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wombat · Posted: Sun Jul 26, 2009 5:02 pm Post subject: Injector cleaning

I have been having a few running problems of late (the last week or so) and I decided to check the system for spark and fuel delivery to see if I could clear some of them up a little. What I found supprise me a little as the injectors were quite blocked one had a spray pattern that looked like a jet rather than a cone and one was almost totally blocked delivering only a tiny ammount of fuel. So I have decided to clean them. As I have access to a sonic water bath I have decided to use this to see if I can get them better before I send them any where does anyone have any suggestions about doing this? chem to use? etc etc? Thanks

The wombat
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1977 924 2.0 Auto

wombat · Posted: Sun Jul 26, 2009 7:43 pm Post subject:

Oh I have another question while I am here. I thought that I would also replace the fuel lines from the fuel distributor to the injectors as mine are looking a little dull and I have some braided hose the correct size and banjos to fit also. The banjos came from an early BMW running a bosch system. On the BMW there were just plain jane rubber hoses connected to the banjos without any clamps. On the 924 the lines are braided and they have a cover over the connection. what is the best way to connect the banjos to the hose?? Can I get the covers like the originals?
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1977 924 2.0 Auto

tux · Joined: 02 Jul 2006 Posts: 133 Location: Nottingham UK

I just used meths when I dropped mine in the bath. Maybe not the best chemical, but you wouldn't believe the gunk that came out of them!

Not sure what is best for connecting the banjo's but bear in mind they run at quite a high pressure.
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Pete
Merlin Guards Red 1985 N/A

weekend_warrior · Joined: 14 Jul 2009 Posts: 42 Location: Hayden, Idaho

Initially I'll use some diesel fuel, followed by some acetone. Works wonders. I think it;'s a good idea to replace those braided fuel lines, too-- they always fray and stick me in the arm while I'm tinkering on the engine.

stevekat · Joined: 19 Jan 2008 Posts: 719 Location: Los Angeles, CA

I used this service for testing and cleaning my injectors. SD over there was able to clean and save two of my injectors. The other two were out of range. You do not only want a good pattern, but also a similar opening pressure and flow rate. The cost was quite reasonable and there clearly was a lot of care and thoroughness put into the process.

http://www.jaguarfuelinjectorservice.com/
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"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."

Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's.

wombat · Posted: Mon Jul 27, 2009 9:21 pm Post subject:

I have just realised something with this fuel hose replacement, The original Braided hose nylon or something so there is no give in it I am guessing if I use a standard braided hose that has more give in it it will stuff with the fuel pressure causing problems out the injector (well I am sort of not guessing I made one up and the injector on that hose has a very little spray and when I change the injectors the same thing happens regardless of injector used so I am guessing it is the hose) anyone know the exact type of hose I need??
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1977 924 2.0 Auto

D Hook · Joined: 02 Nov 2002 Posts: 3158 Location: Omaha, NE

They still sell the individual injector lines new at Performance Products in the states. But they're pricey, around $35 each and up, IIRC.
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'80 924 n/a SOLD

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

I use throttlebody or carb cleaner (contains methylene chloride) to clean mine. Spray the cleaner into the inlet side until it is full (use eye protection) then blow it through with 60 psi of compressed air. It may take two or three applications to get a good spray pattern. Plain soaking doesn't reach all the components for a thorough cleaning.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

wombat · Posted: Tue Jul 28, 2009 4:07 pm Post subject:

wombat · Posted: Wed Jul 29, 2009 3:24 am Post subject:

Thanks alot guys, I used the sonic (sonicating) water bath, and a method that combined all of your products.

first I soaked them in diesel for a few hours (no sonic action just a soak) then sprayed in the inlet end with carb cleaner and put them in the sonicating water bath upright (standing up the way they would go into the engine) for 5 min on 50hz, 5 min on 60hz and 5 min on 80hz. Then I took them out and sprayed some more carby cleaner in the inlet end filled the bath with metho and gave them 30 min on 60hz but this time on there sides (laying down) and then once again upright after having more carb cleaner sprayed in the inlet end this time in hot water with a little soapy stuff for 10 min on 50hz. The spray patterns look great compared to what they did.

I will now flow test them (sort of) I have a very accurate measuring cylinder I brought home so I was thinking of just using a single line form the fuel distributor for the test to elliminate differences caused by anything other than the injectors. Then meatering fuel from them for a set amount of time. maybe even rigging up something to cut power after a set time??

If they are close I will just live with them but if they are not then i may need to look at some new ones.

just had an idea on the line also will brake line work, my dad has a roll of braided brake line from his track car, I could steal some, and he told me that the original clamping method is called a crimp collar and you can either get it done by someone cheap or buy a crimping tool?? any ideas on the brake line or crimping collars??
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1977 924 2.0 Auto

flames · Joined: 28 May 2007 Posts: 88 Location: Perth Australia

Just a note to keep in mind, When I was having big problems with irregular patterns from my injectors it turned out ot be a fuel supply issue. The flex hose out of the tank had broken down inside and was collapsing on itself. The pressure at the injectors tested fine at a low flow rate, it only showed up when I decided to pull the fuel pump out and fuel only dribbled from the hose.

The spray pattern from 2 injectors was fine and the other 2 were all over the place, appeared to be dirty injectors but wasn't.
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'78 924
Carrera? Body Kit
Bright Yellow

wombat · Posted: Fri Jul 31, 2009 1:24 am Post subject:

El Chato · Joined: 22 Aug 2006 Posts: 205 Location: El Paso, TX

true its best to clean the whole system, I opened the the Fuel dizzy, and cleaned all the rust from inside and cleaned it after and the sonic, then reasemble with a couple new orings that fitted, still need to test it,

as for the injectors, I put them in the sonic cleaner, then I pulled the opening a little and then place a small wire, like 0.5 mm to keep it open and then place a hose from a fuel pump, and pumped gasoline and fuel injector ccleaner plenty and back flushed the debris,

on the other had I took out the little filters that go before the banjo bolds to the fuel lines in the distributors, anyone knwo where to get new ones?
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1979 924 N/A, Snail Shell
1980 924 N/A
1976 924 N/A

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