Restrictive fuel filter

[JMac11]

72 Blazer, in tank wlbro pump, 40 micron inline filter. 5.3 acts as if fuel starving at wide open throttle. Several post indicate 40 micron filter is too restrictive. Thoughts???

[solidaxel]

Following !

[mongocanfly]

Can you monitor your fuel pressure at the rails under wot ?

[BR3W CITY]

Originally Posted by JMac11

72 Blazer, in tank wlbro pump, 40 micron inline filter. 5.3 acts as if fuel starving at wide open throttle. Several post indicate 40 micron filter is too restrictive. Thoughts???

1. are you running a sock?
2. is the inline filter pre, or post the pump?
3. Have you verified fuel pressure?

40 micron filters can be used, but depending on the fueling requirments and what the pump moves, they may be too small (especially as a pre filter). I use a 100 micron filter AFTER the pump only.

[JMac11]

1) Yes on sock, new tank, new pump
2) FIlter post pump
3) fuel pressure verified, increases with vacuum disconected from regulator 5#'s, 58 pounds at idle, does drop 5 or 6 pounds high rev for extended period with no load on engine.

[Hart_Rod]

Factory injectors?

[JMac11]

Yes factory injectors.
Literally act as if you are lifting/matting gas pedal once you get over 2000 rpms. Can run a steady 1500 going down the road. If it were carb is would say low fuel column.

[Hart_Rod]

Any trouble codes? Almost sounds like the engine is in REP mode. Can you scan the injector duty cycle?

[JMac11]

P0500 VSS signal. (Could this trigger rpm limiter??)

Rare P0507- IAC. Rare, cleaned DBC throttle body thoroughly, code seems to be gone

[Hart_Rod]

Possibly

http://www.obd-codes.com/p0500