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[Bojan]

Few days ago I had my first problem with wifes Rover 25 (2000, 1.6 engine) - it didn't want to start in the morning -> the starter motor just clicks, and wouldn't turn over -> took it off, tried on direct power and it started working -> put it back on and it worked like a charm. I think it was either stuck, or had a bad earth on it (accidantly making it good while removal-refiting). All in all, it works fine now.

However, since that, I have a problem with idle -> somethimes is OK, around 900rpm, but more often it is 1000-1500RPM, and sometime it starts rising up to 3000 or 4000rpm (it doesnt hold that highe, it just jumps 1000-3000 or 1000-4000 rpm).

When driving with pressed accelerator (then the IACV is not working), all perfectly fine.
Sadly, it's a MY 2000 car, so it's not ODB2 - can't scan the errors, and see the live data wiht universal diagnostic tool 

So far - checked for leaks (there are none), reseted the TPS/IACV (pedal trick), cleaned IACV.

Have been reading on other forums (rover ones), but no answer. Came across terry paget's situation on one of them, so decidet to post here.

[terry paget]

I had changed the head gasket on daughter-in-law's Rover Streetwise. On reassembly I plugged the leads in where they fitted, and the car would not idle properly, though the engine ran. I twice replaced the idle control valve with no improvement. Then I learned that the connectors for the idle control valve and the cam sensor were identical, and both leads branched out of the same harness. I swopped the connectors over, and the car has run perfectly ever since. I was amazed, and miffed, that the two connectors were the same, thus allowing me to make this error - bad design I call it.

I put the picture of the two leads on this forum recently, after the Rover passed its MOT. If not easily found, let me know and I will post it again.

[TheBoy]

If its a 1.6 25, it'll have MEMS3 which *IS* ODBII compliant, but pre 2001 versions have the functionality purposely disabled (good old BMW).

Anyone with a Testbook can re-enable the OBDII capability


Erratic idle, the ICV or an air leak would be my first 2 ports of call.

[Bojan]

Regarding the ODBII -> it's really frustrating finding definitive info on this. Some say MEMS3, some say MEMS 2J. Will check the connectors on the ECU today. Also, some say that 2000 25 1.6 was MEMS 2J.
When I was trying to plug diagnostics (MaxiDAS and Bosch) it was dead - it has ODB connector, but no K-line.
No T4 nowere near here. 

Terry - now I see what happened in your case -> really poor design, putting two identical conectors so close.

Regarding my problem -> I've pinpointed to IACV -> when on high idle (around 2000rpm) i've unpluged IACV inlet pipe, cover it with finger and engine stalls. So I know that all the air is coming trough the IACV.
Turn it of, unpluged the IACV, and it runs on 900rpm idle (for now, at least).

So, it's defintely problem in IACV openining too much -> now I just need to find out is it broken, or the ECU says to him to open that much, or there is a problem in wiring between ECU and IACV.
Will try Autocom CDP+ today.

Also, by any chance, does anybody know what is pin layout for the IACV connector, and what read-outs should I have?

[TheBoy]

Regarding the ODBII -> it's really frustrating finding definitive info on this. Some say MEMS3, some say MEMS 2J. Will check the connectors on the ECU today. Also, some say that 2000 25 1.6 was MEMS 2J.
When I was trying to plug diagnostics (MaxiDAS and Bosch) it was dead - it has ODB connector, but no K-line.
No T4 nowere near here. 

All Rover 25s without VVC are MEMS3. MEMS2J used on 1.8 VVC 25's.

(excluding L series diesel, obviously)


Pre 2001 had OBDII disabled in software, this is enabled by applying the latest tune (basically, firmware) to the MEMS3, but does need Testbook.  Any nearby Rover specialist should have access to this, or they occasionally come up for sale (but pricey as its a full laptop set).  T4 mobile occasionally comes up cheaper on its own, and can do most items on 25, but the software install on a laptop isn't straightforward, and best left to computer junkies.

[Bojan]

Just to report - installing new IACV cured the problem