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Ok, I was always told the only stupid question is the one that you do not ask, Sooo. Can someone educate me on the cold start injector, and if a 90 240 DL has one, then where the heck is it located at. I'm chasing down a running rich, bad idle issue on my grandsons 240 and after eliminating all the usual suspects, I'm running out of ideas.
If I recall from my old K-Jet Audi, the cold start injector looks like an extra fuel injector so you should see something with fuel line that's not quite the same as the regular injectors. With that said, cold start issues can be caused by leaky injectors or bad injector seals so that may be something to look into. There are shops that will clean/test injectors - just google around. You can also test the temp sensor etc as well.
The cold start injector is underneath the intake manifold and screws into the intake manifold. My '90 240 had one but it was around that time frame that they disappeared.
When I first purchased my '90 with 180k miles on it I had trouble with a rich running condition. I chased all of the usual suspects but I finally found that it was due to a crack in my downpipe where the "Y" is welded. Any exhaust leaks upstream of the oxygen sensor allow fresh air into the exhaust stream. This is detected by the oxygen sensor and the computer reads this as a lean condition and enriches the fuel mixture. If you have a verified working oxygen sensor then check for exhaust leaks upstream. I use a plastic hose as a stethoscope and check all joints/connections for leaks. Be careful not to burn yourself.
If you have a 5th injector - it's visible on top of the manifold (#45)- And is fed with a hose from the fuel rail - I have seen them leak when supposed to be closed - easy to test - pressurize the fuel system and see if it drips.
(#49 is a blanking plate for cars that don't have a cold start injector)
If you have a 5th injector - it's visible on top of the manifold (#45)- And is fed with a hose from the fuel rail - I have seen them leak when supposed to be closed - easy to test - pressurize the fuel system and see if it drips.
(#49 is a blanking plate for cars that don't have a cold start injector)
Thanks Hoonk,
Is there a way to easily disable the fuel flow to the injector? I can unplug it electrically, but I am wondering if it is possibly stuck open and injecting un-needed extra fuel into the intake causing a rich condition.
How would you verify a leak with the hose? Would you hear a hissing sound as pressurized exhaust gas escapes, or would you hear a sucking type sound as fresh air is puled into the damaged area?
When using the hose as a stethoscope you will hear engine noise when listening. As you get close to a leak the noise will be louder. You'll find it to be obvious when you find a leak.
If your cold start injector is leaking when inactive then it will likewise leak when disconnected.
Ok, instead of electrically disconnecting the cold start injector (since that plug on mine look like a beeyotch to remove) I would prefer to disconnect fuel to it. Now from what I see, the easiest way would be to disconnect the fuel line that screws into the fuel rail. However, if I do that I would need to cap the port where the fuel line was connected. Now for the $64,000 question.....has anyone capped the port at the fuel rail, and if so, what type of cap did you use (i.e. thread size, type, etc) a part number or link to buy a proper cap would be golden.....
Just pull the cold start injector out - put a cork or stopper in the hole - start the engine and see if the cold start injector leaks. Or simply pressurize the fuel system with the injector out and see if it's dripping.
Stupid question?
