Z3 2.8 power loss - help required!

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lmrdave
Joined: Tue 29 May, 2012 12:30
Posts: 55

  Z3 roadster 2.8
Location: Lincolnshire

Z3 2.8 power loss - help required!

Post by lmrdave » Sat 20 Feb, 2016 15:30

Hello,
My poor old 2.8 didn't feel as quick as it did. A bit sluggish to rev like the brakes were on slightly. As I was having to do a few hundred mile trip I got the fault codes read at a local specialist.
None found.
Checked all wheels were free and induction side had no obvious faults. All OK.
Drove it last night and was much the same. Only when I started the return leg it was much worse. Struggled to rev under load, really struggled up hill. At one point started to sound like pre ignition when applying too much throttle.
On checking to inspect temp rose to one increment past vertical. Something I've never ever seen it do. But it soon settled back to normal.
Carry on home it got really bad, but I thought if the damage is already done so carried on.
Today it starts, but runs rough. Revs under no load to over 5k but struggles after that.
Plugs look fine. Compression test is fine.
Anyone around Lincoln have a pre OBD2 reader and want to earn some beers??
Anyone had anything similar and found the problem.
So many variables it's got be beat at the mo. Timing/ignition, temp, fuel.
1998 Z3 2.8 Arctic Silver
1991 Mazda MX5
1987 Nissan Silvia

John Wilson
Joined: Fri 12 Jun, 2009 13:11
Posts: 240

  Z3 roadster 2.0
Location: Diss

Re: Z3 2.8 power loss - help required!

Post by John Wilson » Sat 20 Feb, 2016 20:52

Have you seen this current thread
http://www.zroadster.net/forum/viewtopi ... =5&t=43817
Might be of some help

deni2s
Joined: Mon 25 Mar, 2013 22:02
Posts: 745

  Z3 roadster 2.8

Re: Z3 2.8 power loss - help required!

Post by deni2s » Sat 20 Feb, 2016 21:32

How is the oil level and coolant level? Got something similar when there was a crack in the head and coolant was sucked in to one cylinder. I was lucky to not get the hydrolock.
If there are no error codes on ECU and coolant/oil levels are ok, try to check injectors and fuel supply, that's what doesn't have fault detection to ECU.

BTW if there are serious faults, engine goes to "limp mode" and is limited to ~5000rpm.

lmrdave
Joined: Tue 29 May, 2012 12:30
Posts: 55

  Z3 roadster 2.8
Location: Lincolnshire

Re: Z3 2.8 power loss - help required!

Post by lmrdave » Sat 20 Feb, 2016 23:13

Oil level is spot on no mayo present.
No coolant loss no oil spotted in there.
Taking exhaust off - collapsed cat theory.
And will take the fuel filter out it see if it's blocked.
1998 Z3 2.8 Arctic Silver
1991 Mazda MX5
1987 Nissan Silvia

Dino D
Joined: Fri 10 Feb, 2012 16:59
Posts: 376

  Z3 roadster 2.8

Re: Z3 2.8 power loss - help required!

Post by Dino D » Sat 20 Feb, 2016 23:59

The camshaft sensor failing has similar symptoms when mine went. Very common on these, just need your codes read, will save you a lot of diagnosis.

RobTFC
Joined: Mon 29 Dec, 2014 14:23
Posts: 26

  Z3 roadster 3.0i

Re: Z3 2.8 power loss - help required!

Post by RobTFC » Sun 21 Feb, 2016 17:12

It's funny I was just thinking this the other day when driving mine (a '97 2.8) - I know exactly what you mean about it feeling like the brakes are slightly on! I've thought this on and off for a couple of years! I had to drop it down a gear on a hill the other week and was thinking to myself "would I have needed to do that a few months ago?" but couldn't be certain!

My car sits idle a lot of the year, and I got her out last year and found the engine would not rev beyond 5000rpm as deni2s mentioned. I did consider this being a sort of limp mode, but 5000rpm seemed too high a "limp limit" to me so wasn't sure what was going on. That week I took it to my local specialist although the day I took it the engine then decided to allow me to go beyond 5000rpm. They checked the fault codes, nothing. So I got an oil change, had her looked over and all seemed OK, never had the limit kick in since. I put it down to the fact it had been stood for a while.

Going back to the first point however, I can't help shake the same feeling about the performance and due to the fact I've decided I'm keeping her and doing a bunch of work, in lieu of any fault codes my plan has been the following;

- Get a service done (just had an inspection I done last week as well as both a coolant/brake fluid change and told everything looked in good order)
- Have Mr. Vanos check the VANOS seals and replace if necessary (the car has just ticked over 90k so I'm under the impression this could be an issue as I've heard these start to go at around 20-30k?). Mine is a single VANOS M52B28.
- Remap & Dyno - I have had the M50 manifold conversion fitted for a couple of years or so, and never got round to this and I probably should. A dyno readout should hopefully tell me if this is all in my head.
- DRIVE IT MORE! My promise to myself for this spring/summer.

After the above I'm going to see how it goes and take it from there. So you might want to consider a plan similar to mine, I'd be interested to know of any other ideas too!

The other thing that did occur to me is that a couple of years back I traded in the 118d for a 650i and some of this could simply be that my perception has changed of the power due to the change in my daily driver, so that's something else to consider if you've done something similar. At the end of the day my Z seems to drive ok, and as long as I know the car is doing the best it can and is mechanically fine then I'm happy!

lmrdave
Joined: Tue 29 May, 2012 12:30
Posts: 55

  Z3 roadster 2.8
Location: Lincolnshire

Re: Z3 2.8 power loss - help required!

Post by lmrdave » Sun 21 Feb, 2016 20:58

Fixed. Cat was blocking exhaust flow.
Popped the exhaust off at that the down pipe and it revs crisp and clean to the red line.
Put the cat on and it ran ok but quiet way to quiet then started struggling on load.
Got brutal to get me mobile and knocked the stuffing out the cat and blew it out.
Now drives fine. Thanks for the advance and the offers of help. Hope this helps if anyone has the same problem.
1998 Z3 2.8 Arctic Silver
1991 Mazda MX5
1987 Nissan Silvia

Dino D
Joined: Fri 10 Feb, 2012 16:59
Posts: 376

  Z3 roadster 2.8

Re: Z3 2.8 power loss - help required!

Post by Dino D » Sun 21 Feb, 2016 22:07

No chance you took a video when revving it to the redline with exhaust off? ;)

lmrdave
Joined: Tue 29 May, 2012 12:30
Posts: 55

  Z3 roadster 2.8
Location: Lincolnshire

Re: Z3 2.8 power loss - help required!

Post by lmrdave » Sat 12 Mar, 2016 18:31

Funny you should mention that . . .
Might post it up as the engines swan song . . The CAT being blocked did the engine no favours and it died this week I guess it's linked. Exhaust gases in coolant according to the AA who got me home. No time to investigate as yet.
And just on the way home from getting a new rear screen fitted. :head:
1998 Z3 2.8 Arctic Silver
1991 Mazda MX5
1987 Nissan Silvia

Wookee
Joined: Thu 10 Dec, 2015 19:45
Posts: 166

  Z3 roadster 1.9i
Location: Herts

Re: Z3 2.8 power loss - help required!

Post by Wookee » Sat 12 Mar, 2016 20:59

When you removed your exhaust did you replace the manifold gasket? I'd start there if you didn't.....

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