'L' Series 2.0 Diesel - Power Loss

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redandwhitE
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'L' Series 2.0 Diesel - Power Loss

#1 Post by redandwhitE » Sun Jun 27, 2021 7:54 pm

Bought my first 45 diesel last year and although not fast, I was happy with it. Bought the second one and realised this had much more power/acceleration than the first one. Realised first one had a fault and been meaning to get the it looked at but not got there yet.

Now the second has lost power and by considerably more than the first one. It's precarious when pulling out and only when up towards 3000 rpm and beyond, does it move on but even then, nowhere near as it did when purchased.

My mechanical knowledge is limited but I'd imagine it's the turbo(s) and perhaps the waste gate not fully functioning. If so, is this something the keen amateur (me) could diagnose and subsequently repair?

As both are below par, it's now time to sort them out so any start points would be appreciated.
1995 416 SLi (BRG) - OTR
2004 45 Imp Diesel (silver) - OTR
2004 45 Club SE (red) - OTR
1993 416 GSi (BRG) - not OTR
1972 Mercedes 350 SL (red) - not OTR
1998 Audi Cabriolet (maroon) - not OTR

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220 GSi turbo
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Re: 'L' Series 2.0 Diesel - Power Loss

#2 Post by 220 GSi turbo » Sun Jun 27, 2021 8:37 pm

It is most probably the MAF (mass air flow) sensor which is in the black tube with wires connected to it between the air filter and engine. These degrade with time and the ECU relies on the signal from the MAF to determine how much fuel to send to the injectors.

If cleaning the MAF sensor does not help, the fix is to fit a new one (ideally genuine Bosch, not a much cheaper alternative) or to fit a compensator device which I believe amplifies the signal from the MAF sensor.
I have one of them fitted to my 25 diesel and it was bought several years ago from https://www.tuning-diesels.com/ (also known in the past as 'Rover Ron') although I have looked tonight and they no longer list the Rover 25/45, ZR, ZS etc. The products they sell for the older 220/420/620 SDi cars and for the 75/ZT range are probably not compatible, so it would be a good idea to contact them and ask first.

However, you should also check that the intercooler and its hoses are not leaking, as any boost pressure lost will obviously affect performance. Boost leaks are usually accompanied by black smoke from the exhaust, as the engine is not getting enough air to deal with the fuel that the ECU has sent to it. This would generally affect performance under acceleration, rather than the first few moments from standstill.
1995 220GSi Turbo: owned for 20 years
1994 216SLi
2000 25GTi

Daily: ZR Trophy TD

Previously: 216 Sprint (1988-91)216 Coupe(1993-95) 214SLi(1995-96) 420GSi Turbo L955UKV(1997-2004) 214SEi M884BMR(2004-11) 420GSi Tourer M650XEX(2005-6) 214 SEi M103BCW(2011-12)

Montegoman
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Re: 'L' Series 2.0 Diesel - Power Loss

#3 Post by Montegoman » Sun Jun 27, 2021 10:09 pm

We have had a similar issue on two of our 25 diesels and on both occasions it was the MAF sensor.
214SLi H706JPJ
214GSi G79XKV (R8 No.1)
25GSi 2.0TD KX56KXM Owned from new.
75 2.5 Connoisseur SE Tourer (16 yrs of ownership)

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Russnp
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Re: 'L' Series 2.0 Diesel - Power Loss

#4 Post by Russnp » Fri Jul 02, 2021 5:25 pm

CJL tuning in spalding is worth contacting as he does remaps on the L series and keeps quite a few spares .
My ZR had had a few mods done to it before I bought it CJL remapped it which gave it more power, better economy and no smoke
98 Rover Coupe VVC
99 MGF VVC
03 ZT 135
03 ZR 115 TD
15 MG3 , partners car

Off the road at present

Maestro van , British Rail
Maestro EFi - in body shop
Metro Turbo

redandwhitE
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Re: 'L' Series 2.0 Diesel - Power Loss

#5 Post by redandwhitE » Fri Jul 02, 2021 11:02 pm

Thanks for the pointers.

I've got a MAF sensor on the way and will try it on both cars. If it solves the problem, I'll order a second one.

For info, there's no smoke to speak of although one does burn a little oil. Will keep you informed.
1995 416 SLi (BRG) - OTR
2004 45 Imp Diesel (silver) - OTR
2004 45 Club SE (red) - OTR
1993 416 GSi (BRG) - not OTR
1972 Mercedes 350 SL (red) - not OTR
1998 Audi Cabriolet (maroon) - not OTR

redandwhitE
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Re: 'L' Series 2.0 Diesel - Power Loss

#6 Post by redandwhitE » Fri Jul 16, 2021 4:31 pm

As promised, here's an update:

Whilst waiting for the MAF Sensor, I disconnected the existing one and the car drove practically as good as it ever did. I'm guessing without the sensor, it resorts to a default setting that is good without being optimum. I've now changed the sensor, re-plugged it in and all is well.

A strange event happened when we had heavy rain and plenty of standing water however. When I drove through a large puddle, the car responded and picked up momentarily to close to its optimum performance. For a second or two, the engine provided full revs. This was with the existing MAF sensor still connected. I can only imagine the water was bridging a split/hole in a pipe or something. Anyway, I've replaced a couple of lengths of vacuum pipe that were split so that can only help.

Thanks to those who suggested the MAF sensor.....speeded up diagnosis.

Cheers Richard
1995 416 SLi (BRG) - OTR
2004 45 Imp Diesel (silver) - OTR
2004 45 Club SE (red) - OTR
1993 416 GSi (BRG) - not OTR
1972 Mercedes 350 SL (red) - not OTR
1998 Audi Cabriolet (maroon) - not OTR

RoverTD
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Re: 'L' Series 2.0 Diesel - Power Loss

#7 Post by RoverTD » Sun Jul 25, 2021 9:57 am

Richard
I have the same problem, since it was contaminated by water spray earlier in the year. Did you get a new Bosch MAF or some other make? Thanks Derek

redandwhitE
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Re: 'L' Series 2.0 Diesel - Power Loss

#8 Post by redandwhitE » Mon Jul 26, 2021 2:49 am

I just ordered one from my local motor factors but can't recall the brand. Definitely not Bosch as it was only just over £40. Not with car for a few days but will see if there's 'owt written on it when I get back.
1995 416 SLi (BRG) - OTR
2004 45 Imp Diesel (silver) - OTR
2004 45 Club SE (red) - OTR
1993 416 GSi (BRG) - not OTR
1972 Mercedes 350 SL (red) - not OTR
1998 Audi Cabriolet (maroon) - not OTR

RoverTD
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Re: 'L' Series 2.0 Diesel - Power Loss

#9 Post by RoverTD » Fri Jul 30, 2021 10:43 am

I have just unplugged the MAF and its running much better , more bottom end power and smoother pick up all round, so a new MAF required or not bother connecting it up again!

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220 GSi turbo
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Re: 'L' Series 2.0 Diesel - Power Loss

#10 Post by 220 GSi turbo » Fri Jul 30, 2021 8:06 pm

If you leave it unplugged, the engine speed tops out at around 3000-3500 rpm.
1995 220GSi Turbo: owned for 20 years
1994 216SLi
2000 25GTi

Daily: ZR Trophy TD

Previously: 216 Sprint (1988-91)216 Coupe(1993-95) 214SLi(1995-96) 420GSi Turbo L955UKV(1997-2004) 214SEi M884BMR(2004-11) 420GSi Tourer M650XEX(2005-6) 214 SEi M103BCW(2011-12)

redandwhitE
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Location: North Lincolnshire

Re: 'L' Series 2.0 Diesel - Power Loss

#11 Post by redandwhitE » Fri Jul 30, 2021 9:02 pm

Yes, that's pretty much what happened but it meant I could use the car without too much concern when pulling out or negotiating traffic.

In further developments, the car has coughed and spluttered today during a prolonged downpour. I'll see if there's some way to prevent water getting into the airflow/intake so as not to damage the new MAF sensor.
1995 416 SLi (BRG) - OTR
2004 45 Imp Diesel (silver) - OTR
2004 45 Club SE (red) - OTR
1993 416 GSi (BRG) - not OTR
1972 Mercedes 350 SL (red) - not OTR
1998 Audi Cabriolet (maroon) - not OTR

RoverTD
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Re: 'L' Series 2.0 Diesel - Power Loss

#12 Post by RoverTD » Tue Aug 03, 2021 1:57 pm

New MAF fitted and now running properly, better idle, smoother take up and power throughout rev. range

redandwhitE
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Re: 'L' Series 2.0 Diesel - Power Loss

#13 Post by redandwhitE » Tue Aug 03, 2021 11:22 pm

They say the definition of insanity is to keep doing the same thing even though you don't want the same outcome. I've just knackered the new MAF sensor through ingress of water....AGAIN!

Engine management light on but cars runs fine other than occasional misfire at idle speed.

Now found the cause too: air intake runs from engine bay, into front n/s wheel arch then back into engine bay and up to Sensor. The pipework had separated in the wheel arch and on very wet roads, it drew water into the intake.

Idiot!!!!!!!!!
1995 416 SLi (BRG) - OTR
2004 45 Imp Diesel (silver) - OTR
2004 45 Club SE (red) - OTR
1993 416 GSi (BRG) - not OTR
1972 Mercedes 350 SL (red) - not OTR
1998 Audi Cabriolet (maroon) - not OTR

Topcat Tomcat
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Re: 'L' Series 2.0 Diesel - Power Loss

#14 Post by Topcat Tomcat » Wed Aug 04, 2021 7:38 am

On the bright side, not only have you found the root cause, your experience will almost certainly help a fellow member in the future!

And I'm sure a lot of people have been there, done that...........I neither confirm nor deny.........😚😚😚
Topcat Tomcat (aka Conductorwomble)

1990 216 GSi Auto 5 Door
1995 214 iS 3 Door
2001 1.8 Connie 45 4 Door - Wedgewood Blue
2005 1.6 GSi 45 5 Door - Firefrost

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Plodder
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Re: 'L' Series 2.0 Diesel - Power Loss

#15 Post by Plodder » Wed Aug 04, 2021 9:37 am

redandwhitE wrote:
Tue Aug 03, 2021 11:22 pm
They say the definition of insanity is to keep doing the same thing even though you don't want the same outcome. I've just knackered the new MAF sensor through ingress of water....AGAIN!

Engine management light on but cars runs fine other than occasional misfire at idle speed.

Now found the cause too: air intake runs from engine bay, into front n/s wheel arch then back into engine bay and up to Sensor. The pipework had separated in the wheel arch and on very wet roads, it drew water into the intake.

Idiot!!!!!!!!!
You’re not alone in having moments like this, it happens to us all.
You just have to convince yourself its part of the learning curve.
I would have given my Rover so much more TLC in past years if I’d realised I would still own it after 24 years and it was only one of a small number of examples left.
1991 Rover 416 GTI Auto - Flame Red

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