I absolutely flat out give up. - Page 4

thrown_hammer · 09-26-2002, 03:02 AM

I don't know what the insulators are but, the o-ring seals and injectors are new.
It has vacuum assist. I will try that when I get a chance.

SeaDweller · 09-26-2002, 05:07 AM

The injectors themselves have an "O" ring that seals them in the insulator. The insulator is an orange (usually), plastic-like "thing" that looks sorta like an upside down hat like the band Devo wore. It slips in the injector intake port, and also has its own "O" ring to seal it. The "O" rings on the insulators get hard and flattened over time, opening the system up to a vacuum leak.

You have to be VERY careful taking these out, because old ones will be brittle, and break apart. the bottom edge is very thin!! When I replaced my injectors, I replaced all the insulators and "O" rings as well, but I had my intake assembly off the car which made it much easier. You can pull an injector, and you'll see the insulator. If you can easily wiggle the insulator, then the "O" rings are bad and you likely have a vacuum leak. Whether this would cure your problem or not, I can't say, but it's one of those little improvements that typically provides a more finely tuned engine.

thrown_hammer · 09-26-2002, 05:11 AM

Very good suggestion! I will look into that tonight.

SeaDweller · 09-26-2002, 05:13 AM

By the way, the insulators are installed/held in place by using a punch, and creating a little dimple on the intake port edge. Typically, you have to remove that dimple to get them out.

thrown_hammer · 09-27-2002, 03:13 AM

Seadweller,
I went out last night and wiggled the insulators. They all moved around like there was no o-ring. So being the cheap a$$ that I am and not having time to grind and pull them out to refresh the o-rings, I gooped in some silicone sealent around the base of the injectors and let it dry overnight. This morning I drove the car to work. It has improved greatly. It still has a slight sputter, but will pull clear to redline in one and two. I will try out third tonight, there aren't any 90MPH stretchs in town.

My fingers are crossed and I am off to price o-rings and insulators.

thrown_hammer · 09-27-2002, 03:17 AM

This part is called a "sleeve". Is this what I am looking for?

SeaDweller · 09-27-2002, 10:21 AM

Yep, that's the one! It's even orange in the picture!!!

I can't stress enough to be careful when you remove these things. It's not likely that a small piece of plastic will kill the engine, but I'd still tread with caution!!!

Did you pull the injector, and then wiggle the "sleeve" itself, or did you wiggle the injector while it was in the "sleeve"?

john70t · 09-27-2002, 10:36 AM

Good call on checking the injector o-rings, they are definitly a commonly ignored maintenance item, but wouldn't a vacuum leak show up mostly around idle rpms where precise fuel metering is most necessary?

thrown_hammer · 09-27-2002, 11:19 AM

I wiggled the sleeve. I am going to open it up a little after work. It is improved. Of course the car wasn't warmed up and it was cold and damp. I plan to warm it up properly before my run this afternoon.

Rot 911 · 09-27-2002, 11:23 AM

Shawn, I've been following this thread since it's inception. I'm keeping my fingers crossed for you!

thrown_hammer · 09-27-2002, 11:34 AM

Kurt,
Thanks. I am trying not to get all excited. Been there done that.

It just isn't right for a car that looks like mine to fall on its face when you hammer it.

CamB · CamB's Garage

Shawn

Just thinking about a problem I had on the BMW.

How do you check the dwell? Using a dwell meter?

Can you try checking the dwell at idle and at 4000 (or even 6000 if it will get there) rpm. It shouldn't change.

If the BMW is set to the correct dwell at 1000rpm, the dwell changes by 5 deg per 1000rpm and the dwell is in the 80s by 5000 and it just wouldn't rev any further). I have to set the dwell about 10 deg "low" at idle, just to make 6500rpm. This isn't supposed to happen! My distributor is worn.

Remember a 911 is six cylinder so my 90 deg (4 per 360 deg) is your 60 deg (6 per 360).

thrown_hammer · 09-30-2002, 03:31 AM

This weekend I messed with the car alot. Since I can't find the "flow#'s" anywhere it wouldn't do me much good to check the flow.

I drove the car all warmed up on a beautiful day. At half throttle clear to redline, no sweat. At full throttle around 4-5000 RPM sputterville. After a few passes I pulled over and disconnected the Vacuum line on the dizzy. Tried again, ran exactly the same. So I went home and pulled the distributor cap and checked the vacuum advance. It moves freely and has plenty of grease. So then I held my thumb over the line itself and cracked the throttle and it pulls vacuum.
I am taking the car to a mech in Fort Wayne. I hear he is good. I will let you guys know how it all unfolds.
If Wayne ever writes a book about troubleshooting a CIS car may he use this thread as inspiration!

SeaDweller · 09-30-2002, 04:41 AM

Injector leaks do manifest themselves at idle, but I believe they could also cause a severely lean mixture at high RPM, which is a can of worms in and of itself......

subdewd · subdewd's Garage

I forgot, but did you check the advance with a light w/engine
on? Check the advance diaphram an the linkage that
connnects to the dist. plate

thrown_hammer · 10-07-2002, 03:03 PM

Tonight I checked the fuel pump flow. The spec per the Porsche tech manual says 750cc/30seconds minimum. 750cc is approx. a large baby food jar. I filled the jar in about 5 seconds using the line from the pump to the accumulator.
Does this rule out a weak pump? I think it does...but I think alot.

So should my next step be the Fuel distributor? Please advise.
I will change out the fuel filter first. Then I will dig into the fuel distributor unless anyone has a better idea.
Which is the reason I am here, for better ideas.

RoninLB · 10-07-2002, 04:48 PM

Shawn..the scene your going thru is f---ed up..man, I don't remember everything that you have done so far , so excuse me if I'm wasting your time now..but it does seem like electrical to me, some what.. because a fuel dist to me is a mechanical device..it either works or it doesn't [not an expert].. so tell me that you did a ohms check on plug wires including the shake test with the VOM connected to the Beru connectors only..in other words connect the VOM and while connected shake and slightly tap the Beru connector and see if the ohms change...I hate those connectors..I don't even trust relatively new ones..and if that's your problem thank our head electrics instructor, not me........Ron

CamB · CamB's Garage

Check the timing, please. Both specs.

Only takes a minute. If you don't have a timing light this is the perfect chance to get one (you need one).

autobonrun · autobonrun's Garage

just to see what could have been missed. All excellent suggestions and I'm also at a loss and can only think of one thing.

One statement you made bothers me.

"When I replaced the coil with a Pertronix flamethrower the car ran great for about a week, then it slowly headed back to sputterville. I have also recently pulled the plugs and they look textbook. When it is cool out(like in the morning) it sputters less. When it is hot out it almost dies when I floor it above 4000".

I keep asking myself why would the problem go away at all then stay away for a week. My, and I'm sure your first thought would have been the problem was the coil. Instead, I'm thinking the problem was in something you moved or shifted while replacing the coil and that over that week, something moved back to where it was before you made the replacement. What comes to mind are 1) a ground connection and 2) the plug wires.

I know you said you checked the connectors but did you check the insulation on the wires. One thing that leads me in this direction is you say the problem is temperature dependent. Resistance of a wire goes up as temperature goes up, so at high temps and high revs (eg. higher current) it will pick a path of less resistance; eg. through the insulator to the engine frame.

Try checking at night to see if you see any spark from the spark plug wire insulation. Also, wherever the plug wires cross near or touch the engine, wrap a piece of rubber insulation around them. Secure it and see if the problem goes away. If so, you have cracked insulation on your plug wires. I'd try this even if they are new since there could be a cut or manufacturing defect.

Good luck, we're pulling for you to fix this.

thrown_hammer · 03:04 AM

Okay,
I will recheck the timing this weekend and play with the sparkplug wires. I don't have VOM but I can get one. ( I assume VOM is voltmeter?)
If it wasn't for you guys this car would of been sitting in the yard with a sign in the window a month ago.