Car running rich

Post Fri Sep 13, 2013 6:52 pm

Evening all my car over the last couple of years has started to run richer.. I don't drive it as much as I would like its more of a weekend car. I've been told its because the mixtures need resetting is this the case if so anyone know someone around heathrow area that can do that? I've read on a few forums that its to do with the air flow meter?

Post Fri Sep 13, 2013 7:09 pm

Whatever is wrong with your car, the answer is NOT "the mixtures need resetting". The adjustments were set correctly at the factory, and should never need resetting.
If the mixture is now incorrect, it's because of a fault, or combination of faults, that need correcting. When everything is back into spec., the mixture will be correct without any 'adjustments', and the engine will perform as it should.
Can't suggest anything at this stage, because you haven't told us what car you have, or its age.
What makes you think it's running rich?

Post Sat Sep 14, 2013 12:20 am

Hi thanks for the reply ..the cars a 325i cabriolet on a D reg

Post Fri Sep 20, 2013 11:58 pm

Post Sat Sep 21, 2013 12:03 am

First port of call would be to check the air filter is clean, followed by the blue temperature sensor:

http://www.e30zone.net/e30zonewiki/inde ... emp_Sensor

Post Sat Sep 21, 2013 10:04 am

Brianmoooore wrote: What makes you think it's running rich?

Post Sat Sep 21, 2013 6:05 pm

Spray some brake cleaner / diesel start around the induction side of the engine, it may be a simple as a perished hose
If the revs increase, then you just need isolate where the leak is

Unmeasured air in the system will cause the fueling level to increase

Post Sat Sep 21, 2013 8:12 pm

Brianmoooore wrote:
Brianmoooore wrote: What makes you think it's running rich?

Changed the spark plugs on my 325 today along with oil and oil filter and new air filter.
Spark plugs have dry carbon deposits, which means mine is running rich?
Still trying to determine my low/rough idle..
(Apologies, not meaning to hijack your thread RS)

Post Sat Sep 21, 2013 10:21 pm

Nothing wrong with dry carbon deposits, as long as the spark plug tips are a light brown/tan colour.

If it's running too rich, the spark plug tips will be sooty and black.

Post Sat Sep 21, 2013 11:58 pm

The whole tip was dry black carbon, any thoughts?

Post Sun Sep 22, 2013 12:05 am

Did you check the blue temperature sensor?

Post Sun Sep 22, 2013 12:27 am

Yeh, that appeared to be with in range according to the wiki stats.
Checked at plug and ecu end and cold/warm

Post Wed Sep 25, 2013 9:57 pm

air leaks--blue temp switch and its wiring--clogged injectors--put the car on a gas
analyzer
failing that may be the fuel rail pressure regulator
test every thing first!

Post Sat Oct 12, 2013 7:30 pm

anyone know a good mechanic around heathrow airport area which would be able to check all the things listed above? preferably someone who knows their E30's

Post Sat Oct 12, 2013 11:30 pm

Forgive my lack of knowledge but if they test using a gas analyser and the measurements aren't what they should be, how would they adjust/alter this?

Post Sat Oct 12, 2013 11:34 pm

The AFM has an Allen key adjuster on it that can be altered to adjust the idle mixture, but it should only be used as a last resort after checking everything else, as they are factory set and in theory, should need no adjustment.

Post Sun Oct 13, 2013 3:49 pm

Ah, ok, thanks bud.

While we are sort of on sensors and such, my brown sensor plug has two ports but the plug itself only has one pin, is this normal? (mine is 325 touring, manual, non a/c)

Post Sun Oct 13, 2013 5:33 pm

JM2012 wrote:my brown sensor plug has two ports but the plug itself only has one pin, is this normal? (mine is 325 touring, manual, non a/c)

Perfectly normal, except on the very earliest E30s, which had a two pin sensor, which was an earth connection, instead of earthing through the sensor's body.
If the AFM obviously hasn't been adjusted before, then resist the temptation to adjust it. Find the real fault instead.

Post Sun Oct 13, 2013 6:13 pm

Thanks for the input Brian, cool to know.

I have tried various things but with limited knowledge am running out of things to try..
Keep on keepin' on I guess

Post Sun Oct 13, 2013 6:19 pm

Set of recon. injectors (see trader's forum) is the place to start. An E30 (except for the post '92 ones) has no feedback loop monitoring mixture strength, so this unknown needs to be dealt with first.

Post Sun Oct 13, 2013 8:55 pm

That is one thing I haven't tried so will look in to it. (injectortune from other posts I have seen iirc?)

While on the subject of injectors, I have heard of people using the M50 injectors as an improvement/upgrade over stock ones.. would this make any difference/would there be any point on a stock engine? (I do have one of Maurice's ecu chip here but would like to sort of the car running rich before installing it)