924Board.org

[Johnny_Haywire]

I was finally able to loosen the compression fittings from the fuel lines to the injectors and am planning to clean the injectors, test them, and adjust the fuel metering. I also have an injector seal kit, so I'll be changing those, as well.

However, I'm not sure what is the best way to lift the lines and injectors enough to get them into jars for testing/adjusting. Do you just loosen the hold-down clamps with the little nuts and bolts. I see that one is just on a bracket to a valve cover bolt, so that should be simple enough, but what about the rest of them?

Thanks in advance, guys.
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1981 924 N/A 5-speed

[ideola]

Yes, if you loosen / remove all those little brackets (carefully!), the nitrile flex portion of the fuel lines should give you enough slack to maneuver the injectors into the glass jars. Just be careful not to bend / crimp the nitrile lines. Don't worry too much about the outer rubber sleeves, it's probably crumbly, and will fall off in places. I've not found a good solution for replacing that stuff.
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erstwhile owner of just about every 924 variant ever made

[Johnny_Haywire]

Thanks for the quick reply, Dan. I think mine are steel and not nitrile from the distributor to the injectors. Here's a pic.


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1981 924 N/A 5-speed

[ideola]

[Johnny_Haywire]

Thanks, Dan. This is exactly what I needed to know. I'll be sure to update with my test results!
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1981 924 N/A 5-speed

[ideola]

If you have an NA, your engine bay should look roughly like this:


The black lines that curve around the bleeder hose right smack in the center of the photo are flexible nitrile with an outer rubber protective sleeve. The nitrile connects the hardlines at the fuel distributor to the hardlines at the injectors.

From my photo above, it appears that there should be three brackets to loosen, two connected to the head, and one connected to the upper radiator hard pipe / expansion tank bracket (IIRC).
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erstwhile owner of just about every 924 variant ever made

[Johnny_Haywire]

I've got all three of the brackets loosened and ready to roll. I'm going to try to do the test/cleaning after dinner tonight. Assuming I can get the injectors out gently enough, when I lube them up after replacing the seals, I'm supposed to not use a petroleum based lubricant when popping them back in, right?

Thanks again and in advance for all the wisdom!
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1981 924 N/A 5-speed

[Johnny_Haywire]

A quick update before I hit the sack...

Made some progress tonight. The injectors came out pretty easily once disconnected from the fuel lines, though prying them out was a real pain. I ended up just clamping some vice-grips gently to the hex portion and pulling on them.

The outside and tips were pretty filthy and covered in oil, but when spraying the insides with carb cleaner and using the "tap-tap" method, nothing was really coming out in terms of particles. I gave them each several blasts, though.

Then it came time to test them. I disconnected the battery, hooked up my fuel pump relay jumpers (which are wired to a switch), put the injectors in small jars, reconnected the battery, and fired up the pump. I pushed the air metering flap and away they squealed, pumping more into the jars than I would have expected in such a short period of time.

The fuel was clean and the volume in each was just about the same. Here's a pic of the results of the first test.



The second test was even closer to identical.

Here's a video of the injectors during the test:

[IMG]http://i176.photobucket.com/albums/w162/pgrens/1981%20Porsche%20924/th_injector%20test.mp4[/IMG]

When it came time to change the seals, well, the kit I got from Pelican Parts seems like it's for a 944 or something. There only appears to be one seal on my injectors, and it's not close to any of the things in this bag they sent me. While it looks like an o-ring at a glance, the seal around the injector seems like it's on a metal ring, and not just an o-ring. Someone please correct me if I'm wrong. I just didn't want to ruin the existing seals getting them off to find that the stuff in this bag wouldn't work:



So back in the injectors went with their old seals.

I did not adjust the fuel metering as the injectors started firing just as the flap moved up.

I put it all back together and fired her up. At first, she ran like usual, very sluggish to start, with a bit of lag in the response from the accelerator/throttle body, idling kind of lumpy at around 850 RPM. After a few minutes, I gave her a few revs and something changed, the idle went up to around 1,100 and she was much smoother, though she seemed to be hunting a little bit. After a few more minutes, she smoothed out, right around 1,000 RPM and finally the revs were responsive, though with a few blips here and there.

I should note that I found a cracked hose when taking apart the intake boots. The crack was at the end of the hose that runs from the lower crank case (back near the bell housing) forward and up to the bottom of the plastic tube between the rubber TB boot and the rubber fuel distributor boot. It was cracking just below the clamp area, so I put some electrical tape on it for now, it was just too tight to chop a couple inches off the end. That will definitely need to be replaced, though.

At any rate, I'm really pleased with how she is running now. So much better than before, so perhaps the injector cleaning did help it out. Probably blocking the crack in the hose helped, too. Definitely wasn't immediate after start up, though.

The cooling fan went on eventually, as well, though the temp gauge is definitely not working on the dash. Glad the fan is working, but I'm curious about the gauge not reading. Ah, well, another battle for another day.

Thanks again to everyone for all their help. I'm definitely one step closer to getting her on the road!
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1981 924 N/A 5-speed

[ideola]

The seal on the CIS injector is definitely an O-ring. They get really hard with age and can be difficult to remove. Replacements are typically green in color, not black. Not sure why that kit is showing up as for the 2.0L car as it appears to be a kit for the electronic fuel injectors in the 2.5L cars. The only part you need is 999.701.423.40, which are about $0.50 each. It's possible the black o-rings in that kit will work, but the rest of the parts are superfluous.

Temp gauge not working could be a fault in the wiring to the temp sender, which screws into the rear water flange at the back of the head. It is a single spade terminal type sender. It's possible the female spade terminal on the wire itself has come off of the sender, or it's possible that there's a break or fault in the wire there, as the wire will often get hard and brittle and break. I would check there first, as it's the most likely fault. The other possibility is bad ground to the gauge cluster, but if the other indicators in the multi-indicator gauge are working, it's unlikely to be as simple as a ground.

Have you drained the tank? You might consider removing the in-tank pump, removing all the gas into a gerry can, and doing the best you can to remove any sludge or particles in the tank. Use an air compressor to carefully blow any debris off of the tiny "fins" at the suction end of the in-tank pump. Replace the seal and reinstall the pump. Before you refill the fuel tank, pour in a full bottle of Techron fuel system cleaner (for 20 gallons). Put in about a quarter tank of gas and run the car as much as you can. I wouldn't hesitate to run 2 or 3 bottles of techron. It will clean up fuel lines, the WUR, and the fuel distributor where you can't really do it by hand.

The hose you are describing sounds like the main breather hose from the crankcase to the airbox. Be aware that there should be a restrictor in that hose. If you remove it and replace it, you will want to extract the restrictor and make sure you get it into the new hose. The OEM hose is NLA, so you will need to get some generic heater hose or silicone hose in the correct I.D., install the restrictor and cut enough length the the hose can bend enough to connect to the airbox without kinking.
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erstwhile owner of just about every 924 variant ever made

[Johnny_Haywire]

Thanks again, Dan.

I have just written Pelican Parts so that they'll send me the proper seal kit. Taking them out a second time should go much quicker now that I know my way around it. My seals are definitely hardened, then, as they seem to rotate around the injector as though they had a metal race behind them.

The wire for the sender at the back of the block is disconnected - thanks for reminding me about that. When i bought the car last year, the seller had mentioned that it was not connected because he couldn't get his hand back there to reconnect it. I'm thinking i can figure out a way to do it

The tank has been drained and was pretty clean. I'm about to change the fuel filter for the second time since initial start-up about 3 weeks ago, as it probably has collected whatever debris that has been stirred up since then. I've got a lot of Techron in the tank right now and have another bottle for when I add more fuel.

I'm thinking I probably have some vacuum leaks as I have not gotten to replacing all those hoses yet.

Thanks also for the info on that hose - it is indeed the one you mentioned. Good to know that there is a restrictor in it. I think I am going to try to splice some hose toward the end of it for now if I can find a coupler. I'll definitely be mindful of the restrictor when doing so.
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1981 924 N/A 5-speed

[Johnny_Haywire]

I fired her up again this afternoon and it was the same as yesterday, sputtering and died twice before settling into an idle around 1000 RPM. At that point, a bit of a delay/lag in throttle response when the TB butterfly is opened. Once it warmed up, the response is good and rev-up is also smooth.

Perhaps the warm-up regulator is dirty or not working?

I found the coolant temp sensor connectors between the firewall and the head, and there is an empty connector there. Looks like two wires run down from it (those seem to be connected), but I don't see the missing wire that should be plugged into the sensor.

I'm going to look under the car tomorrow, hopefully I can find that wire flopping around. Also going to try to do the timing belt/tensioner/water pump and alt belt. Wish me luck...
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1981 924 N/A 5-speed

[dubrict]

Not to derail, but when did injectors go to screw-top style? My '79 and '77 have banjo connections
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1979 924 NA
2009 Chevy Impala
2005 Dodge Dakota

[ideola]

[kuhdad17]

beck arnley makes a replacement seal... Like 1.69 a piece at your local parts store. I bought the kit as well and it was wrong so I returned it. If you need a part number let me know
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'78 924 N/A

[kuhdad17]

By the way, I'm in the process of timing belt v belt water pump thermostat (subsequently housing) replacement. My first suggestion is love yourself some pb blaster on all bolts. I snapped the housing bolt on the neck piece off. You can find replacement housings for $20 or so, but then you're waiting on parts.
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'78 924 N/A