Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: Gary t on Friday,June 23, 2023, 07:46:29 PM
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History
My car has been starting and running great then a few days ago I was out and it started missing on the highway. When it was missing the tach was all over when it smoothed out the tach settled down.
I returned home and at slower speeds it seemed OK, put it away and a few days later I tried to start it and no go. There was no voltage on the coil found a loose wire on the ignition switch now I have voltage on the coil but no start.
There is fuel at the carb with accelerate pump, now what to check?
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Okay, so there's power to coil, but sounds like no spark?
Can you work your way back from plugs, wires? Maybe you're getting spark but a bad rotor/cap isn't distributing? Points okay in distributor?
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I've had a tach go berserk and traced the problem to points that were not opening far enough. I now keep the points at the high end of the gap setting spec. and regularly check the lube on the follower block.
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Please tells more about what you are running. Stock Renault engine, or? Points or Electronic? If electronic, what system? Stock coil? Anything else not stock?
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It is all stock I think.
Points are set 0.018.
This is going to be a journey as I have none lotus things but I will be fitting car work as I can.
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Spark when cranking? If not I would check your positive at the coil again and negative coming through tach to dist. check points if they're clean.
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First, buy yourself a test light with an incandescent bulb. They apply a small load to a circuit and are much better for troubleshooting than a digital multimeter which applies literally none.
go to the engine
lift off the distributor cap
Are the points open? (If not, put the car in fourth gear and nudge it back and forth until the points are open. Put it back into neutral.)
turn on the ignition
Do you have power at the white wire at the coil?
Do you have power at the white/black wire at the coil?
Do you have power at the points' insulated connection?
Let us know the answers to the above three questions and we'll go from there.
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Thanks John
I had done those checks using my antique Simpson 240 but this morning I built a proper test light.
I found voltage where I expected to find it (with the light)
I get a nice fat spark off the coil lead when I manually open the points.
Next I plan to remove spark plugs maybe after supper.
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A nice fat spark is great. Now we know the wiring is fine, coil works, etc. I would next test the spark at the plug. If there's a problem then, check the cap and rotor for shorts to ground and the ignition wires for connection break or high resistance.
Sometimes everything tests great but it still runs poorly. Spark voltage requirements are very low when testing in the open air. Voltage requirements rise dramatically as cylinder pressures rise (load). So again, high resistance in the ignition wires and shorts to ground with the cap and rotor. Also condensers can work well at cranking speeds and break down at higher speeds and loads. Ignition coils can also fail as voltage requirements rise.
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I needed to make a remote crank switch in order to crank the engine while attending a spark plug, that is done but I am too lazy to hook it up tonight. Plug 1 looks about as I expected.
I know about cylinder pressure effecting the operation of spark plugs, in another life we tested aircraft plugs in a test set where we could apply pressure up to shop air pressure. They would occasionally work fine at ambient but fail at pressure.
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I needed to make a remote crank switch in order to crank the engine while attending a spark plug, that is done but I am too lazy to hook it up tonight. Plug 1 looks about as I expected.
I know about cylinder pressure effecting the operation of spark plugs, in another life we tested aircraft plugs in a test set where we could apply pressure up to shop air pressure. They would occasionally work fine at ambient but fail at pressure.
Cylinder pressure can be 1,000 psi at wot. Testing at 120-150 psi won't show much unless it's beyond bad. If it's a plug or spark miss in general it will usually show up with increased load, wide open throttle. If it's missing at cruise and not worse at wot it may not be spark.
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I'm not really thinking plugs as it was running fine when I switched offbut a few days later no start. But who knows.
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The reason I returned home was intermittent total missing and tach jumping all over. I thought it was a ignition supply fault. At idle in the driveway it was running fine.
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Does it have a white wire at the coil? If yes, then try this. Go for a drive until the problem appears. Now disconnect the white wire and run a jumper from the battery to the coil. Problem solved? Then you have an issue upstream from the coil (connection, ignition switch, etc). Problem unchanged? It's an issue with a condenser, coil, distributor, etc.
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Hi John no it will not start I had some time this morning so rigged my remote crank button and yes I have spark at the plugs. When I crank I get occasional sharp barks from exhaust and occasional puffs at the carb but not a bark.
It has gone from what looked like a manageable DC fault to this what looks like all the plug wires are on the wrong plugs while sitting still in the garage
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IS the timing correct? Could the distributor have slipped?
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It won't move if I push it
I'm starting to wonder if it is a cap fault.
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Check inside the cap for arcing. Check for high resistance in the wires (which could cause arcing).
Swap in another condenser. The engine can behave very oddly indeed with a failed condenser.
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I had the cap 9ff and it looks nice and clean inside I'll get a new condenser tomorrow but there is no indication of point arcing. And I'll check the resistance of the wires.
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I had a similar situation and it was the ground strap. All looked good, but the bolt to the frame was loose and that was enough to provide the symptoms that you are experiencing. Cleaned it and tightened it and all worked.
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Thanks for the suggestion but I am pretty confident in my ground strap, it cranks fine, and I spent a good bit of thought into it when I did the electrical work.
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OK new condenser in no change
What am I missing? Do these engines skip teeth on the timing chain? Can I check that with the engine in the car?
And yes the rotor goes around.
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Put 12v power directly to the coil ,see if it starts.
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They have very good chain wrap on both sprockets so, no, they are not known to jump teeth. That said, anything can happen.
Remove your plugs. Plug #1 spark plug hole with your thumb. "Bump" the starter until you feel pressure under your thumb. Put it in fourth gear. Nudge the car forward until the timing marks line up. Look at your cap and rotor, everything line up? Rotor points to the correct cylinder? Nudge it back and forth around the timing marks. Points opening at (roughly) the right time?
That should tell you if something has jumped or slipped.
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Thanks John that is more or less what I had in mind for the next step. Today is full of non car stuff so you won't hear anything until tomorrow.
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G'day Gary,
I might be off on a tangent here but is the tach wiring secure behind the dash?
I'm picking up on a possible tach related issue because I experienced a similar thing when my car was first rebuilt, only in my case, the ignition went out altogether. It turned out to be a wire on the tach which was shorting to something or other though I can't remember precisely.
I'm thinking there should to be an explanation for both the ignition issue and the tach going berserk in tandem and all of which occurs intermittently.
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OK everyone thanks so much for all of the help and suggestions. John got me on the correct path, it was in fact that the distributor had turned. I did a static timing and got it to start. Timing set and now it starts an the engine accelerates nicely. I now have the distributor clamp bolt torqued to about 100 ftlb (well maybe not quite).
On a side note how does the distributor shaft get lubricated?
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Glad it's sorted.
It is lubricated on assembly. The odd drop of oil into the works is a good idea. By "works" I mean the advance mech, not the points.
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So anybody that thinks a result is the end of the problem I say ha ha fooled you.
As I said last time fixed all is good, well not true. I took it out for a drive around the neighborhood, about a km out the car just switched off it was running fine just like I had switched the ignition off.
Troubleshooting lead me to the ammeter, yes open shunt. Now why did that happen, put my 15 Amp fuse in the battery positive lead, plugged the battery lead into the ammeter them the alternator lead and a nice little 15 Amp spark. Why? The distributor had turned again and shorted the alternator to ground through the vacuum advance. Now to put it all back together.
But there will still be a problem, why does the distributor turn?
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I would suggest bringing the engine to No. 1 TDC and removing the distributor from the engine.
Remove the cap and spin the distributor by hand, does it spin freely (Only point drag if you still use them) or does it seem a bit tight?
If tight it may be close to seizing and the extra drag is turning the body.
Distributor may need refurbishing or replacement.
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Has the cylinder head been off?
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Not in my time. I have driven the car about 2000 km in the past couple of years.
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Is something bottoming and preventing the distributor clamp from tightening properly?
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That was my thought also but I am in the process of putting the dash back together after the ammeter extraction. I replaced the ammeter electrically with a 40 Amp fuse, the ammeter shunt gave its life to save my car.
Is removing the distributor a big deal (assuming I can replace it in same orientation)?
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It's easy.
Mark the original position, remove the nut & clamp and it just lifts out.
There should be no clearance between the dizzy flange and the head.
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Gavin, Isn't there a gasket under the distributor? I dropped one on just as a security blanket for oil leaks, but still able to stop movement of the distributor. so zero clearance would be correct, don't get me wrong, just tight. remember I'm a novice on these engines.
dakazman
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Well another answer yes it is the distributor. When I removed it it was totally locked put pliers on the drive gave ita wiggle and it started to turn but all rattley and catching so I assume a whole new unit is in my future.
Any suggested suppliers or parts sources or the best way forward.
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What do I win? ;)
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What do I win? ;)
You win the most valuable thing, internet points 8)
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Ignition123 make a new programmable distributor. Handy if you modify the engine but not cheap.
If you are not in a rush, you can send it to me and I’ll overhaul it for you. I’m in Edmonton and I have a distributor advance machine and the necessary machine tools.
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Thanks John I'll keep your offer in mind. We are away for a couple of weeks I'll see what jells in that time. What is your definition of not in a hurry?
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It's summer and I'm busy with fun so a couple of weeks?
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PS: I'm offering because you are, relatively, close-by. Only charge would be for any parts and shipping. Worst I can see is a couple of brass bushings.
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Thanks so much for the offer John. We are away for two weeks so no shipping of anything until I am back home. As you say this is fun season I have emailed the usual suspects, I will keep you posted.
I didn't take anything apart but it will need a new drive lug other than that I don't know.
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Gavin, Isn't there a gasket under the distributor? I dropped one on just as a security blanket for oil leaks, but still able to stop movement of the distributor. so zero clearance would be correct, don't get me wrong, just tight. remember I'm a novice on these engines.
dakazman
Dave, there's no gasket as far as I know – and it doesn't seem to weep oil.
Just be aware a gasket would inevitably affect the dog engagement in the dizzy drive adaptor.