Lotus Elan

Fuel Pump problems?

PostPost by: elan4me » Thu May 17, 2007 3:48 am

I continue to have a problem with my 69 elan s4 sputtering and almost stalling at 4000 - 4500 rpms in 4th gear, especially under load. It was recommended that it might be the fuel pump. Does that make sense? If so, should I rebuild the pump or put in a electric fuel pump? If so, any recommendations? The weather here in California is too nice not to be out motoring about.
Thank you
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PostPost by: rgh0 » Thu May 17, 2007 10:51 am

If the problem has come on suddenly it could be fuel pump, could be ignition, could be something else.

Is the problem in all gears at same revs or only top, does it happen at part throttle at same revs or only full throttle at 4500 rpm.

regards
Rohan
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PostPost by: elan4me » Thu May 17, 2007 2:04 pm

It seems to mostly in 3rd and 4th gears, and not really under full throttle. I will be cruising along at about 68 give it some gas to increase my speed and it starts to miss. If I take my foot of just alittle it seems better. If I give it more gas it gets worse.
I hope this additional information will help.
Thanks, Stan
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PostPost by: john.p.clegg » Thu May 17, 2007 2:34 pm

Sounds like muck in one of the main jets to me,but it could be many things ,fuel starvation related...
John :wink:
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PostPost by: davidfost » Thu May 17, 2007 3:11 pm

I had exactly the same symptoms a few years ago on a Dellorto Elan. It turned out the fuel tank to pump line was partially clogged with years of fine debris - disconnected, blown through with an air line, fixed.
Hope it's as simple for you
Pulled out of a Castle Combe track day because of the problem.....
David
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PostPost by: Rob_LaMoreaux » Thu May 17, 2007 7:20 pm

I had a similar problem after I got my car on the road. Ended up being rust particles had gotten into the fuel pump and were holding the valves partly open. I took it off cleaned it up and moved the fuel filter to before the pump not after and it was better. I also had a similar issue when the float valve in one of the carbs was sticking. They were new float valves that were junk. I replaced them with NOS ones the guy at the local parts store had in his garage and everything was better.

But it does sound like not enough fuel

Rob
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PostPost by: Frank Howard » Thu May 17, 2007 9:54 pm

Rob,

Your answer reminded me of an experience I had with my TR-4 37 years ago. I put some fuel system cleaner in the tank and that stuff really works. It gathered up all the crud in the tank and sent it straight to the fuel pump where it quickly plugged it up, stopping the car. When I took the pump apart, I removed a lot of fuel tank debris from the tightest spot in the pump, right where the line enters it.
Frank Howard
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PostPost by: elan4me » Fri May 18, 2007 4:47 am

I did have some rust and/or muck in the tank. Although I have had filters in the gas line, one before the fuel pump and one before the carbs. It sounds like it is time to do a complete cleaning of the fuel system. I have already had the tank boiled out and it is clean. I will continue to work my way to and through the carbs.
Thank you for all your responses.
Stan
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