Lotus Elan

Stops when hot! Why?

PostPost by: Andy8421 » Sun May 08, 2011 5:37 am

Ian,

I should have been clearer. The sprue is on the outside of the cap. If the cap was mounted on the distributor, and if you looked down onto the cap (and if you could actually see the damn thing), the sprue was in the middle, on the top of the cap.

I would post a picture, but I threw them all out.
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PostPost by: seaandmoor » Tue Jun 21, 2011 5:50 pm

Right try again as I can't seem to beable to post a reply now... things go from bad to worse don't they!
Any way hello again everyone - I've had to come back to the forum again.

I sourced a new Bosch blue coil which arrived just before the weekend and fitted it.
Today is a nice hottish day and full of high hopes I took the car out and did the usual few miles and guess what.... it stopped again. Well you can just keep it going by slipping the clutch but not up a hill at all.
There is no vacuum in the fuel tank because I tried it with the filler cap flipped up and it really doesn't sound like fuel starvation.
Any way, I've replaced everything now with good equipment and checked the timing by the way aswell. It doesn't have an alarm.
I'm stumped. What else might I try? Is it possible that a wire is overheating and resistance goes up? What am I left with?
Cheers everyone for helping through this aggravation.
Saggy
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PostPost by: rgh0 » Wed Jun 22, 2011 11:14 am

You need to try to do some diagnosis when the problem arise.

Compression, spark and fuel are the 3 prime factors you need to check.

Compression - carry a compression guage and do a hot check

Fuel - check fuel level in the carbs and fuel pressure when the probem occurs and the car is hot

Spark - check voltages and current for low voltage circuits. Harder to check the high voltage circuit but you can check for presence of spark at each plug when hot and the problem occurs

Once you know which areas is the problem then you can work on what it is pecifically and how to fix it.

cheers
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PostPost by: seaandmoor » Wed Jun 22, 2011 8:30 pm

Hi Rohan, I thought you might be along on this.
I don't have a compression guage but purely for checking the engine performance I coincidentally had the compressions checked at a local engine tuners and they were close together just either side 170.
I've also pulled the plugs and, particularly with the new coil, there is a cracking good spark.
The problem doesn't come on gradually either, it pretty much runs well then in the next moment it is spluttering.
As I've checked there is no vacuum in the fuel tank and the car still has a mechanical fuel pump, then is it most likely a fuel issue?
I can cope with a carb on a lawnmower (!) or even twin SU's but just a glimpse of the exploded diagram of twin Dellorto's sends me into paroxisms of terror. Is there a quick easy way of checking fuel level in the carbs? (I do have a fire extinguisher!) It will recover once cooled down or, as I've now discovered, after a short idle at the roadside - which may allow the fuel level to improve?
Thanks again. Saggy
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PostPost by: rgh0 » Thu Jun 23, 2011 11:07 am

If the engine has compression and a good spark when it is hot and the problem arises, then it is probably a fuel / carb problem.

You can pull the top off the carbs easily as it is only a few screws or you can check by pulling off the smaller jet plastic cover and remove a jet and check the level in the well. Just shut the engine down when the problem occurs and see if level in the carbs is the same as when you first start the engine cold and its running well.

Temporarily piping a fuel pressure guage into the fuel feed and monitoring it when the problem occurs may also help show the source of the problem.

regards
Rohan
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PostPost by: spanner » Thu Jun 23, 2011 2:02 pm

seaandmoor wrote:(I do have a fire extinguisher!)
Saggy


Best diagnostic tool made just for this problem..... A cold blast of CO2 on individual components/vapor-lock areas should give you the answer. Keep it simple!

Jim
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PostPost by: pauljones » Thu Jun 23, 2011 3:59 pm

Have you considered taking out your electronic's and putting back in points.that may sound strange but if you get the same symptoms then perhaps ignition is not the problem.however I agreed it could be the coil but as yours is now new then I would look at the rest first.it sounds like the same problem I had a while ago,in my case I had points and went electronic,new leads ect and it was then fine.so if you were to go back to points and it worked ok,then it could suggest a faulty box of electric stuff.

If that fails,then fuel could be the issue,clean the filters and lines,and clean the carbs as best you can.


Happy fault finding,paul
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PostPost by: billwill » Thu Jun 23, 2011 6:29 pm

I don't see any indication that you have tried a new rotor arm in the distributor.

They can fail with no visible indication that they are no good anymore. Can be very baffling when that happens I guess it could be temperature dependent.
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PostPost by: types26/36 » Thu Jun 23, 2011 7:41 pm

billwill wrote:I don't see any indication that you have tried a new rotor arm in the distributor.


[quote="seaandmoor"
I've changed plugs, leads, cap, rotor arm -



.......sooo I would presume the rotor has been replaced :roll:
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PostPost by: Galwaylotus » Thu Jun 23, 2011 8:24 pm

I know you said you have a mechanical pump but the symptoms sound very like the problem I had. Took about a year to get to the bottom of it. In my case I'd start the engine and could warm it up and even rev it a bit in the drive but as soon as I got on the road I'd go about a mile before it got really weak and then cut out. I first tried pulling the fuel line at the carb inlet and, with my electric pump running, I saw fuel flow. That put me off and I spent a lot of time replacing all the ignition parts including having to pull the Webers to get at the distributor. All to no avail. Eventually in despair I tried the fuel line again and . . . nothing but a few drips! I then went searching to find the electric pump and found it had been installed very well with an in-line filter between the tank and pump inlet. Problem was the filter was filled with scale!! I also had what seemed to be a dodgy electrical connection at the pump. When I corrected both of these things the engine fired and that was the end of the cutting out issue. Just a thought . . . 8)
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PostPost by: terryp » Fri Jun 24, 2011 6:31 am

Going on from Galwaylotus says it does sound as if the fuel supply can't keep up........what about the small filters in the banjos on top of the dellortos?

Bon Courage
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PostPost by: alexblack13 » Fri Jun 24, 2011 7:48 am

Follow Rohan's spot on advice. But.. Also, as stated somewhere watch that rotor arm. If it has been recently changed make sure you don't have one of the wonderful Chinese items fitted. They breakdown as they heat up and cause misfiring and eventually stoppage. Allow it to cool and away it goes again only to fail again as it heats again and again.... and so on. :?

Be careful with the cheap Ebay items...

AB.. 8)
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PostPost by: spanner » Fri Jun 24, 2011 5:20 pm

Saggy,

I'm not familiar with the +2, but I had similar symptoms back in 1969 with my '65 Elan S2. The plastic fuel line was simply connected to the tank with a press-fit rubber hose (no doubt to save weight and $) and when hot, the hose would loosen up. The mechanical fuel pump would begin sucking air into the line at this point, especially when working at higher RPMs. Two small hose clamps solved the problem.

Good luck!

Jim
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PostPost by: Galwaylotus » Fri Jun 24, 2011 5:33 pm

Good call!
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PostPost by: seaandmoor » Mon Jun 27, 2011 9:37 pm

Hi thanks again guys.
I'm making some useful notes on all of this.
I think I will have to be methodical on this and check out every single suggestion. It does all take time (especially for me) but I'm sure I'll learn more about this car as I go and hopefully the problem/solution will be found.
Hope to report back when I've checked some of these things out.
Again many thanks for the moment - the help gives one the determination to keep going.
Saggy
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