JoeMag

Well figured I'd take the car out for a spin today and can not get it to idle. Remember this is recent rebuild, and all i have done is initial 20min high idle run. '82 CIS car.

-- Control pressures okay
-- will run if I keep foot on gas, but nothing below 2k rpm
-- at 2krpm AFR ~19, at 3k rpm ~16. ???? WB O2 is in calibation.
-- CO adj screw seems to be maxed out rich
-- Flapper plate seems hard to push down. I recall when I had engine apart, the flapper seemed to move very easily (ie: you could tap on it and make it move) I checked flapper right after I turned car off. ...is it harder to move when system still has pressure?

What else should I check? ..other fuel system mods during rebuild is IA fuel head mod and new injectors.

WERK-I

Shouldn't be any pressure underneath the CIS metering plate. Did you have a backfire when you started up before? Flapper plate should move easily regardless. Sometimes they get varnished up from the oil breather, but cleaning the throat and outer circumference of plate with carb cleaner is an easy remedy.

JoeMag

- No oil breather on my car and hasn't been for 5 years.
- Car is back firing a little when at 2k rpm
- The flapper moved free as ever when I took off. I don't recall checking after I put fuel head, etc back on. I'm going to pull it off tomorrow morning to see if something is up.

Here's what this engine looks like so you can see what's on and what's not.

DonE

When I took mine apart to shave the travel stop for the plate, I seem to remember the plate tried to bind up at the pivot point. It looked like it had vasoline as a lubricant, so I adjusted the plate to move easily and put some axle grease in the pivot.

Check your plugs to make sure they aren't burned. High AFR for 20min, even at low RPM , will develop big heat.

After the fuel pressure bleeds off, the plate should be able to be pushed down with a feather.

JoeMag

Don -- Thanks. I bled the pressure off and it moves very easy. I'll check plugs tomorrow and see if I can grease up the pivot points.

I am very surprised at how hard that thing is to move while under pressure.

What else should I check?

--Joe

NSXTC

Hi Joe,

Did you check your advance/retard using timming lights? I had the same problem where the air bypass screw didn't do jack and I had to hold the pedal to get the car to idle. Also had a bad case of popping on decel. Adjusted the timming and it's dead on.

BTW, how's your fully adjustable WUR?

David

JoeMag

Haven't checked timing, because I was too concerned about the high AFR's. ...I recall previously (ie; 4b rebuild) when starting the car the LM1 would indicate too rich to read shortly after startup.

Jean

Beautiful engine.
I had a very similar issue and turned out the vaccum line going to my boost controller was loose. It might not apply to your car, just a thought.

911rudy

I had a similar problem but I did two things and so I don't know which one cured the problem. I checked all of the vacuum lines and one of the round relays on the left relay panel in the engine bay was almost out of it's socket. I believe it was the cold idle or choke type relay. Anyway, once I did those two things it was fine. It would not run before unless I constantly patted the throttle and nursed it above 2000 rpm. LOL

JoeMag

Well checked the timing. Just after start up, at 2krpm it was reading ~29 btdc. I adjusted back to ~5 btdc (which looks like where it should be at 2k rpm based on rpm adv curve) and it would barely run even at 2k rpm. Still high AFR's... Checked vac lines, etc, and could find anything wrong. I'm at a loss

DonE

I'm assuming you didn't do anything to the CIS system when you rebuilt the engine. In that case, we can rule out re-adjusting the metering plate for clearance (all around the edges). Do you have a schematic of the CIS system so you can check everything? For example, there is a small plunger on the side of the fuel head I left out once (wondered for 2 months why it ran so crappy).

If the plate moves easily with no fuel pressure, the only answer is that there is too much pressure being supplied by the WUR. I read where you have a fully adjustable WUR. You might try adjusting the pressure downwards to see if that has a positive affect on the AFR - then you will know where to start working. When I made my WUR completely adjustable, it took me about 1/2 day to dial in all the values according to my WB sensor. If found that the stock values were fairly close, but with the modified engine I had, I needed to back off most (not cold) pressure values.

Good luck

PorschePhD

The CO can not be maxed out. Something is a miss. If it was cranked all the way to the rich side then the plate would actually start to show a gap in the meter housing. Not to mention the car would not idle at all.

If you have only one pump working that too would cause a lean condition.

JoeMag

I'll check CO adj screw again and check gap in flapper plate. Should I be able to see movement on flapper plate when I turn it? Thought I recall reading in factory manual that total adj on it is only 0.5 turns.

fyi... other mods on engine that can not be seen in pic are, 964 cams, fully finned '91 p/c's, 36mm intakes, no AAR (plugged)

I'll also give once over again on leaks. If all look good I think I'm going to plug all pressure sensing and vac lines (except distributor) and see if it helps.

PorschePhD

.5 turns. Oh no, you could crank that thing until is floods the cylinders with gas from pumping so much. There are maybe 10 turns on that thing in total. Be careful though.

What happens is the screw gets junkl on it causing it to become hard. You may need to remove the housing and see what is going on.

jalexand

I hate to butt in here, I have been following this thread out of curioisity and to maybe learn something more and I just cannot come up with an understanding of the term "AFR". Can someone explain this term?