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Hi all,
My son's '83 245 has a no-spark condition. Per the Bentley manual, we've confirmed voltage at #15 on the coil, and at #A on the Hall sender plug. We've confirmed voltage at #2 on the ignition control unit, but have been unable to confirm ground at #10. Not sure if this is really a problem, since it's quite difficult to back-probe the connector.
When we did the B-to-C jumper test on the Hall connector, we got no spark, but did hear a chattering sound. Bentley makes no mention of this. Is this sound telling us anything?
Thanks,
Monty
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Past: '79 245, '91 240, '88 245. Current: '90 245, '83 245, '95 940
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If Chuck (porkface) is right, and the "chattering" you heard is from the injectors, then the ECU must have got the "Go Ahead" signal from ICU terminal 1 at the Chrysler CU. Bentley doesn't show it, but that wire from ICU 1 splits and goes to Coil 1 (as a pulsing ground) and also to the ECU pin 1 to get the FI system going (by grounding pump relay 85 blue-green wire, for example).
I think Bentley has the B-C jumper test wrong -- that is, the spark and FI action is triggered when the B-C jumper is removed, simulating an Impulse Sender "vane" leaving a "window" (which is when the timing pulse is initiated), rather than when B and C are connected.
So I'd say to try that B-C test again, looking closely for spark at a plug, and listening for the pump to run briefly (which Bentley doesn't mention), or the Pump relay to click ON for a second, when the jumper is removed.
Speaking of the Pump relay, you might try back-probing the Blue-Green wire at terminal 85. With the key ON, that point should be show +12v (reading thru the coil from 86 (IF fuse 13 is good). Then, when the B-C jumper is removed, that 85 relay terminal should go briefly from +12V to 0V (ground) when the ECU reacts to the B-C jumper removal.
I don't usually have much good to say for Haynes vs Bentley — but Haynes pages 4A-27 (fuel) and 5-7 (ignition) might be helpful here, showing how ICU pin 1 relates to the Coil 1 and FI ECU pin 1 for example.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Lucid,
Tried the test again, and as you suggest, watched for spark upon the removal of the jumper. No spark. So, with +12v at A on the Hall sensor plug, but with no spark during the B/C jumper test, is the Hall sensor the likely culprit?
Does the Hall sensor tend to fail all at once, or can it degrade, causing poor performance along the way? I'm hoping the answer is Yes, because it would explain a lot.
--
Past: '79 245, '91 240, '88 245. Current: '90 245, '83 245, '95 940
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To make sure you have no spark, pull the coil wire out of the distributor and put a spark plug in that end and ground the shell of the plug on a handy spot where you can see/hear if there is a spark. Then follow Bruce's Hall sensor test steps. This eliminates the possibility of a bad rotor, bad cap, or that the rotor is pointing part way between terminals in the cap and not sending coil voltage through them.
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Bob: Son's XC70, daughter's 940, my 83 240, 89 745 (V8) and S90. Also '77 MGB and some old motorcycles
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My Hall sensor is definitely bad, the cheesy aluminum foil has gone away and wies are item, hard and cracked/'broken. Looking up the part online from chain auto parts store the VOLVO item,(with the Chrysler ignition), is listed for near $200. Taking a chance, I looked up the same item for a Plymouth Reliant K-car of the same era. The listing is visually identical and costs $26!
Anybody have any info on cross referencing the Chrysler part for the Chrysler ignition?
I used to work in a BMW dealer. A part from say, Bosch or other supplier, for a BMW in a BMW labeled box was $$$, the identical part for a Benz was more $$$$$, for an Audi, another price and for a VW, way, way less. Made a big difference in selling customer pay repairs on older cars
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"Tried the test again, and as you suggest, watched for spark upon the removal of the jumper. No spark."
• Spark is only 1 of the 3 things that should happen. How about the "clicking" noise you noted before -- that porkface thought might be injectors? And any brief sound from the pump(s)?
"So, with +12v at A on the Hall sensor plug, but with no spark during the B/C jumper test, is the Hall sensor the likely culprit?"
• Can't say for sure yet. Below is an old canned post on the subject. It's a 2-part test. The B-C jumper test is part 2, Part 1 tests the Hall sensor. Give it a try.
=========canned post================>
A) To get sparks from the coil, the spinning distributor's "Hall Switch/sender" must send weak pulses (1 per cylinder/plug) to the Ignition Control Unit (ICU).
B) The ICU must then respond to each pulse by "triggering" the coil's negative terminal #1 to generate the high voltage in the coil's center wire, to be "distributed" to the proper plug.
C) At the same time, the ICU must also send a timing pulse to the Fuel ECU to keep the Fuel relay energized, control the injectors, etc.
Either test below can be done first, and both assume +12V at Coil terminal #15 with Key On.
Hall Switch Test (tests for A — to initiate B and C)
1) Pull coil HT wire from distributor cap, attach/adapt to spare (grounded) sparkplug.
2) Remove distributor cap.
3) Rotate engine till an open Vane "window" is centered in front of the Hall Switch.
4) Turn Key ON.
5) Pass a feeler gauge blade (or similar) through the Hall Switch (simulating a moving Vane segment).
•) If the Hall Switch and ICU are OK, you should get a spark at the test plug and fuel pumps should run for a second.
•) Repeat step 5 as needed to verify spark and pumps.
•) If no spark, test ICU operation below (eliminating Hall Switch).
ICU Switching Test (bypasses A and tests only for B and C)
1) Key OFF. (Coil wire and spare plug still set up as in Hall switch test).
2) Remove the 3-wire connector plug from distributor body.
3) Insert a jumper from plug socket B (Yellow wire) to socket C (Black wire). When jumper is REMOVED (step #4) the plug should spark, and the fuel pumps should run briefly.
4) Key ON. Check for spark and pumps as jumper is removed.
•) If Spark & Pumps operate now, suspect Hall Switch or wiring.
•) If no spark, suspect ICU or wiring.
<===========end of canned post=============
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Lucid,
Well.... it would appear that neither IPD nor FCP carries the Hall sensor for an '83 240. They do carry one for later model 740s.
Monty
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Past: '79 245, '91 240, '88 245. Current: '90 245, '83 245, '95 940
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Thanks to all for the help. After closer inspection, in a very cramped space, we found a break in the wire leading to the Hall sensor. A bit of splice-ology and the trusty '83 is back on the road, soon to pass the 300K mile mark.
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Past: '79 245, '91 240, '88 245. Current: '90 245, '83 245, '95 940
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did you read the link I sent? if you don't have spark when you jump b and c, it's not the hall sensor. ASSUMING you are jumping them at the harness side and not the dist side. it's all in the book. good luck, chuck.
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the chattering is the injectors opening. here's the factory manual-
www.k-jet.org/files/greenbooks/TP30432-2_ignition_systems.pdf
good luck, chuck.
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