I am determining a no-start situation and started by checking the coil primary and secondary resistance, 0.04 - 2.0 ohms and 6K - 15K respectively, they showed normal values or 1.0 & 7.97K. It is not the French coil, so it must have been replaced by the PO. I then moved to the distributor and disconnected the pickup from the amplifier and checked the two-wire plug for 2.2k - 4.5k ohms. For each selection of the ohms range on my multi-meter, I got OL. I just want to confirm whether this means the circuit is open, shorted, or other. My gut feeling is the pickup is toast and may be the cause of my no-start problem. The amplifier was missing and I replaced it with one from e-bay. I have a new ACDelco D1906 amp. module, which I will be installing, if the ebay one doesnāt check out. I checked the condenser in the amp and it functions, but the values seem high, compared to a video on rebuilding amps. So that may also be replaced. I am not an electrician and am not sure about the values for the pickup. Would appreciate clarification. Thanks in advance.
Jim
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Hello James - āOLā usually means āOpen Lineā on some meters - when ready to measure Ohms you should always verify that your meter is working: 1) place meter selector on the scale of Ohms you wish to use; 2) turn on meter power; 3) with the two meter leads plugged in to the āOhmsā and āCommonā jacks, connect the lead ends to each other; 4) the reading on the meter should designate the measurement of the resistance of the meter leads, thereby verifying a working circuit via the leads; 5) separate the meter leads ends and the meter should designate and āOpen Lineā; 6) when testing the wire circuit, on the vehicle, make sure that there is no battery voltage on the circuit while doing the Ohms test; 7) touch one meter lead to one circuit wire, and the other meter lead to a āgroundā point on the vehicle to check for a āshort to groundā condition of the circuit; 8) test the circuit resistance by one meter lead on one wire of the circuit, and the other meter lead on the other wire of the circuit - set the scale selector on the setting that is greater than what you expect the circuit to be in the range of - example: 10K selected, not 1K - hope this helps you - Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - sent 8/11/2020 1526hrs. EDT USA.
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Getting 1 ohm (coil primary) and some 8 ohms (secondary) implies that your gauge is working, Jamesā¦
Then no reading between the the two wires at the ign amplifier end of the pick-up coil wires, with the correct meter range selected (5 Kohm or nearest higher range) implies faulty pick-up coil or broken wires to it. To eliminate a possible wire fault; access the pick-up directlyā¦
The resistance checked is just the resistance in the wire wound pick-up coil. As is the resistance of the coil. Incidentally; coil wires must be detached while ohming. As Tex say; there must be no power present when ohming - and ohming a connected item is misleadingā¦
Frank
xj6 85 Sov Europe (UK/NZ)
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Multi-Meter (MM) check in ohms range was performed. Got ohms reading with both leads touching. The battery was disconnected. Distributor pickup connection removed from amp. MM test leads inserted into removed distributor pickup plug. OL reading displayed on all ohms ranges, including 5K and above. Will be removing the pickup from the distributor and checking again w/MM before purchasing a new one. By chance, either of you know the nut size of the crank pulley. Seems to be around 1-5/16, but not sure.
Thanks for the info.
Jim
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Just to make sure, James - the two multimeter probes into the two plug wires?
If so; either the plug, wires or the pick-up itself is faulty. Off hand; you may also measure each of the wires to ground to see if one of them is shorted to ground? Or indeed from each wire on the pick-up to the connector, to verify continuity. The pick-up itself seldom fails - but impossible it ainātā¦
Frank
xj6 85 Sov Europe (UK/NZ)
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An update on the situation has included the following. I removed the pickup from the distributor. Checked for resistance from plug-end to where each of the wires connects to the pickup. I got a reading for each wire. Therefore, I assume there is no break in the supply wires to the pickup. Then tested for resistance at the point where the wires exit the pickup, and got the over limit (OL) value for all ohms ranges. My assumption is that the pickup is bad. Subsequently, on this information I have ordered a replacement pickup. Hopefully, in a few days I will have good news and a running SIII. Til next time.
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Sounds perfectly logical, James - we share your hopesā¦
Frank
xj6 85 Sov Europe (UK/NZ)
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Distributor module replaced. Car still wouldnāt start. Searched for correct distributor cap configuration and finally got car to start, but, ran at fast idle. Checked timing and the indicator was flashing at the e in before. Adjusted and got it to 17BTDC, still idling high. Checked throttle valve clearance, and was ok. Then got my trusty allen key and attacked the idle block screw. After many turns in, the idle is now at 850 in Drive. On to the next project. Thanks all for your help and direction. It is much appreciated.
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As the ign advance was likely set at the āwrongā idle, James - check and set idle to specā¦
You did the work - you take the kudosā¦
Frank
xj6 85 Sov Europe (UK/NZ)
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Sometimes you run across a car where all the settings are bollixed-up. Somebody was in there trying to compensate (knowingly or unknowingly) for for xxx-problem by over-adjusting yyy-setting. Which then requires another adjustment to zzz-widget. Andā¦andā¦
This isnāt me being holier-than-thou. Iāve been caught-up in the trap myself a few times over the decades. Pretty soon you donāt know which way is up
Cheers
DD