1985 308 QV running too lean, need help

What do the fuel levels in the four graduated cylinders represent? If they represent the fuel delivered by 4 of the injectors with the fuel distributor in place under the same airflow plate position x time = bad sign for the fuel distributor indicating that it needs to be rebuilt/cleaned. If they represent the flow of 4 injectors supplied at the same fuel pressure without the fuel distributor in place = meaningless as it's the fuel distributor that determines the amount of fuel delivered to each cylinder, not the CIS injectors.

When you say "I can get the idle afr to 14 now, but car still starts very bad. upon revving it goes very lean again (about 19/20 afr) with loud afterfires." -- those can both be symptoms of the Frequency Valve not operating (if by "upon revving it goes very lean again (about 19/20 afr) with loud afterfires", you mean during the engine RPM decelerating rapidly after being revved to high RPM). Have you confirmed that the Protection Relay is working and that the Frequency Valve is buzzing/vibrating whenever the fuel pump is running (which can be either: 1) with the safety switch unplugged and the key "on" and engine not running, or 2) engine running).

 

Maybe its the ECU's... one or both may be going bad

 

Throwing random thoughts out here... but if your timing is too far off, it will be running lean.

 

No, CIS doesn't work that way. The "injector" does not control the amount of fuel delivered. In fact, the "injector" should really be called an "atomizing check valve" as those are the functions that it provides (it only needs to open within a certain pressure range, make a good spray pattern when open, and close well). Certainly, no harm to put in a fresh set of injectors, but you really need to measure the flow volume from the injectors when the are attached to the fuel distributor at several airflow plate positions to see if they are about equal or not. Here's a shot of how I did that on my TR (the "Dixie Cup Test" ), but you'll need to measure all 8 at the same time (whereas, on a TR, BBi, or 400i/412 they can be done 6 at a time having two fuel pumps):
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The Frequency Valve provides some other functions, too -- like adding enrichment during starting. You should just be able to touch it to feel if it buzzing, or not, when the fuel pump is running.

Yes, that's a very bad thing, and suggests IMO that you need to confirm/deny the fuel delivery being equal as described above. Extended disuse is a really bad thing for CIS as it has a bunch of very small openings/orifices downstream of the fuel filter (so any varnish/deposits that develop in the fuel system can cause problems when reawakened from disuse and they get dislodged). Good Hunting!

 

I’m not sure how this will affect the AFR reading at the tailpipe. If the timing is off ignition will occur either too early or too late and while the mixture may be correct it won’t be compressed fully so the combustion will be incomplete and there will be unburnt fuel in the exhaust. Timing for CIS involves only the ignition, there is no injection timing.

 

But unburnt fuel shows up as in HC reading, not AF/R, yes?

 

total long shot, but have you inspected the rubber o ring that is housed in the idle mixture control ? if that is perished you will get false air through there.

also if your metering unit has been of the car - I'm not sure how you get it back to factory standards - that is what determines lean / rich mixture is the throttle plate balanced? or is it not centered right... you could be getting false air through that as well. also check for the aux air hoses under the air box - that recirculate crankcase vent gasses - ( I doubt that will be the issue. ) last but not least check the protection relay in the bottom of the right trunk, if that fuse is blown or the relay is corroded you can get some weird idle / missing from that.

 

Have you also checked the bushings for the injector housings for leaks. This can lead to inconsistencies for fuel delivery. I just replaced a set in my 85qv from Jan at
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see pics.
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This might help from the archives.

https://www.ferrarichat.com/forum/threads/308qv-mixture-adjustment.170589/

 

Have you done a compression test to rule out valves and valve timing?

 

Might be of assistance:

 

Have you checked the frequency valve as Steve suggested. And the fuse on the protection relay.

 

All the terminals on the coils except the high tension side should have two wires. Yellow/Black is the trigger signal fore the 1-4 bank; Green is the trigger signal for the 5-8 bank; and Yellow is 12v power. For the yellow/black, one wire is from the 1-4 digiplex and the other goes tot he diagnostic port. Same for the green, but for the 5-8 bank and digiplex. The yellow, 12V, comes from the ignition to the 1st coil, then the 2nd wire from the 1st coil jumps power to the 2nd coil. The 2nd yellow wire from the 2nd coil goes to the diagnostic port. So one coil has two yellows and two greens and the other coil has two yellows and two yellow/black.

 

Exactly, have you checked your baselines? maybe even make sure a cam hasn't slipped.

sjd

 

A friend of mine had a mondial with k tronic, it was running rough and back firing. On top of that the sump level was coming up from fuel passing the pistons- after a lot of head scratching it turned out to be the fuel distributor diaphragm was split, it was putting full fuel into some units which it could not handle so it went past the pistons into the sump. Volvo overhaul kits fit by the way

 

That's right - the crankcase vent is before the plate...