'93 520i (M50) Flooding Plugs ?!!

[henry161]

When my car is cold , it is a pig to start - it is soaking the spark plugs with petrol (gas). As soon as it has any warmth in it , it runs and starts beautifully. I would appreciate any suggestions as to what to try to solve it please !!! The coolant temp sensor has been tested and is ok.

[henry161]

When my car is cold , it is a pig to start - it is soaking the spark plugs with petrol (gas). As soon as it has any warmth in it , it runs and starts beautifully. I would appreciate any suggestions as to what to try to solve it please !!! The coolant temp sensor has been tested and is ok.
I should have added - what could make the car overfuel when cold so that it floods ? It has only been doing this since the cylinder head was replaced.Once started it runs great for the rest of the day.

[henry161]

Well , I am glad it has beaten all of the "experts" on here because it certainly has beaten me for the time being.

[Blitzkrieg Bob]

Injectors.

But it's still kind of odd since they would leak hot or cold and flood the engine.

Are you sure it's gas...not oil or coolant?

cold..the fuel would have time to evaporate and be less noticable.

hot...the fuel is still in the manifold and floods the intake. You'd smell gas once it started after a few cranks.

I just replaced the injectors on Sunday, after experiancing intermitant flooding after a hard drive while still hot. cold starts were fine.

[henry161]

I am starting to suspect the injectors - if they weren't so much money I would buy a set and try them. I took the pipes off the fuel rail the other day to swap the pressure regulator and there was no pressure in the rail - there was still some fuel in there but definitely no pressure - does this mean that they are leaking ?
Today after cold starting I could smell the fuel.

[632 Regal]

if you have no pressure with the new regulator than I would suspect the injectors, they are available and not expensive.

http://www.fiveomotorsport.com/Injector_Sets.asp

[joshua43214]

Its almost for sure bad injectors. Unbolt the assembly so you can pull out the injectors complete with fuel rail. Run the fuel pump briefly by bypassing the relay. Pull the assembly out, there should be no leakage or driping. Some will claim that a tiny amount of fuel at the spray tip is ok, but my experience is that a good injector will not leak at all. If they are leaky, you can either use an injector cleaner or take it to a shop for an injector flush. This will somtimes fix the leak, but normaly you will be into new parts.

[henry161]

Thanks for your help guys. It is booked back in to the BMW dealer tomorrow for them to have another look. I will ask about the injectors but I bet they are crazy money over here in rip off britain! They will be twice the cost at least. That site looks good - are re-con injectors okay or should I go for brand new ones ?

[henry161]

Finally got the car back from the main dealer - they have had it on 2 occasions totalling 6 days and charged me £520 GBP (about $900) to tell me that it has leaking inlet valves. What do you think about that ???? I almost turned green and tore my shirt off. Could it be leaking valves causing starting problems when cold ? I am undecided. I guess if it doesn't start more or less instantly it is going to wet the plugs - simple as that.

[Dave M]

Dear Hulk,

I'll take a stab. I don't imagine leaky intake valves alone would cause you to foul your plugs with fuel (if this is in fact your problem). Leaky valve stems would allow oil to foul your plugs after sitting overnight, but would cause tell-tale smoking at start-up. However, leaky valves seats may exacerbate the flooding situation by allowing additional fuel to trickle into the cylinders.

So the dealer charged you $900 to tell you your intake valves are leaking? Did they do a leak-down test? Did they tell you how this affects starting or why it would cause your plugs to foul? Do they smell fuel? Do they agree its fuel related? Maybe they need to reply to your question;)

Alright, I don’t want you turning green again. RRrrrrrrrrr. We / you’ll figure it out.

Dave M

[henry161]

I think I ought to change my name to Hulk ! I think that the main dealer may be on to something here as it all started when the head was replaced. If there is not enough compression at cranking speed it may not fire straight away which will wet the plugs and make it even harder to start. I have just dropped the car off with a local guy who is going to remove the head for me- I will collect it in the morning and strip out the valves and hopefully re-lap them, replacing the valve stem oil seals. I am praying that this will cure it as this is another $800 and I am out of cash! I thought that was a crazy amount of money for the main dealer just to tell me that. The problem is that they send out a guy to explain the work/problems to me and he knows a lot less about engines than I do so it is difficult to be convinced by them - that and the fact that my bill was so enormous means that from now on I will only be getting parts from them.

[joshua43214]

hmmmm leaky intake valves causing flooding? I am trying to muddle my way through the dealers logic here, bear with me. You have fuel leaking down onto the valves , and rather than pooling ontop of the intake valves and then evaporating, its dripping past a leaky valve seat into the cylinder and flooding.

Well, each statement above is flawed. Injectors don't leak normaly. The intake system is for all intensive purposes a closed system when the key is off, the gas will not evaporate into the atmosphere(this is EPA regulation in the USA BTW). And last but not least, this logic would assume that all the intake valves close when the engine is stopped, a physical impossibility.

I would find it hard to believe that even a Yugo dealer would have this flawed a understanding of an engine. Either the tech who worked on your car doesn't want to deal with your antique and sold a bill of goods guarenteed to make you go away. Or your diagnosis of flooding is incorrect.

I am sensing that the entire story here is not being told.

What led you to believe the car is flooding on cold soak?
What led the dealer to say the engine needs a valve job?
What is the story behind having the head replaced? Where did the head come from?
Does it blow a cloud of smoke when first started? if so, what color is it?

Tell us the entire story

Let us know the entire story.

[henry161]

Well , I think that maybe if it is cranking and compressions are down at cranking speed (due to leaking valves) it may not fire up instantly - continued cranking will wet the plugs. I have just put the valves back into the cylinder head and they were in a sorry state. I have been grinding them in for most of the day and now my hands are ready to fall off - will return the head to the garage tomorrow for reinstallation.
A bmw guy told me that it was flooding the plugs when cold starting - he tried to start it - it played him up and he took some plugs out and found they were soaking.
The dealer performed loads of tests on the car and during one of those the technician could hear leakage past the valves - can't thnk what he called that test now.
The temperature gauge went up on a couple of occasions and I have been adding coolant for a while so it went ot be looked at - this revealed a cracked head. A used head was bought and installed but the garage did nothing with the valves - they were not tested , reground or even removed which I am dissapointed about. The head came from a breakers.
I have noticed the car smoke only once and that was when it had been cranked for ages - couldn't see what colour the smoke was.

[joshua43214]

Well, the short story is, you pay for what you get.

Don't be disapointed that the garage didn't remove the valves on your used head. Used head+valve job = cost of reman head in most cases. No one is going to take your head apart unless they are doing a valve job at the same time. Since you are doing the valve lapping, I assume you provided the head to the shop. When you provide the part to a shop, you assume all the risk, don't put it off on the shop. The only other explanation I can see is that the shop gave you a clear warning about the danger of used parts and made you assume all risk again, otherwise they would be handling any needed repairs to the head.

If the valves where so seriously abused that they car was a no start, I highly doubt that simply lapping them will be any thing other than a temporary fix, the guides will almost for sure be worn, and at the very least, it will flake out the stem seals and you will start to burn oil.

The test is called a leakdown test for what its worth.

[henry161]

Well, I am only a DIY mechanic. The shop are supposed to be professionals. They told me that the head was being stripped and sent away to be checked and if necessary skimmed. I think that would have been a suitable point for them to mention to me about the valves. As it transpires , the head was skimmed with the valves still in situ so most of the valves have a little flat bit milled on part of their radius. Needless to say - I am not very impressed , or is that the kind of treatment I should expect for not buying a remanufactured head. To me it is butchery and indefensible. The car did start - it just took ages when cold and lots of cranking. The guides were fine and the car was not using any noticeable amount of oil so I expect them to be ok with new stem oil seals fitted.

[henry161]

Just to finish this thread off - it did indeed turn out to be my valves leaking. There were carbon deposits on the backs of the inlet valves and the seats looked pretty cruddy too. A few hours of relapping the valves and a set of valve stem oil seals later and the car runs like a dream - better fuel consumption than ever , more lively performance and now starts instantly.