Is this the pin that needs to come out

[uhhair]

So we pulled our fuel distributor off, is this big pin in the middle the one that needs to come out? Once we get it out, do we simply grease it and put it back in, or what do we do? Are there any other parts on the air meter, throttle, or distributor that needs replaced or oiled before we reassemble? I know there is a gasket for the air meter that goes between the top and bottom pieces, but is that it?

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[Grover]

From what I understand, when you removed the fuel distributor the plunger should freely slide out of the unit. There is no pin removal necessary to remove the plunger (someone correct me if I am wrong). In that case, you may have to soak it with some chemicals to break it free.

Now if you are taking about splitting the fuel distributor open (in half) to service and clean it, I wouldn't do that either, as most people who have, when it is put back together, it leaks.

Your best bet is to get the plunger out and clean it (DO NOT SCRATCH IT) and to then clean the little filter screens.


So we pulled our fuel distributor off, is this big pin in the middle the one that needs to come out? Once we get it out, do we simply grease it and put it back in, or what do we do? Are there any other parts on the air meter, throttle, or distributor that needs replaced or oiled before we reassemble? I know there is a gasket for the air meter that goes between the top and bottom pieces, but is that it?

1224212243

[WelmoedJ]

The "pin" as you call it, actually serves a piston.
You could use a little oil, but it doesn't need it.
Anyway I never have used oil.
Make sure you do not scratch the piston's surface.

More important is that your picture shows old fuel around the outside of nut that secures the cylinder (the cylinder is the part the piston goes up and down in as you know) .
This probably points to a cylinder leak, which in turn may lead to excessive fuel in the mixture unit.
Between the cylinder and the lower FD case there's an O-ring (on the cylinder's outside) to avoid leaking.

The gasket you refer to is a very thin metal membrane used in regulating the quantity of fuel in the upper chambers and also serves as a seal between the two halves of the FD.
This membrane can leak if it is not totally flat and unscratched, especially at the places where the spring in the upper case presses a small metal piece against the membrane.
Over the years this metal piece can make a dent in the membrane and this may cause possible leaks after the FD has been re-assembled.

I have added some pictures of an FD I opened for inspection.
From left ro right: the top case with the springs and metal piece; the membrane; the lower case with membrane, cylinder and cylinder parts; the cylinder and all its parts and the piston (at the left)
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Hope this helps.

[Ron]

+1 on the advice, but I think he meant this gasket (http://store.delorean.com/p-6387-gasket-mix-conn-unit.aspx) ?

I think last count was 90% of FDs taken apart by owners wind up leaking??
I'd just clean it up and make sure the plunger slides freely then give it a chance to prove itself...
Look down in the six ports for blocked screens.

[Grover]

Ron, the gasket you linked to is for the Air Metering Unit. But you are correct, at least from what I have read, that just about anyone who takes it apart and puts it back together themselves to service it, end up having the distributor leaking.

Take Ron's advice and clean up the plunger, and clean out the 6 little filter screens.


+1 on the advice, but I think he meant this gasket (http://store.delorean.com/p-6387-gasket-mix-conn-unit.aspx) ?

I think last count was 90% of FDs taken apart by owners wind up leaking??
I'd just clean it up and make sure the plunger slides freely then give it a chance to prove itself...
Look down in the six ports for blocked screens.

[uhhair]

Sounds great guys! What is the best method for getting that piston free? I saw in one thread an individual soaked the entire distributor in mineral oil, and then i believe he put the pin into a vice and just pulled on the rest of the distributor. Will this method work?

[DMC5180]

You might submerge it in Berryman B-12 Chemtool (available at Walmart and Most AP stores) This stuff is great for dissolving varnish.

[Ron]

Ron, the gasket you linked to is for the Air Metering Unit.
yeahl..I thought WelmoedJ thought unhair was thinking about the FD's steel plate diaphragm.
(...Hey, Mo! ;-)


Sounds great guys! What is the best method for getting that piston free? I saw in one thread an individual soaked the entire distributor in mineral oil, and then i believe he put the pin into a vice and just pulled on the rest of the distributor. Will this method work?
That is a precision fit- As said, you don't want to even scratch it. A vice sounds a bit...impatient.
Soak it and soak some more....

[uhhair]

So it's OK to just drop the entire distributor in a bowl of mineral spirits?

[David T]

You need something a LOT stronger than mineral spirits. I use Acetone. You need to use it in a well ventilated place. Drip some onto the plunger and wait a little. Be gentle with it, you do NOT want to bump, scratch, bend or otherwise damage the surface of the plunger. When you are done cleaning with Acetone the plunger should be able to fall out of the unit by it's own weight, you should not have to pull it out.
David Teitelbaum

[DMC5180]

I'm not sure how well the mineral spirits will penetrate the micro tolerances. But I'm sure using the B-12 chemtool will do the job.

[DMCMW Dave]

I'm not sure how well the mineral spirits will penetrate the micro tolerances. But I'm sure using the B-12 chemtool will do the job.

And do a fine job of dissolving the internal o-rings. I would be very careful with this.

[uhhair]

And do a fine job of dissolving the internal o-rings. I would be very careful with this.

Dave, what would you suggest?

[DMC5180]

Yeah , I was wondering if the O-rings would be effected by submerging it. Perhaps just brushing it on the outside and and pouring a little in the bore to allow it to penetrate around the piston would be better.

[Ron]

So it's OK to just drop the entire distributor in a bowl of mineral spirits?

I use P7 (by Polywater, NOT PB) if I'm worried about plastic or rubber (and for most anything electrical). It will not bother Nitrile and although Viton will absorb it, it doesn't make it swell/dissolve (even when soaked at 120F for days, IIRC). NAPA and others can order it if they don't stock it...

If you are not going to take it apart, just concentrate on the plunger. Patience is the key!
If you are going to take it apart (don't), drop it in acetone and ATF 50/50 mix.

[uhhair]

Thanks guys! I will try just getting some solvent down around the plunger and hoping it can work loose. Also, the brass ring surrounding the outside of the piston in the picture, is this where a rubber o-ring goes when I put the unit back on?

[Ron]

It goes against the base...looks like the old one may still be there in your pics...

[OverlandMan]

And do a fine job of dissolving the internal o-rings. I would be very careful with this.

Hey guys. I know this is an old thread but I never saw a response from anyone to what Dave S. said about using B-12 on the fuel dist. I'm still troubleshooting some starting issues and I'd like to attempt to clean/soak my fuel dist to see if that helps at all. Here's my thread re that whole ordeal: http://dmctalk.org/showthread.php?11991-Trouble-starting

[WelmoedJ]

Hey guys. I know this is an old thread but I never saw a response from anyone to what Dave S. said about using B-12 on the fuel dist. I'm still troubleshooting some starting issues and I'd like to attempt to clean/soak my fuel dist to see if that helps at all. Here's my thread re that whole ordeal: http://dmctalk.org/showthread.php?11991-Trouble-starting

As I do not know B-12 I haven't replied to judge it.

I however can add to my previous entry:
The nut securing the cylinder in place can also cause issues that show up as a very difficult movement of the piston.
This nut shoudl only be tightened enough to ensure a smoothly up and down running piston.
If the piston is stuck try slackening the nut a bit (after releasing the securing washer) and see if that improves the movement.

In some cases I noticed the too tightened nut causing the cylinder to no longer being exactly round and thus hindering the free movement of the piston.

[OverlandMan]

As I do not know B-12 I haven't replied to judge it.

I however can add to my previous entry:
The nut securing the cylinder in place can also cause issues that show up as a very difficult movement of the piston.
This nut shoudl only be tightened enough to ensure a smoothly up and down running piston.
If the piston is stuck try slackening the nut a bit (after releasing the securing washer) and see if that improves the movement.

In some cases I noticed the too tightened nut causing the cylinder to no longer being exactly round and thus hindering the free movement of the piston.

Thanks WelmoedJ. I should have been more specific. My piston is fine (to the extent is slides freely in the sleeve). My issue is pertaining to general fuel system starting problems and I thought maybe soaking the fuel dist in a chemical like Berryman's B-12 carb cleaner bath, acetone, or similar might do some good.

[David T]

Thanks WelmoedJ. I should have been more specific. My piston is fine (to the extent is slides freely in the sleeve). My issue is pertaining to general fuel system starting problems and I thought maybe soaking the fuel dist in a chemical like Berryman's B-12 carb cleaner bath, acetone, or similar might do some good.

I would leave the fuel distributor alone and check the spray pattern and quantity of each fuel injector. You can try a can of Techron in the fuel. Very little to go bad in the fuel distributor. If the piston slides freely and your fuel pressures are good leave the fuel distributor alone.

[OverlandMan]

I would leave the fuel distributor alone and check the spray pattern and quantity of each fuel injector. You can try a can of Techron in the fuel. Very little to go bad in the fuel distributor. If the piston slides freely and your fuel pressures are good leave the fuel distributor alone.

Fuel pattern already checked multiple times as well as volume.

According to Dave S. there are about 20 different ways a fuel dist can fail so I'll argue that point with you.

Seeing as I have to hold the air plate down in order to get it to try and start (other than the brief CSV 1-2 second run time), and seeing as I've already replaced the WUR/CPR, this is my next culprit. I don't have a fuel pressure gauge/kit to test that with but have eliminated a kinked pickup hose in the tank.


pump and tank components are all new
accumulator newish (2013)
fuel filter new


Those are the only components between the gasoline in the tank itself and the fuel dist.

I did have a stuck plunger earlier this year. I was able to get it free; however, that makes me think some other "gunk" may be in the fuel dist potentially causing this issue.

[David T]

Fuel pattern already checked multiple times as well as volume.

According to Dave S. there are about 20 different ways a fuel dist can fail so I'll argue that point with you.

Seeing as I have to hold the air plate down in order to get it to try and start (other than the brief CSV 1-2 second run time), and seeing as I've already replaced the WUR/CPR, this is my next culprit. I don't have a fuel pressure gauge/kit to test that with but have eliminated a kinked pickup hose in the tank.


pump and tank components are all new
accumulator newish (2013)
fuel filter new


Those are the only components between the gasoline in the tank itself and the fuel dist.

I did have a stuck plunger earlier this year. I was able to get it free; however, that makes me think some other "gunk" may be in the fuel dist potentially causing this issue.

Rule out vacuum leaks. If the car ran well previous to this do not touch the mixture screw. Make sure the frequency valve is buzzing. Although the mixture unit can fail, it is rare. Other causes are more likely.

[WelmoedJ]

Fuel pattern already checked multiple times as well as volume.

According to Dave S. there are about 20 different ways a fuel dist can fail so I'll argue that point with you.

Seeing as I have to hold the air plate down in order to get it to try and start (other than the brief CSV 1-2 second run time), and seeing as I've already replaced the WUR/CPR, this is my next culprit. I don't have a fuel pressure gauge/kit to test that with but have eliminated a kinked pickup hose in the tank.


pump and tank components are all new
accumulator newish (2013)
fuel filter new


Those are the only components between the gasoline in the tank itself and the fuel dist.

I did have a stuck plunger earlier this year. I was able to get it free; however, that makes me think some other "gunk" may be in the fuel dist potentially causing this issue.

I agree with Dave S.
Firstly check the injectors.
If you never have exchanged them and the car has been sitting for some - long - time the injectors may have acquired rust (making small pits in the nozzle's wall).
That causes leaking injectors with a bad spray pattern.
It will be clear that a non perfect spray pattern influences all kinds of behavior, including bad start and running.
If you have start problems it's also advisible to check the CSV injector and it's electrical system for proper operation.

Should there be gunk insde the FD chambers, if not totally solved by acetone, the gunk will clogg the screens to the piston.
Then you will have to clean the FD again until the screens are open again.
Mind that the filter screen around the piston also is fragile as the plastic it's contained in, is very brittle after 30+ years of duty.

[bfloyd]

Seeing as I have to hold the air plate down in order to get it to try and start

Same here. I've got to crack the metering plate just a little to get it to start. Once it does, it'll stay running.

[David T]

Same here. I've got to crack the metering plate just a little to get it to start. Once it does, it'll stay running.

Check that the cold start valve is working when starting cold and cranking. Always check for vacuum leaks, they are insidious. All of the rubber is getting old, hard, and brittle. Injector seals are a very common leak as is the "O" ring for the idle motor in the metering unit.