Troubleshooting 98 pete cruise

[Exile]

Damned thing has never worked.  I would appreciate any insights you all have.

1.  Clutch switch verified ok and adjusted ok

2.  Cruise will rev up engine 

3.  Brake switch appears to be tied to brake light switch? and it is ok

4.  Pto switch verified ok

5.  When i connect with blue fire system, it shows cruise switch on at ecu, with speed of 0 (when i’m sitting In the shop) and moving the switches around shows up in the ecu

6.  Driving and simultaneously fiddling with blue fire on tablet not a good idea, so haven’t done that yet

7.  Peterbilt wiring diagram sucks, i have the one for my vin, it is really basic, i can only see what pin number the cruise is on the ecu, but don’t know how to test that.  There is a rumor of a better diagram for units with the modular fuse block, but I don’t have it  

8.  Had a bad ground on the ecu, fixed it

9.  Throttle position sensor was throwing a code, it cleared up after disconnecting and reconnecting it.  No open codes.

Engine is a 12.7 dd

maybe i need to take it to peterbilt and see if the previous company set the highest available cruise speed to zero?

 

 

[Steve from SoCal]

Wheel speed or trans sensor?

 

Steve

[Exile]

I found one transmission sensor. . . You saying the cruise might use a wheel sensor?

 No wabco errors, so i think abs wheel sensors are ok. 

[Darryl&Rita]

#2 proves both #1, 3 , & 4 are satisfied. Also proves input to ECM is good. Do you have a separate idle-up button? It's looking like a programming issue. 

[Steve from SoCal]

On a cruise control that will high idle but not hold or set a target speed, a common issue is there is no target speed signal.     The speed signal is either from a wheel speed sensor, hall sensor on speedo or transmission.      Where is the speed referenced on your truck?

 

Steve

[Exile]

2 hours ago, Steve from SoCal said:

On a cruise control that will high idle but not hold or set a target speed, a common issue is there is no target speed signal.     The speed signal is either from a wheel speed sensor, hall sensor on speedo or transmission.      Where is the speed referenced on your truck?

 

Steve

Ah, thank you.

I found a hall effect sensor on the back of the transmission, the plug did not look fully seated. I took it out, will see if i still have a speedo.

it looked like there was another sensor on the transmission itself, so maybe that was where the speedo was reading from.  It is an electronic speedo, i assume controlled by the ecu, because i could not find any dip switches to calibrate the speedo.

will report back after testing.

if i have speedo, and no cruise, should be the sensor.  If i have no speedo, then i assume it is a programming item.

 

[Exile]

19 hours ago, Darryl&Rita said:

#2 proves both #1, 3 , & 4 are satisfied. Also proves input to ECM is good. Do you have a separate idle-up button? It's looking like a programming issue. 

Yes, idle up switch works fine, that is what i meant when i stated cruise will rev up engine, my apologies for inexact language.

Edited May 20, 2020 by Exile

[Darryl&Rita]

2 hours ago, Exile said:

Yes, idle up switch works fine, that is what i meant when i stated cruise will rev up engine, my apologies for inexact language.

Some rigs have a separate "Idle Speed" button. It will hold incremental idle increases, regardless of clutch, brake, or cruise inputs. It MUST be used sparingly, and by an experienced operator, because it also affects Jake brake effectiveness.

[DesertMiner]

On some of the older Volvo’s wasn’t there some sort of procedure you had to do either before you started the truck or just after you started to get the cruise to work? Something with applying the service brakes before trying to use the cruise. Just thinkin’ our loud.

[Exile]

Speedometer didn’t work when the speed sensor was removed.  This was the only speed sensor the parts guy seemed to know of  

I think The idle up doesn’t work while truck is moving, i seem to remember trying that.  It is a separate switch.

i have to use the brakes to get out of my neighborhood, so shouldn’t be that. 

[geodog]

On my 03 Volvo you must keep the clutch depressed while starting and the until all of the lights on the dash go out in order for the cruise to work. High idle will work without doing this procedure.

 

ShortyO

[porky69]

Try turning the engine brake off...I have driven trucks in the past where the cruise control would not work because the engine brake switch was in the on position. Sounds ridiculous but.....

 

If this is the issue you should be able to have it disabled in the engine ECM settings.

 

Also ....my Detroit powered requires the cruise control on/off switch to be turned off and then back on before the cruise control works....nothing you can change to disable this.

Edited May 22, 2020 by porky69

[Exile]

Omg.  Looks like i might need to do the hokey pokey at each start up, hold my mouth just right, stand on my head and pour water in my . . . Bottom.

Thank you, i will continue trying these things before i take it to the shop.

i never ever use the clutch at startup, i figured the button is by the door so you can fire it up and go get coffee while it builds air without climbing in.  

The joys of thinking like a computer programmer.

[chief916]

17 hours ago, Exile said:

Omg.  Looks like i might need to do the hokey pokey at each start up, hold my mouth just right, stand on my head and pour water in my . . . Bottom.

Thank you, i will continue trying these things before i take it to the shop.

i never ever use the clutch at startup, i figured the button is by the door so you can fire it up and go get coffee while it builds air without climbing in.  

The joys of thinking like a computer programmer.

I know your angst.  It can be really frustrating.  On the bright side....no DEF, no Regen, no derates, very few sensors.  Most people with the newer rigs have to put up with all of the modern stuff that can really be frustrating.  Hang in there.

Chief916

[noteven]

If you can find a dealer or 3rd party shop where the shop foreperson has been around since your engine and truck model were in mainstream commercial service, they can be a wealth of knowledge.

It can be hard to stay on topic but often the best way is to say “I have this such and such. I don’t have the Engine Operators Manual* for it. Are there any Special Instructions?

 

*see what I did there?

[Exile]

On 5/24/2020 at 9:08 AM, noteven said:

If you can find a dealer or 3rd party shop where the shop foreperson has been around since your engine and truck model were in mainstream commercial service, they can be a wealth of knowledge.

It can be hard to stay on topic but often the best way is to say “I have this such and such. I don’t have the Engine Operators Manual* for it. Are there any Special Instructions?

 

*see what I did there?

👍

[Exile]

And it goes on. . .

local Peterbilt guys say they can’t change settings on a series 60, maybe Vanguard can.  They claim they can, so i show up at 0700 when they said they opened . . .nope, shop door closed till 8.  

After 8 I get fussed at by a cyborg with a headset for setting foot inside the shop, i retreat to the lounge, where the cyborg comes to tell me they can’t change any settings. And magnanimously informs me there’s no charge.

I refrained from any rude comments.  It was difficult.

I trespass into the shop to ask the techs if the ecm is fried, and they tell me their generic software can see the settings but not change them.

And he tells me the cruise is set to 75 mph, so at least I got something other than an excuse to rant.

dammit.  

Called some more, and Freightliner says if I show up when the old guys are in the shop they can do it.

thinking i should just buy a gps to find out how fast i’m going.

[Exile]

Thank you all for your help, it worked my last trip, I haven’t figured exactly what it was, either operator error or a bad park brake switch.

Resource for older detroits:  Fitzgerald manuals https://www.fitzgeraldgliderkits.com/wp-content/uploads/2016/09/owners-manual.pdf

it says among other things, cruise must be turned on to work, if already on, must be turned off first.  

Also found detroit troubleshooting guide at 

http://www.detroitmanuals.info/ddec-singleecm-troubleshooting/400A07.html

Someone on truckers forum suggested park brake switch, even if not in troubleshooting guide, so I disconnected that too.  Will try it again with switch reconnected. 

Now, onto fixing a/c.

[GlennWest]

On my Freightshaker unitl I fixed the abs I didn't have cruise. Got abs light after module changed and found wheel sensor setting wrong. Fixed and abs light went out and suddently cruise worked. 

[Pete Kildow]

My 1995 Kenworth stopped working. Found out what causes it, but not fixed it yet. I do have cruise now. But also have a air leak on the trailer brake valve on the dash. I can Hold the tractor valve and push on the trailer valve. Then the leak stops, but cruise does not work. So ran all week hauling gravel. With a slight air leak on my trailer Valve knob.

Going to order the kit and rebuild the parking valves. Then see if the cruise works right. If not will hook my trailer lines together. Then push both valves in and see if it works.

[Brad & Jacolyn]

On my Volvo the cruise stopped working and it turned out to need a brake pedal adjustment. Until then I used a small bungee to hold the pedal a bit higher and the cruise worked fine.