82 can't keep it runningc ---long

[Tempermental]

/hi folks,
1st post here - got a similar one one r-list - hoping that the more eyes that see it the better my chances are
82 usa auto

The car will crank and start no problem, engine rises to 2,000 rpm and then dies -sounds like it should for these brief seconds

Unplug the AFM electrical connector - car will start and keep running but it runs horrible and very rich with black soot coverning that side of my garage.---while running like that I've jiggled ,wiggled everything vac or electrical I can get my hands on -no change, though I did find and fix a injector vac leak with a small propane tank

So cold starts gets the car running with the AFM plugged in but doesn't tell the ignition brain to take over

I've Y jumpered ignition relay, and jumpered fuel pump relay (pump alwas runs) -always the same results. AFM plugged in, brief start to 2,000 rpm and then die -AFM unplugged crappy rich soot but it runs

Green wire is very green , 14 pin plug taken apart and cleaned, hot jump taken apart and cleaned.
I would immediatley think green wire but when I unplug AFM the car runs --can't be running like that on just the cold start?

New coil
New plug wires magnecore kv85
New plugs bosch wr8dc copper
New battery duralast 49-dl

New engine and injector gas lines
Injectors serviced and cleaned, new o rings large and small
New vacuum lines -all -removed one at a time, cut new length then on to the next
New intake gaskets
Removed air pump plumbing from orange hose back, wasn't hooked into the exhaust anyway,capped vac line

No 02 sensor

New ignition relay
New temp II sensor
Used AFM
New 2/0 battery ground cable
New 4/0 engine ground cable -passenger side
New AFM o ring -black one in the U
New rotor

Removed CE, inspected backside, lightly crimped a few loose spade terminals
Tested continuity of the fuses
Cleaned the CE grounds
Cleaned injection grounds 3x
Cleaned pod grounds
Cleaned front and right grounds by radiator

Battery is on a maintainer and I have 2 gallons new gas in it.

It feels like its something so simple and I'm missing it
Anyone?

[Maleficio]

I see your AFM is used, and the car reverts to open loop when you disconnect it. That's where I would look.

[Tempermental]

Ok -- open loop=horrible can't drive it?

I have 2 afm's. I have done some tests and will post the ohms....original thought was I had a bad afm, so ibought a used one

I'm looking for diagnostics on afm wiring

[Maleficio]

Open it up and clean the .... Out of it, then read it out slowly moving the mechanism watching the ohmage climb up and down. It should be a smooth transition through the range.

[Maleficio]

My '82 16V runs pretty good, but I really don't know HOW it should run.

My AFM has been opened up before, and closed up with orange RTV and duct tape.

The car runs good, but gets 9 mpg. That is not right.

I'm conducting the fundamental steps right now to establish a baseline of performance.

I've got some strange tricks up my sleeve which I'll not divulge until they pay off.

928's kick ass!

[Tempermental]

Allright, I've sprayed the heck out of one of then with carb cleaner-but that didnothing...you aren't telling me to screw w/ the innards--I've opened one and the wiper contact strip looks fine

yeah our 82's are ol'and comfy-but they still give when u stomp on the gas @ 80 and want 100+

[Maleficio]

fork yeah!

[Tempermental]

baaaaawaaaa haaaaaahhaaaaa

nothing like the scream @ 4,000 from a 16v with an rmb -

Anyway here are some ohm readings from the 2 AFM's I have-
1st # original AFM
2nd replacement

Pin 6 & 7 -132, 100
Pin 6 & 8 -438, 362
Pin 6 & 9 -679, 561
Pin 7 & 8 -373, 302
Pin 8 & 9 -245, 201

I haven't found the spec range in the WSM yet so both or neither could be cooked

[jstobo]

Have you checked your fuel pressure. If too low will cause poor idle. Also is the AFM set properly. Of course that's hard to do if it won't idle. Good luck.

[Landseer]

Good thought on fuel pressure. Building on that:

Pull the vac hoses off the regulator and dampers, too, to see if there is gasoline leaking. That's the only reason for the vac hook-ups, to siphon off gasoline if those parts fail.

Injectors partially clogged could cause this also.



There is a reference to AFM testing in the archives on rennlist. I've seen it in the manuals/documents but don't remember where. I think your problem is elsewhere.

[Tempermental]

Thanks landseer, you are a voice of wisdom and I follow your hints - there's no gas leaking -I wish there was!

I get gas afm unplugged the whore will spit holy amounts of black death (soot) out it's tail

i also had 2 small gas leaks drivers side forward and back fuel rail that I fixed- I know get gas but idont think I get either ignition or gas when Im supposed too

[Landseer]

My 84 was difficult. All new to me.

Could just get it to catch and run a bit after TB.

Turned out that I'd reversed one of the cam gears and was aligning on the wrong mark. Something similar happened to MP Dano on before his maiden voyage after engine work.

If it were me, I'd pull your covers and double check your settup. Distributor location confirmation as well.

[Maleficio]

Originally Posted by Tempermental

Anyway here are some ohm readings from the 2 AFM's I have-
1st # original AFM
2nd replacement

Pin 6 & 7 -132, 100
Pin 6 & 8 -438, 362
Pin 6 & 9 -679, 561
Pin 7 & 8 -373, 302
Pin 8 & 9 -245, 201

I haven't found the spec range in the WSM yet so both or neither could be cooked

They are not the same, but each one is consistent.

[Tempermental]

The thing is that the initial startup with afm plugged in sounds just like it should ...If the timing was off I don't think it would feel right, even though it's only running briefly

now I did raise the distributor just enough to get that last air intake bolt tightened...I'll see where the rotor points at tdc

[Tempermental]

Those readings are probably close enough ...continuing to suspect the wiring from afm connector

another thought ...Would the 2 micro switches have anything to do with this condition? I can hear a click on the top one

[vdubr928]

Test them. They are just an open closed switch. Idle side should be closed at idle and open quickly when You slightly hit the pedal and Max throttle should only close at Max throttle.

[mikeyb6s4]

Maybe need a Valve Adjustment? My 911 is doing something completely similar. Can you give it gas to keep it running? If so, look into adjusting your valves. It could be causing no vacuum at idle. I am doing the valves on my car tomorrow.

[Tempermental]

Yikes- an intake refresh
turning into a valve adjusting adventure--

[Landseer]

How do you adjust the valves on a 928?

I think your distributor is a tooth off.

[Tempermental]

I've got a new dist cap coming....the contacts on the old one are gone, barely get a reading, old rotor looked really bad...fingers are crossed that this is what I've overlooked....doesn't explain everything but heck it'll be one less thing to worry about