S1 Elise Fuel Problem
Discussion
Hi,
Last week my 1999 S1 Elise broke down on the motorway. It was if the car ran out of fuel and it would not start again. The AA brought it back on a truck.
A couple of days later the car started OK and so I thought it may be a fuel problem. I've replaced the fuel filter and just taken it around the block but it does still have a fuel issue. If i floor it the car has fuel starvation symptoms. The car runs fine if I go slow or idle. I've never had this problem before it broke down.
I've filled the fuel tank up to eliminate that.
I have noticed in the past year that the fuel pump seems louder than normal.... but this may just be me getting used to a modern car and just driving the elise on the weekend etc !
The car has 35k miles and an emerald ECI tune up.
Anybody got any idea what it may be ? carb blocked ? fuel pump on it's way out etc?
Thanks
Tom
Last week my 1999 S1 Elise broke down on the motorway. It was if the car ran out of fuel and it would not start again. The AA brought it back on a truck.
A couple of days later the car started OK and so I thought it may be a fuel problem. I've replaced the fuel filter and just taken it around the block but it does still have a fuel issue. If i floor it the car has fuel starvation symptoms. The car runs fine if I go slow or idle. I've never had this problem before it broke down.
I've filled the fuel tank up to eliminate that.
I have noticed in the past year that the fuel pump seems louder than normal.... but this may just be me getting used to a modern car and just driving the elise on the weekend etc !
The car has 35k miles and an emerald ECI tune up.
Anybody got any idea what it may be ? carb blocked ? fuel pump on it's way out etc?
Thanks
Tom
would not assume the pump is the problem, not saying it's not, but don't start there.
worth tracing the wiring back as the plugs on this can be problematic, the last thing to check is the pump itself, as this required the fuel tank to be removed from the car.
in order check:
1) inertia switch (Black thing bolted to the LH longeron close to the ECU)
2) then get somebody to turn the ign on whist you stick you head next to the MFRU and listen for the click of the fuel relay (what you waiting for is the click some 5 sec's after the ign as it turns the pump off).
3) the fuse
if all of these are OK, then it's probably the imob, they do this.
if you have a meter, then follow the power for the pump, it goes:
1) starter solenoid (Brown wire with black sleve on it)
2) fuse
3) Engine Harness connector 3 Pin 2
4) MFRU Big plug pin 4
5) MFRU Big plug Pin 1
6) Engine harness conector 1 Pin 4
7) Imob in
8) Imob out
9) Fuel tank harness connector
10) fuel pump
worth tracing the wiring back as the plugs on this can be problematic, the last thing to check is the pump itself, as this required the fuel tank to be removed from the car.
in order check:
1) inertia switch (Black thing bolted to the LH longeron close to the ECU)
2) then get somebody to turn the ign on whist you stick you head next to the MFRU and listen for the click of the fuel relay (what you waiting for is the click some 5 sec's after the ign as it turns the pump off).
3) the fuse
if all of these are OK, then it's probably the imob, they do this.
if you have a meter, then follow the power for the pump, it goes:
1) starter solenoid (Brown wire with black sleve on it)
2) fuse
3) Engine Harness connector 3 Pin 2
4) MFRU Big plug pin 4
5) MFRU Big plug Pin 1
6) Engine harness conector 1 Pin 4
7) Imob in
8) Imob out
9) Fuel tank harness connector
10) fuel pump
Hi Scuffers,
Do you think it could be electrical even though it's only when I floor it?
I.e. it works fine when idle or at low speed.
Also given that filling the tank up and replacing the fuel filter the problem persists.... i would have thought a weak fuel pump may have worked better with a full tank etc?
I will go through your list mind ...... unless anyone else has an idea.
Cheers
Tom
Do you think it could be electrical even though it's only when I floor it?
I.e. it works fine when idle or at low speed.
Also given that filling the tank up and replacing the fuel filter the problem persists.... i would have thought a weak fuel pump may have worked better with a full tank etc?
I will go through your list mind ...... unless anyone else has an idea.
Cheers
Tom
yes, low voltage = low fuel pressure....
putting a meter across the pump connections to see what you have would be a good start, if it's within ~1V of battery, then it's the pump, else it's the wiring.
replacement pump is here
and it's a fuel tank out job....
putting a meter across the pump connections to see what you have would be a good start, if it's within ~1V of battery, then it's the pump, else it's the wiring.
replacement pump is here
and it's a fuel tank out job....
Edited by Scuffers on Saturday 23 July 19:18
I'm having a bit of a nightmare with this!
I've looked at the electrics and I can't see any obvious bad connections.
- The fuse next near the ECU is fine.
- The MFRU is clicking off after the pump has primed on ignition on 5 sec.
I can't seem to access the pump electric's to test the voltage (the access whole is very small).
LBird - Did you say you had exactly same symptoms? i.e. car starts fine, pump seems to prime, but when you hit the gas you get fuel starvation? and for you it was the fuse?
Looking at the diagram the fuel pump has chambers and if one of these is not filling quickly enough it might be the cause.
Planning this weekend to try and access the electrics on the pump to see if I get 12v and if not I'll be dropping the tank to replace the pump.... i wish i had a car lift !
I've looked at the electrics and I can't see any obvious bad connections.
- The fuse next near the ECU is fine.
- The MFRU is clicking off after the pump has primed on ignition on 5 sec.
I can't seem to access the pump electric's to test the voltage (the access whole is very small).
LBird - Did you say you had exactly same symptoms? i.e. car starts fine, pump seems to prime, but when you hit the gas you get fuel starvation? and for you it was the fuse?
Looking at the diagram the fuel pump has chambers and if one of these is not filling quickly enough it might be the cause.
Planning this weekend to try and access the electrics on the pump to see if I get 12v and if not I'll be dropping the tank to replace the pump.... i wish i had a car lift !
tomgoring said:
I'm having a bit of a nightmare with this!
I've looked at the electrics and I can't see any obvious bad connections.
- The fuse next near the ECU is fine.
- The MFRU is clicking off after the pump has primed on ignition on 5 sec.
I can't seem to access the pump electric's to test the voltage (the access whole is very small).
LBird - Did you say you had exactly same symptoms? i.e. car starts fine, pump seems to prime, but when you hit the gas you get fuel starvation? and for you it was the fuse?
Looking at the diagram the fuel pump has chambers and if one of these is not filling quickly enough it might be the cause.
Planning this weekend to try and access the electrics on the pump to see if I get 12v and if not I'll be dropping the tank to replace the pump.... i wish i had a car lift !
Sorry for the delayed reply.I've looked at the electrics and I can't see any obvious bad connections.
- The fuse next near the ECU is fine.
- The MFRU is clicking off after the pump has primed on ignition on 5 sec.
I can't seem to access the pump electric's to test the voltage (the access whole is very small).
LBird - Did you say you had exactly same symptoms? i.e. car starts fine, pump seems to prime, but when you hit the gas you get fuel starvation? and for you it was the fuse?
Looking at the diagram the fuel pump has chambers and if one of these is not filling quickly enough it might be the cause.
Planning this weekend to try and access the electrics on the pump to see if I get 12v and if not I'll be dropping the tank to replace the pump.... i wish i had a car lift !
Yes, the problems you describe are exactly the same as those I experienced for both the failing fuel pump AND the faulty fuse (hence the over-hasty replacement of the fuel pump when the problems started occurring on the second occasion).
Even though the fuse seems fine, have you actually tried replacing it? Mine looked fine too and replacing it was based on the philosophy that if you've tried all the most likely things and there is one thing that really CAN'T be the cause of the problem, then it probably IS the cause of the problem....
Keeping fingers crossed for you!
It may be a bit late now but it is possible to check the pump without taking it out. If you measure fuel pressure and flow that tells you pretty much all you need to know. Aside from this you can check the current draw on the pump and if you view it on a scope you can even check the segments of the commutator.
I think with a job like this it could have been worth while paying someone to check the pump.
I think with a job like this it could have been worth while paying someone to check the pump.
Hi All,
Finally got around to fitting a new fuel pump.
The new one does sound different like when it primes it's actually coming under pressure.
Now my problem is the car won't fire at all!
I've check for a spark at the plug and that's OK.
If I loosen the fuel line when the pump primes fuel comes out under pressure, so I guess my new pump is working.
I'm stumped ! any ideas ?
Finally got around to fitting a new fuel pump.
The new one does sound different like when it primes it's actually coming under pressure.
Now my problem is the car won't fire at all!
I've check for a spark at the plug and that's OK.
If I loosen the fuel line when the pump primes fuel comes out under pressure, so I guess my new pump is working.
I'm stumped ! any ideas ?
Sounds like identical symptoms to what I've experienced i.e. car cuts out, won't restart but wait a while and it'll re-start but only runs for a short time before cutting out again.
I had this problem last year and solved it by cleaning out a large amount of corrosion debris that had built up inside the tank and collected around the fuel pump pick-up gauze filter. There was also fine debris inside the plastic fuel pump canister which could hold open the rubber one-way valve in the bottom of the canister.
One of the symptoms was that when trying to re-start immediately after the engine cuts out, you could hear the pump overspeeding as though there was no fuel in the tank. Trying again after a few minutes and the pump runs at normal speed so I suspect the plastic canister (which is in effect the reservoir for the second, high pressure stage of the pump) empties and the pump runs dry.
Did you find the cause of your problem?
I've just had the same problem again only a year, and again there's corrosion debris in the tank and pump! I'm considering treating the tank with a liner compound and/or magnets to catch the debris (because it's all ferrous material), but if you've found any other causes I'd be interested to hear.
Cheers,
Martin
I had this problem last year and solved it by cleaning out a large amount of corrosion debris that had built up inside the tank and collected around the fuel pump pick-up gauze filter. There was also fine debris inside the plastic fuel pump canister which could hold open the rubber one-way valve in the bottom of the canister.
One of the symptoms was that when trying to re-start immediately after the engine cuts out, you could hear the pump overspeeding as though there was no fuel in the tank. Trying again after a few minutes and the pump runs at normal speed so I suspect the plastic canister (which is in effect the reservoir for the second, high pressure stage of the pump) empties and the pump runs dry.
Did you find the cause of your problem?
I've just had the same problem again only a year, and again there's corrosion debris in the tank and pump! I'm considering treating the tank with a liner compound and/or magnets to catch the debris (because it's all ferrous material), but if you've found any other causes I'd be interested to hear.
Cheers,
Martin
Hi ALL,
I changed the fuel pump in the end and it was I right pain to do on axel stands.
Problem still persisted ... In the end turned out to be faulty leads, got a spark ok when idle but as soon as it exceeded certain revs it would fail to spark correctly ... Could have fixed it v easily if I changed that first !
On the whole a good reliable car ... First problem with her in 12 years
Tom
I changed the fuel pump in the end and it was I right pain to do on axel stands.
Problem still persisted ... In the end turned out to be faulty leads, got a spark ok when idle but as soon as it exceeded certain revs it would fail to spark correctly ... Could have fixed it v easily if I changed that first !
On the whole a good reliable car ... First problem with her in 12 years
Tom
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