2001 idling high, rough idle

[CumminsHokie]

Gents and ladies,

This is my first post on any forum ever but I figured mopar mans forum would be the best. I'm really stuck on what's happening with my truck and it's so annoying because I just got it running beautifully not too long ago. I will start off with some back ground of the truck and the problem.

 

Its a 2001 with about 210k miles, 2wd, automatic trans, bhaf air filter, 4 inch straight pipe, and until recently (I took it off thinking maybe it was causing my issues) an old quadzilla adrenaline that replaced my super chips (I say old because it is one of the first boxes made and I got it used, had the big power resistor replaced, then tested at quadzilla and verified). Now the problem started about a week ago when I noticed that my rpms were kind of bouncing around at 1000 when coming to a stop from higher speeds. I would be doing about 50 and then let off the accelerator pedal, apply brakes, and once in maybe 2nd gear the rpms kind of bounced at 1000 and you could hear it in the engine. They would then return to about 750 once below say 10 mph. This happened for 2 days and on the second day I arrived home and placed the truck in park and noticed it was idling at 1000 rpms. I also noticed a very random, intermittent spike in the rpms as it sat there idling and could hear it in the engine. I'm not sure what a miss sounds like but that's my best guess. This is when I removed my adrenaline. The next day the problems persisted and I noticed that the truck was running rougher than usual. I hooked up my scan gauge 2 and saw that my tps was at 1 and was spiking to about 12 at all times. Once above 12 or so it would stop spiking. As a quick fix attempt I turned down my timbo apps until the rpms sounded about normal and then reset/calibrated the apps. The tps is still stuck on 1 and spiking to around 12 randomly.

 

I recently replaced my iat sensor (not with a CUMMINS part) as it was faulty and was causing dead pedal issues so I unplugged that thinking the cheap sensor I bought was causing it. No luck. I then unplugged my map sensor as I've read many times that this cause rough idling. No luck. It has also been cleaned recently and seems to be functioning properly per my scan gauge. Since readjusting my apps the rpms have come down a little but are still high in park and neutral only(goes to normal when in drive). The only other information I could see worthy to include is that when I had the quad on I didn't tap the pump wire so I only had levels 0-2. When driving with it on 2 or 1 I noticed what seemed to be the tc locking and unlocking and it got more noticeable as the levels increased from 0-2(can't really feel it with it on 1). I assumed this was because it is an old box but idk that it could have been creating additional ac noise? 

 

I havent been been able to do any troubleshooting but when I get time this weekend I will be first checking the alternator for excess noise (even though it's fairly new) and then testing the entire apps harness per instructions found on this site. The only other thing I can think to check is the camshaft position sensor. Any thoughts? I have no codes being thrown and no dash lights illuminated. 

 

Any suggestions would be greatly appreciated and I really want/need to get this thing fixed. She's the love of my life.

 

forgot to add that I also have a raptor 100 and gauges, though glowshift. Fuel pressure has always been 18 at idle and 16 at wot. It seems to be a little lower now from what I assume is because the truck is idling higher. It sits closer to 17 idling in park.

Edited March 22, 2017 by CumminsHokie

[CSM]

First off, God Bless you for paragraphs!  

 

You mention dead pedal, and some odd behavior with idle.  You've done most of the work.  You've even mentioned codes.  

 

I am inclined to wonder if the APPS needs replaced.  Is there a link with the APPS?  Meaning, with the info you gave us, is it running roughly above the 12% that you  show as spiking? 

[Dieselfuture]

Welcome to the greatest cummins site ever.

Sounds like you're on the right track checking the alternator. I'm not sure if your scan gauge can monitor your apps, or you can use a Multimeter and check resistance and make sure there is no dead spots. I don't believe it's a good thing unplugging sensors and leaving them unplugged, not only you should get an ecl light but you're breaking the 5-volt loop. 

I believe your old quad as you say, is capable of being a new badass quad. Just get a quad BT for Android device if that's what you have and flush new software to it from this site. You'll be able to monitor a lot of things, apps included, and get lots more power without wiretap. I believe someone like @Me78569 will be able to help most on your issue, as he knows how to debug and rewire a grumpy woman's brain. Not calling your truck a woman or anything just a reference, no offense to anyone.

[CumminsHokie]

9 hours ago, CSM said:

First off, God Bless you for paragraphs!  

 

You mention dead pedal, and some odd behavior with idle.  You've done most of the work.  You've even mentioned codes.  

 

I am inclined to wonder if the APPS needs replaced.  Is there a link with the APPS?  Meaning, with the info you gave us, is it running roughly above the 12% that you  show as spiking? 

I just recently graduated and had the craft of scientific writing beaten into my skull only to continue using it with my job...who would have thought?!

 

The dead pedal issue happened about 6 months ago and was taken care of by replacing the IAT sensor. I have done most of the work indeed and i did mention codes, but the lack there of. I too am wondering if my apps needs replacing but it would be odd as it is only about 6 months old as well. There seems to be a link with the apps as the truck drives completely fine except for when i am decellerating from higher speeds and the rpms get stuck at 1000 until about 15 mph where they begin to come back down to normal idle. Other than that the truck feels greeat when driving around.

 

54 minutes ago, Dieselfuture said:

Welcome to the greatest cummins site ever.

Sounds like you're on the right track checking the alternator. I'm not sure if your scan gauge can monitor your apps, or you can use a Multimeter and check resistance and make sure there is no dead spots. I don't believe it's a good thing unplugging sensors and leaving them unplugged, not only you should get an ecl light but you're breaking the 5-volt loop. 

I believe your old quad as you say, is capable of being a new badass quad. Just get a quad BT for Android device if that's what you have and flush new software to it from this site. You'll be able to monitor a lot of things, apps included, and get lots more power without wiretap. I believe someone like @Me78569 will be able to help most on your issue, as he knows how to debug and rewire a grumpy woman's brain. Not calling your truck a woman or anything just a reference, no offense to anyone.

 

I like the scan gauge but i find that its very low sampling rate (i assume) makes it near useless for real time debugging. How would i check the resistance of the apps? Just hook up between the supply wire and output wire of the apps?

 

I have all sensors plugged back in at this time. Unplugging them was only to try and facilitate some type of change in its behavior. I call it old because it has the old circuit board thats more prone to burning up (especially the big white resistors - my box only has one of tthose). Does your statement still stand, i would love to make it more badass! Im hoping to get this resolved, and i appreciate all input.

 

Watch out now, my truck and i are both millennials and could easily be triggered by anything you say...ANYTHING!!!

LOL just kidding, she's definitely a girl, just a rugged looking one...i call her gertrude. Shes not the prettiest but has a great personality...most of the time. Here she is hanging with her big sisters.

[Me78569]

does your Quadzilla have a screen or just the pod?  

 

 

I would connect itback again and use it to watch the tps etc if possible  It has a much faster sample rate

[CumminsHokie]

11 minutes ago, Me78569 said:

does your Quadzilla have a screen or just the pod?  

 

 

I would connect itback again and use it to watch the tps etc if possible  It has a much faster sample rate

Unfortunately it just has the pod. Ive been brainstorming ways of monitoring the tps but i cannot think of a secure way that doesnt involve wire tapping the harness on the apps side. Which isnt a huge deal i just would like to avoid it if possible.

[Me78569]

Well it is important to know what the ECM is seeing for values.  I would buy a live data tool like a cheap elm327 device or a obdlink mx device.   

 

This will help troubleshoot your issues.  

[CumminsHokie]

22 minutes ago, Me78569 said:

Well it is important to know what the ECM is seeing for values.  I would buy a live data tool like a cheap elm327 device or a obdlink mx device.   

 

This will help troubleshoot your issues.  

Just ordered a BAFX OBD2 bluetooth scan tool and it will be here tomorrow. It had good reviews and seems like it is somewhere in the middle of the two that you suggested, quality wise. I will download torque pro unless you all suggest a better alternative. 

[dripley]

I have experienced that weird idle you have in the past. Never figured it out. It has for the most part stopped but every once in awhile it will do it. As far as that blip in throttle percentage mine does, sits on 0% and blips randomly to 10%. From talking to others here it seems to be inherent to the scan gauge. The blip also disappears once I get over 10% throttle. I think you are seeing 12% since you are stuck on 1%. Good luck with your problem and I look forward to seeing what you find. And welcome to farm here. 

[CumminsHokie]

3 hours ago, dripley said:

I have experienced that weird idle you have in the past. Never figured it out. It has for the most part stopped but every once in awhile it will do it. As far as that blip in throttle percentage mine does, sits on 0% and blips randomly to 10%. From talking to others here it seems to be inherent to the scan gauge. The blip also disappears once I get over 10% throttle. I think you are seeing 12% since you are stuck on 1%. Good luck with your problem and I look forward to seeing what you find. And welcome to farm here. 

Thanks for the optimism dripley! I was actually just monitoring it again and it seems to have jumped up to 17% not that that matters I don't think. I wondered if it was just a scan gauge thing. I'm excited to get the obd2 reader and see what I can find.

 

also just an FYI since I assume we are all cummins fans here. That haul truck in my picture has a cummins QSK60 16 cylinder diesel that outputs about 11 times what our trucks do stock, hp wise. That thing is the Maserati of the haul truck world.

[CumminsHokie]

So I get my obd2 reader all hooked up and start my truck and the first thing I see is that my throttle position is stuck at about 17% (fluctuating above and below 17). I'm using torque pro btw. Interesting that 17 is what my scan gauge was spikeing to when at idle. So now my question is what is that 17% is it what the ecm is requesting or what's being requested of it?

[Me78569]

%17 is what your ECM is seeing as being requested from the APPS  

[CumminsHokie]

so would it be safe to assume my apps is the culprit? i was just looking at it and I noticed that the PO added a wire from the apps harness to the negative terminal of the battery. I'm not sure what wire it's connected to as it's pretty crapily covered in electrical tape but any ideas what he was trying to do there? Makeshift Apps noise isolator? 

[Me78569]

I would guess the PO tried to adjust hte apps to get rid of TC lockup issues.  

 

I would check for AC noise first and foremost.

 

Return wiring back to stock

 

Then replace the apps as you have no idea what the PO did to it.

[CumminsHokie]

I replaced the apps about 6 months ago when chasing down a dead pedal issue. 

 

The wire is on the "truck" side of the harness, meaning the main harness side.

 

I will check for ac noise and report back.

[Me78569]

What apps did you install?

[CumminsHokie]

Ac voltage read at the alt was 0.03 v with the truck almost at op temp. The grid heater was kicking on and it'd ramp the ac noise up to over 0.1 v is that normal? I've got 14.16 v Dc coming off the alt and 14.11 v measured at driver side battery. 

 

I installed a timbo apps.

 

i revved the rpms a little and then the truck started idling very rough. Here's a video

IMG_1073.MOV

I also think I just found an actual ac noise filter. It's a wire going from a ground to the pcm?(passenger side computer) and the wire has components in the middle. I think it's a bd noise isolator.

[Me78569]

.1v is a fail    .03v idle is border line.

 

that's a noise filter, pull that bad boy off and put it in it's rightful home, the trash.

 

Did you adjust your timbo apps?

 

[CumminsHokie]

Okay a few questions.

 

1.) what would cause my apps voltage at idle to randomly increase to .93?

 

2.) should I look into replacing my alternator soon if the ac reading was 0.1 volts while the grid heater was cycling? And because I read 0.03 v at 160* coolant temp. 

 

3.) what's to say my tc won't start locking and unlocking really badly when I pull off the noise isolator?

 

as for the ground wire added into the apps sensor by the PO, the harness is pretty jacked up, I'm going to try and borrow a Deutsch kit from work and remake that's plug.

[Me78569]

1.That's odd I would give Timbo a call.

 

2. @Mopar1973Man whats the load ac limit?

 

3. TC lockup issues are %95 of the time related to AC noise.