injector flowing with key on 76 911S with CIS
 

Hi guys,

havn't posted in a while

I'm trying to get my dormant 76 911S running. Its been sitting for about 8 years.

The engine started and ran this morning, on and off. I checked for spark and it was good. I drained the tank a while ago and installed a new fuel pump. The original was still working but making noise. I routed the return line to a gas can and fuel is flowing like it should.

It won't start now. I pulled an injector and found that injector to be flowing a little fuel with the key on and the engine not running. This may be my problem but I don't know if its the injectors or the fuel distributor.

any ideas?

thanks

I pulled 2 more injectors and both are flowing with the key on and engine not running. This makes me think the fuel distributor is the problem. I probably should dump my oil and replace when I get this problem solved.

Yep, the fuel distributor is likely the cause.

But test again and this time pull down on the air plate slightly, do the injectors stop leaking? You can also push up on the air plate slightly and the injectors should really start spraying fuel.

The slight leak on injectors could also be that the CO screw is improperly adjusted and causing the pin to be pushed in a bit to far with the air plate at rest? This is why I suggest you pull down on the air plate by hand a bit.

The fuel distributor center pin is not coming back to the rest position.
Bruce

thanks scarceller,

I have not pulled the air filter off yet. I stopped for lunch. I may work on it some more or go for a ride :)

+1 on this. Could be it's sticking or the air plate is to far up for some reason.

Also note that, if you only pulled two and they are going, the other injectors have probably flooded their cylinders.
When I was working on my CIS, I picked up 6 baby bottles at the dollar store and numbered them. Stuck an injector in each, and I could do all the testing I needed without flooding cylinders or making a mess.

http://forums.pelicanparts.com/uploa...1436483967.jpg

Also these bottles are a great way to verify all 6 injectors spray same amount of fuel when you lift the air plate up.

Oh yeah, they worked great. I inverted the bottle nipples and widened their tip holes, and then the injectors fit in snugly. No risk of leaks if they fall over, and no gas fumes.

Bruce,

is the center pin called a plunger in all the videos I've been watching?

If are driving it, it may be worthwhile to put in a good fuel system cleaner and run at least one tank thru it that way. Cheap and easy.

Edit: I just went and reread your initial post. Car is not running, so never mind.

You may have two problems.

Problem 1, your fuel pump is obviously running when it should not. With the ignition ON, the pump should not be running and, therefore, no fuel pumped to injectors. If you find leaking injectors with the ignition ON, you have an issue with your fuel pump relay or you or a PO has disabled the system.

Problem 2, leaking injectors, and that has been addressed by previous posts.

CIS troubleshooting..........
 

Otto,

If I were in your shoes, this is what I would do:
1). Disconnect all the six (6) fuel lines to the injectors. Then place the ends of the fuel lines previously disconnected from the fuel injectors in separate individual containers to collect fuel in case there is fuel flow.
2). With the six (6) fuel lines properly secured, start the FP and observe for any fuel flow.
a). There should be no fuel flow at this point. This is normal.
b). There is full flow..........either the FD plunger is stuck up or fuel mixture set too RICH or a defective FD.
c). There is partial flow.........FD leaking due to defective o-ring/s.

Determine the condition of the FD before proceeding to testing the fuel injectors. There is no good reason to test the fuel injectors if the FD is defective. If the FD passed the test, proceed the investigation with the fuel injectors installed. Keep us posted.

Tony

thanks for all the replies, I think I'm heading in the right direction

I'm deciding if I should go farther into the fuel distributor or wait until my move is done and the car is in my new location. I'd like it to be driveable so I can get it on and off the trailer and move it around without having to push

in the mean time I'll just tease you guys with some garage porn

Location.......
 

Otto,

Where are you located? The BMW MC reminds me of someone I met a couple of years ago.

Tony

somewhere in southern California, I don't like to get too specific on an open forum

on the bike I could be anywhere from Solvang to Tucson

that plunger is stuck

and stuck good :(

now how do I unstick it?

Apply the system pressure........
 

Otto,

Your system fuel pressure is about 70 psi. Is it stuck at rest or at an elevated position? Sometimes you could overcome the sliding problem of the plunger by moving it up and down due to some varnish deposit. Many times, you need to disassemble it to gain access to the barrel and piston (plunger).

Tony

Tony,

I got the fuel distributor off today but before I got it off I managed to push the plunger all the way up. I think this was a boo-boo. I have not tried using compressed air in the fuel ports to try to dislodge the plunger.

I think I'm going to soak it in a solvent. I have lacquer thinner and PB Blaster. I may soak for a day and then use my propane torch to heat the body while keeping the plunger cool. Maybe the differential temp will loosen it and free the plunger.

I really don't want to take apart the fuel distributor. I would rather professionals monkey with the guts of this thing.

Fuel distributor.........
 

Otto,

I don’t know where you got the idea of heating the FD to make the plunger slide freely. There are several Viton o-rings inside the fuel distributor that will be compromised or worse damaged by the heat application. Think twice before you make this choice of applying direct heat. Keep us posted.

Tony

Air pressure applied to the center top of the fuel distributor
Soak the FD in WD40 bath overnight if it doesn’t blow out
Heat the unit in oven to expand the casting and apply air pressure to center top.
Bruce

I would just use enough heat to make the body warm. The body is iron or steel, looks cast so it should be a pretty good heat sink.

Maybe warm the body and put an ice cube on the plunger

I'm just thinking out loud right now. I've seen BMW bike mechanics use propane to heat the cover of the motorcycle transmissions so they could open them up.

Otto - Bruce's oven idea allows you to keep the heat pretty low - maybe 90 degrees C, like the oil gets in the engine, whose heat eventually can make the FD somewhat warmer than ambient.

Using a propane torch on something with gasoline in it, even if not much, doesn't seem like a good idea, and controlling the heat trickier and you run the risks Tony mentions.

If you could push the plunger up, it probably isn't firmly rusted in place or something like that (which is improbable any way). Between solvents, and especially air, you should be able to cycle the pin. After enough back and forth it should get to the point where it will pretty much drop down on its own, or at least with just a couple of PSI air, like maybe blowing with your mouth.

With the FD disconnected from the aluminum base plate, the sensor plate lever will no longer hold the "pin" in place, so the "pin" part might just blow right out of the FD. It certainly will when you get it loosened up. You don't want it to whack into your concrete floor or bounce around - its upper part is super precise and supposedly individually honed for an exact fit. I think the fit is so close that no O rings are used to keep the fuel from getting past it downward. I should remember, as I have had a couple apart, but don't - just that you handle it with kid gloves.

If you pulled off the whole assembly, sensor plate part and all, I don't suppose the air pressure will cause a problem as the arm is still there to prevent the pin from coming out.

thanks Walt,

I just finished my morning banana and coffee and I found my air nozzle with rubber tip so I'm ready to see if compressed air will push the plunger out.

except True Grit is on (the original) and I may be delayed a bit...

success..

the plunger is moving again

no heat or solvent, just compressed air

thanks Bruce SmileWavy

http://forums.pelicanparts.com/uploa...1554569325.jpg

now some PB blaster and work the plunger back and forth to get it loose

Good news.

I think one reason Bruce suggested WD40 is that it is a fluid which perhaps can't harm anything. WD stands for water displacement, and it wasn't designed as a solvent but rather to get water out of things where it would cause problems. It isn't sold as a lubricant, either, but it is pretty useful stuff. But it is safer than using gasoline to flush your FD. I might be inclined to use carb or brake cleaner, but Bruce has a whole lot of hands on experience. Maybe he thought of WD40 in conjunction with heat. Carb and brake cleaner fluids are combustible - that's why we use them to check for intake manifold air leaks.

From my personal experience, you are better off not opening up the FD (beyond getting the plunger carefully out) to clean things. With or without a repair kit for the FD, getting it to seal on reassembly isn't easy. I failed the last two times I tried, so I went to Tony to get one which didn't leak out where the two big halves come together. So doing what you can externally by moving fluid through it has many benefits.

But glad to hear things seem moving in the right direction.

one problem solved only to reveal another

so the FD is back in and seems to be functioning but the engine doesn't start

with the key on, the fuel pump is running and I can hear it. Fuel is flowing, I've verified this by plumping the fuel return line to a gas can and I did a visual on fuel flowing with the key on.

I pulled one injector and put it in a clear bottle and turned the motor over a few seconds and checked the bottle: no fuel in the bottle.

I left the injector in the bottle and turned the key back on and pushed the air plate up with my finger and saw fuel flowing thru that injector. I remove my finger from the airplate and the fuel stops.

there is a noticeable resistance of the airplate to move. It feels like I'm pushing fluid thru an orifice. I think the something is preventing the airplate from moving when I'm in the car trying to start the engine.

Try this test........
 

Otto,

Pull the FD out and try this test before putting it back on the motor. Did you test how the plunger slides in and out of the barrel? A very good one will slide down by its own weight and others need some slight assistance. I use a small magnetic pick up tool to test the plunger.

Push the plunger all the way in and use a magnet to get it out. If you could get the plunger out with the magnet, the fitment is good. And the control pressure should be able to get it down during operation. However, if you need a vise grip or plier to get it out, there is restriction and will cause it to bind or get stuck during operation.

Keep us posted.

Tony

………...never mind...…..

its running now, I don't know what happened, maybe I looked at it crossly and she dropped her attitude

smokes but I was expecting that

some clown stopped and wants to buy it

the usual sketchy guy that doesn't have a clue about these cars except its a Porsche

"what is it, 911, 912, 914?"

he has a friend who buys cars and is looking for a finder fee, or that's the story

I told him $30k and the more people annoy me the more the price goes up

Follow Tony's instructions.

But here are some things it is useful to know.

1) The '76 and the '77 are pretty similar. My '77 had a safety feature which prevented the fuel pump from running unless a) the key was in the start position, or b) the metering plate was up a hair from its engine stopped position (i.e., the engine was running and air was flowing to lift the plate a little). There is a plug on the backside of the fuel distributor assembly (but not the FD you pulled off)which connects to a switch inside the assembly which is closed when the plate is at its rest position. If you want to have the ignition on position run the fuel pump - like to do flow testing from injectors - you can pull this plug.

Your '76 has this feature as well - I just checked the wiring diagrams for both. Among other things, it will prevent flooding your engine if things are out of whack somewhere and it doesn't want to start immediately.

Pulling this plug is useful for diagnostic purposes, but you want it connected and working for ordinary use.

As long as the car starts normally, and stops normally rather then by stalling, and you only have the key in the run position with the engine running, you can live without this interlock device. The first CIS systems did not have the interlock. But you have it, so why not use it?

2) It sounds like some parts of the system are working like should. Pressure in the system because fuel pump on, sensor plate at rest, no fuel out of injectors. As it should be. Sensor plate moved up a bit, fuel sprays from injectors - that's what it should be also.

3) With fuel pump running, but not engine, you feel resistance when ypu push the sensor plate up. That's what should happen - the control pressure pushes down on the top of the plunger - what you have called the pin because that's what sticks out. How hard the pressure pushes, which is a direct relationship with the control pressure, determines how far up the sensor plate moves for a given RPM/air flow, and that - plus how you adjusted the sort of hidden mixture screw - determines the ratio of air (measured by the plate) to fuel (which depends on how high up the plunger is).

So other than not starting, what you report happening is what should happen (other than the always running fuel pump).

the clown said he would be back in a half hour

should I take a picture of him and post it here?

thanks Tony

all you guys have been a big help

I worked the plunger out this morning and took a green pad to the part that had the gunk built up on it as you can see in the picture. I hit everything with PB blaster and when I was done the plunger was sliding out on its own weight, but still it was a pretty tight fit, like it should be.

I was careful to install the FD so the plunger rest on the airplate link

I bought new copper seals for the banjo fittings when I was in Tucson Thursday at Dave Radmacher's shop. I like Dave but I try not to waste his time with idle chit chat. He confirmed my diagnosis of the car not running.

everything went together and it eventually started running. Maybe the system had air in it and it took a while to purge.

:)

I didn’t read everything but Walt confirmed the relay shutoff.
A lot of times when the pump runs, and it’s not supposed to, the cold start connector and the air flow sensor are reversed plugged.
Switch them and everything could be correct.
The cold start plug will ohm with the wire to the connection on the left chain box cover to be correct.
Bruce

http://forums.pelicanparts.com/uploa...1554781843.jpg

I've owned this car for maybe 14 years and never done a leak down so this morning I decided to do it. Since I was taking off the top valve cover so I can watch the rocker, I decided to adjust the valves. I only got the right side done. I wish all the cylinders were reading like this one.

so..

#4 was 101/105 :eek:
#5 was 96/98 :cool:
#6 was 55/90 :(

I'll check the others tomorrow. I don't know why the pic uploads like that

I now have a cold start problem.

It won't start cold but if I take off the air cleaner and exercise the air plate up and down a few times the engine will start with a lot of hesitation and some back firing. After it warms a little, it has no problem restarting.

I'm suspecting the warm up regulator now.

CIS troubleshooting...........
 

Otto,

Before you start blaming the WUR , check your fuel pressures:
a). CCP (cold control pressure).
b). WCP (warm control pressure).
c). SP (system pressure).
d). RP (residual pressure).

Or you have unmetered air going into the system. Not until you have pressure tested and confirmed the absence of significant source of unmetered air, the integrity of your vacuum system is a point of interest.

Tony

just finished the leak down on the left side so..

#1 90/92
#2 90/92
#3 91/92
#4 101/105
#5 96/98
#6 55/90

got an issue with #6,