Cold Running problem

[RonA]

Hi
I've got a slight cold running problem with my '99 2.8, since I bought the car earlier this year the engine has a tendency to hunt at tickover when cold, this has been more obvious the past few colder days. It completely disappears when the engine starts to heat up after say about 5 mins running. I've checked the rubber hoses around the air intake etc and they seem sound.
Any ideas?
Ron

 

[Sean d]

Hi and welcome, have you had a code reader on the car

 

[RonA]

Hi, No I don't have a code reader, my experience of tinkering with cars is from the carb & distributor era so the Z3 is a bit of a new experience, as I said it runs OK when warm, the engine has never stalled when it's hunting, the revs just drop away momentarily and then pick up. If I raise the revs slightly with the accelerator it doesn't do it. Can you recommend a code reader I've no experience of them.
Ron

 

[t-tony]

Where are you located Ron? There's likely a member with a reader close enough to help you out.

Tony.

 

[Nodzed]

Have you got an emissions pump fitted?

 

[Sean d]

You may well have an air leak in one of the induction hoses, it's very common

 

[Nodzed]

You may well have an air leak in one of the induction hoses, it's very common

Unusual for that to go away when warm if its a leak is it not? If there is an emission pump fitted this causes this very problem, my 2.8 was horrid when cold, best get a blank off @t-tony and remove it.

 

[RonA]

What does an emissions pump look like?

 

[Sean d]

What does an emissions pump look like?

 

[RonA]

Looks like I've got one of these, it's a different shape on top but it has the same pipework, I'll have a go at blanking off the hose when it stops raining. I'll have a closer look at the hoses as well.
Ron

 

[Nodzed]

Looks like I've got one of these, it's a different shape on top but it has the same pipework, I'll have a go at blanking off the hose when it stops raining. I'll have a closer look at the hoses as well.
Ron

There's a thread on here somewhere, you must do it correctly, you will need a blanking plate. @t-tony should be able to sort you out with one?? Tony?

 

[Sean d]

Looks like I've got one of these, it's a different shape on top but it has the same pipework, I'll have a go at blanking off the hose when it stops raining. I'll have a closer look at the hoses as well.
Ron

Check the inlet hoses behind the MAF,you may well find a small hole that's drawing air, this can present itself on idle

 

[colb]

Air leaks can be very hard to find, best option is to smoke test the induction with the Maf removed, pumping smoke into the inlet bellows so that the smoke works its way through the engine. If any leaks are present you will spot it and lead you to the problem area. If your near me in South Wales I can smoke it at our Zedshed Cymru.

 

[ktnez99]

Air leaks can be very hard to find, best option is to smoke test the induction with the Maf removed, pumping smoke into the inlet bellows so that the smoke works its way through the engine. If any leaks are present you will spot it and lead you to the problem area. If your near me in South Wales I can smoke it at our Zedshed Cymru.

Confound you @colb you’re using the “smoke test” again and I’ve no idea what this is!!!

 

[mrscalex]

Confound you @colb you’re using the “smoke test” again and I’ve no idea what this is!!!

It's what @colb explained in his post. Nothing more complex to it. Mineral/baby oil gets heated by an element in a canister. Pump it in to the vacuum system. If it comes back out anywhere it's found a leak, ie perished/split rubber.

The concept is simple. I think @colb has been rather clever building his own equipment and generous in offering use of it.

 

[RonA]

I removed the emissions pump at the end of last October the day before I layed the car up for winter, on a short test run the problem had disappeared, I didn't want to post the result till I was sure. I put the car back on the road at the beginning of March and the problem has been cured, so my thanks to Nodzed.
It's a very easy job, removed the pump unit from the car, made a small blanking plate (2x 6mm holes at 40mm centres), tied the wiring out the way and blocked the end of the small vac pipe. A cheap and easy fix

 

[colb]

Good for you Ron, lets see if that cured it, if you are still pondering a code reader, what do you want to run it on a laptop or a handheld stand alone code reader. I use a laptop loaded with INPA and BMW Scanner1.4. If your new to all this electrickery and want to use a laptop I would reccomend BMW Scanner 1.4 available on ebay for little money. INPA, the BMW diagnostics is ok once you get it loaded into a laptop but it can be a pain to get it loaded successfully. If you want a handheld code reader have a look through the posts on here for rccomendations. Chepest option however is an App on a phone with a Wi-Fi or Bluetooth emulator attached to the OBD socket, Torque is quite useful and available on the Web App sites to download to your phone. The emulator will be a ELM327 which you can get from ebay, loads on there either Chinese or UK suppliers example here https://www.ebay.co.uk/itm/WiFi-OBD...201586?hash=item3b059c53b2:g:~m8AAOSwEIJbMhcv

Should you want to go the laptop way BMW Scanner here https://www.ebay.co.uk/itm/Diagnost...910172?hash=item2ace3fbd5c:g:WiQAAOSwXmxdBRA6
Programme comes on a usb stick with this one so ok for laptops without a cd/dvd drive these days.

INPA package here https://www.ebay.co.uk/itm/BMW-OBD-...505234&hash=item3fc804ece9:g:T8AAAOSwh21c5xZS

One point to remember is Z3's may have an OBD socket under the steering wheel and a round 20 pin diagnostic socket under the bonnet in the engine bay. The OBD socket will only read engine and transmission modules on the car, the round 20pin socket known as a pacman socket will read all modules on the car in particular the airbag module which you may want to access when you get a airbag fault. To use the emulators on this socket you will need to add a 20pin to 16pin cable, also available on ebay.
https://www.ebay.co.uk/itm/Fits-BMW...948103&hash=item3fdb75813f:g:xOwAAOSwIZJeRRBW

Hope that assists you, once you get your head around all these electronics its quite easy and saves spending out on getting codes read at a garage.