Test fuel pump pressure while it's acting up, it's likely heating up and drop'n pressure, it should stay around 35-38 PSI......

 

I will do that next week. Thanks, but what throws me is the lack of gas in the filter from the tank when it occurs.

 

I will do that next week. Thanks, but what throws me is the lack of gas in the filter from the tank when it occurs.

Fuel filters do not have to stay full all the time and most wont, if you have low fuel pressure your gonna have less pull from the tank (less fuel in filter).

I went through the same exact thing first of the year on a customer's unit, he installed a aftermarket pump without any change then brought it to me. I found the pump faulty (pressure tested), installed a brand new Kohler pump with the same results (run 30-40 min. then falter) and found it drop'n pressure.

Installed another new pump and it ran for two hours so let it go back to customer, he brought it back two weeks later and another test showed the second pump drop'n pressure. I then installed another new one and haven't seen it back, so if you replace the pump and still have this issue don't skip over the "new" pump, test it anyway......

 

Check all fuel lines ... There could be kinks or cave ins .... Lines could be sucking themselves in

 

The engine has a 3 year warranty..
The fuel pump module isn't cheap..
Is the ECU giving any fault codes ?
The computers don't always throw codes when they should...I recently purchased the EFI software and have discovered many shortcomings of the ECU trouble codes..
I had a TPS running at 30% at idle and no trouble codes from the computer..The TPS should be at 0.1 or less at idle...
Without the EFI software it is nearly impossible to troubleshoot the Kohler EFI engines...

 

Check all fuel lines ... There could be kinks or cave ins .... Lines could be sucking themselves in

Already replaced the lines. They had the one routed right next to the engine with alum foil tube on the outside. I routed it away from the heat.

Thanks!

 

Dang it... I will see if I can borrow a pump off another unit. Its out of warranty.

But will have tools ready next week when I'm cutting to check the pressure. Or run it into a tree and call the insurance company........ HA!

 

Join the thread

 

Simply replacing parts probably won't solve much...
When replacing the EFI components you usually have to reset the ECU and relearn the TPS before any changes are recognised..
Take it to someone that has the Kohler software and cables and have it checked out..
Unless the Fuel pump module is flooding its probably not bad...

 

Slapper, the PC software doesn't test fuel pump pressure.....

 

Slapper, the PC software doesn't test fuel pump pressure.....

No....
The newer EFI fuel pumps don't have a port to check the fuel pressure either...though I hear that there's a piece of test eqpt coming..
The 26 efi had a fitting on the fuel rail to check the fuel pressure..

That aside.....I've had 2 units that came in within the past month with intermittent fuel starving issues..and no codes...both ended up needing a new TPS...and nothing more..
Its all guesswork until you have it on the bench..

 

Do the 2011's have a port for pressure?

Thanks.

 

The Bosch EFI systems ...26 and 28 HP ...have a port on the fuel rail to install a pressure gauge..
The Delphi systems don't have any place to install a pressure gauge..

 

There is a tap available. It's part of a tool kit. Testing pressure is a PITA. Time consuming. Module has to be removed. The vent hose is always an adventure.

 

The Kohler rep came by the shop today and he let me borrow his fuel pressure tester hose..Its just a shraeder valve between 2 hoses with a male and female fittings on both ends...
Simple to use and there's no need to remove the pump...just remove the high pressure hose from the pump and install the adaptor hose between the pump and the fuel line...install your pressure gauge and crank it up...
He didn't have the part # handy but when I get it...I will post the #...
Slapper