No power.

[stevieg8571]

Hi,
I went out this afternnon in the car and all was OK for the 1st minute or so but after that Icould only get it to drive if I left the revs below 1500ish. Any more than that and it wouldn't go. It'd either cut out, or cough and splutter until I'd got off the accelerator completely.
It'd idle and start perfectly without the engine light coming on, just seems to want to stay below 1500revs.
The RAC guy could connect to the ALDL, but didn't have Lotus in their system and therefore couldn't get any comms with the ECU.

Anyone got any ideas? CAS maybe?

I'm going to look for get the info on getting the codes now and see what's amiss.

Thanks, Steve.

[stevieg8571]

Hello again.
Code 34's flashed up.

Manifold Absolute Pressure sensor (Low voltage/High vacuum)

Does anybody know where this is and what it does? Does what I've described sound like what would happen if it failed?

I've emailed SJ and paul Mattys for a price as they're not listed. are they much?

I was going to MOT it yesterday, timing eh!!

Thanks for your help.
Steve.

[Dovey]

Is it an s2 by any chance?

[johnbenk]

Hi

MAP SENSOR FOUND under BULKHEAD. MAP SENSOR is a solid state sensor which is provided with a 5 volt ref: source and an earth and produces an output signal to indicate intake maifold pressure.

If you are reading a code 34 you could do a "non-scan" Diagnostic Check.

You need to clear code 34 First.( Remove Battery Leads) then reconnect.

Next Disconnect MAP sensor and jumper harness connector terminal "B"
and "C" So that Diagnostic teminal not grounded.

Start engine run for one minute or until check engine light comes on.

Ignition "ON" engine stopped. Ground diagnostic terminal and note CODE.

If CODE 33 REPLACE MAP SENSOR.

If CODE 34 remove jumper from "B" to "C" check voltage between connector terminal "A" and "C" using volt meter.

If 4 to 6 volts check for short to ground in CKT SR11G INTERALLY SHORTED TPS ----if OK check CKT SR11G is OK or faulty ECM connector
or ECM.

Below 4 volts check circuit UO11F for open or shorted to ground internally shorted TPS-----if OK check for faulty ECM connector terminal or ECM (see below picture sorry not very clear

[F1 LOTUS]

Hello again.
Code 34's flashed up.

Manifold Absolute Pressure sensor (Low voltage/High vacuum)

Does anybody know where this is and what it does? Does what I've described sound like what would happen if it failed?

I've emailed SJ and paul Mattys for a price as they're not listed. are they much?

I was going to MOT it yesterday, timing eh!!

Thanks for your help.
Steve.

From the drivers-side (RHS) end of the intake manifold there is a right-angle tube fitting, the tube is the pressure / vacuum take off for the MAP sensor which you should be able to find by following the hose to somewhere below the centre of the windshield

[stevieg8571]

Thanks for the replies guys.

It's a 91(J) SE.

[johnbenk]

Information can be obtained page EMK Lotus SERVICE NOTES EMPPFI (open loop)

[a5gcd]

Steve

I had the same problem as this a few weeks back. The actual fault was only a split vacume hose. Where the hose connects to the plenum chamber there is a small detachable elbow that had perished and split.

It cost me £0.60 at a motor factors to replace it.

Check the pipe for splitting before you do anything else.

Good luck Geoff

[Enright]

Ah yes, I remember now - I had that happen to me too.
I was told most people just remove it.

[ESM]

I think the 90° angle piece Enright13 and a5gcd are talking about is not the same one - its behind the throttle body and its pipe goes to the vacuum reservoir. The pipe that goes to the MAP sensor (as Brian said) is at the other end of the plenum. I wouldn't try to remove its 90° section.

[stevieg8571]

All appears to be fixed..for now.

After clearing the fault codes by disconnecting the battery, I simply pushed the connector upwards and felt that it wasn't in properly.
It's connecting properly electrically, but won't travel up into the sensor enough for the catch to engage on the clip so I've tie-wrapped it on which will hopefully keep it in place/stop it sliding out.
All the hoses that I thought were involved with the MAP seem to be OK, and as I've driven around 50miles today, included getting the car MOT'd (no probs at all ) I should be able to enjoy another day of roof-down driving tomorrow.
I've one more question though. To clear the ECU's fault codes, do you have to disconnect the battery, or can you disconnect the ECU itself, therefore not having to reset the radio, clock and disconnect the alarm?

Thanks again for all you help, Steve

[JLSELAN]

If there are no other problems, the ECU fault code(s) should clear themselves after some number of fault-free engine starts (maybe 10 or 20).

[stevieg8571]

Thanks for the info JLS, but I'm curious to know if simply unplugging the ECU will clear all fault codes too, without having to wait for 50 engine starts, or disconnecting the battery?
I know this happens on other GM cars so thought it may be applicable here too. it is far easier it seems.

Thanks, Steve

[Doug]

I'd recommend undoing the negative lead to the car battery for a minute to clear the codes--or it is 50 starts you have to do before it is gone from the memory in ElanScan. You could unplug the ECU but there's slight risks of stunning the ECU with voltage or a shock or of messing up one of the contacts in the harness lead--and then you'd be pissed off! Leave that sleeping dog lie and work it from the battery . . .

[stevieg8571]

Thanks Doug, I think it'd probably be best to keep it safe by using the battery neg method. Hopefully I won't need to do it too many times anyway.
Steve