-
replacing injecters
1998 XL11 entertainer coach…. series 60 12.7…. does the engine need to be pulled to repaces injecters???? also do anyone know if I have a check valve on the fuel line at the rear of motor…. engine looses prime when off . runs great after prime…. This happened after engine overheated…. computer says 240 degree…
-
14 Replies
-
Access to injectors is dependent on how the converter constructed the rear stateroom.
In some cases a lot of the interior has to be disassembled to get at and open the engine cover, in others it may just involve lifting some carpet to access the engine cover.
-
On my H, they did my overhead by access the valve cover thru my rear passenger side door. No disassemble requried.
None of my injectors were broke, but they were significantly out of timing and were adjusted. I noticed immediately while traveling down the road at the same speed that my RPM’s went down at least 2,000 RPM’s.
-
Wow Tim, you must have had a high reving series 60 before that adjustment to have 2000 less rpms now.
Mine only gets up to 1500 at highway speeds.:)
-
Oops,
I meant 200 🙂
Going 65mph, I averaged 1,600 rpm’s before the overhead. I now average 1,400 rpm’s going 65mph.
-
Gotcha
-
Tim wrote: “Going 65mph, I averaged 1,600 rpm’s before the overhead. I now average 1,400 rpm’s going 65mph.”
This doesn’t make sense to me. Why would working on the engine have an impact on how fast the engine turns to move the coach at 65?
If this is the case, wouldn’t this improvement translate into an improvement in fuel mileage?
-
It is not possible to run the same speed at a lower RPM unless you changed gear ratio. Period.
-
DD stated that the injectors were throwing my timing off and, combined with tuning the jake, I should see increased fuel mileage, as well as a smoother running engine.
Just reporting the facts of running now at a lower rpm.
-
I agree with Mark from Duluth. I don’t know for sure, but the Allison likely has a torque converter, which inherently has a little slippage. Is there a lockup feature? With the “fix” to the injectors does it now lock up where before it didn’t?
If there is no lockup feature on the Allison and you do infact have a decreased RPMs at a given speed, I would really like to hear the proper explanation. It defies all the understanding I have of drivetrains and how they work.
-
It may appear to be turning slower at highway speeds Tim, but at the same speed as before your RPM is going to be the same unless somehow your DDEC was misreporting RPM.
You should be at 1500 RPM at about 62MPH. There is no slippage due to a torque converter because it is locked and the engine is literally directly connected via the transmission and differential to the drive wheels.
-
I trust you guys who are the gearheads, and it’s probably just a misreading on my part.
Next Wednesday when I leave DC, I’ll make sure I’m around 1500rpm at 62.
-
Is it possible that if he had an injector issue his available torque didn’t allow the trans to shift into 5th or 6th for a 6 speed. Maybe running below the high gear at highway speeds. I’m not a mechanic at all but I know all of us have run the same given speed in different gears.I guess that would depend on if the drive train computers adjust to actual available power or are set to react to a predetermined load such as a hill or more weight. Not sure how that works
-
Sorry, but there is just no way that a tune up and jake brake adjustment are going to let the engine run 200 RPM slower at the same speed.
We played around with transmission ratios and rear axle ratios all the time when specing out trucks to get the best fuel economy. 200 RPM’s is a huge change and it will never happen with a tune up. Period.
-
200 rpm is about the difference between 5th and 6th gears. Maybe it’s been down on power so much that he’s been running around in 5th.
Log in to reply.