More anomalies!

CMOORESY · 11th March 2020, 17:29

I have owned my latest rover 75 since new year, and I have to say, its a reasonably good one. Its my 3rd diesel auto and replaced my ZT diesel outo of 9 years standing.

I have swapped all the little mods from my ZT to make it a bit more reliable and have attempted to cure its sluggishness with varying degrees of success -

Replaced EGR valve with a dummy one
Cleaned out inlet manifold and Map sensor

Still sluggish,

Replaced air filter with K&N, Inter-cooler Viton O rings, silicon inter-cooler top hose.

Still sluggish

Fitted new thermostat (in line type in top hose), cleaned MAF sensor.

Still sluggish

Gave a dose of high quality fuel injection / turbo cleaner

Still sluggish

Unplugged the MAF - GREAT! It now drives like it should, exactly like my ZT did. It was the MAF all along.

Now here's where I noticed something strange. When I unplugged the MAF on my ZT, the engine management light came on and on reconnecting I had to turn the ignition off/on 40 times I think to reset the light so it went out.
On this Rover 75 its not on? The engine management light works and extinguishes, so its not taped over, but it remains off with the MAF unplugged.
Another anomaly that I discovered only today, was that the car will start with the auto selector in any gear! You can start-up and then whizz off backwards if you leave it in reverse or forwards if in a forward gear.

What am I dealing with here. how is this so...

COLVERT · 11th March 2020, 17:38

Sounds like the detent safety switch on the selector lever has decided it's not going to work any more.--

Urgent fix needed before you run yourself or somebody else over.----

---Fix it NOW.---

Mike Noc · 11th March 2020, 17:53

Only the later cars will show an alarm when the MAF is unplugged.

As for the car starting in any gear maybe the wrong ECM is fitted and it thinks it is a manual?

.

CMOORESY · 11th March 2020, 17:58

Thanks,
Its a late car on a 54 plate Mid October 2004.

My Previous ZT was on an 04 and this showed the engine management light when the MAF was unplugged and also wouldn't start in gear!

It the safety switch on the selector easy to get at?

Mickyboy · 11th March 2020, 18:08

It’s plausible that it’s had an ECM kit swapped over due to a blocked plenum chamber at some point and now has a ECM from a manual vehicle fitted, you can tell if it has the original ECM just by removing it from the plenum chamber and looking at the Vin number that is labelled on the ECM,

We have 4 different ECM types that are fitted to the 75 and ZT range they are as follows
NNN100692 MK1 manual
NNN100720 MK1 Auto
NNN500340 MK2 Manual and Auto
NNN100693 these I believe we faulty ones that X part had.

As you can see the MK2's use the same ecu, mainly as a cost cutting measure so they only had to stock one part

They altered the tune assemblies so that the manual and auto could share the same ECU on the MK2.

Credit for the above info goes to Brian who provided it some time ago, as for the MAF as Mike said facelift versions had a sensor by the intercooler and the removal of the MAF plug on the sensor sets off the management light for emissions control reasons.
Mick

CMOORESY · 11th March 2020, 19:22

Thanks, Interesting.
I'll check the ECU at weekend.
By Vin, do you mean the number stamped on the R/H strut top. Another anomaly with this car is that the printed vin decal on the 'B' post is blank? Looks like its either faded over time or been wiped with solvent?

If it has the wrong ECU then can the existing be rectified or will it need changing. The issue here is that its basically a near worthless car. so probably not worth going to town on swapping ECU's etc? Also the issue could lie elsewhere as in the selector?

suzublu · 11th March 2020, 19:50

Quote:

Originally Posted by CMOORESY

Thanks, Interesting.
I'll check the ECU at weekend.
By Vin, do you mean the number stamped on the R/H strut top. Another anomaly with this car is that the printed vin decal on the 'B' post is blank? Looks like its either faded over time or been wiped with solvent?

If it has the wrong ECU then can the existing be rectified or will it need changing. The issue here is that its basically a near worthless car. so probably not worth going to town on swapping ECU's etc? Also the issue could lie elsewhere as in the selector?

The plate vin should be stamped

it's also on the lower n/side windscreen.

trikey · 11th March 2020, 20:28

As the others have said, you will have a manual ECU set fitted to the car, pull the ecu and see what the NNN code is, and the SARR number, the SARR number should match the VIN on the strut top (Or your log book)

BigRuss · 12th March 2020, 07:11

Yes as the others have said likely that a manual ECU set has been fitted, had this a few times now.

If it is then it can be rectified, drop me a p.m. and I'll be able to sort that out for you.

Russ

Sheraton · 12th March 2020, 10:34

r.e the K&N Air Filter - Is it the Oiled type that fits the Factory Airbox/Housing ?

I've no experience of the Diesel - However i believe the MAF sensor may be located close enough (to the Air Filter) to allow the Oil from this type of Air Filter to affect the MAF Sensor Readings

I have this type K&N Air Filter in my 1.8t - they are Great

However I have no sensors Close enough to be affected by the Oil from the Air Filter.

worth a thought maybe

Paul.

11th March 2020, 17:29	#1
CMOORESY Avid contributor MG ZT Auto and 75 Tourer Join Date: Feb 2013 Location: Nantwich Posts: 182 Thanks: 8 Thanked 52 Times in 20 Posts	More anomalies! I have owned my latest rover 75 since new year, and I have to say, its a reasonably good one. Its my 3rd diesel auto and replaced my ZT diesel outo of 9 years standing. I have swapped all the little mods from my ZT to make it a bit more reliable and have attempted to cure its sluggishness with varying degrees of success - Replaced EGR valve with a dummy one Cleaned out inlet manifold and Map sensor Still sluggish, Replaced air filter with K&N, Inter-cooler Viton O rings, silicon inter-cooler top hose. Still sluggish Fitted new thermostat (in line type in top hose), cleaned MAF sensor. Still sluggish Gave a dose of high quality fuel injection / turbo cleaner Still sluggish Unplugged the MAF - GREAT! It now drives like it should, exactly like my ZT did. It was the MAF all along. Now here's where I noticed something strange. When I unplugged the MAF on my ZT, the engine management light came on and on reconnecting I had to turn the ignition off/on 40 times I think to reset the light so it went out. On this Rover 75 its not on? The engine management light works and extinguishes, so its not taped over, but it remains off with the MAF unplugged. Another anomaly that I discovered only today, was that the car will start with the auto selector in any gear! You can start-up and then whizz off backwards if you leave it in reverse or forwards if in a forward gear. What am I dealing with here. how is this so...

11th March 2020, 17:38	#2
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	Sounds like the detent safety switch on the selector lever has decided it's not going to work any more.-- Urgent fix needed before you run yourself or somebody else over.-------Fix it NOW.---

11th March 2020, 17:53	#3
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,547 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Only the later cars will show an alarm when the MAF is unplugged. As for the car starting in any gear maybe the wrong ECM is fitted and it thinks it is a manual? . Last edited by Mike Noc; 18th March 2020 at 20:49..

11th March 2020, 18:08	#5
Mickyboy SERVICING AND DEALER DIAGNOSTICS MG ZT CDTI 135 + & MGZT CDTI AUTO 160 & ROVER 75 TOURER CDTI 160 TROPHY YELLOW Join Date: Aug 2013 Location: Hernebay Posts: 4,331 Thanks: 818 Thanked 2,414 Times in 1,141 Posts	It’s plausible that it’s had an ECM kit swapped over due to a blocked plenum chamber at some point and now has a ECM from a manual vehicle fitted, you can tell if it has the original ECM just by removing it from the plenum chamber and looking at the Vin number that is labelled on the ECM, We have 4 different ECM types that are fitted to the 75 and ZT range they are as follows NNN100692 MK1 manual NNN100720 MK1 Auto NNN500340 MK2 Manual and Auto NNN100693 these I believe we faulty ones that X part had. As you can see the MK2's use the same ecu, mainly as a cost cutting measure so they only had to stock one part They altered the tune assemblies so that the manual and auto could share the same ECU on the MK2. Credit for the above info goes to Brian who provided it some time ago, as for the MAF as Mike said facelift versions had a sensor by the intercooler and the removal of the MAF plug on the sensor sets off the management light for emissions control reasons. Mick __________________ [SIGPIC][/SIGPIC] T4 Owner Jobs done : new UBP, Spy hole mod, Rear hub(wheel bearing),plenum cleaned and emptied, Inline thermostat fitted,Full service, In car Digital tv/DVD Bluetooth Satnav etc, Replaced UBP, Restored headlights,Fixed airbag connection.replaced HP pump,replaced rear light seals,changed intercooler O rings. Jobs to do: ,replace drivers lock,.[/SIZE] Last edited by Mickyboy; 11th March 2020 at 18:11..

11th March 2020, 20:28	#8
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,759 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	As the others have said, you will have a manual ECU set fitted to the car, pull the ecu and see what the NNN code is, and the SARR number, the SARR number should match the VIN on the strut top (Or your log book) __________________ Lest we forget..

11th March 2020, 17:58	#4
CMOORESY Avid contributor MG ZT Auto and 75 Tourer Join Date: Feb 2013 Location: Nantwich Posts: 182 Thanks: 8 Thanked 52 Times in 20 Posts	Thanks, Its a late car on a 54 plate Mid October 2004. My Previous ZT was on an 04 and this showed the engine management light when the MAF was unplugged and also wouldn't start in gear! It the safety switch on the selector easy to get at?

11th March 2020, 19:22	#6
CMOORESY Avid contributor MG ZT Auto and 75 Tourer Join Date: Feb 2013 Location: Nantwich Posts: 182 Thanks: 8 Thanked 52 Times in 20 Posts	Thanks, Interesting. I'll check the ECU at weekend. By Vin, do you mean the number stamped on the R/H strut top. Another anomaly with this car is that the printed vin decal on the 'B' post is blank? Looks like its either faded over time or been wiped with solvent? If it has the wrong ECU then can the existing be rectified or will it need changing. The issue here is that its basically a near worthless car. so probably not worth going to town on swapping ECU's etc? Also the issue could lie elsewhere as in the selector?

12th March 2020, 07:11	#9
BigRuss Premium Trader 75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4) Join Date: Jul 2007 Location: Liversedge, West Yorkshire Posts: 5,405 Thanks: 1,105 Thanked 1,340 Times in 661 Posts	Yes as the others have said likely that a manual ECU set has been fitted, had this a few times now. If it is then it can be rectified, drop me a p.m. and I'll be able to sort that out for you. Russ __________________ Replacement Key Service http://https://the75andztclub.co.uk/...d.php?t=244732 Full T4 Testbook diagnostics available. Diesel ECU repair and replacement. Options enabled or disabled as required. Diesel X-Power 135 and 160bhp, Rover 1.8T 150 to 160 MG 160 V6 to 177 upgrades available P.M. for details.

12th March 2020, 10:34	#10
Sheraton Posted a thing or two Rover 75 1.8t Join Date: Oct 2015 Location: Edinburgh Posts: 1,377 Thanks: 384 Thanked 409 Times in 267 Posts	r.e the K&N Air Filter - Is it the Oiled type that fits the Factory Airbox/Housing ? I've no experience of the Diesel - However i believe the MAF sensor may be located close enough (to the Air Filter) to allow the Oil from this type of Air Filter to affect the MAF Sensor Readings I have this type K&N Air Filter in my 1.8t - they are Great However I have no sensors Close enough to be affected by the Oil from the Air Filter. worth a thought maybe Paul.

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