zaggato1

I have not been able to figure this out, I have done the following:
replaced all intake tube gaskets and connecting boots(also sanded down the mating surface where gasket goes).
replaced MAF.
replaced all vacuum lines.
tested all injectors with 9 volt battery and all click.
replaced all injector gaskets(both on each).
soaked fuel rail and all injectors with F/I cleaner.
replaced fuel filter.
Had computers sent out and tested(passed).
add F/I cleaned to fuel tank.
replaced plugs and wires.
replaced Dist. cap.
cleaned ground wire for F/I harness, connects to right head.
replaced fuel dampeners and pressure regulator.

Engine idles extremely smooth, see video1(use to have a shake before replacing intake tube gaskets and vacuum lines) idles around 700-750. but it smokes lightly(see video2) and seems to have a lack of power. What have I missed?
Sorry I forgot to include: 1982 Porsche 928, automatic trans and catalytic converter with 71,000 miles.

Speedtoys

1. You don't list your fuel regulator(s) pressures are absolutely correct.
2. A battery test doesn't mean the injectors flow right.

GregBBRD

What year/model? I can't figure it out, from your parts list.

The Forgotten On

^^ Video shows a US spec L jet, so 80-84.

C531XHO

I have similar on my 89. Working through it I expect to test FPR next and then maybe LH module. Might also check AFM but i think this fails lean not rich

All my plugs are sooty so i have ruled out single injector issue

FredR

Whereas I expect you are fully aware by now, the FPR must reference itself to inlet manifold pressure to get the correct AFR it is tuned for. This in turn will set the FPR such that the rail pressure is a constant differential above that of the point of fuel injection. The ultimate test of the FPR operation is to measure rail pressure with a calibrated analogue gauge. At idle [high vacuum] the gauge should read something in the region of 35 psig. At full throttle that reading should increase to something close to 45 psig.

If the FPR is not referenced correctly and the diaphragm is seeing atmospheric pressure [for whatever reason] the engine will be over fuelled at idle/light loads to the tune of approximately 14%. Whether or not that would explain what you are seeing remains to be seen. Testing for vacuum at the FPR is easy enough to do and should help eliminate such possibility from your line of enquiry.

When a MAF gets "tired" as typically happens after 100k miles or so it will under read the air flow and create a tendency in the direction of leaness. Examples that are fitted with NBO2 sensors will generally not notice this issue at other than full throttle conditions as the cruise map will be adjusted automatically. Engines like mine that do not have cats notice it more as the impact is noticed at both cruise map and full load conditions.

zaggato1

Sorry forgot: 1982 Porsche 928 automatic trans with catalytic converted and 71,000 original miles. Let me know if anything else helps.

zaggato1

Both the dampers and regulator are new, do you know what the vacuum should be?

Koenig-Specials 928

+1

My 89 started running terribly a week ago and it drove me nuts because I didn't touch the engine. After a cold start I could tell that it was running richer but this bad a$$ behaviour was exaggerated after a hot start. I had to feather the throttle to keep it from stalling. So yesterday I noticed that my FP had risen from the normal 47 psi(g) to 54 psi(g). I decided to check to see if the FPR and dampers held vacuum. All 3 did. I tested the vac hoses and 2 were bad (see picture showing frayed end) The one not leaking had the little U-bend hose thingy attached. So forcing the bare hose onto the metal nipples caused early deterioration of the hose ends resulting in my vacuum leaks.

The fix was simply connecting the vac hose to the U-thingy hose attachment with a piece of the solid line found in our car (HVAC black feed line or Heater white line).
I know you said your FPR and Dampers are new but what about the vac lines?

Documenting this to help you or others. Such a simple fix.
My fuel pressure has returned to 47 psi(g) and idling back to normal.

zaggato1

replaced all the lines I could find, any idea what the vacuum should be at idle?, it just idles so smooth you would think a vacuum leak would cause the idea to be high or not idle at all plus I spayed carb cleaner every where to find any leaks. I guess I'll send the injectors to be tested/cleaned.

Speedtoys

How old is your O2 sensor?

zaggato1

It is way old and I just checked the wire diagram that someone put on here for the (I think FCU) box on passenger side of cabin on the sidewall by your feet and the pin that was listed as O2 ground shielding is not showing a ground. So I ordered an O2 sensor and will have fun putting that on. From reading it sounds like a bitch.

Speedtoys

That's your issue I bet.

GregBBRD

No video link, from my phone.
His use of "MAF" completely confused me.

GregBBRD

"Rebuilt" AFM's (OP called it a MAF) are notoriously poor, for these L-jetronic engines.
The "chip" which determines the fuel mixture (the part that the "wiper" touches) wears out....and there is no replacement available.
Consequently, the only way to "rebuild" these is to move the "chip" slightly and get the "wiper" to touch a different area.
Fairly random, in terms of function.
I've got a known good "Test AFM" that I use to determine if that is the issue.

The other thing to check carefully is the ignition timing....make sure it has been set correctly and the vacuum can, on the distributor, is hooked up properly and is functional.