What is going on with my MPG

plarkin

Active member
In the frame shown speed difference in the lock up clutch 679!1
Can you explain?
Dennis
Dennis - The “1/min” was just a comment on the Xentry to the right of the actual values. See the screen shots I posted in reply #22
Lance
 

plarkin

Active member
Thanks Dima!!!

Yikes - I am in the condemn territory at 680 in 1st gear and reverse. What does this mean....can I drive to South Carolina and back to Tempe at a cost of fuel economy - or will I be stuck somewhere in the middle of America!

Do I just need to get the torque converter replaced?

Thanks,
Lance
 

plarkin

Active member
Van is running great and I would been in ignorant bliss if I did not check the mpg on that trip to Tucson last week-end. The question is how lucky do I feel now? The only problem I have had with the transmission is not being able to back up a hill without a running start. Only noticed this at our house on a hill in Bend when trying to back up the driveway and not able to move without getting movement on flat ground first. Only did that one and have not been back to that house in two years, finally sold it in May.
 

showkey

Well-known member
Outsider looking in……to me the 678 difference at idle in the driveway is displaying the idle speed.

The difference running down the highway snapshot looks reasonable. 8, 10, 16, 20 rpm difference looks normal.

As the the running start in rev mine have done that since day. Especially when not at operating temperatures. There are many prior posts on low torque cold in revers.
 

98Firebird

Well-known member
As a general rule of thumb anytime a converter slips double digits at highway speeds while locked up it is having issues. Up to 9 is good, any higher is too much. Will likely start to experience some shudder if those values creep up a little higher. The good news is though even with a shudder it has to REALLY slip a lot to overheat the trans and leave you stranded. I'd keep driving it if you need it, but definitely keep it on the radar.
 

plarkin

Active member
Dennis - The “1/min” was just a comment on the Xentry to the right of the actual values. See the screen shots I posted in reply #22
Lance
Actually it is to indicate the “units”
 

plarkin

Active member
We are starting the drive in the van to South Carolina on Monday, allowing 5 days for a leisurely drive. Will keep the Xentry connected the during the trip to monitor the live data on the Torque Converter lock-up clutch. From the test drives this last week the mpg is back up to 16.4 and 17.9 mpg for the 9-10 gallon top-ups. Will keep y'all updated on our progress.
 

plarkin

Active member
Late start for trip this morning after taking care of one one of the cats with the vet. We did make it to Las Cruces late on camping at rest area overlooking the city. Monitoring the TC watched the temperature, in the 80+ degrees centigrade, climbing to the nineties on some grades but could cool down by easing up on the throttle. Driving in the low to mid sixties, be interestingly to see mpg. Topped up outside Tucson and it was about 17.3, not as good as I remember in that past, but will just keel tracking and see when it leads me.
Lance
 

plarkin

Active member
Forgot to mention slippage bounced between 10 and 20 with on the Interstate.
 

vnvet

Member
It is amazing how well and efficient these rigs run when all the commie parts are gone and retuned. Glad I don't live in CommieFornia.
 

plarkin

Active member
Well we made it back to Tempe after a month in SC. We had no issues on the trip and now have another 3K miles on the van having just passed the 120K mark. Think that puts us out of warranty even with the AEM. I did some scans today with the Pico scope and believe I will be be having an issue with the fuel pump in the future although that could way in the future. See the image below with the current for the fuel pump showing 1 commutator in a poor shape - 3rd one after the first vertical dotted line. Although it is not as low amperage as 3 others. Pump speed is 1912 rpm.

FuelPumpAmperage.jpg

The scan below is a capture when the ignition was turned on, showing the fuel pump pressure just before the fuel filter at 56.1 psi with a amperage draw of 4.7 amps. The pressure may be low because I did not purge the diesel fuel through the transductor so there was still air in the transductor chamber, but not sure if that will make a difference. On a test earlier this week it was at 60 psi with the same test. Cannot redo tomorrow since it the wife's birthday and then Monday it is jury duty, so maybe next week-end.

FuelPump_ignition_on.jpg

I also did a real quick deadhead pressure test and the fuel pressure went up to 112 psi with 10.2 amp draw by the fuel pump.
 

showkey

Well-known member
Sure would be nice to have a “known good“ van to compare to ?????
 

plarkin

Active member
Sure would be nice to have a “known good“ van to compare to ?????
Yes it would, meanwhile will keep an eye on it and test it frequently to see if it changes. Looking around it is difficult to find a cache of known good captures for Sprinters. I will be putting mine into the Pico Automotive scope captures in the web, but they will only be accessible with Pico Scope attached to a PC with their new architecture with their free Picoscope 7 software. If anyone wants a copy of my captures just pm me.
 
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Nimpoc

Enginerd in wander
That's some nice data from the PicoScope. At ~$3k it's also a pricey piece of kit.
What led you to picking up the tool, and to probe the fuel pump?
 

Nimpoc

Enginerd in wander
Also, for reference, here's a view of my consumption. 2016 2500 3.0 4x4 tall / short.
I'm probably at 98% logging fill-ups. Upper graph is monthly average, lower is per tank.
Last couple refills were the beginning of an EGR valve failure.

Fleet data is here:

Screen Shot 2021-11-29 at 13.34.12.png
 

plarkin

Active member
That's some nice data from the PicoScope. At ~$3k it's also a pricey piece of kit.
What led you to picking up the tool, and to probe the fuel pump?
I have always been a hacker wanting to find out how stuff works and this just allows me to discover more about the Sprinter. Have lots of projects lined up to get known good captures while shit/stuff works.....other projects with landscaping and adding on patio entrance to the house are getting in the way right now.

Wish I got the scope before I replaced my wiring harness, might of helped me diagnose the short I was having in the injector electrical circuit, but that is how I justified it to myself with the savings my replacing the wiring harness myself. Replacing the wiring harness did get me to do some necessary maintenance with the fan belt, serpentine belt, idler pulleys, belt tensioner, oil heat exchanger and seals, glow plugs replaced, injectors clean and tested (1 failed and was replaced), replaced EGR valve (messed it up taking it out to clean), EKAS motor (not returning to default position quickly or easily even when not connected) and replaced plastic control levers with metal ones. Basically took care of stuff at 110K before it started to break - well at least for the parts that I didn't break :bash:..

What got me checking out the fuel system was the poor mileage before I set off on a trip to SC. I did not get some connectors I needed until I got back from that trip to check out the fuel pressure. I also started to do some scoping of the two wires for the float level sensor, haven't figured it out yet. Need to do more research on those since I caused it to indicate I only had less than 1/4 of a tank when it was almost full. Adding a few gallons got it to reset. Want to change the coding variant so it reads the fuel tank level all the time, will be reaching out to Dima for that.
 
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