Engine Cutting out problem.

Jet · Post by **Jet** » Tue 27 Jul, 2010 13:57

Anyone come across this problem:

Engine was revving funny when started from cold, but it steadied itself, so I didnt think much of it.
Driving along at 20mph, it suddenly revved up briefly and lurched forward, then calmed down again, heavy right foot I thought.
The moments later, engine died completely as im driving, it started up again no problem, straight away.

I plan to have a go at cleaning the Idle Control / MAF unit, but anyone come across this?

Thanks.

Jonttt · Post by **Jonttt** » Tue 27 Jul, 2010 14:01

Not 100% sure with the Z1's but usually the MAF is easy to check as you just disconnect it and the car will run fine on a default setting. If this solves the problem you know its the MAF (nb engine light may come on with MAF disconnected). You can then try cleaning but they are easy to damage (I know from personal experience

BBZ149 · Post by **BBZ149** » Tue 27 Jul, 2010 14:54

Jet, you not been running it on moonshine again

Bluebaur · Post by **Bluebaur** » Tue 27 Jul, 2010 15:18

Hi J,

Whilst going for the obvious ie, Idle air stabiliser valve and the sticking airflow meter. Have a very close look at the black convaluted pipe running to the inlet manifold for some signs of cracking/splitting etc, usually underneath where it is most difficult to see! This is one of the most popular failures, that causes bad running on the M20 engine. ICV's and MAF's can usually be cleaned carefully and the difference in tickover is immediately apparent.
Hope this helps in some way.

Stoertie · Post by **Stoertie** » Wed 28 Jul, 2010 08:38

Good morning Jet,

check also the function of the throttle-valve switch. This check is easy (when you know how to do), please try to find an instruction in english in the i-net... ( or maybe this can help.

)

At the german E30 site there is one, but in german language.

Best regards
Michael

EDIT:
Have you filled up oil before? - Check if the oil cap is closed correct!

Jet · Post by **Jet** » Wed 28 Jul, 2010 17:04

BBZ149 wrote:Jet, you not been running it on moonshine again

Nah, wray and nephew. One 70cl bottle is equal to 1 gallon of unleaded.

Holland Harry · Post by **Holland Harry** » Wed 28 Jul, 2010 19:44

Stoertie wrote:Good morning Jet,

check also the function of the throttle-valve switch. This check is easy (when you know how to do), please try to find an instruction in english in the i-net... ( or maybe this can help. )

At the german E30 site there is one, but in german language.

Best regards
Michael

EDIT:
Have you filled up oil before? - Check if the oil cap is closed correct!

I had buy a new trottle valve switch last week! On our last meet in de Ardennes I had the same problems with my car. New engine but the switch was still 20 years old.

Above 4000 revs my egine wouldn't go. Now it's running fine again. The problem started like yours Jet!

felix · Post by **felix** » Thu 29 Jul, 2010 18:07

Testing the throttle position sensor is a good place to start. Shamelessly nicked from elsewhere:

At the bottom of the throttle housing, there is a 3-pin connector. First make sure it receives voltage. Pull the harness connector. With the ignition on, you should get 12V between the center and either of the outer terminals of the harness connector. Next, test the switch. The left and center terminals are for rest position. Open the throttle part way
by hand. Slowly let it return to its stop. The switch should close when the throttle lever is approximately .2-.6mm from its stop.

While you're at it, even though it doesn't affect idle, you should test the full throttle switch. Move the ohmmeter probes to the center and right terminals. Open the throttle slowly. When the throttle is within 10+ -2degrees of full-open, the switch should close.

If the switch is out of adjustment, unbolt the throttle body via the 4 retaining nuts. There are two screws on the switch body. Loosen the screws and rotate the switch body until it works as specified. If it's broke, replace it.

BBZ149 · Post by **BBZ149** » Thu 29 Jul, 2010 18:17

Jet wrote:
BBZ149 wrote:Jet, you not been running it on moonshine again
Nah, wray and nephew. One 70cl bottle is equal to 1 gallon of unleaded.

Now I know you would not be waisting the good stuff in a petrol tank

Chaps I think Jet has now fixed the problem. It was the cam shaft sensor.

felix · Post by **felix** » Thu 29 Jul, 2010 18:48

BBZ149 wrote:It was the cam shaft sensor.

Didn't think the Z1 has one? Crankshaft sensor?

BBZ149 · Post by **BBZ149** » Thu 29 Jul, 2010 18:53

felix wrote:
BBZ149 wrote:It was the cam shaft sensor.
Didn't think the Z1 has one? Crankshaft sensor?

Maybee not then, but could have sworn that was what he said it was! Maybee timing sensor then as i'm sure there is one on the M20

Bluebaur · Post by **Bluebaur** » Thu 29 Jul, 2010 20:26

Pulse Generator ?

sfh3l · Post by **sfh3l** » Sun 01 Aug, 2010 19:51

Sorry Jet,

When we spoke I didn't think of the crank sensor. I have only ever had that fail on one car (not a BMW) and the evidence was just sudden and total loss of power, no speeding up or anything like you had.

Good luck,

S

Jet · Post by **Jet** » Fri 06 Aug, 2010 12:31

Problem solved, it was a crank sensor, well thats what the engineer called it anyway. Long piece of wire at the front of the engine, with a round silver thing at the end, apparently detects the position of something, (sorry im clueless about these things).
Thats why I call you guys first, helps my understanding, so thanks for the input, I dont expect you to diagnose the fault based on my cryptic symptoms, no apology necessary Sam.
He also sealed the input/output lines of my idle gauge to TB, which was loose.