S4S

[pytliks]

hello, ..on warmup, idle is fine at about 1300rpm and drops automatically to about 1000, I am touching the throttle to bring it slowly up to 2000 then it breaks down, some backfire, maybe hits 2300 then drops off to about 1900 and its ok, cycles repeat like this...have run freescan, replaced Lambda O2 sensor, new fuel pump, new crank sensor....have some relays on order...

anyone close to me who could have a look, anyone had a similar problem ? Melton Mowbray, Leicestershire (midway between Leicester/Nottingham/Grantham/ Stamford....

thanks, paul

[lotus4s]

Sounds like bad plug or plug wires.....

[pytliks]

had new plugs but must say will look at leads... but why so critical around 2000rpm? its perfect up till then...

[pytliks]

I did run the engine at night, hoping to see some sparks across leads but it was clear...

[fmxa]

Have you changed the chip/memcal recently? Or how about the fuel filter (long shot)

Edited November 12, 2005 by fmxa

[pytliks]

no chip changes...it seems strange to break down so specifically?..after its warmer, might get to 2300 but she's struggling and inevitably falls back to below 2000...

[fmxa]

How about the fuel filter?

[pytliks]

no, didn't change that?...might be an idea...the engine does feel better as temperature increases...

[Paul C]

The ECU has a 'get (limp) you home' mode when a serious fault occurs.

Not sure if it limits the revs this low, but one of our more tech people

(Dermot?) might be able to tell you if this is a possible cause of your

problem.

[pytliks]

hi Paul, the freescan software showed following fault...have some relays on order from Lotus, should be here on tuesday, but will also get a fuel filter... have attached the reading....

[pytliks]

thanks, fmxa, maybe the warm/ dry California air would help??...

[pytliks]

can eliminate fuel filter, as fitted new one, same result.... can anyone provide scenario, if say the timing belt had come out of synch, could you get this effect??...spark advance looks to be operating normally....

[hovgaard]

Fuel pump?

[pytliks]

hi Jens...new fuel pump fitted recently...

[hovgaard]

Yes, I should have noticed...

Disconnect battery for 5 mins?

[x6gas]

Stick the most obvious:

You have a freescan log saying that there is a problem - this is the most likely source and I'd eliminate that before doing anything else.

Some cars have a a double contact relay for the fuel pump and the injectors and another for "ignition supplies (rear)" whatever that is! Both relays are part number A082M6182F.

I'd swap both of these out before doing anything else. If that clears the fault code and you still have the problem then you can look for a mechanical solution safe in the knowledge that the engine management is OK.

By the way, these are almost certainly standard relays - probably available from Halfwits / your local auto factor - no need to pay Lotus prices...

[mchlrodrigues]

hi Jens...new fuel pump fitted recently...

<{POST_SNAPBACK}>

How's the TPS reading?

Is it possible the over run fuel cut off is acting up? That is, above a certain rpm and below a certain TPS (often 2%), the ECU will cut the injector signal on the overrun to reduce fule consumption and emissions. Injection is resumed around 1400 rpm or so.

I'm guessing that something is causing the ECU to shut off the injectors incorrectly. Could be an incorrect TPS reading or calibration.

No DTC's?

Michael

[pytliks]

well guys...GOOD NEWS...had an email from Lotus Technical Dept this morning '' Try reversing the two cables on the engine speed sensor'' (had a new one fitted 12 months ago) and had this problem allied to a couple of other items, since then...am advised a manufacturing fault had occurred but Lotus did not do a recall or advise buyers!!!!!...to say i'm pissed off with the factory is putting it very mildly !!!!!!...i'm livid....but happy that engine revs to over 5500 with no difficulty !!!!...thanks all,,,

[hovgaard]

A bit hard to guess, that one...

[pytliks]

so right Jens, would have to be a fortune teller !!!!!!!!!!

[Paula&Marcus]

Hi,

Is the EBPV (= Exhaust Back Pressure Valve) operating properly ???

Maybe its stuck close ... ?

Marcus

[pytliks]

hi Paul & Marcus...all problems solved...see my earlier information News....thanks, paul

[pytliks]

sorry, its Paula and Marcus... anyway have written to Lotus CEO about the poor quality control of parts supplied, 6 weeks ago also had to exchange a defective new fuel pump...wrongly wired up at manufacture, engine speed sensor, hope the new timing belt is ok??....