A/C straining and killing engine

[DMC5180]

Bold highlighted in Dave's quote. In my previous post.


Dennis

[Rich]

Agreeing you should run the idle motor circuit test before worrying about dwell. Also recommend you see to your charging system before worrying about idle speed or at least not plan any trips til you verify good charging.

When you get to 'dwell':
Answers inserted and underlined below, including the voltage answer:

...How to check/adjust DWELL?
See the video for the test
Would a failing alternator cause the RPMs to be lower than normal?
No.
Did a test on mine and it is "going bad" only at 12.2....
Expect something more like 13.8-14.0V when it's running with low load, same as with other cars.

Measure with a good meter at the jump start terminal and the engine block.
12.2V means it is not charging. Have not read whole thread but this may be a separate issue, one you need to sort out before driving very far.

Video or Steps to check dwell? Yes, here, thanks to Rob D for a great how-to: LINK

[DMC-81]

Hi Dennis,
WHERE is this infomation you added? How to check/adjust DWELL? Would a failing alternator cause the RPMs to be lower than normal? Did a test on mine and it is "going bad" only at 12.2.....

Video or Steps to check dwell?

Thanks everyone!

Hi there,

As I am about to adjust my dwell, I have researched and summarized the following information from these posts:

http://dmctalk.org/showthread.php?57...-A-Dwell-Meter
http://dmctalk.org/showthread.php?12369-What-the-dwell
http://dmctalk.org/showthread.php?12...o-Set-CO-Dwell
http://dmctalk.org/showthread.php?11...-dwell-reading
http://dmctalk.org/showthread.php?11...d-Dwell-Meters

Videos
https://youtu.be/MbE-2k4Cy4E
http://youtu.be/cpNB1eRktzM
http://youtu.be/FTUJCUIWFhg

CO Dwell (fuel system duty cycle)

General information and set up:

Use the 8 cylinder scale on a preferably analog Dwell meter.
Divide the numbers in the Workshop Manual by 2 to match the measurements on the meter.
Or, read the 8 cylinder scale on the meter and double them to correspond to the numbers in the Workshop Manual.

We use 4 cylinders rather than our 6 cylinders as we are using a more common ignition dwell meter for measuring fuel system duty cycle, and the 4 cylinder scale is more accurate for this test. The Workshop Manual numbers use a 4 cylinder scale.
Proper duty cycle is a 0 to 100 % scale. Dwell for 4 cylinder is 0 to 90 degrees (i.e. very close)

It's ideal to have all idle issues worked out and idling at around the factory spec of 775 RPM or so, and let the engine warm up to operating temperature to get the Lambda/ECU/O2 functioning, if not, the system is under a closed loop mode.

Remove the anti tamper plug if needed:
http://dmctalk.org/showthread.php?83...justment-screw
After removing this plug, or if a plug is not present, you will need part number 102392A CO Plug to avoid a vacuum leak.

You will need a 3 mm t-handled hex wrench for the adjustment

Connect the meter:
Connect the green lead on the meter to the pin that is in the right rear corner in the diagnostic plug
(Alternatively, to the orange wire in the loose two wire plug/pigtail running along the firewall, or tap the orange wire in the Blue Bulkhead Connector.)
Connect the black lead to the engine block.
(I will be using the Actron CP7605 analog meter)

DMC Workshop Manual instructions:

Follow the 5 steps (A through E) in Section D:01:14 & D:01:15. The chart was created by taking measurements taken on a good system. If it passes all 5 tests, the system (including the O2 sensor) is should be good.
D:04:01 in the manual states that you can also use a "red exhaust gas analyzer" in order to perform a CO emissions adjustment, but it's not necessary.
For test E, just press the WOT switch instead of holding the throttle wide open.

O2 Sensor:

Have a properly functioning O2 sensor if possible before adjusting CO.
You will need to disconnect the O2 sensor during this test during tests B, C, and D.
Disconnect the O2 sensor at the connector where it goes into the body, which is just forward of the left rear tire in the fender well.

Measurements:

Engine cold:
If the system is in a closed loop operation properly, the reading should be approximately 55.

Engine warm:
O2 disconnected: 40 to 50
O2 connected (normal operation): pulsating from 35 to 45 (so, centered about 40)

Adjustment:

To make an adjustment on the mixture screw:
clockwise = more CO and richer
counterclockwise = less CO and leaner

Cover the hole with the bumper/wire again after adjustment to avoid a vacuum leak. Once the hole is covered, another reading and repeat as necessary until the target range is achieved

The adjustment is sensitive. Usually a 1/4 turn on the mixture screw will drive the lambda system to it full maximum (about 95% duty cycle) and it full minimum (about 10% duty cycle). That would be a good indication that your O2 sensor is working.

Optional Tests and other information:

Disconnect the O2 sensor. Now ground the lead that goes to the ECU and watch the needle and listen to the FV.
Then take a 1.5V battery and connect (-) to ground and (+) to the ECU lead, the meter will swing entirely the other way. You will hear the FV change in tone as well.
This confirms that the ECU is working.

There is a ground wire on the forward (back of the engine) end of the intake runner on the passenger side. If unmodified, it has a red tag on it, and the wire is only about 3 inches long before it hits another connector. THIS WIRE is the ground reference for the O2 sensor. If disconnected, the ECU goes kind of nuts. Check continuity from that attachment point all the way to the ECU, and check for bad connections at the bulkhead connection and at the connection close to the intake runner.


If anyone finds an error, please suggest a correction.

Hopefully this is helpful.

Edit: I see Rich has provided information above^.

[Morpheus]

Good info in this thread.