shn7 Posted July 28, 2004 Share Posted July 28, 2004 I have a 1.8KSS which since I put it back in the car (with lightweight flywheel) is idling very erratically. It's hunting between about 750 and 2000rpm. CC over the phone suggested adjusting the fuel pressure regulator. This seemed to have no effect. So has anyone else any ideas 🤔 Bear in mind that I've not actually driven the car any distance yet, that it's 6 years old (ex-track car now re-built) and that I'm pretty sure that it idled ok before I took it out. Any suggestions for who could tune/investigate the problem in the Chichester, West Sussex area 🤔 Steve. Link to comment Share on other sites More sharing options...
Gambo Posted July 28, 2004 Share Posted July 28, 2004 You've put a light flywheel. the engine has less rotational mass to iron out the peaks and trough in the idle. it hunts so much because as it is about to stall the engine managment gives it more juice to put up the revs and stop stalling. My HPC was the same when I fitted a light flywheel. If you increase the idle to about about 1200rpm it should take out the large peaks and troughs.or just play with it untill you happy its as consitent as you can make it. hope this helps 😬 have blown something! I'm sure Link to comment Share on other sites More sharing options...
shn7 Posted July 28, 2004 Author Share Posted July 28, 2004 Gambo, I'm sure the flywheel may be a factor but I not convinced it's the only reason. I fully understand your description about the ECU trying to prevent it stalling (it sometimes fails). I have tried adjusting the little screw on top of the throttle body but with little effect. Mind you it was done in a rush this morning so perhaps another attempt is required. Steve. Link to comment Share on other sites More sharing options...
Tony Whitley Posted July 28, 2004 Share Posted July 28, 2004 Mine did exactly that when I put the new engine in (with light flywheel). After an age I tracked it down to a faulty throttle pot. It also ran as rough as a bear's arse - just about impossible to drive at less than 2000 rpm which made progress in 30 zones, er, problematical. M1 7 SMW 1.4-now-1.8K Mem.No. 10376 Link to comment Share on other sites More sharing options...
jackb_ms Posted July 28, 2004 Share Posted July 28, 2004 I have the same problem with my VVC an it's begining to get worst. What is the part number for a throttle pot? Jack Emily, The Very Yellow 21 Link to comment Share on other sites More sharing options...
Nifty Posted July 28, 2004 Share Posted July 28, 2004 Have you checked out the possiblity of inference from the HT leads with the crank sensor wire. I think it was this that Angus found was causing a similar problem with his. Keep off the straight and narrow 😬 Link to comment Share on other sites More sharing options...
shn7 Posted July 28, 2004 Author Share Posted July 28, 2004 Thanks for the ideas so far folks. Keep 'em coming and I'll check on them over the w/e. Steve. Link to comment Share on other sites More sharing options...
jackb_ms Posted July 28, 2004 Share Posted July 28, 2004 How do you find the crank wire sensor? What Do i need to look for? Jack Emily, The Very Yellow 21 Link to comment Share on other sites More sharing options...
Tony Whitley Posted July 28, 2004 Share Posted July 28, 2004 The crank sensor points into the flywheel so it's at the back of the engine on the opposite side to the starter. Angus found that the signal in the wire from there to the ECU was suffering interference from the HT lead from the coil. As for the throttle pot - £50+VAT IIRC from Rover or a tenner from a scrappy off most (all?) K Series - Rover etc. M1 7 SMW 1.4-now-1.8K Mem.No. 10376 Link to comment Share on other sites More sharing options...
Adam Posted July 28, 2004 Share Posted July 28, 2004 Its not to difficult to testthe throttle pot sensor (TPS) if you need to .... The TPS has three pins; Signal ground, +5v, and the position signal. To test it just move the throttle from closed to WOT and check that the centre pin (signal) varies in a smooth fashion from ~0.5v to ~4.5v. Might be talk rubbish, but I think.... the MEMS ecu controls the fuelling using a lookup table with load (inlet manifold pressure - MAP) and speed (rpm) as the indexes (spelling?). During idle, closed throttle, the engine is "fine" controlled by the IAVC (not sure that the correct name - a valve that allows some air to pass the throttle). On some MEMS ecus the MAP sensor is external, and on the later EU3 engines its combined with the air temp sensor. Other might use a MAP sensor internal to the ecu with a pipe connecting it to the manifold. So, check all the sensors, cables, and MAP pipe if fitted. Theres a Haynes manual called something like Engine Management that describes the Rover MEMS and how to test many of the sensors including the IAVC. Let me know if you want a copy of the relevant sections etc or email me if you want me to talk you through the tests. Link to comment Share on other sites More sharing options...
shn7 Posted July 29, 2004 Author Share Posted July 29, 2004 Adam, Thanks, I have copies of some engine sections of a Rover manual which I've not yet checked but will do over the w/e. If I need more I'll let you know. Steve. Link to comment Share on other sites More sharing options...
charlie_pank Posted July 29, 2004 Share Posted July 29, 2004 Steve, this souds like it might be a problem with one of the sensors feeding the ECU. You can check this by disconnecting any one of them (I disconnected the lambda probe to test this) which will put the car in "get you home mode" if it then runs fine, it's likely to be the fact that one of your sensor connections is dodgy or you need a new one. If you want to find out which one, you'll need to employ a lot of trial and error, or borrow an emerald so you can see all the outputs... (that might be a good idea anyway if there's one near to you, that way you can diagnose the problem PDQ regardless of whether it's a sensor or not). If you plug in an emerald and all the readings are normal, then I suspect you have a problem in the ECU itself... Link to comment Share on other sites More sharing options...
shn7 Posted July 29, 2004 Author Share Posted July 29, 2004 Good idea Charlie ❗ So anyone near Chichester got an Emerald (and s/w) they would like to bring along to assist in diagnosis? Steve. Link to comment Share on other sites More sharing options...
Adam Posted July 29, 2004 Share Posted July 29, 2004 Using an emerald sounds like a good idea... however u may still need to manually check/test the map sensor as I dont think the emarld uses that sensor??. Also remember that the "disconnect" sensor method is good to confirm that the sensor is working if there is a change in the engine running - but its not concusive, eg .. if the sensor isnt working this might have no effect, or if the real water temp and "get home" default value are the same, then removing the water temp sensor may have no effect. Lastly the usual Haynes Rover XXX manual may be useful, but the one I was referring to was specifically regarding Engine Management and cover most popular ecus including the MEMS. Good luck ... Edited by - Adam on 29 Jul 2004 12:05:02 Link to comment Share on other sites More sharing options...
Buda Posted July 29, 2004 Share Posted July 29, 2004 dodgy IACV? Link to comment Share on other sites More sharing options...
shn7 Posted July 29, 2004 Author Share Posted July 29, 2004 OK got someone (thanks Neil) willing to bring an Emerald along. Now all we need is a suitable map for my engine. Can anyone supply an Emerald map for a 1.8K Supersport? Steve. Link to comment Share on other sites More sharing options...
Nifty Posted July 29, 2004 Share Posted July 29, 2004 Can you not get someone with diagnostic equipment to read this adta from your current ECU 🤔 Keep off the straight and narrow 😬 Link to comment Share on other sites More sharing options...
shn7 Posted July 29, 2004 Author Share Posted July 29, 2004 Nifty, Probably but that would most likely involve paying and I'm being a cheapskate. Besides I quite fancy seeing/playing with an Emerald as I've heard lots but have no experience of it. Steve. Link to comment Share on other sites More sharing options...
Kevsta Posted July 29, 2004 Share Posted July 29, 2004 I'm having the same problem (hope its ok to jump in on this thread as no point covering it twice-only mine's a 1400 SS with lightened flywheel-connection?!) I'm gonna have a quick try at adjusting the idle, especially as the guy before me put new sensors just about everywhere. Anyone know how to do this (will get hold of manual hopefully before weekend but just in case) Regards Kev Link to comment Share on other sites More sharing options...
Adam Posted July 30, 2004 Share Posted July 30, 2004 Kevsta, I dont think you can adjust the idle speed. The MEMS will be operating the air flow in a closed-loop fashion to control the idle speed (together ignition adv & fuel mixture/lambda), eg if you "open" the closed throttle position the ecu will counter act that by closing the IACV (the valve that allows air to by pass the throttle butterfly). Thats if all is well and the temp sensors, IACV etc are working. Check the rover manuals, but I think the throttle needs to be closed at idle so the air flow is completely controled by the ecu/iacv. The ecu "target" idle speed will be a function of coolent/air temp and possibly a few other variables. If all is not well and the ecu cant control the idle, you may be able to manually set the throttle for a good idle, but mostly only at some particular operating environment, eg when the engine is hot but not when cold etc. Edited by - Adam on 30 Jul 2004 01:06:51 Link to comment Share on other sites More sharing options...
shn7 Posted July 31, 2004 Author Share Posted July 31, 2004 😬 😬 😬 Problem solved. A quick look this morning has revealed that the pipe from the throttle body to the ECU wasn't fully pushed onto the ECU, Doh! Now ticking over smoothly at a tad over 1k rpm. Steve. Link to comment Share on other sites More sharing options...
Adam Posted July 31, 2004 Share Posted July 31, 2004 Glad u got it sorted. That pipe was prob for the MAP (engine load) sensor. Link to comment Share on other sites More sharing options...
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