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No spark

7K views 33 replies 10 participants last post by  cowboy 
#1 ·
I am having a issue with No Spark from the Coil. Two weeks ago I was leaving a C&C and the 90 died. It would start intermittently start but would die. After and hour and a half it started and I made it the 7 mile trip home. So far I have eliminated the following parts from the cause of the no spark.

Coil (tried multiple)
Rotor Button (tried multiple)
Ign Module (tried multiple)
Ignition Switch
Chicklet
ECU
Lead from coil to distributor

Im am getting 12v to both sides of the coil in the on position. everything appears to be getting power. Just no spark.

Rlynch was over and we had it start a couple times but died soon after. Neither of us thinks this is a fueling issue since we have determined it isnt getting a spark or its very weak of the coil.

I cant think of anything else that would cause the no spark issue.

Any ideas?

Brian
 
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#2 · (Edited)
Did you already rule out that it does not fire momentary with a shot of starter fluid? Do you get a spark from the coil's lead to ground (meaning before you reach the dizzy)? And did you replace this lead with new? Even if it (and the other eight) look good, the conductor can burn back from the cap leaving a weak and intermittent spark.
 
#4 ·
Current thinking is that either a wire broke somewhere in the loom, the ignition pickup module in the distributor or the fuel pump went (would that explain the sometime start then die after 1-2 minutes at idle? Anyone?)

all parts were swapped one at a time and tested - pretty much everything in the ignition system with new or known good spares.
 
#6 ·
we did not change the Ignition Pickup - RTC5090 in this photo.. we DID change the Ignition Amplifier module multiple times - they are different,but i doubt that is it right now - since it doesn't seem like it is getting spark to the distributor
 

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#14 · (Edited)
BUMP

...and I don't know the answer to that question, but I am pretty much convinced that neither the Dsource community nor my old-school, LR oem-lovin' mechanic has sorted the ageing RRC/NAS-era pickup issues. Googling up some keywords/keyphrases might give you some answers from other make & model owner/DIYers that apply to your Rover setup. Pertronix tech support, if it even exists, may be willing & able to inform you re how to test the signal coming into the negtv coil terminal - buy one & return it if they can't answer that question or hoard it if they can? Find out which multimeter mfr has the best tech support & ask them? - I mean c'mon, we drive old cars - we do want to own the multimeter with the best tech support, don't we? That assumes any of them have any tech support at all, of course. I can say with 100% certainty that my Bosch from my local chain auto parts store looks more like a cool lil iphone & has a more helpful owners manual than i expected.

But, back to the main point of this post: BUMP
 
#20 ·
13-14V at both side of the coil. Power from coil to Ing Mod also around 13-14V. I am unsure of how to test the following:

Red and Blue wire from Distributor to Ign Module
Black Wire from Coil to ECU

If all this is ruled out, then I left with the Pickup Plate in the Distributor correct?

Brian
 
#22 · (Edited)
Per the workshop manual, the reading at the lead plug for the PickUp plate should be between 2K and 5K. I check with my multimeter on the 20K setting and got 3.28. So I am looking at 65.6K ohms. Either i am reading it wrong, or my resistance is really high which would mean the pickup isnt sending a signal at all.

If this is the case, can you replace the pickup plate with the Distributor in place? At 186K, can my Distributor be worn out?

EDIT

I was incorrect on the reading. With the 20K scale, I was at 3.28. I believe it would just be the 3.28 X 1000. 3280 and im still in range. So that part is ruled out. Back to square one.
 
#23 · (Edited)
I've determined the Culprit of my No Spark is the wiring. I believe its the Red and Blue wire coming from the Distributor to the Amplifier. When i get the truck to run i can move the wire and cut the truck out.

The Wire from the Distributor has a ground wire on an Ring Terminal at the coil, but it does connect to anything on the other end. Does this serve any purpose?

I've checked the resistance of the wire and the continuity. I dont notice any change when I bend the wire. The only way I have figured out how to test it is get the truck started and then move wires.
 

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#28 · (Edited)
When i get the truck to run i can move the wire and cut the truck out.
Why mess with anything else until this detail is sorted?

------ Follow up post added June 5th, 2017 09:25 AM ------

The Wire from the Distributor has a ground wire on an Ring Terminal at the coil, but it does connect to anything on the other end.
That doesn't make sense. Pic?
 
#25 ·
I peeled back the insulation to see what was going on. The ground strap was on the alternator, but I moved it to the coil to see if It was a ground issue.

The Bare ground wire does actually go anywhere. The pic shows the Distributor end of the wire.

I looked at another truck and its the same deal.
 

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#27 ·
I apologize for the bad wiring. This was much cleaner looking until I started moving bits around and peeling back the insulation.

The Ground Strap was from the Back of the Block to the Alt. The Other ring terminal is for my headlights.

Looking at a wiring Diagram, it doesnt appear this is grounded anyway.

I dont know the best way to test if I have a broken wire somewhere. Everything is intermittent.
 
#29 ·
Reference the first pic above. The Ground cable wraps around the red and blue in the insulation. THe second pic shows the other end of the cable at the Distributor. The ground wire is cut at the end of the insulation. Its hard to see in the pic, but the strands are there.
 
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