Quadzilla coolant temperature reading

[Unreal Summit]

For some reason my quadzilla shows my coolant temps dropping to zero for a second then jumping right back where its supposed to be. Kinda aggravating when its warmed up then jumps back to warm up mode...any help or ideas other than turning off warm up mode is much appreciated.  

[Me78569]

Coolant is read from the ecm, so the ecm is sending this bad signal.  I would data log the issue, then I would start checking wiring for the ect, then I would replace the sensor.

[Unreal Summit]

I got it data logged but I cant figure out how to upload it on here from my phone. You think it could be a bad coolant temp sensor? 

[Me78569]

Or a broken wire.    dropping to 0 tells me that the ecm is loosing connection to the sensor.  I would expect a code though.

 

 

drag and drop the datalog here.

 

[Unreal Summit]

I'll have to use my laptop for it.  I'll check the wires tmw morning. No codes or check engine light. Seems to only do it when I have the quadzilla with the warm up mode turned on. Really odd how it happens. Seems like it started after I washed some fuel off the engine bay after cracking lose a few injectors to start it after putting on my new fuel pump. 

[Unreal Summit]

What would cause my canbus fuel to go to zero or for a half second second  while driving??

[Me78569]

Bad connection under the hood on tge quad

[Unreal Summit]

It was bucking and surging bad this morning  coming to work. Put it back to zero on the quad and it stopped. Back to level 3 and no more surging. I'll check all my wiring today when I leave thanks for your help. 

[Me78569]

check the canbus connection under the hood, also check your grounds for the quad and the power that taps the fuse.  

 

sounds like you are losing connection for a split second.

[Unreal Summit]

All my connections seem good. Should the canbus ever show zero when the trucks running?  The surging didnt happen again but looking in the data log I can see multiple times the quad shows zero canbus. Many when no throttle is applied. sometimes its 13, 45 ,0 then back to 145 so on 

[Mopar1973Man]

10 hours ago, Unreal Summit said:

Should the canbus ever show zero when the trucks running?

 

Yes, if its in full defuel running down grade. VP44 has the ability to shut off fuel completely. These are not like a gas powered car which requires a prefect air fuel ratio. Diesel can cut fuel on down hills. No it won't stall the ECM will rise up keep it running.

 

Another time this will happen is when your injectors are too fair gone. Like I've got @mr.obvious has his showing 0% engine load because the injectors are popping so low that the ECM is attempting to cut fuel deeply to hold the 800 RPM but it cannot do it. His idle is at 810 to 820 RPM. This is a Injectors that are purely worn out need replacing. 

 

Normal good injectors should see 5% to 10% engine load or 204 to 409 fueling command on the quad. It appears your injectors are wiped out. 

 

Minimum pop is 293 bar I'm betting your below 260 bar now. Just for fun my 7 x 0.010 injectors are popped at 320 bar. My idle engine load is 10 to 13% (409 to 532)/ typically but as they wear I'm seeing lows now of 7%. (286).

Edited November 8, 2019 by Mopar1973Man

[Unreal Summit]

Just sitting at a light or something I think its showing about 2**to 3**  I am sure they need to be replaced. For sure on my list to do. Thanks for explaining it so well tho. It had me worried for a minute. guess I just never paid attention to it when looking at my logs.

[Me78569]

do you see more than 1 sensor value drop to 0 at the same time in the data logs?  a group of 0's tells me the quad is loosing connection from the ecm, a single sensor dropping to 0 tells me the sensor or data source is having issues.  

[Unreal Summit]

Just the canbus, throttle position, and load all drop to zero at the same time. Everything else stays like it should. the coolant temp is just random as heck but hasnt done it in a day or two now.  Odd and hard to track down like that 

[Me78569]

did you drop throttle to %0?  

 

if so then yes that is normal.  

[Mopar1973Man]

Yup normal. ECM can cut fuel to zero to drop RPM quickly. 

[Unreal Summit]

Honestly blows my mind that this is a thing with diesels lol. But if I hadnt of been trying to figure out my surge I never would of learned this.  Pretty dang awesome !  Y'alls knowledge never ceases to amaze me. Thanks yall 

[Mopar1973Man]

I had this argument about 10 years ago over on CF. People thinking like a gasser where the fuel and air must be mixed perfect. Diesels are very wide bandwidth of fuel to air ratio. This includes shutting down fuel completely.

 

The other thing we are experimenting with is higher than normal pop pressures for efficiency and longevity purpose. So far a handful of us have tested quit a span of pressure. Stock is 310 (4,500 PSI) bar. I'm running 320 bar (4,641 PSI) at 20 to 22 MPG @Me78569 ran 330 bar (4786 PSI) and was hitting seriously good MPGs. The upper end of the spec is 327 bar (4,750 bar) for information purpose. Few others went as high as 360 bar and found starting issues. The longevity part is if stock is 310 bar you only get to 293 bar (4,250 PSI) and your below spec for Dodge FSM book. About 280 bar (4,061 PSI) and things change, smoke increase, MPG is lower, etc. With the 320 bar I'm running I'm hoping to touch about 100k to 150k miles on the injectors before replacing. 

 

With some injector builders they will pop lower like 300 or 305 bar to increase fuel flow. Makes for poor atomization of the fuel. This is great for racing but not good for MPG. Lower the pop pressure the earlier the injection event occurs (advanced timing). When you increase the pop pressure say to 320 bar the ECM has to command fuel more to get the injector to even open. This tend to occur slightly later. (Retarded timing). Now using the Quadzilla Adrenaline you can make up for the offset in timing by just building a tune for those injectors. 

 

Optimally for MPG purposes you want the lowest engine load or commanded fuel. I typically float about 17% engine load at 65 MPH. With extremely cool EGT's at 550 to 600*F.

Edited November 9, 2019 by Mopar1973Man

[Unreal Summit]

That's awesome stuff with just injectors and the quad.  When I get ready for some I'll definitely reach out and see what my best options are! I had no idea. 

[Unreal Summit]

Well I just had the surging issue again however this time the quad went completely off and wouldn't come back on. So I got to digging and or was the dang add a fuse thing in the fuse panel. So if someone else has the issue check on that!