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Posted by: porsche913b_sp Aug 16 2011, 10:41 AM

Could someone please tell me where the ballast resistor for the cylnder head temp sensor is located. I am not sure if my friends car has it or not.
Is it inline with the CHT sensor ? Pictues of the resistor would be fantastic !!

Trying to help my friend's 73 2.0L with surging after warmed up to 230F. His TPS contacts are clean. Only occurs above 230F. Any clues ?


As always.
Thank you

Posted by: Philip W. Aug 16 2011, 10:46 AM

check the A.A.R.- ( d-jet?) i had the same thing and placed an in-line resistor on that circuit- used a variable pot. to change the idle mix which helped richen the idle mix but- the real problem was the AAR not closing down when system was warm, works like giant vac leak and you'll get this surge when hot---

phil

Posted by: Dave_Darling Aug 16 2011, 12:02 PM

Putting a resistor in line with the AAR doesn't make sense. It would just drop the current going through the heating coil in the AAR, making it take longer to close. I guess that could be useful...

The CHT resistor is found in line with the CHT sender. Just follow the wire out from the engine tin near the #3 spark plug. If it goes to a plastic box connector, then into the wiring harness, there is no resistor. If it goes to a box connector, then a short piece of wire with a big lump in it, then another box connector, that lump is the resistor. It will be very close to the CHT sender itself; none of the wires is very long.

--DD

Posted by: orange914 Aug 16 2011, 12:27 PM

The resister is connected to the CHT inline with the wire

The CHT resister was only on the 73' 1.7's (to help the one year only "universal"- 2.0 or 1.7 ECU work W/ 1.7)

NOTE: unless my brain is working in reverse today, the resister effects the idle/low rpm mix. I was saving a nice (unobtainium ) O.E.M. resister in case I needed it when I converted to a 2056. I still have it if your interested, P.M. me.

Posted by: Jeff Bowlsby Aug 16 2011, 01:16 PM

Attached image(s)

Posted by: porsche913b_sp Aug 16 2011, 01:26 PM

Thank You Jeff !!

Posted by: porsche913b_sp Aug 16 2011, 01:31 PM

Yes D-jet, Thanks Dr Phil, I will certainlt look into that.