Poor Starting in the Morning then fine all day

johnjo · Post by **johnjo** » Tue 12 May, 2009 13:18

I have just aquired a 1.9 1997 Z3. Strange problem it is difficult to start in the morning and if and when it does it has a terrible miss fire. This sometimes clears after a few minutes or can sometimes take several miles to clear. The rest of the day it is fine. Only happens in the morning.
Have changed coil pack plugs filters still no joy
Any ideas

Austin Powers · Post by **Austin Powers** » Tue 12 May, 2009 13:47

Sparks were last changed when?
BW
Austin

johnjo · Post by **johnjo** » Tue 12 May, 2009 13:57

Last week with the coil packs
Problem still there

Guest · Post by **Guest** » Tue 12 May, 2009 14:54

Now you see the folly of changing things such as coil packs in the hope that it may cure the problem! that's the kind of thing garages do when they have no idea . . .

after spending a not-inconsiderable amount of money, yu only know what the probelem is NOT caused by!

It could be a fuel pressure (ie pump) problem, or it could be a tmeperature sensor problem, or and air leak.

You need a decent diagnostic job, rather than guessing, but first check the rubber intake trunking between the air flow sesnor and the throttle body, and also the hoses going into the inlet manifold for damage and leaks.

johnjo · Post by **johnjo** » Tue 12 May, 2009 15:48

Thanks for that Mike The car is showing NO fault codes. I will check the pipework however the temperature sensor might be worth a try as this fault is only when the car is started first thing in the morning. A fuel pressure problem would be there all the time I assume
thanks for your help

maxman · Post by **maxman** » Tue 12 May, 2009 19:37

You dont say if you are losing any coolant,the missfire could be water seeping passed the headgasket overnight and causing the missfire until the motor warms up.When you changed the plugs was there any rust around the electrode area which would indicate headgasket problems.

Austin Powers · Post by **Austin Powers** » Wed 13 May, 2009 06:53

As Mike suggested - check the air sensor and the hoses.
BW
Austin

Guest · Post by **Guest** » Wed 13 May, 2009 07:22

It's possible for the fuel pressure to be too low on the first start, due to such things as a sticky pressure regulator or a low output from the pump, either of which would increase the time taken to build up full pressure after the initial start..

A fuel pressure check would be a basic part of the diagnostic work, as these problems do not provide fault codes.

zroadster.net

Poor Starting in the Morning then fine all day

Poor Starting in the Morning then fine all day

Diagnostics

Fuel Pressure