mkriete

My shark has been running rich since I purchased it, and I have been working on the condition on and off for the last several months. It is better then it was, but still a bit too rich. I have not noticed any black smoke, but I have noted black deposits around the tail pipe. If I build up a little condensation in the exhaust, I'll leave a black spatter on the wall of my garage when I start the car. FWIW, emission testing is not required here.

The previous owner had made some modifications. The thermostat was 75 degree. There is a 330 ohm resistor installed in line at the Temp II sensor. The retard vacuum line had been removed from the distributor and plugged.

I don’t believe I have been able to achieve wide open throttle and I have not had the kick down engage. This still may be a cable adjustment issue.

Here is some info:
1. Idle is around 750 rpm after warm up. It is near 1000 rpm when cold.
2. Exhaust: 2.25" duals with H-pipe, Cat delete, and dual inline glass packs (4 total).
3. Changed the thermostat to 83 degree. This helped. IR thermometer shows the coolant temperature is right on.
4. I reconnected the retard vacuum line. I did not notice a difference, but I got rid of that awful popping sound on deceleration.
5. I replaced the idle switch (it is a retrofit). I believe it is positioned correctly. This seems to have helped a bit as well.
6. Aux air valve – idle increases at about 25 inHg vacuum
7. Distributor Retard - no change when removed at idle, 18 inHg at idle,Reduces to 2 inHg when the throttle is engaged.
8. Distributor Advance - engine drops to 550 rpm when removed at idle; 21 inHg at idle, 22 inHg at 2,000 rpm.
9. Distributor advance drops to around 15 inHg then jumps to 25 inHg before it settles at 22 inHg, when the throttle is engaged.
10. Distributor advance - Idle rises to 600 rpm when the hose is plugged, but not connected to the distributor.
11. Fuel regulators/dampers: no vacuum at idle. Vacuum rises to 20 to 25 inHg with throttle.
12. Temp II Sensor:
- 3.72 kohm at 12 degrees C
- 300 ohm at 67 degrees C
- 260 ohm at 83 degrees C (586 ohm at the ECU)
13. Temp timing Switch:
- G to Ground: 38 ohm at 12 degrees C, 80 ohm at 67 degrees C (Out of spec)
- W to Ground: 3 ohm at 12 degrees C, 153 ohm at 67 degrees C
- G to W: 36 ohm at 12 degrees C, 75 ohm at 67 degrees C
14. Air Flow Meter (I’m not certain where to find the manufacturing date tag):
- 6-9 326 ohm
- 6-8 196 ohm
- 8-9 157 ohm (a little high?)
- 6-7 97 ohm
- 7-8 212 ohm
- 27-6 1.5 kohm at 38 degrees C, 1.78 kohm at 21 degrees C

I know the resistor will trick the ECU into thinking the engine is still warming up, resulting in a richer condition. How much of difference does the resistor really make? Is the temp timing switch possibly causing the cold start valve to stay open? Should I be concerned about carbon build up in the cylinders? Are the deposits in the exhaust typical without a cat? Is there anything else noted above that is of concern? Is it possible the PO advanced the timing based in the other modifications?

Thanks in advance!

Jeff Bowlsby

Remove the resistor at the TS2, that should make it not run rich at operating temperature.

mkriete

Thanks, I'll remove it later this week and see how it goes. Do the other results seem typical, particularly the vacuum response on the advance?