Injector replacement? 170K miles, 535i

[scott 4991]

I have been reading up on injectors. I have never replaced mine; 171K miles. The simple question is, "should I replace them"? The car is running fine, perhaps a bit down on power, idle is OK, but not like new cars. I plan to check the ohm's tomorrow, want to see between .4 and .8 on each.

How would I tell if the injectors are not working up to spec. I assume they are working as the car is running 'ok'.

Thanks

Sc

[632 Regal]

basicly you get new ones when you feel the need. car running good is your call on replacing them. If you can afford them www.fiveomotorsport.com has great deals on the new style.

[winfred]

they go down hill so gradually you never seen a difference, the disc type design II 19# 4.6 mustang injectors work good, one of the first mod's stang guys do is go to bigger injectors so low mile take outs aren't hard to find, i've gotten two sets off of ebay but theres some worn out crap out there too so watch out

you may check out any speed shops in your area to see if they have a pile of them

[scott 4991]

Thanks for the replies. I'll think on this.

sc

[t_marat]

I was also thinking of injectors. Lately I started having problems with cold starts (meaning engine is not hot, not cold weather). It takes longer to start the engine, and after that it idles roughly, sometimes stalling. I just keep the rev at about 1200rpm for about 20 seconds and its ok then. Before this it would take a second to start the engine.
Is this because of "leaky" injectors?

[winfred]

probably a vacuum leak or crappy plug/oil/water in the plug tubes


I was also thinking of injectors. Lately I started having problems with cold starts (meaning engine is not hot, not cold weather). It takes longer to start the engine, and after that it idles roughly, sometimes stalling. I just keep the rev at about 1200rpm for about 20 seconds and its ok then. Before this it would take a second to start the engine.
Is this because of "leaky" injectors?

[t_marat]

probably a vacuum leak or crappy plug/oil/water in the plug tubes
Today I changed the plugs. Old ones were Beru Ultra, new ones Denso (not iridium).

Old plugs were not tight at all. I could remove them with just one hand using the setup in the picture. Some were very easy to turn.
Lots of oil, as is visible in the picture. I changed the valve cover gasket last year, brand Febi. No oil leaks on the outside. I didn't see any traces of leaks from that gasket within the plug sockets.

[520John]

Hi there.

Exactely the same problem I'm having in my "M50 overview" thread.

[t_marat]

By the way, the original problem of the engine running rough or stalling while engine cold is still there. I just put my foot on the gas and keep the rev at about 1200-1500 for about 20 seconds, and the roughness is gone.

Is it logical to think that the gaskets that are on the valve itself is leaking oil. so when I stop the engine, oil leaks to the spark plugs. when I run the engine at 1200-1500rpm for 20 seconds that oil is simply burnt. What makes me think so is that I could not see any traces of oil ieaking from the valve cover gasket from within the spark plug sockets. The oil was only at the bottom. only tips of spark plug boots were oily (2 were dry).

[winfred]

leaking valve stem seals usually show up as a small puff to a decent sized cloud of oil smoke on cold start


By the way, the original problem of the engine running rough or stalling while engine cold is still there. I just put my foot on the gas and keep the rev at about 1200-1500 for about 20 seconds, and the roughness is gone.

Is it logical to think that the gaskets that are on the valve itself is leaking oil. so when I stop the engine, oil leaks to the spark plugs. when I run the engine at 1200-1500rpm for 20 seconds that oil is simply burnt. What makes me think so is that I could not see any traces of oil ieaking from the valve cover gasket from within the spark plug sockets. The oil was only at the bottom. only tips of spark plug boots were oily (2 were dry).

[t_marat]

I didn't see if there was a cloud of oil smoke on startup. but I did see there was slight blue tint to exhaust. Some bluish color, not very accentuated. Environment temperature was about +10C (50F).

To change the valve stem seals, do you have to remove the cylinder head or removing the valve cover gasket is sufficient?

Sorry to have hijacked the thread. Original question seemed to have been answered.

[t_marat]

Today I checked if there will be a blue smoke of oil exhaust on startup. To my joy the startup exhaust was crystal clear :)
But the problem with rough start ups is still there (a little better). At first it idled rough for a second, went to 800-900 rpm, held there for 3-4 seconds, then fell back and again roughness. After that rpm goes up to steady 800-900 levels again.
I don't exactly remember when this problem started to occur, but I know for sure during summer I didn't have this problem. could it be the temp sensor?