Bricky EFI question

 We just installed a new fuel pressure regulator from NAPA and got no improvement, still runs rich. We found one plug wire that has high ohms, and the coil looks old, so will pick up wires and a coil tomorrow at NAPA.

85lebaront2 wrote

I was hoping AllData had some good diagrams or pictures of the EFI fuel rail etc. Does that truck have the small cooling blower in the right front of the engine compartment? If it does then that is the earlier system, and runs around 35 psi fuel pressure. Ford changed to a higher pressure system on the 4.9L to eliminate vapor lock under hot soak conditions, these engines run around 60 psi fuel pressure. If the wrong pressure regulator was used, ie, one for 60 psi on a system designed for 35 psi, it will run rich enough the O2 sensor can't compensate for it. If the emission label is still on the underside of the hood, it may show the fuel pressure spec.

That's intriguing. I just looked for any kind of fan in the forward passenger area of the engine bay. Is that what you meant?  I found naught but the alternator fan which could conceivably cool the fuel rail. So that would make it a 60 psi system. I'm trying to locate the man who installed the tank and pump to see if he knows about the 35/60 psi angle.  I did find the emissions sticker but don't see any psi reference on it (pic #1).


What else I spotted there is air injection. What a monstrosity.  I will defeat it, to save the exhaust ports/valves and manifold from heat damage. I can't see how that would make the motor run rich, whether or not air injection is working. It does have a vacuum controlled valve on it, see pic #2, which presumably vents the pump's output to atmosphere on high vacuum as in idle. Pics 3 and 4 are the air pump itself and its air intake filter (probably dirty as sin by now).

I know the 1987 300s had the cooling fan, it feeds a duct that directs air over the injectors, the fan mounted near the battery with a flexible hose connecting it to the duct. There would be a temperature switch on the fuel rail to control it. It was hot wired and ran after shutting the engine off. The spec for fuel pressure is KOEO 50-60 psi, KOER 45-60 psi

85lebaront2 wrote

I know the 1987 300s had the cooling fan, it feeds a duct that directs air over the injectors, the fan mounted near the battery with a flexible hose connecting it to the duct. There would be a temperature switch on the fuel rail to control it. It was hot wired and ran after shutting the engine off. The spec for fuel pressure is KOEO 50-60 psi, KOER 45-60 psi

I'm looking thru RockAuto listings for this FIPR (fuel injection pressure regulator) by year. 86 was carb.
https://www.rockauto.com/en/catalog/ford,1986,f-150,4.9l+300cid+l6,1121656,fuel+&+air

For 1987 model all brands on RockAuto list 47 PSI except for the Delphi which lists 52 PSI
Same holds right up thru 1994. 1990 model year

But for the 1995 model (4th yr of Aeronose) it jumps to 55 PSI for the Standard Motor Products and 58 PSI for the Delphi.  That must be the change you described.

So even if the truck I'm working on has an in-tank fuel pump that's for a 95-up, then the FIPR I put in there today should still limit pressure to 47 PSI, and not cause the over-fueling I'm trying to fix.  That hope is dashed.  I'm out of possible fixes. Hope that a coil and plug wires fix it tomorrow.

I located that fellow who put in the tank and pump. He seems knowledgeable.   He also installed the new injectors ... which he mentioned that my friend bought on the internet.

DING DING DING...Amazon itself says those injectors are incorrect.  Too much fuel?
Amazon listing

It's run rich since I first heard him fire it up months ago.

Bad thing about those and Amazon in particular, no real comparison to the original injectors. I am going to go dig up the Ford PN for the correct injectors. E5TZ-9F593-A which means they were a 1985 original issue, so may be the same as the 302 ones. Looks like they are the same as the 302 injectors. They should be 19#/hr where as my 460 ones are 24#/hr, my new engine will have 47#/hr, only because the Ford Racing 30#/hr ones were discontinued. Since I can adjust the parameters in my EEC-V system I can allow for the bigger injectors.