Sudden, scary power loss

Tyres, exhausts, suspension, strut braces, air filters, brake pads/rotors and anything else for 'dawn raiders'.

Moderator: Gazza

Post Reply
Rich-Z
Joined: Wed 07 Oct, 2015 11:37
Posts: 10

  Z3 roadster 1.9

Sudden, scary power loss

Post by Rich-Z » Fri 09 Oct, 2015 19:36

Hi guys, I'm currently an extremely proud owner of a '97 cosmic black 1.9 Z3 as of March this year :) .I've given it a hell of a lot of TLC recently and have been fixing a few bits and bobs such as the alarm system and other stuff. It's an absolute dream to drive but I have one little issue that happens on a rarely basis. I would be driving along minding my own business when suddenly I would lose power like as if I let my foot off the pedal. This happens for about 3 seconds then it recovers, jolting me forward a little in my seat. Pretty scary to say the least! I've done numerous Google searches with mixed responses which has led me to think it is maybe the CPS? Any help would be greatly appreciated.

Rich
Image

Z3 > Miata

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2119

  Z3 roadster 1.9

Re: Sudden, scary power loss

Post by Del » Fri 09 Oct, 2015 21:33

I would check first by plugging the car into a diagnostic tool - a simple OBD II one (with a converter for the round under bonnet socket) will probably suffice - works on my 1998 car. Might be the camshaft position sensor but at around £100 from BMW you don't want to guess. Might also be a coil, plug or HT lead issue?

User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10000

  Z3 roadster 1.9
Location: Cheshire

Re: Sudden, scary power loss

Post by Robert T » Fri 09 Oct, 2015 21:54

ODBII will not work on a car built prior to Sept '98. The earlier cars need a different reader (ADS). However, the advice remains the same, you need to get the error codes read. It could be any number of things. I had a fault with mine (same engine) whereby the camshaft sensor gave erroneous output - the car kept stalling, would restart, rev, then die again. AA man had a fiddle with the HT leads and it ran smooth after that, but took it in for a proper diagnostic and it was the camshaft sensor (only one on an M44) - replaced and no more trouble. I'm not implying that this is your problem, just that some faults like this can be intermittent, and that they are likely to log error codes.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image

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

  Z3 roadster 2.8
Location: Lincolnshire

Re: Sudden, scary power loss

Post by lmrdave » Fri 16 Oct, 2015 13:01

If it has an immobilizer check the earth. I had a similar problem on my MX5, it would cut power randomly. Took be ages to find and seconds to fix.
1998 Z3 2.8 Arctic Silver
1991 Mazda MX5
1987 Nissan Silvia

Mugs
Joined: Wed 07 Aug, 2013 02:26
Posts: 341

  Z3 roadster 1.9

Re: Sudden, scary power loss

Post by Mugs » Fri 16 Oct, 2015 20:46

Robert T wrote:ODBII will not work on a car built prior to Sept '98. The earlier cars need a different reader (ADS).

Cheers R.
strange?
i have an oBD11 reader for my other cars and plugging it in to the ZED (1997 1.9) using the round pin adapter it will read and reset the codes.

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2119

  Z3 roadster 1.9

Re: Sudden, scary power loss

Post by Del » Fri 16 Oct, 2015 21:13

I use a simple OBD II on my Z3 also (May 1998 build date). Robert may be referring to an actual OBD socket under the dash on newer cars - I don't have one of these and have to use a round adapter and the round socket under the bonnet.

Mugs
Joined: Wed 07 Aug, 2013 02:26
Posts: 341

  Z3 roadster 1.9

Re: Sudden, scary power loss

Post by Mugs » Sat 17 Oct, 2015 19:28

Del wrote:I use a simple OBD II on my Z3 also (May 1998 build date). Robert may be referring to an actual OBD socket under the dash on newer cars - I don't have one of these and have to use a round adapter and the round socket under the bonnet.
yes, i think he may be.

User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10000

  Z3 roadster 1.9
Location: Cheshire

Re: Sudden, scary power loss

Post by Robert T » Sat 17 Oct, 2015 22:33

Mugs wrote:yes, i think he may be.
No I'm not. My car is Jan '99 built and has not got an OBDII connector under the dash. There was a big change to the electrics in Sept '98 and the diagnostics became much more OBDII compliant, such that you can read most modules using INPA and an ODBII-to-20 pin adapter cable. I have not connected to many early cars, but my USB OBDII reader could not read very much on the early cars I did try. It has be said many times on the forum that the early cars require an ADS interface and serial port to connect to them using INPA. It may be that handheld code readers can manage better, but they are likely to be restricted to reading engine codes only.

I will try and bring my laptop along to the next meet I do and see if I can get some more data on the earlier cars, as it would be good to pin down exactly what is and is not accessible from both my setup and some of the handheld readers that people have bought.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests