Hard starter

[showfabloke]

Hi,
I have a 1990 525 M20 with 140k on the clock. When I try to start it from cold it normally takes 5 or 6 attempts, cutting out and needing a boot load of gas before it eventually keeps running. It's not such a problem when it is hot and runs ok apart from that.I'm thinking it's the fuel pump but don't want the outlay unless I'm sure. Any ideas?

[632 Regal]

ever change the plugs?

[JonE]

So, when engine is cold, does it "start" then die right away? Then you need to thread the throttle as you crank the engine over until it catches then rev it up till it is smooth? I had this issue with my m20 in the '89 325iC and cleaning the idle control valve seemed to help for awhile. Just take it off and spray a bunch of carb cleaner through it, a bit of wd40 to make sure it is working. Other than that I'm not sure, maybe the coolant temperature sensor is faulty? Like Jeff said, how are the plugs?

[632 Regal]

could be anything

[melteezin]

I have a '89 525i M20. Last summer I rebuilt the top end. New Shrick
cam, valves and rockers. (highly recogmended--gained about 15-20 hp)
As of late though, I have had the same starting problems. I installed new
Bosch Plat 4 plugs, (old ones seemed to have fresh oil on them. Maybe
someone can explain cause for this, which may lead to cause for hard start)
and a new fuel filter. Starting was no problem after this. But that was about
a month ago. Now it seems to be having the same problem again. I noticed someone mentioned coolent temp sensor in this thread. I have had some problems with mine. How does this relate?

Mel

[melteezin]

I have a '89 525i M20. Last summer I rebuilt the top end. New Shrick
cam, valves and rockers. (highly recogmended--gained about 15-20 hp)
As of late though, I have had the same starting problems. I installed new
Bosch Plat 4 plugs, (old ones seemed to have fresh oil on them. Maybe
someone can explain cause for this, which may lead to cause for hard start)
and a new fuel filter. Starting was no problem after this. But that was about
a month ago. Now it seems to be having the same problem again. I noticed someone mentioned coolent temp sensor in this thread. I have had some problems with mine. How does this relate?

Mel

[CheapCheap1]

I would replace the plat-4 plugs w/ the regular one. (Yeah, my '95 540i doesn't like plat-4...& it's cost me too much $$$ ! :D)

[Kalevera]

yes, get rid of the Plat-4's. I think the M20 uses W8LCR's, as does the M30. Plat 4's are a bucket load of trouble for our engines.

Need more info on the hard start issue to diagnose. Best bet is to do a fuel pressure test to rule out the obvious stuff.

best, whit

[shogun]

Could be a leaking check valve so that the fuel flows back into the fuel tank overnight.
Do the following:
switch ignition to position 2 and wait 10 seconds. Switch off ignition and repaet same procedure 2 - 3 times. The fuel pump only runs for about 4-5 seconds and switches off when engine is not started.
By this procedure you will have the right pressure inside the fuel system.
Then switch the engine on. If it starts immy, you found it. Change the check valve
http://www.bmwe34.net/e34main/trouble/535ihot_start.asp