M20 coming out of hibernation

[Peace_Power]

Hello, I've spent the winter restoring an old -89 325i Touring. And today was the grand start-up for the season. (I've never driven this car before).

The engine sounds alright to me but after the first test drive I'm sure it could be running better.

It revs fine w/o a gear but once in gear it seems to stop at around 4500 rpm.

And also the catalyst was making a loud ticking sound for a minute or two when I got back from the test drive.

And it doesn't feel that much more powerful over my old 320i that I expected so I am unsure of if I am close to the 170bhp it once had. =/

Any ideas?

Thanks! (=

[MR 325]

I would start with a valve adjustment and checking the condition of the spark plugs, cap, and rotor.

Not that this is the issue at hand but check the condition of the timing belt as well!

[Peace_Power]

I would start with a valve adjustment and checking the condition of the spark plugs, cap, and rotor.

Not that this is the issue at hand but check the condition of the timing belt as well!

The valves were perfectly adjusted to spec so I didn't need to adjust them.
Spark plugs look good and have normal wear.

I'll check to cap and rotor though.

I just changed the timing belt and pulley and water pump as well.

Thanks for the help! (=

[Peace_Power]

There is a thick layer of oxidation on the rotor, does that mean it's time for a new one or will a good clean bring it back to life?

[dnguyen1963]

Rotor is cheap. I would get a new one. Cleaning it will probably be okay short term.

[Peace_Power]

So I took the rotor out and cleaned it and the cap up with some sand paper. And I also installed some new NGK spark plugs and it does drive better but not great. =/ I think I still have a rich running engine.

I took the car to a road inspection station (mandatory to do every year here in Sweden) and they had an exhaust-gas-meter-thing and they said it ran rich before they gave her some throttle and also that the values were OK, but not by much.

I'll drive it the way it is for sure, but if there's more things to rule out let me know please! (=

Thanks!

[Peace_Power]

I've got an issue with the idle, it seems to move up from a steady 800 to 1000 then down to like like 700, then have trouble keeping up only to jump back up to 1000.

I cleaned out the idle control valve, but no difference.

And my new spark plugs are already covered in black after only an hour or 2 of driving. =/

And the throttle will stick at like 1600 rpm whilst driving and eventually drop by itself. =/

Oh, and also the temp gauge never reaches the middle mark, it goes up above 1/4 and stays there. The coolant was pretty dark and had lots of gunk in it when I emptied it out for the cam belt change. Maybe some of that gunk is stuck in the termostat and a good clean will save it?

Weird. =(

[Peace_Power]

The spark plugs were looking fine before I messed around with the engine, so it could be related to something I've done like...
1) removing the open air filter and putting the stock airbox on. (maybe it ran better on hot air from near the engine?)
2) cleaning it with water.

I've basically got;
1) a rich running engine
2) a rough idle when warm
3) hard warm starts
4) a temp gauge that only reaches the 1/4 mark

[e30onBBSs]

Check the thermostat, if it's stuck open then that could be your problem for it not getting up to temp. Also if you have a voltmeter check the coolant temp sensor plug just to see if it's feeding the signal, it's probably not broken but it's worth the couple minutes it takes to do. The gauge is a 19mm deep socket and then just turn the key to on and see if you get any voltage at the plug

[Peace_Power]

Check the thermostat, if it's stuck open then that could be your problem for it not getting up to temp. Also if you have a voltmeter check the coolant temp sensor plug just to see if it's feeding the signal, it's probably not broken but it's worth the couple minutes it takes to do. The gauge is a 19mm deep socket and then just turn the key to on and see if you get any voltage at the plug

I checked the coolant temp sensor and I got a reading of 4.400 Ω at the plug and the same at the ECU, then I warmed up the engine to the 1/4 mark and got 450 Ω at the ECU.

The car started right up when cold and the idle was steady, but it got worse and worse the hotter it got.

[Peace_Power]

I'm now thinking it could possibly be the O2-sensor since it's ignored when cold and this problem only occurs when warm.

And also I've noticed the idle can stick at about 2000rpm when downshifting and you wait a little bit and it usually comes down, or you force it a gear and engine break that shit away.

Can it be worth 200 bucks for a new one?

[Peace_Power]

I took the O2-sensor out and found it to be covered in black soot.

I wonder why this hasn't triggered some kind of engine code. =/



Imma try and clean it in some gasoline and reinstall and see if it does anything.

[turbo55]

I heard that you can use a standard o2 sensor and just wire the e30 connector to it:

http://www.r3vlimited.com/board/showthread.php?t=256671

[Peace_Power]

I heard that you can use a standard o2 sensor and just wire the e30 connector to it:
http://www.r3vlimited.com/board/showthread.php?t=256671

Hu, that's a clever solution! Thanks!

After the cleaning however, the car definitely runs better and the idle is nice and steady even when warm. I'll ride like this for a while and see how the spark plugs look.