Recent Posts

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1
Hi Ziggy,
Thanks for the suggestion. I've thought about this some but never actually tested it. At idle there seems to be free flow, as you can detect individual pulses from each cylinder. However at higher air volume it could be building up back pressure, so perhaps worth checking once I get back up north for the summer.

Glenn
2
Gbarney, have you checked to see if you have any exhaust restriction beside the prac break.
3
Hi Dave,
Thank you for your thoughts. I do understand that you are busy with a project, and the problems I am having are not urgent. The coach does run, and I am headed back to the NW for the summer. It will be at least another month before I will have anymore time to devote to this myself.
It is interesting that you are thinking I still have an overheating problem from the coolant temperatures I was posting. I was simply trying to provide as much information for you as I could on all the operating conditions as I could, not suggesting an overheating problem. I was satisfied that there was a way, following the chassis manual recommendation, to have the coolant temperature stabilize anywhere within the normal operating range. That wasn't the case in the past. The fact that I have to downshift all the way to 3rd to maintain 2000 rpm is the result of low engine power output, which is the issue I've been trying to resolve.
As for further work with Caterpillar, I think I've pretty well exhausted that avenue. There are no trouble codes, and all the component tests they can perform are OK. The Dyno did confirm I am only getting about 250 hp. Next recommended steps from the shop is to just start replacing components, starting with injectors, to see if something changes. After they have replaced everything on the engine, if performance isn't improved then contact Caterpillar engineering for further assistance. This is way to much money to spend without any assurance of success. For less money, and a more certain outcome, I can trade this coach in on one with a better running engine. I've just been trying to avoid that option.
If you do have time later this summer to send me any suggestions, we can pick this up again then.

 
4
Glenn, cannot really understated problem one time we are posting no heating problem,
than now your posting heating problem on grade. Been very busy and have not had chance
to get into technical issues. Maybe you should compare your code reader to Cat ET and
Take Cat technical information and stay with Caterpillar. I would get another opinion from
Caterpillar because if you feel your scan gauge code reader information is taking you
away from if there is really something going wrong and Cat  ET will address your problem.
at this point getting second thoughts from Caterpillar think you should listen to what is
being offered from therm. Ask Dave, Dave Atherton Retired Cat Mechanic
5
Hi Dave,
I haven't heard back from you on steps to investigate the possibility of ECM locked in Cold Mode. However since the regulator seems to be operating normally, and the IntelliDrive is reporting Cold Mode: Off, this may not be the problem.
I wanted to verify that I had accurate boost pressure indication because the analog dash gauge was reporting 3 psi more that the ECM was through the IntelliDrive, so I replace the boost pressure sensor to see if there would be a change. There wasn't. Based on this I must assume now that the lower ECM/IntelliDrive indication is correct and the analog gauge is incorrect.
I left Cottonwood this morning headed north on I-17 to Flagstaff AZ. There are several long 6% grades on this route. Highest boost pressure reached was 20 psi, and that was infrequent. Mostly 18 / 19 psi., in 4th gear, for as long as RPM was still above 2000. Maximum fuel consumption rate was 2 mpg, briefly, but mostly 3 mpg at WOT. This is an engine that used to routinely go to 1 mpg at WOT. On all these grades, I was eventually forced to downshift to 3rd after RPM decade below 2000 and coolant temp headed toward 220. In 3rd engine rpm is at redline, speed is 37 mph, and coolant temp will stabilize.
Last year when this rig was on the Dyno, fuel rail pressure was 75 psi with no bubbles in the return line, and the HEUI oil pressure was 3300 psi. So there is fuel available to the injectors, and oil pressure available to power the injectors, so appears that the ECM is limiting the amount of fuel injected for some reason. Any thoughts on what to check next?
6
Air System / Re: Turbo Questions on a C7 with fault code 102-07
« Last post by LPD218 on April 13, 2019, 05:17:03 PM »
Dave,

Thank you! 

Dave T.
7
Air System / Re: Turbo Questions on a C7 with fault code 102-07
« Last post by David.e.atherton on April 13, 2019, 03:36:44 PM »
LPD218, the 102-7code you have is an event code. This code,possible, boost pressure sensor
Caterpillar part number 161-1704, boost pressure regulator caterpillar part number 234-9944,
Little hose that goes to turbo wastegate pod. The possible waste gate sticking is remote but
Can check. Ask Dave, Dave Atherton Retired Cat Mechanic
8
Air System / Turbo Questions on a C7 with fault code 102-07
« Last post by LPD218 on April 13, 2019, 09:28:13 AM »
Hello folks,

On our way back from three months parked in Arizona I had a Check Engine Light and Stop Engine Light occur only when I was rapidly accelerating.  As soon as I released foot pressure the lights went out.  This occurred several times until no more lights after the second day home and all was well from then on.  I did change my single fuel filter but the lights persisted on rapid acceleration the rest of the first day.

My scan gauge showed 102-07 code which I used the internet to find it listed as Boost Pressure Sensor Not Responding.  That was the only code.

On the second day of our leg I set my scan gauge to read boost pressure and received a boost pressure reading of 29 once after first leaving the campground.  The boost remained at or under 25 the remaining of our trip after that and no lights occurred.

Can a turbo waste gate stick and unstick?  Is there a lube location on the turbo for the waste gate? 

Is the pressure sensor needing replacement?

Any ideas?

Many thanks.
9
Hi Dave,
I ran a little test on the regulator this morning. Basically just started the engine and monitored the coolant temperature during warm-up. Following are the results:
Outside air temp: 59 degrees
Starting coolant temp: 59 degrees
Cold Mode: Off (as reported by "Engine Status" panel of Intellidrive)
Fast Idle: for about 30 sec. after start, then 700 RPM

Idle time     /   Coolant Temp
20 min.       /   152 deg.
25 min.       /   163 deg.
30 min.       /   172 deg.
35 min.       /   179 deg.
40 min.       /   187 deg.
45 min.       /   181 deg.
50 min.       /   181 deg.

Until about 43 minutes the air exiting the radiator remained cold. At that time the regulator appears to have opened and the coolant temp droped to 181 in less than 30 seconds. After that coolant stabilized at 181 degress and the air exiting the radiator was warm.

During a normal warm-up, while driving slowly, engine reaches 187/188 within 10 minutes, then drops to 181, following the same pattern as above but in a much shorter time.
Based on the above, the regulator appears to functioning normally, possibly a little slow to open initially, and the Intellidrive reports Cold Mode is off.

May have to look elsewhere for the cause of the low power problem.

Glenn
10
Journey, will get back with both of you with more detailed information on running in
what is called the cold mode. Ask Dave, Dave Atherton Retired Cat Mechanic
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