1999 24v cummins changes engine tone while keeping steady speed on highway

[daav544]

First time posting on this site, i have to say this site is amazing always have found stuff that has helped me. Well im hoping someone could explain whats houng on with my truck. First and foremost the truck is a 1999 2wd 5 speed 3500 2nd gen cummins and it has a cold air intake and a intake horn, edge ez, 50hp injectors, new H. O vp44. The truck has 307k miles and runs amazing and has no issues. But when im driving on the highway at a steady speed around 80mph the sound in the engine bay will change every 15-20 seconds it is most deffinetly the sound of combustion changing and or the injection timing changing. The truck will have the typical knocky 24v clatter that sounds kind of like a machine gun but every 15-20 seconds that knocky sound will totally disappear and the engine sounds so smooth at this point, after about 5 second, sometimes a little longer it goes back to the klattery machine gun sound for another 15-20 seconds and then back to the smooth sound. It is most deffinetly the sound of combustion and not like valves or anything like that im 100% sure of that. Its like the ignition timing is changing and changes the engine sound. Exhaust note doesnt change its all under hood noise . Has anyone ever seen this or have a clue at how and why it does this? I wish i had a way to view the timing commands in real time and see if their is a correlation in timing changing and the sound changing. It would be nice to find a way to make it have that smooth quiet tone all the time while on the high way it would deffinetly keep some decibels off  

[IBMobile]

Unplug the Edge EZ and see if that makes a difference.

[Mopar1973Man]

Sounds like heavy cruise timing and then your hitting heavier engine loads which it now retarding timing to build boost. Then it engine load drops and the cruise timing kicks in again.

 

SECRET: IAT temperature below 80°F ECM will add roughly another 4 degrees of timing.  Warmer intake air works way better than excessive cold which is kicking that excessive timing in.

 

MyQuadzilla I'm running right near 29°BTDC at 2500 RPM at 82 MPH. But I limit my maximum cruise boost to 5 PSI or less. Your over advancing why the knock.

 

SECRET: If you monitor engine oil temperatures you can find your optimal timing but you need a Quadzilla to do this. So optimal timing your engine oil temperature should be 30°F cooler than engine coolant. I'm running a 200°F thermostat from a 6.7L Cummins I see 200 to 210°F coolant temperature and engine oil top out at 175°F so all my fuel is burned in the cup of the piston and little flame front on the cylinder walls. If the timing is wrong there is excessive flame on the cylinder walls the coolant near the oil cooler is warmer and engine oil temperature will rise because the fire isn't at the right time.

 

Trans Temp on the display is engine oil. 

Coolant will rollover to -40°F when coolant is greater than 204°F.

 

Edited March 19 by Mopar1973Man

[Sycostang67]

I had that problem too for awhile when I first got my Quadzilla.  The load would change which would adjust the timing and alter the engine sound.  Reducing my load and having Mike help me with my tuning got it to go away.  I would start by unplugging the Edge as mentioned and see if it’s malfunctioning.   It may be time for an upgraded tuner. 

[daav544]

Thanks guys i appreciate the info and i see you mentioned intake air, my grid heater doesnt work, would that have any affect on this or do those only come on when starting the truck? Also ive noticed it will still do it even if im accelerating and its litterally like clock work ive counted how long the knock comes and goes and its always around the same amount of time roughly 20 seconds of knocking and 5 seconds of smooth sound. And thats at a steady 80mph no hills or change in pedal pressure trying to do like the most accurate baseline test of it. And it seems to really only do it around 80mph. Now is this bad for the engine or is it just kind of doing its thing? Again like i said before the truck runs amazing just thought this was like a weird quirk. And as far as tuner upgrade ive been dieing to get a quadzilla just dont have the money for it right now. Are there any other good tuner options that are cheaper that you guys would recommend? 

[Mopar1973Man]

IAT still will control engine timing regardless of the grid heater being missing or broken.

 

The best I can say you could have the ECM sent into @Auto Computer Specialist and let them test the ECM and verify you have right software. Then only other thing i will suggest is doing W-T ground wire mod. To make sure it's not AC noise from the alternator fouling timing.

[Doubletrouble]

 I don't know if the a/c noise is the issue here but I can't stress enough (I'm sure @Mopar1973Man agrees) how important the w-t ground mod is to these trucks. Both manual trans and automatics benifit. More so the automatics I believe.

 Just my $.02

[Mopar1973Man]

[daav544]

Ive heard of this mod before, what is the actual fix/ way of doing it? I should probabily just look it up i know you guys have so much info on here. I appreciate the help though im deffinetly guna do that and ill see what happens. Also will probabily try disconnecting my tuner and see what happens. I like the added power though lol as we all do. Its deffinetly time for an upgrade though. Whats you guys recommendation for a tuner that wont break the bank, belive me id love a quadzilla adrenaline but just cant swing it right now. 

[Mopar1973Man]

Quadzilla is the best on the market with full timing and fuel control which no other product can do.

[daav544]

I noticed on power driven diesels website that they sell the quadzilla and had a few different options one being the android&apple one and the other has a little controller with it. 1000$ for android and apple one and ability to buy their tunes. Are the tunes that come with the one with the controller any good that one was 699$ or is it best to get the one thats customizable. And who has the best tunes out there, do you mopar1973man make tunes for peoples trucks and their specific mods? 

[Mopar1973Man]

Yes I build tunes. Best to go to the source of Quadzilla which is @Quadzilla Power at https://quadzillapower.com/

[daav544]

Awesome i hope one day ill be all hooked up with a set of your tunes but until then i just found this out on a different form. Some guy had an edge ez like mine and described the same exact problem i have with the timing changing every 15 -20 seconds. Well he called edge and sent his back and in return he ended up getting 2 of the wrong edge boxes from them. One was labeled LBZ on the inside for a duramax lol. Anywho got it sorted out and got a new one and problem was fixed. I wonder if ill be able to send edge my box even though i didnt buy it. I think its time for something new though would be nice if they would honor their **** and trade me out one

[Doubletrouble]

 Back to the w-t mid for a sec, there is a good write or two on how to do it in the articles section.

 I to want a quad adrenaline someday, I'm in the same boat, the money just isn't available right now but it is definitely on my list of must haves in the future. 

[daav544]

Yea i found one of the write ups and it has alot of good info. Is there any evidence of it actually doing something for a manual?  Ive just always heard it fixing tranny hunting problems on autos. Also i just found a quadzilla xzillaraidor for 200 bucks that im guna buy. Its the 120hp one not the 65hp one apparently.  The serial number on it is DXZ01s. From what ive read there pretty decent. Also if i get an adrenaline one day will the wiring harness from this work with it? I was on the quadzilla website browsing and saw you can buy just the box itself no wiring and it even said on the page to specify at checkout if you have the older 4 button controller. The controller look the same so was hoping for the ease of manufacturing they kept **** the same

[Mopar1973Man]

Don't buy Quadzilla XZT you cannot do custom tuning. You have to send in the module to be programmed. I cannot do any tuning or support it.

 

You need the full Quadzilla Adrenaline to do custom tuning. I'm constant tweaking my Quadzilla tune to for weather and conditions. With a XZT you'll have remove the XZT and send it in to be reprogramned every time conditions change winter to Summer. Towing or empty truck. 

 

Just an example when my engine oil temperature rises to match coolant temperature I know my timing is off. I can pull over knock 2 degrees off the cruise timing program the Adrenaline drive 5 miles my oil temperature drops to 30 degrees cooler than coolant which means my timing is correct. I'm also running 24 to 26 degrees at 2k RPM. This is some thing you cannot do with a XZT.

 

Trans temp is oil temp.

Coolant over 204 shows -40. Yes I'm running a 200 degree thermostat. 

Yes I enjoy my high 20s MPG. Again an XZT can't do this.

 

 

Cold air degrades MPG. Hence my 200 degree thermostat and my attempts to keep IAT above 80 degrees because optimal IAT is 80 to 140 degree any lower than 80 it degrades MPGs. Air is too cold to convert diesel fuel to vapor to bang.

Edited March 21 by Mopar1973Man

[daav544]

Jesus christ your a damn smart man  and i already bought it im guna sell my edge ez and use the zillarator till i can save up some money for the adrenaline. How come i would have to have it programmed everytime conditions change? Obviously that would be for the optimal tune but it cant be worse than the edge right? The edge doesnt do any changing so in theory id have to have that programed for an optimal tune to right? Belive me theres nothing i want more than an adrenaline but for 200 bucks i said screw it ill try it and see if i can atleast get the timing hunting to stop. Would there be issues if i just ran it as is or will it just be like any other canned tuner and be just ok like my edge

[daav544]

I was just doing some searching on the web and saw that people were downloading tunes onto the xzt? And some people got tunes from you apparently? Is there a way id be able to do that with the xzt with my laptop at home? 

[Mopar1973Man]

If you watch engine oil temperature that will tell you how far out of time you are by temperature. If your too retarded then the fire burn down the cylinder wall heating the coolant jacket. Same is true with too far advanced but your trying to squeeze your fire making negative torque. Hence why you watch engine load because it will rise.

 

As weather changes and cetane changes then timing changes low cetane burns slower but longer. High cetane lights easy but burns out fast which high cetane has less btus per gallon than low cetane. Depending on intake manifold temperature now the air is above 80°F no problem it will light easy. Colder you might try more timing but because with high cetane fuels already advanced lights easy might be off on timing again watch engine oil temperature you'll now which way is right. Cooler engine oil mean better timing being all the fuel is burning in the bowl of the piston.

 

Anything that creates heat is a loss of power. Then thermal dynamics basically states difference of temperatures will attract like magnets. This is why I'm running 200°F thermostat from the 6.7L Cummins. If I raise the coolant temperature then my cruising cylinder temperature are fail close and it doesn't dump much heat in the coolant jacket. Again watching engine oil temperature I seen a rise from the 190°F to the 200°F but still floating cool at 172 to 175°F engine oil temperature. Now I produce more power to the tires.

 

I've done it a few time doing heavy throttle from a stop to about 70 MPH. I know Beast will possibly fry the tires in 2nd gear. Grab 3rd I've seen it resume frying tires. 4th gear get a squeak. Now pulling 4th grade up Goose Creek I've broke tires lose in just about every corner marked for 25 MPH but pulling 40 to 45 MPH.

 

Level 3 I can mat the throttle and never even let up. I've been clear to 105 MPH but EGTs hover 1,000°F to 1,100°F. 

 

Level  4 and up I've got too much fuel so the lower levels are usable but in a burst fashion like passing semis I'll be tiping 1,400°F EGTs but oil temperature will surge for a few miles and drop again. Lots of fire.

 

Timing hunt I feel might be AC noise issue. Pull your field wire off the alternator and test drive. If the problem leaves then the alternator has AC noise issues and needs replacement. Then I would do the W-T ground wire mod.

Edited March 22 by Mopar1973Man

[daav544]

My alternator is brand new the truck still did the timing hunting thing even with the old alternator. I have a feeling its the edge causing this issue as some one had the exact same issue with their edge ez and get it replaced and it fixed it. Im guna unplug the edge and see what happens. And when i get time im guna do the w-t mod. Would a 200 degree t stat be a good thing to do even though i dont have an adrenaline? And are there ways to get different tunes at home for the xzt and download them off a laptop