View Single Post
356-930 356-930 is offline
Acceleration Junkie
Join Date: Aug 2007
Location: Laguna Beach, CA
Posts: 263
Bad Fuel Head Or?

I run a '79 3.3 liter engine, SC cams, CIS - Euro Head, no intercooler.
Present problem is a fueling issue.
With stock WUR, 95psi system pressure, cold control 25-psi, warm 50-psi, AFR at idle set to 14.5 warm. AFR will not hold steady. It's 14.5 +/- .5 at best. Sometimes engine wakes up lean, sometimes rich. Drive it like I stole it and AFR settles on rich side between 12.5 and 13.5, engine seeks as though it's rich (which it is). The hotter the engine (never gets over 180) and the longer I drive it, the leaner it gets - until I flog it and it goes rich again.
Replaced stock WUR with UTCIS-PT digital WUR. Symptoms remains the same (using 930 starter MAP download from UT.) Only new twist with the DWUR is the engine sometimes seeks at idle like it's rich except AFR is 15.5 - 16.5 or lean.
Injectors cleaned with hi-press hydraulic cleaner, spray pattern of carb cleaner driven by air hose is good. Condition of fuel head unknown (plunger was frozen as engine in hibernation for 10-years - freed up with pliers, polished shaft with 3M abrasive - free operation after clean-up).
I've run this engine for 4,000 miles in this condition and would like to nail the fueling issue down so I can safely dyno and drag race without concern for the big bang.
If consensus is the fuel head, who best to rebuild?
TIA for your help.
Old 09-04-2008, 08:32 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)