MEMS not happy

[Tony Whitley]

I have replaced my EU2 1400 SS engine with a standard (118 bhp) 1800 from an Elise (using the SS inlet with Elise injectors) and although it's on the road I can't get it to run anywhere near properly. The biggest problem is the MEMS going into what I guess is a breakdown mode - the engine will only tick- over, any press on the throttle makes it cough and threaten to stall. This seems to happen when I boot the throttle (four or five times so far in 50 miles or so, the car starts to accelerate then the power dies completely) but is instantly cured by turning the engine off and starting it again.

 

Other problems that may throw some light on the cause: I have to "baby" the throttle for about 30 seconds after starting before it will idle on its own; then the revs at idle are completely unstable, dropping very low before the IACV kicks in and takes it back up to 1500 or so, cycling continually; the car hesitates when I press the throttle though otherwise performance is "adequate".

 

I've reset the MEMS by pressing the throttle five times (though is there anyway you tell if it has reset?) I've arranged to plug in

an Emerald next week so I can see what all the sensors are doing but I want to explore the performance NOW - and more important, I'd like to be able to overtake with the knowledge that the engine is not going to die at a crucial moment.

 

M1 7 SMW 1.8K Mem.No. 10376

[dogvet_rules_ok]

tony are you running the 1400 supersport mems and a 1400 flywheel?

[Tony Whitley]

Yep.

[Myles]

Erm, maybe completely off the ball - but yesterday I was tinkering with my EU3 1.6k (bleedin' temp sender again) when I unplugged both the MEMS temp sender plug and a plug that fits into the engine-side of the plenum near the rear of the engine (NOT the IACV, IMHO - that's close by - perhaps the TPS although I might have them confused).

 

I refitted the plugs and tried to start the engine - it was really unhappy, but finally fired - and got stuck at 1500RPM (IIRC) and absolutely hated any attempts to rev.

 

I reset the MEMS by using the FIA battery switch, and it was then fine.

 

Note - if it *is* your TPS, then doing the manual MEMS reset (i.e. 7-13 presses on the accelerator with ignition on, then turn ignition off again) probably won't work...

 

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[Tony Whitley]

The "plug that fits into the engine-side of the plenum near the rear of the engine" is the Intake Air Temperature sensor I think (the description is slightly confusing as mine is an early model with the throttle stuff in the nose of the car rather than at the back of the engine, with the IAT on the inlet manifold). Anyway, good thinking, I'll re-check the various signals at the MEMS plug.

[fordy]

Tony,

 

I thought idea behind that conversion was to retain the supersport ECU AND the supersport cams ??

 

Maybe your supersport mems is not running happy on standard cams?

 

As far as I know, supersport cams are the same whether 1.4, 1.6 or 1.8 (except the 1.4SS 'race' engine for mechanical tappets). Same with the standard cam.

[Peter Carmichael]

It is just running lean. MEMS doesn't have a "get you home" mode. My bet is you need to up the fuel pressure a good bit to get the fuelling right.

[SLR No.77]

I've re-read your original post a couple of times and I'm still unsure whether you're running standard or SS cams 🤔 The 1400 SS mems is going to work better with SS cams. The only item that you may need to also modify is the fuel pressure regulator, although in the past this has not been found to be necessary (on 2 known conversions anyway!). Fordy is correct that all SS cams (apart from 1400 race ones) are the same - the same mems ecu is used for the 1400 race cams but the profile is different needing the vhpd solid followers.

 

Green plug on rear of plenum is inlet air temp sensor. Check also you have the 2 water temp take-offs fitted correctly at the back end of the water rail - one is for the gauge, the other lets the mems know the engine temp.

 

You refer to your inlet being the early type - if it's the plain/black ali version with "Supersport" cast into the top, it's actually a bigger bore item fitted to the 1400 Supersports, with a bigger throttle body - IIRC 52mm. the 1600 & 1800 Supersports have the standard poxy plastic manifold & TB. This goes someway to explaining (along with valve sizes) the proportionately better performance of the 1400 SSs relative to the 1600/1800 versions.

 

Stu.

[Tony Whitley]

Sorry for the confusion - I still have the standard 1.8 cams as the SS cam bearings are shot - cause or effect of the original failure, I don't know. I was hoping just to get the car running, less than optimally but reliably, until I can fit another SS head I have lined up.

 

I've checked the inputs to the MEMS and they are all there, in particular the throttle pot goes from 800R to 5K ish which is about right.

 

Maybe I'm chasing two faults - fuelling/MEMS/cams plus an intermittent electrical fault ☹️ I set off this evening and the engine died (completely this time, not just "tickover only") without apparent cause after half a mile. I parked, turned off the ignition, turned it back on and everything was fine. I can't see that that's lean mixture or anything which is why I postulated a "breakdown mode" although I haven't found anything like that in the literature.

 

Le Mans in three weeks 🤔

 

M1 7 SMW 1.8K Mem.No. 10376

[Delberts Wallet]

Tony, If you need one I have a spare 1.6 non SS MEMS kicking around. You'll have to get it matched to the immobiliser but your local rover dealer should be able to sort that out.

 

Blue and Carbon 6 Speed Supersport

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[Mick Day]

The other thing to check is the coil. Are you running the original "Land Rover" coil mounted on the pedal box or the later coil mounted on the side of the engine? With the 1400 supersport mems & flywheel you should retain the LR item.

[Tony Whitley]

I think (hope) I've found the problem. The crank sensor is slightly different on the Elise engine - it only has a screw on one side of the sensor [ x O rather than x O x ]. I couldn't work out how to connect the Elise one so I used the 1400 one and I don't think it was quite in the right position. I had a fiddle this evening and it seems better - still running as rough as bear's 🙆🏻 but no longer conking out. I hope connecting an Emerald will show me more.

 

Where's the "fingers crossed" smiley 🤔

 

M1 7 SMW 1.8K Mem.No. 10376

[SLR No.77]

My 1400 cps is bolted into the 1800 block using just one of the screws. Apart from the addition of a 2nd threaded hole in the 1400 block, all the dimensions of and around the hole are identical on the 2 blocks. This appears to have purely been a cost saving measure by Rover. ie. 1400 cps should perform perfectly in the 1800 block.

 

Stu.