mass air flow problem?

[rosemont83]

Hi, I have a 1993 bmw 525i with an automatic transmission.. When I start my car in the morning, or after it has been sitting for a few hours without being touched, I have to press the gas very very slightly or it will shut itself off. It feels like its about to go when i push the pedal normally, but then it feels like it "choked' itself and will shut off. Unless I give it very little gas and drive very slow for a couple minutes. Could this be my mass air flow sensor?

Also.. sometimes when I start my car it idles up to past 3000, then down to about 700 then up again.. then down.. then up.. and after doing that about 2 or 3 times itll go back to normal idle by itself.. or if i give it some gas while its idling up.. usually only happens after I drive the car and shut it off then start it again.. like at a gas station or if I go shopping.

[rosemont83]

lol... no one knows??

[Ryan M]

sounds like it could be a maf or o2 sensor issue.

[Lanc3r]

Also.. sometimes when I start my car it idles up to past 3000, then down to about 700 then up again.. then down.. then up.. and after doing that about 2 or 3 times itll go back to normal idle by itself.. or if i give it some gas while its idling up.. usually only happens after I drive the car and shut it off then start it again.. like at a gas station or if I go shopping.

Check your other thread for fuel issue.

With idle we need to know if its during cold or warm start.

[rosemont83]

I pulled the maf yesterday and cleaned it with isopropyl alcohol.. but no difference at all...
how would you test which one it would be?

[rosemont83]

it happens when its a cold start or I havent turned the car on for about 6 hours...

[Lanc3r]

I pulled the maf yesterday and cleaned it with isopropyl alcohol.. but no difference at all...
how would you test which one it would be?

Voltmeter and Bentley manual.

Doesnt sound like MAF to me though. when those fail its pretty consistent.

[Lanc3r]

it happens when its a cold start or I havent turned the car on for about 6 hours...

Easy then. Cold start valve. You can either live with it or fix it.

[rosemont83]

lol. Ive never heard of a cold start valve before.. thank you!! So how would I go about fixing it?

[Lanc3r]

lol. Ive never heard of a cold start valve before.. thank you!! So how would I go about fixing it?

Poke around here: http://bmwfans.info/original/E34/Lim/525i-M20/USA/L/A/1990/08/mg-13/ill-13_0293/

I believe it is #3. Pretty easy plug and play.

[rosemont83]

wow... that looks complicated..

[bimmer dot info]

Part 3 is a fuel injector for an M20.

This is what your injector system looks like.
http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=13_0347&hg=13&fg=15
There is no cold start valve.

Your problem is the idle control valve.
Part 6
http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=13_0381&hg=13&fg=15
You can try to clean it by spraying seafoam down tube 10. Remove the tube at part 12 and with the engine running spray quite a bit down the tube but not enough to cause the engine to stall. If this does not fix it you will need to get a new ICV.

[rosemont83]

yea it look like that.. thanks.. I was gonna say uh oh.. someone messed with my fuel system.. lol..

I'll try that.. where can I get seafoam?
am I gonna be messing up any gaskets by removing any of the tubing or anything for the ICV?

[bimmer dot info]

I'm not sure out in your area. I got mine at an autozone or advance.
http://www.seafoamsales.com/buy.htm

Part 12 plugs into the rubber intake boot and part 10 is a rubber hose. There are no gaskets. If the rubber is weak you might crack it but if that happens it was due to be replaced anyway.

[rosemont83]

alright I'll do that and let you guys know how it goes

[broncodw]

I have a 1994 530i m60 and have been having the same type problems for two months. I replaced MAF. Did not resolve problem. Replaced idle air valve, did not solve problem. I was also getting intermittent check engine. It would start and run but would idle rough at red light and check engine light would come on. Idle about 4-500 rpm. Changed air filter, made a whole lot of difference. It then would idle rough and check engine light would come on. give it a very little gas and when it would start to speed up, the light would go off and then it would die. After all that, I checked my throttle position sensor and as I touched the wiring plug, it fell off. I re-plugged it and it now runs PERFECT. Your problem could possibly be an intermittent TPS sensor. Take it off and check for continuity while turning the actuator. it should change. :dunno::rolleyes:Maybe just a loose wire like mine. GOOD LUCK!!

[rosemont83]

Well I took off my tps sensor yesterday and made sure the plug wasnt cracked or anything.. the sensor itself looks fine.. the little bearing turns fine too.. how would I check for continuity?

[ruf-porsche]

Are you getting a check engine light? Check the code if you are getting a check engine light.

If you are not getting a check engine light it could be a small vacuum leak.

[rosemont83]

well see the problem there is my check engine light bulb is gone... lol... I wish I could check my codes..
But I bought the seafoam... I just want to finish this excel work crap for school then Im gonna go try and put that stuff in.

[bimmer dot info]

It is not that hard to replace the bulb.

[rosemont83]

Dont I have to take the steering wheel off?

And I found out some new things...
When I went to go unplug the hose that I'm supposed to pour the seafoam in, I found that there is a crack on where the hose plug plugs into the intake air boot..

could that be my problem?
I felt around and didnt feel or hear any air leaks tho..

[ruf-porsche]

Dont I have to take the steering wheel off?

And I found out some new things...
When I went to go unplug the hose that I'm supposed to pour the seafoam in, I found that there is a crack on where the hose plug plugs into the intake air boot..

could that be my problem?
I felt around and didnt feel or hear any air leaks tho..


NOPE

Could be one of the problem.

How did you ever find out that the bulb is missing?

The hose that you pull off, was it attached to the ICV? I think that for an 93 M50 engine , the ICV is toward the front of the intake manifold and not behind as shown in the diagram or realoem.com

[bimmer dot info]

There is a chance that you can get it out with the wheel still in the car but it is much easier to do it with the wheel out. It only takes 2 screws and a bolt to remove it (and you have to pull the airbag connector).

It can not hurt to replace the intake boot but it is not the only cause of your problem. I'd still recomend cleaning the ICV.

When you go to put the seafoam in bring a funnel. It will make your life a lot easier.

[rosemont83]

alright.. I'll clean it and get a new boot later.. actually.. as soon as I find one.. lol

[rosemont83]

Ok tried the seafoam... helped a little bit.... shouldve brought a funnel tho... LOL

[pehoffman]

Don't forget that a stalling at Idle can also be due to failure of the fuel pressure regulator.

[rosemont83]

it doesnt stall at idle. when its in drive and I give it a go with the gas pedal it'll idle down and die if I don't let off the gas and press slowly.. I think its the vaccuum leak.. because it happens when its cold.. the lines are hard and there are cracks in the intake air boot connector.. so yea... have to get another one.. low on cash right now tho

[sstuner]

get a roll of electrical tape and start taring up the cracked area, did it on my e30 2 years ago and it is still holding. and mine was cracked right on the bellows and it went all the way around


got to the point that i didnt want to spend anymore money on it cause i was going to get a newer BW

and right now the e30 is sitting in the parking lot warming up, havent started it in almost a year. and it fired right up,

these cars are amazing

[pehoffman]

You may want to check your fuel pressure. I fixed the exact same "symptoms" by replacing the fuel pressure regulator.

[rosemont83]

Where is the fuel pressure regulator at? is it in the tank?

[bimmer dot info]

It is on the fuel rail. Part 6.
http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=13_0347&hg=13&fg=15

[rosemont83]

what is the difficulty in replacing it compared to changing a valve cover gasket?
and hey bimmerdotinfo do u think that the regulator could be the cause of the other problem of no power at the 2800 rpm range too?

[bimmer dot info]

It is easier You will need to remove the upper engine cover (pt 25) to get to it though.
It will be held on with a locking ring (pt 10). After you remove the locking ring and vaccum line wrap a towel around it and pull it off. Put the new one on with new o-rings.
Bentley PG 130-17.
http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=13_0347&hg=13&fg=15

Have you done anything with the ignition system yet?

[sstuner]

just bleed off the system pressure before you pull anything off, avoid the spray of gas everywhere. especially in the eyes, it stings.

[rosemont83]

Yea I put the ngk plugs in it and started moving my coils around.. but nothing happened.. and my coils look fine.. no brown caster crap on any of them..
but how can i test if its the regulator? And would I have to unbolt the fuel rail?

[bimmer dot info]

To test you will need a fuel pressure gauge. You have to disconnect the fuel line to attach it unless they added a fitting on the later cars.

Moving the coils you have around will do nothing. You need to get at least one known good coil to swap around.

[rosemont83]

O alright... maybe I'll just borrow one from my friend that has an e34.. lol

[ruf-porsche]

O alright... maybe I'll just borrow one from my friend that has an e34.. lol


Is that a LOL because none of your friends drives a BMW

or LOL

Because you don't have any friends?

LOL

[rosemont83]

thats an LOL because I am wondering what he's gonna say when I go " Hey bro.. let me borrow one of your ignition coil for a while.. and he goes "wtf?" haha

[rosemont83]

Ok so instead of borrowing a coil I just bought a multimeter...
How do you test them to see if they are good.. is it just resistance?
I dont have the bentley manual..

[bimmer dot info]

It is resistance. I only have the bremi values with me (.4-.8 ohms and 1.8k for the boots) and I think you test at the outer pins (?).
I had a bad coil that tested good. I found out that it was bad when I swapped in a good coil and my problem has been gone for over 2 years.

[rosemont83]

alright I'll go check them now and see what happens.. hopefully one tests bad

[rosemont83]

Ok I just did the test.. I got..

Coil 1 Boot 2.3 ohms Coil .7 ohms (MBC)
Coil 2 Boot 2.4 ohms Coil .4-.6 ohms (MBC)
Coil 3 Boot 2.38 ohms Coil .7 ohms (MBC)
Coil 4 Boot 2.49 ohms Coil.7 ohms (MBC)
Coil 5 Boot 2.5 ohms Coil .7 ohms (MBC)
Coil 6 Boot 1.083 ohms Coil .7 ohms(Bosch)

Are these within the range they are supposed to be?

[sstuner]

hey i just did the same tests.

boots are done as they are way over the spec

coils are ok as they are with in the spec.

for the boots once it hits that 1.8 number its time for new ones.

[ruf-porsche]

According to Bentley

Ignition Coil Resistance M50/M60 Terminal 1 (-) Terminal 15 (+) 0.4 to 0.8 ohms

You can find the pin terminal number on the plastic portion of the coil

Couldn't find any spec. for the boots

[sstuner]

scroll down 6 posts, including this one. and BDI has already told you what the specs are.

and then if you scoll up from thereto my earlier entry i have already said what is good and what is bad according to what BDI has said earlier,

wow and does this ever read like i am am being an asshole,

lol,

[rosemont83]

He gave me the bremi values... I checked and dont have bremi coils. I have 5 MBC coils and a Bosch coil :P
but yea the boots need to go... dont know if they would cause the specific problem i was having though..
but also I put my check engine light back in... its giving me the 1223 code... I think.. which is coolant temperature sensor... that doesn't really make sense.. my temp sensor works!

[ruf-porsche]

....but also I put my check engine light back in... its giving me the 1223 code... I think.. which is coolant temperature sensor... that doesn't really make sense.. my temp sensor works!


It does make sense, the 02 sensor work in conjunction with the temp sensor. The idle mixture is controlled by the 02 sensor and is also dependent on the temperature of the engine. I'm not sure if they use a sensor for the temp gauge and a different sensor for the fuel system.

[rosemont83]

ok so uhh... how can I check if my temp sensor is really faulty? And see the only thing with that is my idle is fine..

[sstuner]

+1

good call ruf

the computer ignores the oxygen sensors until the coolant temp sensor tells the computer that the engine is warm, then the oxygen sensors are tuned on and the computer then adjusts the mixture according to waht the oxygen sensors tell it.

i have been studying the last few days.

there are 2 sensors on these cars, and most for that matter, one coolant sensor is for the guage, ans the other is for the computer,

if the CEL is telling you coolant temp sensor then it is the sensor for the computer, not the guage,

and the coil reading will be the same, bremi,bosch or who ever else makes them run under the bmw quality control, and if the parts dont met spec then they dont use them.

and i realy didnt mean to sound like an ass, so ruf i apologise .

[rosemont83]

So which sensor is the 1223 code for? The one on the right side of the radiator? On bavauto they only have 1 temp sensor that is for the coolant

[ruf-porsche]

On Page 130-14 of the Bentley Manual, it gives directions on replacing the ECT (engine coolant temperture) sensor for a M50 and M60 engine.

For the M60 engine, the ECT sensor is located at the rear of engine, in coolant crosspipe (white Plug). You need to remove the top engine covers to access the ECT.

[rosemont83]

Its an m50.. I dont have the bentley manual though.. Im pretty sure I just unscrew the sensor and plug the new one in.. IF its the sensor on the passenger side of the radiator..
I'll wait for BDI to confirm. lol

[sstuner]

both temp sensors are at the back of the engine on the right side, one is white the other is brown

the one on the rad is for the electric fan in front of the condenssor