Engine missing and then dying when hot

pcattera · Post by **pcattera** » Tue Jun 24, 2008 4:24 pm

I have had my 1970 Series 2 E Type for two years now. It was brought back from the USA so has USA specs. I have encountered one annoying problem. When the weather is very hot and the car is also quite warm, I start to miss fire when accelerating and then when pulling away from a standstill (lights, junctions etc.), the engine dies. Embarassing. It will not start for about 15 minutes after that, probably when cooler and even requires a touch of choke. I have noticed when I have been stopped with the car bonnet up that there is air or petrol vapour in the fuel pipe between filter and carbs. I believe this is the problem but what to do about it. This certainly shouldn't be normal as these cars were built to run in a Californian climate. Anybody else had this problem or can help me to solve it. A couple of garages have had a look but find no problem. Best regards Peter (janettsky)

Post by **Heuer** » Tue Jun 24, 2008 4:50 pm

Peter

Things to try:

1. Remove the air filter and go out for a run. When the air is hot the engine may not be getting enough air due to the density and an old or blocked filter might be strangling it. Worth eliminating.

2. Swap the coil for a new one. A faulty coil can start to fail as it gets hot but will heal again as it cools. Try a new Lucas Sports coil or Bosch Blue.

3. Presumably the points have been checked?

4. Spark plugs - you could try going for a cooler grade. Normally they are fitted with BP5E's but you could change to BP6E's or BP7E's which are designed for warmer climes or tuned engines.

5. Put a fuel pressure gauge in the line between filter and carbs (eBay about ?15) so you can see what is going on. Could be the pump failing when hot

Shaguar · Post by **Shaguar** » Wed Jun 25, 2008 7:38 am

Peter,
I had a similar issue (misfiring, difficult to restart when hot etc) recently and discovered the low tension wire (arrowed) in the distributor was stripped and down to just a few strands:

Ordered new LT lead/cover, fitted and not misfired since. Although in my case I think the restarting when hot is a different problem and on David's advice I ordered a new coil, haven't fitted yet so can't tell you whether this cured it.

Post by **Heuer** » Wed Jun 25, 2008 8:39 am

Another thought: how old are the ignition leads? I have also seen people wedded to the Champion 'bowtie' plug caps and change the leads but keep the original caps. These can fail and produce symptoms very much like yours. Suggest a complete new set - these are very good: http://www.rob-beere-racing.co.uk/ignition.html#ignlead and you get a D-Type lead separator as well.

David

MarkE · Post by **MarkE** » Wed Jun 25, 2008 9:00 am

I?ve had this problem on many old cars, and it?s nearly always the same thing, as identified by David and Shaguar. I now replace all the ignition bits as a matter of course, to bring them all up to the same standard?points, condenser, distributor cap, leads, caps, coil, plugs.

Only on one occasion did this fail to sort the problem, and it turned out to be rust scale in the petrol tank. Worth checking the fuel filter to see if any particles are present. If there are, the E Type tank has a very good little sump which can be unscrewed and cleaned. Both of mine were full of rubbish. One with sand and muck?I just cleaned it and put it back. The other was full of rust scale, so the tank was replaced. If there is rubbish in the tank, it?s also worth blowing out the fuel line with compressed air, and cleaning the carb filters?check the float chambers as well.

Mark

Post by **Heuer** » Wed Jun 25, 2008 2:15 pm

Yes the sump filter is at great little 'catchall'. Cleaned mine out recently and it was full of paint chips. When the car was repainted they did everything, including the filler neck. Over time petrol pump nozzles had knocked off the paint straight into the tank.

Moeregaard · Post by **Moeregaard** » Wed Jun 25, 2008 6:02 pm

The symptoms described sound like vapour-lock. After ruling out ignition troubles, check the carb float levels and fuel pump.

Post by **Heuer** » Sat Jun 28, 2008 5:29 pm

If it is vapour lock check the filler cap. There should be a hole in the centre so air can get into the tank and prevent a vacumn forming. Sometimes the hole can become blocked (check by blowing) or the cap may have been replaced with one from another Jaguar, some of which do not have a breather hole but look otherwise identical.

Scenario is the car runs for a while and then stops. You assume it is to do with heat but when the car is left to stand the vacuum created in the tank gradually releases and you are off again.

pcattera · Post by **pcattera** » Sat Aug 02, 2008 8:06 am

Thank you all for your advice, I have checked out all the things you have mentioned and am now basically coming to the conclusion that it is the fuel pump sticking when the weather and car are hot. (I now have a small hammer and will go for a spin this morning and try and prove the point) I have ordered a new fuel pump and a Filter King with attachable/detachable pressure guage. I believe 2.5 lbs/sq in is the correct setting. Delivery will take about two weeks, so I will advise the results when fitted and tried. Regards Peter

Post by **Heuer** » Sat Aug 02, 2008 10:47 am

pcattera wrote:I have ordered a new fuel pump and a Filter King with attachable/detachable pressure guage. I believe 2.5 lbs/sq in is the correct setting. Delivery will take about two weeks, so I will advise the results when fitted and tried. Regards Peter

Mine is set at 2psi which is the recommended pressure for SU carbs. Start there and if the car misfires (unlikely) under hard acceleration increase the pressure.

pcattera · Post by **pcattera** » Sat Aug 02, 2008 10:54 am

Right, I will start at 2psi. My carbs are twin Strombergs. USA spec.
Peter

pcattera · Post by **pcattera** » Tue Oct 21, 2008 1:57 pm

Subsequent to my original posting of this topic back in June this year, I checked out all the advice posted on the forum, for which I am grateful. I eventually came to the conclusion that it was infact fuel starvation due to the petrol pump sticking when the weather and car where quite hot. I have now fitted a Filter King ( brilliant) and a new pump. It took some time because the pump got lost in the German postal system. I have not had a recurrence of the problem and have even taken the car on a 600 km round trip where I pushed her quite hard on the motorway. No problems and now I do not see any air/vapour in the fuel line. Albeit, the weather has not been quite as hot since I had the original problem, I am accepting that the Filter King and new pump have cleared the problem. Many thanks for all your advice and I would recommend that if you haven,t already fitted a Filter King do so. Best regards Peter.

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Engine missing and then dying when hot

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