325i tickover uneven

[david106]

Any idea what this could be when the car is ticking over it's increasing and decreasing rev's but not by much
thanks

[--alpina--]

check for air leaks, also on the adjustment on the aif flow meter has been knocked out (co2)


j

[Cloggy Saint]

The ICV could be on the way out, or just need a good clean.

[Brianmoooore]

If the car has a cat and lambda sensor, this is a symptom of a failing lambda sensor.

[david106]

Hi no cat as it's an 88 model when i started it from cold it is very lumpy and feels like it will cut out but its fine when its been warmed up

[Brianmoooore]

Try changing the ECU coolant temperature (blue) sensor.

[david106]

I'm an e30 virgin where do i look for this sensor
cheers

[Brianmoooore]

Right at the top front of the engine on the water outlet elbow. There are two sensors there, one with a brown connector (for the temperature gauge), and one with a blue connector.
Bit difficult to get a socket on to remove, but I've heard the E30 toolkit sparkplug socket fits.

[alpina527]

The throttle body will probably be leaking at various points. Get yourself a Bbtb from the zone shop. They are re-sealed, and you also get a nice bit of extra power.

[j555boy]

get some carb cleaner and clean the ICV and then change the blue sensor like brian says and it will prob run like a dream. i did it and my 325i idles smoothly starting at just over 1000 revs then after warming up down to 800 - 700 revs. cheers jamie

[bigdek]

poss inlet manifold gasket

let it idle and spray around the inlet manifold joints with carb cleaner or wd 40 .

If there is a leak the spray will seal it momenterily and your idle should change for a sec or 2.

Had this prob on my sport

[old_skool]

ECU coolant temperature (blue) sensor

Any idea what the resistance at a given temperature is Brian? I guess it is a negative temperature coefficient sensor (thermistor)? I have this problem on the 320 and was going to take the ohmmeter to it tomorrow.

[kunjani]

i had this problem on my honda and in that instance it was the airflow meter

[Brianmoooore]

ECU coolant temperature (blue) sensor

Any idea what the resistance at a given temperature is Brian? I guess it is a negative temperature coefficient sensor (thermistor)? I have this problem on the 320 and was going to take the ohmmeter to it tomorrow.

These figures aren't from any official source. They are readings I measured myself on a good sensor a few years ago:
As it came off the engine (cold weather) = 3910 ohms
In cold tap water = 3400 ohms
In hot tap water = 980 ohms
In very hot water (from kettle) = 306 ohms

[old_skool]

As it came off the engine (cold weather) = 3910 ohms
In cold tap water = 3400 ohms
In hot tap water = 980 ohms
In very hot water (from kettle) = 306 ohms

That is quality information Brian. Now anyone carrying out fault finding has a benchmark to work from.
I don't suppose the brown sensor will offer the same values? If it does then it could be used in comparison whilst testing in the same environment?


I will experiment tomorrow on both and post the results at incremental temperatures. I knew that low resistance ohmmeter and a degree in mechanical engineering would come in handy one day

[david106]

The ecu coolant temp sensor [blue] is it part no. b93490 -water temp sensor Ԛ£10 +vat as listed in the gsf cat ,
is this the best place to buy it?

[Brianmoooore]

The ecu coolant temp sensor [blue] is it part no. b93490 -water temp sensor Ԛ£10 +vat as listed in the gsf cat ,
is this the best place to buy it?

That's the one. Alternative is the dealer if carriage charges from GSF are involved.

[david106]

thank's I've got a gsf 10 mns away so i will buy one this week .