Working on an 89 F350 with a EFI 460. Just got done with a short block swap from a running 84 van. Rebuilt heads and all new ignition components except coil. Old engine ran fine before I pulled it just ate 1qt of oil every 100 miles. Turns over and won't fire. I hear some what sounds like to be mild intake backfire but can't be sure after cranking for about 10 sec. Here is what I have checked and done.

Fuel is getting 40 PSI at the schrader valve. Pulled #1 plug, had fuel on it. Couldn't get anything even with starting fluid to pop except once out the intake. Tested the injectors with a test light with key on run and both wires are hot.

Pulled valve cover made sure I was not 180 out. saw ex. valve go down then intake, brought it to the next TDC on balancer and dropped the dist. in at 10 deg BTDC and rotated the cap slightly till coil sparked.

I have made sure I have spark, at the coil, with timing light, and at the plug all are a yes.

So my brain tells me, I have fuel, spark and should be timed enough to get a rough start anyway. It should catch.... but its not.

I have looked for loose connections and cannot find any.
Tried it with the spout in and out.

Where do I start now? I don't want to just throw parts at it.

 

Sounds flooded.
Pull the vacuum hose off the FPR and turn the key off and on a few times to see if any fuel comes out of the nipple. If it does the FPR is bad.
Also check the MAP sensors vacuum line and electrical wiring.

 

MAP is plugged in and has new hose. No fuel comes out of the FPR when vac line is off.
I took the plugs out and cleaned them, and am letting the cylinders try to dry out. I'll let it sit overnight and do a compression check tomorrow.
Any Ideas where the fuel pump relay is on this thing.

Any other ideas of what I can try?

 

Anyone that can help? Dried the plugs out and tried again, now it sounds like it is trying to fire but is still sounding like a contained backfire. Could my exhaust be clogged? A lot of coolant went in there when I pulled the old heads.

 

The only other thing I can think of other than the FPR stuck closed or its return hose pinched I can think of would be a bad TPS.

 

Looks like it might be bigger issues. Did the compression test, stopped after 4 and noticed a trend. All 4 cyl. I tested were at 85 psi. That would probably be why shes not lighting off correct? Test was done cold and cranking, I did not add any oil in the cyl.

I hope its not my head piston combo. I put 89 heads on a 84 van short block with 89K on it. After I learned theat the heads from both motors had close to the same chamber size I figured it would drop compression only slightly. Was I wrong?

What else could be causing that low of a reading on all cyliders? I tested two on each side.
I think I will open up a new thread with these results as I think I won't get a large response the way it was previously listed.