No idle - '74 2.0l FI Options

[detoxcowboy]

74 2.0 does not use the "missing" advance vac line.. there is only one port on the throttle body as well.. good eyes though.

[underthetire]

Now how do you remove and replace? Do I need to take the intake runner off?

It is not hard but be very carefull not to cross thread it when putting it back in!!

Passenger side between the two cylinders there is a loan wire coming out from the tin!

You need to make a tool out of a socket extension by putting a notch in one edge of the extension so the wire can feed through and out the top! I will see if I can find mine and take a photo!

Sorry, I couldn't find my notched extension!!

Soak with PB Blaster or Kroil first ! You can pull the threads out of the head real easy !
and just one more ! ! ! (IMG:style_emoticons/default/biggrin.gif)

[Spoke]

I took the car out for a quick drive and didn't have any issues except when I stopped.

It would seem that if the CHT sender was bad that it would affect the running of the engine at all RPMs, not just idle. I believe the CHT sets the pulse width of the injectors throughout the entire RPM range. If the CHT sender was truly zero ohms, the car shouldn't run.

[detoxcowboy]

From the link I posted further up this post..


The longer I drive, and the hotter the engine gets, the more the idle drops until it wants to stall (fully warmed-up)

Rich idle mixture: This seems to be fairly common on 914's where the idle mixture is set "by ear". When you have carburetors, you learn to set idle mixture by looking for the setting where you get the highest engine speed with closed throttle. This doesn't work for D-Jetronic cars! Set your idle CO to spec by having a shop use a quality CO meter. Trust me on this one, I chased this condition for at least 5+ years!! Note that when I say "rich", I'm talking about idle mixtures of 5% CO or greater. I've seen as much as 8%

and...

Engine bogs from idle (poor idle to part-load transition), or idle drops down well below 1000 rpm after the car is fully warmed up or is hot from running hard

Idle mixture too rich
Retarded timing
Check that timing is set to spec. Set the CO level to factory specs by using a quality gas analyzer. If a gas analyzer is not available, use the "trial-and-error" method of adjusting the ECU knob one click counter-clockwise at a time, re-adjust the air bleed screw to set the idle and repeat if necessary. Usually, if the idle is too rich, the idle speed is very responsive to adjustments to the air bleed screw.

and..



Cold resistance of the cylinder head temperature sensor is too low.
This problem seems to get worse on older cars as the engine wears. There are a couple of solutions. You can "cherry pick" a cylinder head temperature sensor with the highest value you can find, or you can add ballast resistance to the sensor - however,
and...

"My car runs rich and I don't know why!!"

Cylinder Head Temperature Sensor - open in either the sensor or in the wiring harness or connector, failed sensor (stuck at high resistance value), wrong sensor for application.

[detoxcowboy]

I took the car out for a quick drive and didn't have any issues except when I stopped.

It would seem that if the CHT sender was bad that it would affect the running of the engine at all RPMs, not just idle. I believe the CHT sets the pulse width of the injectors throughout the entire RPM range. If the CHT sender was truly zero ohms, the car shouldn't run.

depends how its reading and or failing... he only tested cold and stated it was 1.. 1k? 1ohm?..

[brenz]

Now how do you remove and replace? Do I need to take the intake runner off?

It is not hard but be very carefull not to cross thread it when putting it back in!!

Passenger side between the two cylinders there is a loan wire coming out from the tin!

You need to make a tool out of a socket extension by putting a notch in one edge of the extension so the wire can feed through and out the top! I will see if I can find mine and take a photo!

Sorry, I couldn't find my notched extension!!

If/when you do replace the CHT you can use a 13mm long socket. Cut the wire off the old one so you can get a good seat so the threads don't get stripped on the way out.

The new ones from PP have short wires. Stuff the wire into the 13mm long socket. It will stay in pretty well. Another tip is to use a drop of super glue on the washer to adhere it to the CHT. Then line it up with the threads the best you can and gently thread it in until you feel it catch. Might want to use just a little anti-seize thread lube too.

[watsonrx13]

OK guys the engine started right up and is now idling.... and the problem was.....




















































CHT

I picked up a new CHT this afternoon and installed it using the shaved extension suggestion. Before I installed it I checked the resistance, it was 2.35k. I checked the old one and it never registered anything but 1 on any of the scales on my multi-meter. The price on the CHT was $21.00. If anyone has any issues with their FI engine running, cold, hot or whatever, replace the CHT.

Thanks to everyone that gave me guidance to this problem.

BTW I did some internet surfing and found this link for D-Jetronic:
http://w107.pbworks.com/f/DJetronic.pdf

Now I can break in the engine properly and drive it like I stole it... (IMG:style_emoticons/default/driving.gif)

Detox, thanks for the suggestion to have a shop check the CO and timing. After I get the engine broke in and some money saved I'm going to contact Bowlsby to replace the wiring harness.

-- Rob

[Jeffs9146]

(IMG:style_emoticons/default/first.gif) (IMG:style_emoticons/default/first.gif) (IMG:style_emoticons/default/first.gif) (IMG:style_emoticons/default/first.gif)

I win!! (IMG:style_emoticons/default/beerchug.gif)

[detoxcowboy]

(IMG:style_emoticons/default/pain30.gif) done, It's over! Congrats! CHT delightfull (IMG:style_emoticons/default/biggrin.gif) !