Rawze.com: Rawze's ISX Technical Discussion and more

Hi all, didn't see anything in searches that matched my issue so I'm asking a new one.

I have a 2010 isx cm2250 that on the first startup of the day is tough to start. Will crank, catch, and run for a second or two and shut down. Does this 3-5 times before it will stay running.

I have monitored all the parameters via insite while starting and running and nothing catches my eye as to what could be the issue. I did a fuel leak down test, injector performance test, cylinder cutout. Nothing shows as wrong.

Once it has warmed up it has a slightly rough surging idle and jumps between 600 and 750rpms.

Any help would be appreciated as I have a pain in the ass driver in my shop every other morning with an attitude about it.

Also, no faults are present.

what is the actual vs commanded fuel pressure during the surge

Is it possibly sucking air and losing prime?

I'm with Unilevers on this one.....possible fuel pressure sensor issue. Any active/passive codes in Insite?

No active or inactive codes. I will have to get actual numbers later since I'm no longer at work, but the command pressure surged up and down along with the idle.

(03-17-2017 )benjiisx Wrote: [ -> ]No active or inactive codes. I will have to get actual numbers later since I'm no longer at work, but the command pressure surged up and down along with the idle.

It appears you have a bad fuel return valve. very inexpensive part.

Ok. Well after more trouble shooting with very little info gained, the big boss man wanted the fuel pressure sensor changed out. No biggee, 5 minute fix. Yesterday morning my guy comes in, starts it, same problem. It starts and runs for about 2 seconds and then shuts off. Does this twice and then will stay running and not do it again all day.

Still no codes. It idles better now with the new fps but still having that morning start problem.

(03-23-2017 )benjiisx Wrote: [ -> ]Ok. Well after more trouble shooting with very little info gained, the big boss man wanted the fuel pressure sensor changed out. No biggee, 5 minute fix. Yesterday morning my guy comes in, starts it, same problem. It starts and runs for about 2 seconds and then shuts off. Does this twice and then will stay running and not do it again all day.

Still no codes. It idles better now with the new fps but still having that morning start problem.

that is usually only caused by air getting into in the system. Maybe pressurize the fuel tanks to about 10 psi and look for leaks.