Ah! Thanks David. You are correct, I was thinking SU’s.
Greetings Folks,
So I have been working on some of this trying to isolate the issue. This car has a Pertronix Ignitor and it’s negative ground.
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I changed the rotor and cap. Both were looking very tired and I had new replacements I got with the car. I did not change the condenser.
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I pulled the plugs and brushed them off. They were not wet with oil. They seemed to have “black crusty” deposits on them. Petrol fouling? One had a too-close close gap, so I corrected that so they are all at .25. After brushing them clean, I replaced them and made sure the leads were solid and tight. I’m happy to replace the plugs (and would love a recommendation) but I don’t think that’s crucial at this moment.
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I took off the dashpots (mainly to drain any old oil) and taped the holes on the pistons and confirmed they were all “falling” at the same rate (drop test.) Apparently if the pistons were ever swapped in the pots, that’s a problem. All fell evenly. I didn’t do anything further to the carbs besides filling the dashpots with oil.
The car seemed to run “better.” Still a rough start with some clicking adn popping from the carbs. But sure enough, as soon as it warmed up it was fine. Then after about 30 mintues, I had the quitting problem again. I limped back home.
I thought it might be related to being very low on gas (bubbles in the fuel line?) so I started it up again the next day. It had a rough start and limped to the gas station. Filled it up with 13.5 gallons of gas. Seemed to run much better. I drove 15 miles home and had no further problems. I was really excited figuring maybe I’ve isolated the problem to a fuel pump / fuel supply issue…
However, when idling (splendidly) in the garage after 5 minutes, (I was going to try and see if I could look a little closer at the carbs a bit) it immediately stared to overheat. Overflow was hissing there was some horrible honking sound. Coolant was escaping through the overflow. Temp was too high. Turned off the engine. Tried again 30 minutes later, but still overheting so I obviously will need some kind of cooling solution if I am every to work on a running engine when this car is not moving.
I looked at the ignition system because the Pertronix is about 18 years old. They said to check some things and I found what could be a problem…
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There is a 5.9 ohm resistance between the negative and positive terminals on the coil. Is this good or bad? This coil looks old. Bosch?
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When I run my meter leads between the the plate to which the Pertronix is mounted and the neg battery terminal, I get a -.4 reading. Pertronix says this means there is a grounding issue. They said this would certainly get worse when the car warms up. They also said if the car had points, I wouldn’t be calling them because points cars can tolerate grounding issues, but electronic ignition needs a PERFECT ground.
So, now I’m even more chagrined.
Oh, and look at that positive white/black lead that was attached to the positive terminal of the coil. That extra clip was just hanging loosely inside all that Radio Shack plastic shrouding…
Ugh. Is it too late to switch to a Miata? 
Thanks for help, folks…
Andrew
Out of curiosity which Pertronix module did you install and what type of wires are you running? I ran with the original Pertronix for years with nice silicone wires, but they were plain braided copper. I switched to the new and improved module (I think it’s red) when the car was switched from pos to neg ground and tried running with the same cables. It was an absolute nightmare. It ran very rough, backfired, and after a few minutes stalled.
I contacted their support person and after a long wait got back a gruff message that said suppression core wires must be used with the newer module. I went ahead and spent the excessive price for Pertronix wires figuring there would be no more excuses. It was fiddly installing them into the Lucas cap with those screw on terminal caps, but once accomplished it ran like a dreidel and continues to.
Your coil is knackered, to use the correct British term. You need to get a fresh 3 ohm coil. I wouldn’t worry about the grounding issue just yet, but if the new coil doesn’t fix it, you want to check your block grounding strap.
Is this the distributor condenser, or a radio suppressor? If distributor, I am not familiar with all the different pertronix variations, but I thought the module did away with points and condenser.
Tom
Correct, no condenser needed. The module sits where the condenser would be.
When measuring a low resistance with an ohmmeter, connect the leads together and see what you get. Then subtract this reading from the reading you get measuring your device. This way you illiminate the resistance of the meter and leads.
Exactly. Based on the information presented, I would guess that the ground issue is a red herring. But the coil reading is still high. If the baseline resistance of the meter and leads is .04, then the coil is still 5.5 ohms. Toast.
From personal experience I know that the ground resistance to the pertronix module ground is very important. I had a car which would idle beautifully and start instantly but the moment you took it out on the highway it would miss like crazy. I Replaced the original ground in the distributor (which measured less than an ohm) and all was fine.
Thanks for everyone’s advice. I ordered a 40,000 volt 3ohm Pertronix for my Ignitor. It’s black so it should be fairly low-profile and with a name like “Flamethrower” how can I go wrong?
Quick questions…
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How do I know if a ballast restrictor has been installed in my car? I’ve looked around, but I’m not sure what I’m looking for. Pertronix says I need to determine if one has been installed. The current coil says none is needed.
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Would it be prudent to replace my wires? I’ve been recommended a Mag-Wire set. My blue BWC wires are “suppression rated” so they would seem sufficient for now, but I’d also like to get a set that looks more OEM.
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Looking at the inside of the distributor, is that ratty-looking wire screwed to the body the “original ground?” Shouldn’t I replace that for good measure?
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I re-tested the coil from the car, as well as two others I got with the car and here’s what I came up with. After a dozen tries, I can now get a consistent .2 ohms base-reading on my Fluke-115 tester. All three of the coils have the same reading: 3.6 ohms so if I subtract the base-reading, that’s 3.4 ohms. The coil on the left is the one that came off the car. Sorry for earlier readings…… I had a heck of a time with consistency.
Many thanks for the help, folks…
Andrew
Pertronix requires a primary circuit resistance of at least 3 ohms. If you had a 3 ohm coil, you don’t need a ballast resistor and probably never had one. If your prior reading was incorrect, then it’s probably not the coil. It’s hard to distinguish between experimental error and a problem with the data you’ve posted.
Did you try one of these other coils?
Back to the ground problem, if that’s not also a fluke of the Fluke. Place your probes as shown in the diagram, and check the resistance. If it’s high, then remove the ground wire by removing the two screws. Clean the contact area and replace. Then test again. Then test resistance between the Probe 1 location and the battery negative. If this is high, find the body/engine grounding strap and clean it up. Then R&R the battery negative from the bulkhead. Then check again.
Greetings Jaguar Friends,
I am continuing my quest. Here’s what I’ve done so far from the beginning…
- Replaced rotor
- Replaced cap
- Filled dash-pots
- Cleaned and checked gaps on the NKG BP6ES plugs
- Looked inside of carbs for obvious problems and performed a “drop test” to confirm the three pistons are matched properly with their respective dash-pots.
- Filled the tank with 14 gallons of 93 octane gas
- Replaced the coil
- Cleaned/reconnected inside-of-distributor grounds
- Cleaned/reconnected battery terminals
- Confirmed a 0.1 ohm resistance inside various parts of the distributor
- Confirmed a 0.1 ohm resistance between various parts of the distributor and negative battery post
The car is still exhibiting the same “sputtering” problems. It looks like it’s just someone who can’t drive stick, but honest, it’s the engine. The four brief videos, filmed with the assistance of a friend, are with the engine progressively warming up. You can hear the sputtering and popping. It runs sort of OK once we really got moving in 3rd gear at 3500 RPM, but anything else is wonky. The weather was also VERY humid so much so that the steering wheel was wet and some of the gauges fogged up, if that matters.
My next steps (some of which now seem unnecessary) are:
A. Check, clean, and re-attach block-to-body ground connection
B. Check, clean, and re-attach body-to-battery ground connection
C. Check carbs for symptoms of dysfunction by pushing up the lift-rods one at a time and seeing how the remaining two carbs cope with the change.
D. Look closer at the needles for good alignment with the jets
I’m considering.
E. Temporarily switching to points, but my understanding is that this will likely involve resetting the timing, which I’m not thrilled about doing insomuch as it will introduce another variable.
F. Replacing the plugs with Champion 404/RN12YC’s.
Photo of the cleaned up distributor internals. The “advance” and “retard” seem to move freely (noticed when tightening up the mounting screws for the Pertronix module.)
Photo of my collection of points and condensers. Suggestions on which set of points to use? I hear the old ones are better than the new ones…
Thanks for all help. I’m inspired now… the solution is out there.
Andrew
Did you check the float bowls and needles per my earlier post? It’s an easy check. All you need is a small hammer!
Do you think a Colortune tool might help you tell if you have mixture problems and perhaps weak or intermittent spark ? I used it on my E when I switched my ZS carbs to adjustable needles. I was nervous about setting them too lean. Also used it help dial in dual Webers on my Cosworth Vega when I rebuilt them a few months ago. Here is one demonstration video when I use google. Just a thought plus I think it is great fun to see the flame in each cylinder.
David
68 E-type FHC
I am sure you are overwhelmed with so many different suggestions. Here are two more I have not seen.
Dirt in the fuel tank. Sometimes it seems to cause an engine problem to come and go. It often will cause a total shutdown.
Leak in the pickup fuel line sucking air into the pump.
Tom
Last time this happened to me it was because the fuel pump was failing. It couldn’t keep up with demand and was especially prevalent on climbs and under load.
I also had a very similar issue caused by a bad out of the box condenser coil. But if you have Pertronix it’s not that. Switching to points would at least rule out the Pertonix. If you get the same issue, high probability it’s fuel and depending on the age of the pump, a decent probability it’s that.
Also make sure the fuel cap vent is not blocked…
From the very beginning I have suspected you have a fuel problem. The next time you have popping and hesitation pull out the choke, what happens?
I wholeheartedly agree: fuel delivery. I have mentioned the float needle scenario, which has hit me three times in 30+ years. Deprives the engine of fuel.
Will no one else validate this? The symptoms are as described, and it’s a five minute check. For obvious reasons, always check the easy stuff first. Sheesh!
Possibly a bit of grit, if it made it past the filter screen. When mine have got stuck, they’ve stuck open and leaked on the floor but the reverse is likely possible too.
But I know the fuel pump can cause it. The DPO of my car had bodged a wing mounted pump in my 3.8 and had disregarded the “UP” so it was turned sideways and burned out fast.