bmw drawing air.......

x in the city

bah, my 94 316 is pretty buggered, found out the emissions are sky high, reading 9 or something. and its drawing air (from a leak or something), i replaced the idle air valve. not much of a difference.

mech said all the gaskets need to go, no time to get it repaired, but in a few months.


any opinions?

the throttle position sensor is ok, and the MAF or cat didnt show up on the diagnostic check.

lomb

could always sell it and buy a better cared for one. not a bad option if it has a current nct.

alternativiely, systematic checking is the way to go.

Interceptor

Sounds fishy to me - who ran the diagnostic and what gaskets are they suggesting need to go? When was the car last serviced and did the emissions 'suddenly' get high or climb slowly over a period. Is it using much oil? Is the car starting/running ok? What is fuel economy like since you noticed this problem?

Lotsa questions but its not easy to figure this stuff over th'internet...

'c

BrianD3

It may be the exhaust manifold gasket or other gaskets in the exhaust system (eg CAT) whcih are causing the exhaust to draw in air and give an unacceptable lambda reading. Is this what the mechanic was talking about?

But I agree with lomb - it may be time to get rid of this car before it causes you any more hassle. You do seem to have had a lot of problems with it. TBH, it sounds like a bit of a nail.

BrianD3

AMurphy

Sky high in what, Carbon, HC, NoX, CO?

lets assume it is "drawing air" furst items to check are for leaks in the intake side.
So look for cracked/split/damaged/collapsed rubber hosing.
Check the seals on the oil cap, Dipstick and the feed from the Valve cover to the Intake. PCV it's generally called.
Also, Check your brake vac booster for leakage.

If you want to find the leak, get a gaz soldering torch, etc. Start teh engine and run it up to hot/operting temp.
Then get your gaz item and let the let teh gas flow, aid it at potential leak locations. if there is a leak, the engine will draw in the gaz and up the rpm's.
do this outside where the gas will not collect and/or cause a fire of expl.

Seth Brundle

or instead of gas use carb cleaner!

MercMad

Seems odd that the emissions are sky high AND its drawing in air. Usually that would lean it out wouldn't it ??

x in the city

right folks

generally speaking the car is pretty much in great nick, i had to change the lambda and thermostat since i bought it, and then i noticed the idle problem.

the car runs fine, its just that sometimes it gets a mind if its own and revs up and down on its own accord.

the mech said its deffo fixable, its just i dont have time. as for the emmissions, i dont know which ones, i didnt take notice which reading he was doing, maybe co2?

he said he would need to look at the car for 4 hours before he orders parts, he said basically all the gaskets around the head manifold have to go.

when he took off the water cap, you could see the water level rise and fall as the engine revved up <by itself of course!>

also, there is a broken butterfly yoke in the manifold, under the idle air valve, its a small narrow plastic gadget. but the mech said this would never cause the problem.

thanks for the tips guys <and kbannon>

e

Seth Brundle

thanks (not sure why Im singled out though)
You are down in Limerick direction IIRC - maybe head over to Gort:-
Roches Garage
Bridge Street
Gort
Co. Galway
091 631100

BrianD3

x in the city wrote:

right folks
he said he would need to look at the car for 4 hours before he orders parts, he said basically all the gaskets around the head manifold have to go.

Huh? he's going to look at the car for 4 hours *before* he gets around to even ordering a part? How long is it going to take him to fit the parts once he orders them? How can he say for sure that the gaskets are the problem if he's going to be fiddling around with the car for 4 hours before knowing what parts he actually needs and before doing anything to rectify the problem.

Sounds fishy......is this the same guy who used a hammer and chisel to take your thermostat out?

BrianD3

Dades

kbannon wrote:

or instead of gas use carb cleaner!

I used fuel cleaner for a couple of months before my NCT, including a few squirts directly into the carburator.
My emissions passed and were miles better than the results two years before, when I had gone to a garage for emissions work.
Cheap and effective.

AMurphy

x in the city wrote:

right folks

generally speaking the car is pretty much in great nick, i had to change the lambda and thermostat since i bought it, and then i noticed the idle problem.

the car runs fine, its just that sometimes it gets a mind if its own and revs up and down on its own accord.

the mech said its deffo fixable, its just i dont have time. as for the emmissions, i dont know which ones, i didnt take notice which reading he was doing, maybe co2?

he said he would need to look at the car for 4 hours before he orders parts, he said basically all the gaskets around the head manifold have to go.

when he took off the water cap, you could see the water level rise and fall as the engine revved up <by itself of course!>

also, there is a broken butterfly yoke in the manifold, under the idle air valve, its a small narrow plastic gadget. but the mech said this would never cause the problem.

thanks for the tips guys <and kbannon>

e

What type of MAF has this item, Hot wire or Flap type. The old Bosch Flap type did have a pulsating idle problem that was easily fixed. There is a hidden (maybe) bypass screw on the underside, adjust it back and forth see is pulsating stops.

However, even before you get to that.
You mentioned there is a "broken butterfly thing". Irrespective of what your man says, you might want to solve these little items first before making any major setting changes.
The low cylinder. Squirt some oil in the plug hole and see what happens. If it stays the same it is not the rings, but valves. (a burned valve is the result of a lean & faulty injector) Or you mayhave leaks about the "O" ring seals at the tips of the injectors. Again they are easy to find with the gas or carb cleaner... anything that burns.
If you had a head gasket problem of that size of leak, you'd have overheating/boiling.
I do not agree with the general statment "all the gaskets need replacing".
Only the ones that are leaking oil out or air in and as he has not actually located any specific leaks, changing the lot is a fail safe but expensive alternative. BMW parts are not cheap. And again, check your oil cap and dipstick seals. Air leaking in those points will upset the PCV balance.

If the idle is oscillating/hunting and the water cap off, of course the water will pulsate up and down.....what do you expect as the waterpump speeds up and slow down. Rev it up enough and it will overflow. Nothing to do with leaks, head gaskets, etc.

Lots of Co2 is what you want. CO, HC and NOX are the problems.

meanwhile, here are a few items to read, different car, much the same EFI.

http://www.swedishbricks.net/700900FAQ/EnginePerformance-Symptoms1.html#Poor%20Performance%20Idle%20Surge%20and%20Hunt%20%20Dirty%20Throttle%20Body

So, for starters, back to the basics. Clean, repair and replace any minor leak, cracked hoses, etc. then you can get to teh more serios problem.. if they really exist.

lomb

BrianD3 wrote:

Huh? he's going to look at the car for 4 hours *before* he gets around to even ordering a part? How long is it going to take him to fit the parts once he orders them? How can he say for sure that the gaskets are the problem if he's going to be fiddling around with the car for 4 hours before knowing what parts he actually needs and before doing anything to rectify the problem.

Sounds fishy......is this the same guy who used a hammer and chisel to take your thermostat out?

BrianD3

i think the guys brother changed the thermo with a hammer

seriously it does all sound very fishy to me as well. very very fishy.