Electrical Problem E30 not running right

[tibbs.james 1]

1990 E30 320I motronic injection

Hi I have just put my E30 320i back togeather after having my cylinder head rebuilt.

I put everything back together how it was and reconnected all earths and plugs etc. But it wont idle right and usually dies after a few seconds as well as running rough at low throttle. It never did this before as the day it blew the HG it still started up and ran very well.

My Tacho no longer works. The pickup next to the toothed wheel has been adjusted to correct specs with a feeler gauge as per the Haynes manual. The inspection light on the dash is showing up also.

***I figure this can't be spark

as when you get the car moving it feels like normal and it runs on 6 cylinders.

***It can't be the Airflow meter as the car would not be running well as once you are above idle (around about 1500 rpm it seems fine) ie it seems to be metering air and doing its job.

***I assume the wire coming from one of the HT leads is the signal for the tach, as this is how my automotive multimeter can measure RPM as well.

I also assume the pickup at the toothed wheel is for ignition timing retarding and advancing spark.

Any idea's on what the problem could be? i can get access to a reset/diagnostic tool.

[will 169]

1990 E30 320I motronic injection

I assume the wire coming from one of the HT leads is the signal for the tach, as this is how my automotive multimeter can measure RPM as well. Correct

I also assume the pickup at the toothed wheel is for ignition timing retarding and advancing spark. Correct, it senses the engine speed and tdc mark and the computer sets the timing from the signals it gets.

Any idea's on what the problem could be? i can get access to a reset/diagnostic tool.

I would first look for air leaks into the intake. Did you correctly seat the oil drain tube between the manifold and the block and put the O seal at the top of the tube?

Tach problem could be the plug connecting the tach lead to the main loom isn't properly assembled... check plugs under the diagnostic plug for proper connection.

There is also another circular plug under the intake manifold just ahead of the starter that is famous for making a bad connection, water gets into it and corrodes the contacts resulting in all sorts of electrical faults. I normally cut it out when I find problems with it and solder the wires together using heatshrink tube to waterproof the wires.

hope this helps

Will

[tibbs.james 1]

Hi

I put the oil drain tube in exactly the same way as it came apart so that is all good and it feels solid inbetween the manifold and the block. I'm positive that can't be leaking.

I did disconnect the plug for the tach signal and install it correctly with the wire clip ect. some contact cleaner might be required here.??

"

There is also another circular plug under the intake manifold just ahead of the starter that is famous for making a bad connection, water gets into it and corrodes the contacts resulting in all sorts of electrical faults. I normally cut it out when I find problems with it and solder the wires together using heatshrink tube to waterproof the wires."

which plug is this? i can't have checked it as i don't know which one you mean

Do air flow meters normally give trouble?

[hotwire 352]

There is also another circular plug under the intake manifold just ahead of the starter that is famous for making a bad connection, water gets into it and corrodes the contacts resulting in all sorts of electrical faults. I normally cut it out when I find problems with it and solder the wires together using heatshrink tube to waterproof the wires."

which plug is this? i can't have checked it as i don't know which one you mean

Do air flow meters normally give trouble?

As Will said - Plug is in front of the starter under the intake manifold - same type of round multi plug as on L/H side of firewall that connects engine wiring to car.

AFM's can fail although would seem coincidental if OK previously. Did you play with AFM settings? If so - could cause problem if not set correctly.

Check all vacuum hoses for leaks.

Is cam timing correct??

[tibbs.james 1]

well it beats me whats happened to my car, i jumped in started it up and for some reason it was idling real nice ( as it always has ) and the tach was working again and yeah it was just running totally different from last night. perhaps the ECU just had to find its groove after the battery being disconnected for so long.

But now i have a new problem, My temp seems to climb slowly and i have my suspicions the water is not getting around to the radiator ie tons of air in it, Its presureing but when i squeeze the pipes there does not seem to be water in there ( the ones going to and from the radiator )

I have never had problems before, when i open the bleed valve on the thermostat housing water comes out as expected, but something still isn't right and im not sure what. I got my thermostat in october last year brand new one , and it tested ok when i checked it tonight, opened up after a few seconds in boiling water. The arrow is facing up and it is in the only way it fits.

any idea's

[nz320i 0]

water pump?

try bleeding it again? this fixed mine, i just had an air lock.. heater on full when you bleed the system?

[tibbs.james 1]

brand new water pump 2 months ago, i did not have my heater on as i was bleeding it i will give that a go

thanks !

[will 169]

If possible jack it up in the front of the car when bleeding it, helps get the air out. Also, drilling a small hole at the top of the thermostat plate helps with getting rid of the airlocking. Heater must be on as chris says.