Another stumblng issue.

[Norwegiandiesel]

Truck is a 1995 Tahoe (not in my sign). Heath chip, Suburban no EGR intake, Walbro liftpump, S&B air intake, 4" no muffler exhaust

ISSUE:
When i make a quick step at the ACC petal,(dont have to floor it) the engine stumble and nearly dies. If releasing it a little, the engine comes
back to life.

If I make a smooth push on the petal, the engine is very responding, the turbo spools up quick (13-15 Kpa)and the engine pulls hard up to at least 3400 rpm.

Replaced the fuel filter, checked and double-checked two new PMD's, still same issue

Any suggestions?

 

[FellowTraveler]

I've had issues like this and traced them to the harness at the passenger footwell being pressed on by passenger especially when on longer trips as the stretch out over time some of the harness pins get pulled out at the ECM making for some strange electrical gremlins, one other time it was the ignition starter switch gone bad.

 

[Will L.]

What is fuel pressure before the ip?

 

[Burning oil]

What is fuel pressure before the ip?

x2. Sound like lack of fuel.

 

[Norwegiandiesel]

Hi all, thanks for Your replies. Thought the Walbro solved a lack of fuel issue? But honestly, haven't checked fuel pressue between FFM an IP. Will do ASAP. With the T-valve open ther's a lot of fuel coming out of the hose under the engine, opening up the bleeder screw at the fuel filter shows a significan amount of fuel as well. Will try to install an inline gouge before the IP- Thanks again.

 

[WarWagon]

Any codes? use a paper clip to read them if you don't have a scanner.

 

[Norwegiandiesel]

Hi
Have skanner but haven't scanned yet. Figured it out to be a fuel issue and no Readings on a skanner. But will do it. Been thinking if the filter harness might be the issue?

 

[JMJNet]

Check for fuel leak also? The Walbro is powerful so if there is small leak, it can suck a lot of air.

 

[jrsavoie]

fuel cap?

Injection pump filter screen?

plugging return line?

Do you have the optic sensor filter removed?

 

[matuva]

Hi all, thanks for Your replies. Thought the Walbro solved a lack of fuel issue? But honestly, haven't checked fuel pressue between FFM an IP. Will do ASAP. With the T-valve open ther's a lot of fuel coming out of the hose under the engine, opening up the bleeder screw at the fuel filter shows a significan amount of fuel as well. Will try to install an inline gouge before the IP- Thanks again.

Did you clean the input filter inside the Walbro itself?

 

[Will L.]

Oh yeah, Do you have a clear 1/4" line on the ip return to look for air bubbles in the system?

 

[Norwegiandiesel]

Hi all.
Thanks for all suggestions, will check them out, one at a time to see which of them that might cause the problem.
Thanks again