Okay codycool55 ... I have a little time today for a little more thorough advice / explanations. …
I decided to go ahead and replace the OVP... to very little if any improvement ...
I have no doubt that you‘d better say “to no improvement“
instead of “to very little if any improvement“
As I said in post 21: “Nothing you reported so far indicates a problem with your OVP“
Call me old-fashioned … but I don‘t like replacing parts that are still good … and trust me, the OVP is one of the most often unnecessarily replaced parts on cars equipped with KE-Jetronic. …
... In the ignition on position, pin 3 to pin 2 read a voltage of 1.84. Pin 6 to pin 2 measured a voltage of 12.14. The quotient is .1515
When I saw your location (Eastern Washington state) I didn‘t bother about asking you if your car was originally registered in California. Maybe I should have, because in that case the quotient of your two voltage measurements would be spot on
… which is a good sign for the ECU (although that alone would not prove there‘s nothing wrong with it).
... The green wire on the 02 sensor fluctuated between roughly .46 and .49 volt. It should be at about .45 correct? So the engine is running slightly rich? ...
o2 sensor voltage of 450 mV stands for the optimal (better: optimal compromise regarding) air/fuel mixture (Lambda = 1, air/fuel mass ratio ~ 14.7:1 in case of non-ethanol fuel). A healthy o2 sensor (at its operating temperature) should fluctuate with at least +/- 350 mV around 450 mV, hence between 100 mV and 800 mV, at a frequency of about 0.5 Hz with the engine running at idle.
I explained that in more detail in the link mentioned in post 15.
With the non-fluctuating X11 pin 3 & 2 voltage of 14+ volts you reported in post 14 ... you should see a non-fluctuating
o2 sensor voltage of at least 800 mV
(on the green wire with the o2 sensor connector connected
, the hot
and ECU and EHA connected
The fact that you see less than 500 mV, indicates a problem with the o2 sensor
, the ECU
, or the EHA
There‘s a number of very informative tests, which can not be found in any service manual (at least not as far as I've seen) and which to describe all would by far exceed the maximum number of characters in one post. That‘s why I only suggest one simple test for now (might even be enough in this case already):
Check the o2 sensor voltage on the female part of the disconnected
o2 sensor connector while the hot
engine is running at idle
, with the ECU connected
- EHA connected
- EHA connected and male part of the o2 sensor connected to ground (with a wire)
- EHA disconnected
- EHA disconnected and engine speed risen to 2000 - 3000 RPM
In post 7 you said that lately you've been needing to replace spark plugs excessively frequently as they are becoming fouled to the point where the car will not start. … As I said above, your o2 sensor should provide at least .8 volt with the 0% duty cycle you reported in post 14. Maybe it's not providing voltage higher than .49 volt, because it can't, because it is fouled too
! … Can happen by (already mentioned) extremely rich mixture, or by burning too much oil !
So, let‘s first check your o2 sensor with the above tests, before we come back to your “extremely rich mixture“ indicating voltage measurements at X11 pin 3 & 2 ... and before we touch the adjustment screw!
... In addition, while doing these tests with the key the ignition on position I noticed an intermittent quiet clicking /fluttering sound coming from the vicinity of the fuel distributor. I initially thought it was the EHA, but after unplugging it the sound persisted. Any idea on this?
The first thing I suggest to check in this case is the carpet in the footwell (if there is any). Your gas pedal might not be completely released and the throttle linkage moved to the point where the throttle linkage‘s micro switch switches. ...
With the gas pedal completely released, it should be switched to continuity. When the gas pedal is pressed it should switch open, before the throttle plate starts to move. … So, it‘s quite a delicate adjustment, which I strongly suggest to check, because if it‘s not correct, it could be the cause for some of
the symptoms you described.