hupp

I've been replacing my injectors '79 over the last couple of days and found something rather perplexing. Upon removal of the number 1 cylinder injector, I immediatly noticed that it was bent. I don't know how this could have happened, but I do know that it was not caused by the removal process. My car has been runnig rich with a slight miss since I took ownership, and I think this may have been the culprit. Other than the bent injector, other problems mainly included removing the darn things. They would not budge even after three days of soaking in WD40. I managed to strip 6 of the 8 sleeves when attempting to unscrew the injector, but thanks to the good folks at 928 Int'l I have everything I need to replace. The solution to the stripped sleeves was to remove the intake tubes and then remove sleeve/injector assemble with (and I'm grimmacing when I type this) a small pipe wrench. Imagine that, using a pipe wrench on a Porsche -- but it was effective. While tubes were off, I was able to inspect the intake bowls and was please with how clean they were - very little grime. Can't wait to get the shark back together and go for a test drive. It's so damn hard to be patient when working on the shark because it's just too much fun to drive it.

Don Carter

I've had the same problem. Were your sleaves aluminum? The aluminum gets chewed up by vise grips or channel locks, haven't tried a pipe wrench yet. I have pretty much decided to soak and clean the injectors while installed in the tubes, but I know that's not the best approach.

Pics of mine on this thread...

https://rennlist.com/forums/showthre...5&pagenumber=2

hupp

My sleeves are aluminum. Once the intake tube was removed, I placed in a vice using two pieces of wood to protect the aluminum. There is plenty of room to grab the sleeve with a small pipe wrench when the tube is out of the car. I used an approx. 1 foot piece of pipe as a breaker and loosened the sleeves with minimal effort. The socket I was using prior to removing the tubes would not budge the sleeves. I replaced the sleeves, injectors and rubber seals and used a touch of anti-seize upon reassembly.

jpitman2

When I first tried to pull mine, I bent an injector, but it was in the waisted section near the top - it was one I replaced anyway, but it wasnt hard to do, IF you try to do the 'pull-it-out-through-the-sleeve' trick. All my sleeves screwed out fine with a socket on the injector hex.
jp 83 Euro S AT 47k

Dennis Wilson

All of mine except two came out with a socket on the injector. On the two stubborn ones, I was able to get the loose with channel locks gripped at the very top so there would be less deforming. About half of the injectors were bent at the waist, but that could have happened when I pushed them out of the sleeve. Since I was replacing them anyway, I pushed them into the sleeve and used the channel locks on the outlet end to finish pulling them out with the seal.

Dennis

Carl Fausett

Check your injectors for spray pattern and volume.

http://forums.rennlist.com/upload/in...aypatterns.jpg

glenn faken

carl,
how did you set up that fuel injector pump test set that powers the fluid thru those injectors.

on another note i removed my injector covers by first pulling the injector with a slide hammer and then i took a 12pt internal wrench with a six sided size of 13mm and ground down on the sides to get to a size 11mm. i put this in the empty injector housing. used a deep socket on the shaft and was able to put some torque to it and they all broke loose. did not have to take the intake off and go to the vise. (80 euro)

Carl Fausett

Glenn -

we went lo-tech to set up our CIS injector testing real quick-like.
bought a used 928 fuel pump so I would be producing the right pressures,
(the injector test are useless unless you supply the right pressures), we mounted this fuel pump to the bench, one fuel line hose goes into a gas can, one fuel line hose gets clamped to the injector over the threads. Power for the fuel pump was supplied by a 30amp cranking unit, but you could use a battery to. We used the cranking unit cause it had a handy on/off switch and our hands were full. Beware the 3 amp trickle charger battery charger - the fuel pump will not run at rated delivery volumes or pressure... A fuel pressure gauge spliced in to the pressures side with a T fitting will give you that pressure number.

You observe 1) the shape of the cone (the spray pattern); 2) the quality of the atomization, and 3) the volume of fuel sprayed in 10 seconds.

One note on how you removed your injectors and the aluminum injector cups... I applaud your ingenuity, but I worry that the aluminum oxide from breaking those injector cups loose with the manifolds on the car fell in, behind the intake valves and are waiting to scratch your cylinder walls. Remember that aluminum, as it corrodes, turns into aluminum oxide, which is a fine abrasive and often found on commercial grade sandpapers. Thats the white, gritty crap that forms around the threads and stuff.

Suggest you make a snorkel from a hose and duct tape to your smallest vacuum attachment and get in there behind every valve that is closed. You probably have done this already. At least one intake valve will be open, though, and you are just SOL on that one.

If you coat your new injector cups with anti-seize as you install them, they will come out nicely next time.

Rich9928p

I replaced all of my CIS injectors a month ago in my track car ('79 Euro CIS). A fellow 928er with a EURO CIS engine was having injection problems, so I gave him all of my old injectors with the hope some of them might have been good.

They had them tested by a mobil injection shop, some of my old injectors would work one time, then not work a second time. It looks like when they get clogged they are very erratic. So my fellow CIS ower also had to replace all of his injectors. It really pepped up the car.

Since CIS injectors aren't as costly as the newer electrical types, I'd suggest that OB owners consider changing them if you're haveing erratic behavior. BTW, most shops clean them by just forcing a fluid through them, per Porsche's recommendations you should flow the sovent backwards (input from the spray side).

Mads

Hi

Does anybody know what the Bosch part number for the 1978 EURO CIS injectors are ?

Mads

Don Carter

Hupp, the vise/pipe wrench trick worked like a charm. Now I need to pull the other 7 tubes and injectors. Thinking about replacing all the injectors with new ones.

Made one big mistake though. Decided to play around with the buffing wheel and compounds, now the one tube I have off, has a mirror finish. No choice now but to polish the other 7, and the center peice.

T_MaX

Mads, the Porsche # is 928.110.225.00 The Bosch number is 0 437 502 012.

This injector is not 928 specific!

Check out this Google search.




That will teach yea Don!

hupp

Don Carter,

I almost made the same.... mistake and will make the mistake in the Spring when I yank the engine.

My shark is still running rich, even with the new injectors. Time to hook up the gages because I think my control pressure may be too high. Some things are better, but she is lacking is the power department. Power has not been there since I replaced the pressure control regulator or (as some may call it) the WUR.

jpitman2

Running rich is control too low, not enought back pressure on the pin moved by the air plate - or adjusted rich at the air plate screw? The injector test should note not only pattern, but pressure at which they break open (55 psi?), and that they close and dont leak at ~30psi (level held to stop vaporisation). The proper cleaning tool opens the valve at the end of the injector and back flushes the filter inside.
jp 83 Euro S AT 47k

hupp

I'm more inclined to think its a control pressure issue, I've ordered some gages so hopefully I'll know soon. I've tweaked the CO screw to both ends of the spectrum and still rich.