I have a 1984 f150 2wd 3.55
motor known:
was said to be rebuilt
302 86 HO roller motor
.040 over
E6 heads ( I know.. I know)
plugs gaped at .40
Fitech EFI
Duraspark distributor 14 initial 10L setting (20 mech) vacuum settings - 0° @ 4.5" Hg, 11.5° @ 8" Hg, 20° @ 12.5" Hg.
dual plane intake
Cranking compression 154 cold

Unknown:
cam ( guessing stock)
Compression im going with 9.3-4 ( running online calculators guessing stock parts were used I get 10.3:1 with a dynamic compression of 7.8)

Here is the issue
14 inital 20 mech no vacuum advance 1st will break traction on 2nd will too if wet or dusty at part throttle..

Hook up the vacuum advance and it feels like I have my brakes partialy engaged. It lacks power at part throttle and wot.

What could be the issue?

Thanks

 

Does your advance pod on the distributor have two ports ? If so the front port is advance, the rear port is retard. Might also have too much initial with a stock cam at 14*. Also where on the carb are you plugging the vacuum into ? Should be a port above the throttle blades.

 

1. It has 1 port, never seen one with 2
2. Where should I drop the initial?
3. I have it in the manifold vacuum port

 

Full manifold vacuum gives you full advance soon as you fire it up. Hook it up to a port (what carb ?) above the throttle blades, that's where it's supposed to go with a single port pod. Try setting the initial at 10* BTC also. All the Ford distributors since the late 60's had a dual port vacuum pod. Vacuum was directed from full manifold thru a temp controlled switch on or just before the T-Stat to either advance or retard.

 

It is an aftermarket EFI.. It has both ported and manifold vacuum ports.. As far as the pod your talking about the thermostatic vacuum switch? If the switch is hooked up to full manifold vacuum and the other port to the distributor, wouldnt it pull full vacuum when warm?

 

It would if the switch is working, depending on how the switch is designed.

 

Also if I recall, the E6 heads don't like as much advance as the other heads, so that may be your problem, too much advance altogether. These were called "fast burn" heads by Ford.

 

I think I found the issue.. The truck was not warmed up and the efi puts in more fuel when cold.. I tested the vacuum advance when warm the other day. Cold the motor revs a little higher needs more throttle without the advance hooked up.. Cold with it hooked up the rpms stay down and it pulls. Warm it lacks a little power with both ways... I think I have to play with the pump shot and fuel delivery as it is running lean and the plugs are a tad hot. Thanks all.

 

"pump shot" ? I thought this was EFI ?

 

It is an aftermarket EFI.. It has a handheld that you can change parameters...It is almost like the fast efi.. Holley efi system. You can change the wot, part, throttle, cranking , and idle fuel. You can also change the Air fuel Ratio targets. After driving a while it learns and adjusts