Severe misfire - Engine dies

[stuartgb100]

It moves on.

Problem finally (I hope) chased down to "carp" in the fuel tank !

Took the tank out over the weekend and flushed it out best I could by sloshing fuel around,
rinsing and repeating, etc.

Set off for MOT this morning.

Sailed through MOT, but broke down 3 times on the way, and once on the return.
Each time, a disconnect from the tank outlet and a blow back through the tank fixed it for a while.

So the tank's now out again, and I'm still getting a little debris.
I removed the sender unit and from what I can see peering in there and also via the filler,
the walls of the tank are like stainless - just a little rust where the drain plug boss was welded.
Course, I can't see past the middle baffle, towards the pickup.

So, 2 questions:

1. Does anyone have a better method to flush the tank ?
2. Can anyone recommend a cheap endoscope ?, to have a look behind that baffle ?

Regards,
Stuart.

'71 Sprint with mods & probs !!!

[dusty]

Would this stuff cure your problems?

http://www.rust.co.uk/popup.cfm?p_n=405062&p_i=405062



I used it in an old Ford Thames fuel tank that despite being cleaned out kept blocking fuel filters.

[RotoFlexible]

Problem finally (I hope) chased down to "carp" in the fuel tank !

Your explanation sounds a little fishy to me.

My tank was professionally flushed and sealed before I put the back on the road last year, but I think there must be some residue that is still working its way through the system. I have had some fuel feed issues that I'm still working through.

[neilsjuke]

Is the tank/cap vent hole blocked.
Neil

[andyhodg]

Stuart

I see that Frosts are selling an endoscope for ?215 (cheap is always a relative term )
Although I seem to remember that they do hire our equipment (I enquired about hiring a body roller from them)

Good luck

Andy

[stuartgb100]

Neil,

The vent is fine.

Andy,

I found an endoscope for ?45, but two problems:
The end of the scope was 14mm diameter, so not going in via spark plugs.

The main problem was the focus, which was infinity down to 150mm. So
no good when you can only look when up close.

Finally settled on a combo unit from Sealey. Flexible shaft, illuminated
mirror head, and interchangeable illuminated magnet head. ?23.

If it saves a new tank, then it's a steal !

Regards,
Stuart.

[Galwaylotus]

I found an endoscope for ?45, but two problems:
The end of the scope was 14mm diameter, so not going in via spark plugs.

Just ream the spark plug holes out to 14.1mm! Then the scope will fit!!!

Sorry. Couldn't resist.

[pauljones]

surely if it worked fine on the dyno then the fuel blockage could possibly be eliminated, just a thought. my main reason for the post is i was wondering if you could post your engine spec and the results.i too have an early spyder chassis that my xflow based twink will one day appear in side.

but as i say,if it worked on the dyno then it could be a simple fault with the coil over heating.as for the fuel blockage,i have seen too many posts suggesting fuel lines/tanks being a weak link,im fitting new tank in stainless steel with larger diameter fuel lines and an electric pump with filters. expensive i know,but it eliminates the problem i think.its up to you.

[enskr]

Stuart
I, like many others here it seems, have experienced a problem which sounds pretty similar to yours. After changing most of the ignition system (including coil), fuel pump, then a carb rebuild etc, I rigged up a temporary fuel tank in the form of a 2 litre coke bottle under the bonnet, going directly to the fuel pump inlet. This solved the problem completely, so out came the fuel tank. After removing the sender unit I fished out (what looked like) a six inch length of masking tape swilling around in the fuel tank - as soon as the fuel was pumping out, the tape was trying to follow the fuel and blocking the pipe. No idea how it got there, but I don't have a locking fuel cap.
Problem now solved and has never recurred.

It was about this time I found 3 condoms taped to the side of the fuel tank......see earlier thread on "Hidden Surprises"!

Kevin

[Alex Rankin]

My '68 S3 (restored by AN Other in '89 - bought by me in '98) is suffering from this very problem at the moment - the misfiring is barely perceptible - just enough to bring on the cold sweats before the onset of sudden (engine) death. It comes and goes ever since I changed over to the Lumenition system a few years back (complete with uprated coil) but has now happened the last three outings with maximum embarassment (and some verbal abuse from indignant cyclists when I had to push it on to the cycle lane).
An hour or so later it starts fine and I can always get home OK because I haven't travelled very far in the first place - but that's not the point of owning a Lotus Elan!
I had started to suspect the coil - maybe the de-luxe one is too much of a prima donna. I recently fitted an electric fan - that cured a long-running overheating problem and I thought it might help with the conk-outs but no such luck. I also tied back the bottom radiator hose to give a bigger air gap with the coil - again no luck.
I was thinking of dumping the Lumenition system and reverting to the old points, etc but it sounds like I should maybe invest in a new coil and/or Lumenition amplifier. I still have the old coil from the pre-Lumenition days - I might give that a go first.

[stuartgb100]

Well, it seems problem solved - touch wood !

Just back from a good run, and the smile on my face is a mile wide !
yes I know - big mouth !

So carp in the tank was the problem all along. The bits I finally flushed out looked suspiciously
like dried up red loctite. The only loctite around this tank is where a PO used it on the screws
locating the sender unit, so maybe that was the source.

Thanks for all the help and support.

Regards,
Stuart.

[cjones60]

Glad it's fixes, I had exactly the same problem a couple of weeks ago, the posts on here helped
me identify the fuel line as a problem and it was choked with a red sand-like debris, i thought
it was rust at first but its more like glass.

I changed the filter (Facet and filter king) both has the red stuff in it, Supplier of filter says they
see it all the time, particularly motorcycles and they think its stale petrol that causes it, I think it
might be a bi-product of the lead replacement additive and I have stopped using it for a while.

Chris

[gjz30075]

Stuart, don't use as much as the PO when putting the sending unit back in. I didn't put anything on the screws when I put mine back in, just a good petrol resistant rtv (can't remember which) and I put it on the sealing surfaces only, and surrounding each screw hole, rather than covering the screw hole itself.

Greg

[stuartgb100]

Greg, thanks.

It's a low pressure interface between the tank body and the sender unit
so I simply cleaned all the surfaces and removed the loctite from the securing
screws.

Left the old gasket pickling in engine oil overnight.

Fitted all dry back together next day, with just a smear of engine oil on the
gasket (both sides).

No leaks.

Prefer to avoid all sealants where possible.

Regards,
Stuart.

[69S4]

I had the sender unit in and out probably a dozen time earlier in the summer trying to work out which of the three units I've got was the correct one for the car and then repairing it when it stopped working. Each time I used Welseal on the gasket but nothing on the screws and never had a leak or a weep.

About the seventh or eighth time I damaged the gasket and made one from a cereal packet. Again, Welseal on both sides and no leak. The cereal packet is still in there now and doing the job. I wouldn't had considered rtv or hylomar for fear of lumps dropping off inside the tank (although, for all I know Welseal may do the same but at least I've lived in happy ignorance for a while )


Stuart