3.2 rebuild will not start For the love of God please help

[kühn tune]

3rd post here, I can't seem to keep these threads going.

Backstory; I last drove the car in late 2001, It was running, but losing enough oil for every place I parked to become a superfund site. I took the engine down to the crank for a re-seal. I recently re-installed it, but can't get it to run. It will fire on cylinders 1 and 5 only. It has fuel in the rails, but I don't know how to know if the injectors are working. I have gone as far as putting the old plug wires in because they were the only thing I changed.

Someone said that it was typically the cam timing if the car wouldn't start at all and "Bump bump bumped" like mine does. First I verified, with my homemade compression guage, that the cams were not 180° out. Then I checked the time of the 1-3 cam.

Unless I just don't understand the process or have lost my mind otherwise, I think it is within spec. Should be between .1.1&1.4mm or .043&.055" ov movement on the gauge. If I am reading this right, it is at .045" from zero. (sorry about the photo size I'll reduce them when I get back to work)



I really need help here, I have a two year old and have spent most of my precious "me time" trying to sort this out. A couple of times I even turned off the radio and quit drinking beer just to ponder it. Desparate times indeed.

I'll reward you that have read this far with a picture of the my beloved SC in the "Abu Grage".

[DW SD]

Any chance you had the firing order on the distributor reversed?
What were the results of your home made compression test? Was compression uniform between all cylinders?

Doug

[kühn tune]

God Bless you for posting DW SD.

I have checked the firing order probably 50 times. Good call though, the sticker in the SC engine compartment is oposite the actual direction of the Carrera distributor.


The homemade compression tester is really just a piece of fuel tubing stuffed with plastic from a Wal*Mart bag that rises up, so I can't say if anything is uniform, just building pressure. I looked around for a proper one, but no luck. I'll try again this week and post the results if possible.


I'd love to hear from someone about my cam timing either confirming that It is right or I that am a nincompoop.

[Grady Clay]

kühn tune,

Well you have a fellow nincompoop here. Most don’t know
what that is.

Some serious and patient testing is necessary.

Pelican DW SD is right on. It isn’t clear that this is
resolved. The SC distributor can rotate the opposite
direction from many 911s. You need to ascertain both
the direction of rotation and the wiring (firing) order.
If either is incorrect, you won’t start.

Here is the factory description:

New_Folder\911SC_Distributor_Rotation01.jpg
"
"
© Dr. –Ing. h.c. F. Porsche A.G.

Best,
Grady

[ChrisBennet]

I feel your frustration!
From reading the title of your post and looking at the picture I see you have a 3.2L Motronic motor so the distributor will turn clockwise.

Just some thoughts:

With the cap off, the rotor will point a little before the mark on the distributor - not dead on. By before I mean it will point a little to the left of the faint mark on the distributor.

Whenever I've mixed up a plug wire or two I get a good "pow!" (backfire) or two. I assume you aren't getting that behavior.

I wonder if it would possible to have the distributor a couple of teeth off enough that with the plug wires backwards the rotor would sort of straddle #1 and # 5?

I've had an electronic fuel injector stop working after sitting around after coming back from being "cleaned and flow matched".

If you pull a spark plug it will smell like gas if the cylinder is getting gas but not igniting it.

-Chris

[kühn tune]

Thanks again everyone. The rotor definately turns clockwise, I have watched it a million times now. I will pay closer attention to the rotor position, but if anything, I believe it would be between 1&6, not 1&5. I will certainly take a look tonight.


ChrisBennet
If you pull a spark plug it will smell like gas if the cylinder is getting gas but not igniting it.

That was one of my first questions. The plugs do not smell strongly of gas, but I wasn't sure if there would be enough gas coming from the injectors at startup to make that happen.

That's worrisome, I finally got to the point where I was ready to accept that this was something mechanical that I screwed up.

Anyone have an Idea what kind of signal I should look for coming from the injector harness and if it could be tested with a multimeter? I wonder if I could get enough out of the wiring diagram to check the harness.

Is the dme relay something that is "on" or "off" or could it have separate paths for Fuel and Ignition?

Could someone please confirm that my dial indicator readings are correct?

Bonus picture of plugs;

[afterburn 549]

poor a little FRESH!! <<< FRESH!! <<< FRESH !!! gas in and crank it...should make noise like wants to run

[Henry Schmidt]

A quick thought on your problem.

After sitting for so long, it would not be uncommon for some or all of the injectors to stick in the closed position.

The injector operate on lower than 12 v I believe 8 v .

Sending the injectors out to be cleaned would not be a bad idea.

We have have some luck freeing up the injectors by putting 12 v into the injector while the engine is running. It will be hard to run the engine on 2 cylinders but if it will run , it's worth a try. If the fuel pump runs and you open the injector you will fill the engine with gas.

There is also a ground that hooks to the intake manifold that if misplaced can cause strange running condition.

Did you check the mark and speed sensors. The engine will run but very poorly if these sensors are reversed.
Good luck.

[ChrisBennet]

An add on to Henry's injector idea.
I've always been afraid to apply continuous voltage to an injector. I apply it briefly (fast as you can snap your fingers) in the (perhaps mistaken) belief that I'd burn out the injector's selenoid if I just left current running through it. An injector (like any selenoid/inductor) becomes a short circuit soon after the current is applied.
-Chris

[Henry Schmidt]

Good tip. Short bursts just like Chris says.

[kühn tune]

afterburn 549
poor a little FRESH!! <<< FRESH!! <<< FRESH !!! gas in and crank it...should make noise like wants to run

Very interesting, the first time it ever fired was after I pulled the # 4 injector and some gas dribbled from the rail and into the hole.

Henry Schmidt
I am definately going to try that. I would have never guessed that the injectors would freeze up, but why not. Can I assume that either terminal is safe to be ground or positive?

How would I go about finding a local place to clean the injectors?

Did you check the mark and speed sensors. The engine will run but very poorly if these sensors are reversed.

Actually, I did lose sight of these and never really figured out a way to tell them apart. I have swapped them back and forth, but it only fires is in the current configuration. I also confirmed the clearance to the flywheel and sensor.

Thanks again for all the help. I think I am really on to something now.

[afterburn 549]

2 things.- old gas will not fire, and you just proved that, or that you are not getting gas at all.1 is your fuel pump running ??

[kühn tune]

The pump runs, but never cuts off afterburn 549. I got all of the gas out of the system and tank before putting in fresh gas. The gas at the rails is not Varnished and the screens of injectors 4-6 are clean (now). Cylinder 4 injector was quite cruddy and was probably the cause of the miss I was having when I quit driving it that I thought was due to plug wires. The fuel seems to have been under good pressure when pulling the rail away from the injector for the first time so I am trusting that it is enough. Of course I can't begin to understand all that pressure and vacuum stuff going on behind the engine. I just checked the hoses and such and hope for the best.

I'd love to put one of those little fuel pressure gauges in the engine compartment like they have on drag cars, I wonder if anyone sells a kit for the motronic cars.

[afterburn 549]

I would on hook the hose after fuel filter the "bridge the pump " till your NEW fuel was coming out...then purge the injectors too.

[kühn tune]

I Did that before I ever started it. I drained the tank, put in 5 gallons of 93 octane and filled a 5 quart jug striaght off of the fuel line with the fuel pump. I am sure that the gas at the back is clean. I haven't pulled the left injectors, but there was no varnish above the screeen in the right side ones. No telling what lurks below.

I would purge the injectors if I knew how. We used to have a bench machine that would force alcohol through injectors and measure the output, but I think it was just for CIS type. I may give them call and see if I can use it.



For what it's worth, I've been adding a quart of the old smelly gas to about 2 gallons in my 1939 ford tractor without any noticeable difference in "performance".

[afterburn 549]

HMmmmmmmmm....not sure on your configuration,,,can you put a paper towel under a couple inj. and turn the engine over - see if anything comes out ??....if they are working it will be surprising little that dose, ("wet " out)..but enough to smell and see (do not expect a lot )

[kühn tune]

Well, I'll try that tomorrow night if I get time.

Tonight I set up this rig from the vast resources in the spatious Abu Grage to try to test injector #4 which is the easiest to remove (easy is relative here). (I'll clean up the picture Tuesday morning.


The clear hose was filled with an inch or two of carb cleaner and the fuel hose was plugged and plunged into the tube to provide some pressure. I hooked the leads to a battery charger and energised the injector a couple hundred times. Absolutely nothing came out of the injector. I realise that the pressure could definately be an issue, but it never even dribbled. I'll try # 1 later. The injector did get pretty warm, but I never heard it click or anything.

Thanks again to everyone for all the help. I really apreciate it, even if you just stop in to say you are stymied.

[Henry Schmidt]

That looks like an interesting attempt but I would be extremely careful with carb cleaner and the possibility of a spark.

I would hate to see a Richard Pryor replay because of something I said.

If they aren't clicking after a few short pulses then you should have them cleaned or buy new ones.

[afterburn 549]

I think as you alluded to you have to have a min pressure to get them to spray.

[jtfreels]

Where in West Tennessee are you?

Jay