on the switch. The truck was wired before I think incorrectly and how they got it to rev to a set revs was to put a 24v feed to one of the wires but that way the only control you have is on or off. My other mixers have variable revs. This been only just over a year old can't do a comparison with the others as the others are 3-7 years old and are completely different. Had electrical probs with this from new and neither the body or truck supplier have been willing to cure the problems. So I said I will rewire and send them a large bill!! Everything's done apart from this part of it. Got half the dash out so might be taking the other half out to trace wires. With a lot of the wires been the same colour it's hard identifying what's what ! Now I know why they were reluctant to cure its problems.

[colr6]

45 minutes ago, Vista said:

................... 

 

 

I'm supposed to take piss on here!!!.....LOL......nice one though?

[colr6]

Just come off the phone with the local dealers................not a flipping clue !!!

[eeb43]

got a mate thats a sparky he was on about bringing a nearly new chevy truck in but when he went into it the cambus system is a nightmare to add or remove lights from as it confuses the brain? i assume thats the same problem you will be having?

[colr6]

3 minutes ago, eeb43 said:

got a mate thats a sparky he was on about bringing a nearly new chevy truck in but when he went into it the cambus system is a nightmare to add or remove lights from as it confuses the brain? i assume thats the same problem you will be having?

It's not only the trucks brain that's getting confused !!......have made slight progression though, took the rest of the dash out to trace wires and found a feed wire connected to a diff lock switch that turned out to be knackered. So now got it to rev to a set rpm but still can't vary it from the back of the truck. Will be having another bash at it tomorrow. Why oh why do they over complicate things???

[DT36]

Col, the throttle pedal is usually twin potentiometers that are calibrated from its 0 position to 100%. By giving it 24v its probably sensing that the drivers foot is to the floor. The second potentiometer is there for a redundancy check, to prevent a runaway if pot 1 fails high.

Have you got a wiring diagram for the truck showing the inputs and outputs on the engine J1939 circuit. Specifically showing the drive pedal if possible?

You also need to consider having an interlock fitted to give a logic along the lines of: park brake signal on/applied while hand throttle is used.

This is a lot of faff, I agree, but I am assuming that this a common rail engine, therefore your only option is via electronic control.

I think the only other option to consider is how the Foden Recker used to work, which was a small hand throttle below the dash that was directly connected to the drivers pedal. Problem with this was that drivers tried to use it for a makeshift cruise control. (not safe).

[DT36]

19 minutes ago, colr6 said:

It's not only the trucks brain that's getting confused !!......have made slight progression though, took the rest of the dash out to trace wires and found a feed wire connected to a diff lock switch that turned out to be knackered. So now got it to rev to a set rpm but still can't vary it from the back of the truck. Will be having another bash at it tomorrow. Why oh why do they over complicate things???

Try it with a potentiometer, so  you can vary the input voltage. 

[eeb43]

25 minutes ago, colr6 said:

It's not only the trucks brain that's getting confused !!......have made slight progression though, took the rest of the dash out to trace wires and found a feed wire connected to a diff lock switch that turned out to be knackered. So now got it to rev to a set rpm but still can't vary it from the back of the truck. Will be having another bash at it tomorrow. Why oh why do theyts to make them more efficient and  over complicate things???

apparently its to make them more efficient and user friendly!!!!!!! lol

 

[DT36]

3 hours ago, colr6 said:

Just a thought. Called in Asda earlier with my Betty and they had house dimmer switches there for £5. Simple in/out wiring circuit.

Not the final solution, but could give you a good indication of varying the input voltage to the system.  Put a Fluke across the dimmer switch in parallel to read your voltage at your desired engine speed. Then disconnect the pos wire on the output side of the dimmer and connect your fluke in series, set to amps to read the current. 

When you know your volts and current, this will allow you to work out your resistance. Remove the dimmer, then stick a resistor and switch in line to give you the same steady voltage and current.

I think...

[colr6]

12 minutes ago, dt36 said:

3 hours ago, colr6 said:

Just a thought. Called in Asda earlier with my Betty and they had house dimmer switches there for £5. Simple in/out wiring circuit.

Not the final solution, but could give you a good indication of varying the input voltage to the system.  Put a Fluke across the dimmer switch in parallel to read your voltage at your desired engine speed. Then disconnect the pos wire on the output side of the dimmer and connect your fluke in series, set to amps to read the current. 

When you know your volts and current, this will allow you to work out your resistance. Remove the dimmer, then stick a resistor and switch in line to give you the same steady voltage and current.

I think...

You sure it was in series first !......LOL

[DT36]

Oops... 

[colr6]

Might even have a dimmer switch in my bag of tricks, will give it a go. Thanks for your help on this one mate.

[DT36]

Got to be worth a pop, as I think it's definitely looking for a variable voltage input. 

Fingers crossed... 

[colr6]

I'll get you pics up tomorrow of the switches and layout of what they use. Cheers Col

[colr6]

Finally got it sorted, the problem all stem from Thr bodybuilder so being a shower of shit. What with bad connections, joint blocks with wire colours not matching each other and a broken wire in the front to rear loom. So basically how it works is to feed one side of the potentiometer to increase the revs to whatever amount you need then break the circuit. Then another feed via another switch to the other side of potentiometer  to reverse polarity and decrease the revs. What made it so hard to figure out was the colour changes in the loom and breaks in continuity. So from day one of installation some one had screwed up so hot wired a feed in just to increase the revs to a given limit pre set in the ecu then to cut revs disable the cruise control on steering wheel. A few pics of what I found and quality of workmanship I was up against. Time for a cuppa and fag I think !!!

[colr6]

In the first pic you'll see a cluster of blue wires 11 in total all to make the cruise control work!! 

[DT36]

On 28/12/2017 at 16:47, colr6 said:

To be fair, at least he put a fuse in there.

Sounds like a nightmare, but good result though. 

[colr6]

24 minutes ago, dt36 said:

On 28 December 2017 at 16:47, colr6 said:

To be fair, at least he put a fuse in there.

Sounds like a nightmare, but good result though. 

The fuse was on the rear work lights of which they'd pulled a feed off the day time running light circuit !