HOW CAN THIS BE????!!!!!!

Need technical Q/A then you're in the right place

Moderator: martauto

Post Reply
User avatar
Ricksta
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Thu Feb 16, 2006 11:00 pm
Location: East Sussex

Mon Mar 26, 2007 9:37 pm

Please Help Technical people!!!

Further to my earlier post 'No cold idle without throttle on start up' which was some time ago now.
http://www.e30zone.net/modules.php?name ... ttle+start

I am STILL having the same problem EXCEPT that if the car is left overnight facing uphill it will start first turn of the key everytime!!!
But on the flat or downhill it will take ages to start even when warm and if cold will spit and splutter and die if not revved.

Now My Dad suggested 'just leave it facing uphill' which is fine until I am at work where the car park is flat!! Also I want to try and rectify the fault!!!
This weekend it had new Fuel Pressure regulator and fuel pipes while I was there and a new BMW Blue sensor even though it was changed 11 months ago! incase the GSF part was not doing the job properly?!

Any advice greatly appreciated!!!
Globulator
E30 Zone Regular
E30 Zone Regular
Posts: 389
Joined: Fri Sep 23, 2005 11:00 pm

Mon Mar 26, 2007 10:09 pm

ICV - Idle Control Valve, sounds a likely candidate...
1986 325i 'vert, funk louder than standard.
"No Mr Bond, I expect you to tell me why your 4 litre, 282bhp sports car can't outrun some lardy old Mercs.."
Audio & electronic software: http://www.cutestudio.net
User avatar
Ricksta
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Thu Feb 16, 2006 11:00 pm
Location: East Sussex

Mon Mar 26, 2007 10:11 pm

Maybe? it was replaced 9 months ago, but unit was secondhand, can this be affected by car being pointed up or downhill? before I spend yet more cash for no result. :roll:
User avatar
Ricksta
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Thu Feb 16, 2006 11:00 pm
Location: East Sussex

Tue Mar 27, 2007 10:36 am

No Other Suggestions then?????????? there must be something obvious I am missing which causes my 320 to start pointing uphill fine and run like S**t pointing downhill :x
Globulator
E30 Zone Regular
E30 Zone Regular
Posts: 389
Joined: Fri Sep 23, 2005 11:00 pm

Tue Mar 27, 2007 11:00 am

Check the earthing strap is good (i.e. take off, clean up, put back on) as the engine will shift on a hill a fraction.
The ICV lays horizontal so may also be affected - clean it out and see if the problem persists.
Fuel pressue at rest will also be affected marginally - but you said you replaced stuff.
- Try starting facing uphill and then turn the car immediately so it faces down hill and see if it still idles OK

You need to find out if on a dodgy cold start/idle that the mixture is lean, ok or rich (bear in mind it should be rich). Maybe get your dad to tell you if it smells petrol laden or not.

Check the airbox etc for obstructions - take the air filter out and check for leaves etc, check the AFM springs back OK, check for loose connections in the air hose, the bits where the ICV plugs in etc.

Check the HT coil connections are not loose.
1986 325i 'vert, funk louder than standard.
"No Mr Bond, I expect you to tell me why your 4 litre, 282bhp sports car can't outrun some lardy old Mercs.."
Audio & electronic software: http://www.cutestudio.net
User avatar
fowler
Boost Junkie
Posts: 3468
Joined: Mon Jan 10, 2005 11:00 pm
Location: New Addington/Croydon
Contact:

Tue Mar 27, 2007 11:02 am

check fuel pressure reg as this some times causes no starting without throttle.
it is the circular thing attatched to the fuel rail for reference
EX A-Tech Workshop bitch !!!
325i Turbo touring (Aka Project Fridge)
gone but not forgotten
User avatar
Ricksta
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Thu Feb 16, 2006 11:00 pm
Location: East Sussex

Tue Mar 27, 2007 11:11 am

Fowler , I Just changed the Fuel Pressure regulator this weekend!!! thanks for the suggestion.

Globulator, I am wondering if it could be the flap on the AFM as I have replaced nearly everything else! bear in mind the slope is very slight!! its so small I thought it could not possibly make a difference, but numerous starts have proved otherwise!!! its also seems worse if its cold pointing downhill to warm pointing downhill. if that helps.
Globulator
E30 Zone Regular
E30 Zone Regular
Posts: 389
Joined: Fri Sep 23, 2005 11:00 pm

Tue Mar 27, 2007 11:49 am

It will only be the AFM if it is badly faulty and blocking the airway - I do not think it is even used at idle.

How does it drive?
Do you get good power even at say 4,500rpm full throttle?
1986 325i 'vert, funk louder than standard.
"No Mr Bond, I expect you to tell me why your 4 litre, 282bhp sports car can't outrun some lardy old Mercs.."
Audio & electronic software: http://www.cutestudio.net
User avatar
Ricksta
E30 Zone Newbie
E30 Zone Newbie
Posts: 74
Joined: Thu Feb 16, 2006 11:00 pm
Location: East Sussex

Tue Mar 27, 2007 11:57 am

It drives beautiful mate, No problem at all apart from starting, its really strange! it idles fine if its started on a very slight uphill gradient but needs throttle to start on flat and if slight downhill forwards and been overnight it is a pig seems like running on 4 out of 6! and will not idle, just stalls every time throttle released
Globulator
E30 Zone Regular
E30 Zone Regular
Posts: 389
Joined: Fri Sep 23, 2005 11:00 pm

Tue Mar 27, 2007 12:41 pm

Fuel
####
Ok so we have to assume that the fuel System is OK - as long as the pump gets the signal to run when starting...
... maybe a question for brianmooooooore.

Put a 5w test-lamp on the terminals to the fuel pump (under the back seat) and check it lights up when you are cranking the engine over. Doesn't explain the bad idle though.

I do wonder if a/the fuel pump is sticking when on the flat... short of a fuel pressure meter you can look at when cranking/idling I'm not sure how to diagnose that. They are cheap but you have to plumb them in to get the reading. I'd be tempted though..

Injectors
######
Find the plug that goes to these and ensure it is clean

Crank position sensor/oxy sensor (if fitted)
###############
Check the wire is not dangling where it should not on both

Air
###
Does the throttle 'cure' the rough idle or just rev it enough that it cannot stall?

Spark
#####
See if the spark is as good facing up or down the hill?

Other
####
The only other items are mechanical - ie.. valves etc. can't see a slope affecting those unless you have big valve/guide oil issues.
1986 325i 'vert, funk louder than standard.
"No Mr Bond, I expect you to tell me why your 4 litre, 282bhp sports car can't outrun some lardy old Mercs.."
Audio & electronic software: http://www.cutestudio.net
Post Reply