e30 1989 320i, now 325i running issues

Post Tue May 20, 2014 1:10 pm

I've recently swapped my m20b20 (timing belt went) with an m20b25. Was running fine for the first few days, now the car seems to shudder and 'kangaroo' a bit when I press on the accelerator (not every time). Happens more often when the engines warmed up, and it doesn't happen all through the rev range. Runs very sluggish, it gives phases of power when I press the accelerator and I can hear a sort of rumbling I think, like a rumble/spitting sound.

Car does have some problems starting up from cold. sometimes will start for a second or two then stall. I have to give it some revs when starting for it to stay alive. And when when the engines a bit warmer it start to rumble at idle, not constantly, for about 7 3 out of every 5 secs (if that makes sense)

Did not get the injectors cleaned so not sure what state they are in, plugs are fine, leads all connected properly, dist cap was slightly loose this morning but I've tightened that now and it still happens. looked for air leaks, did have a good sized hole in the afm rubber boot, replaced that and no difference.

Think I've covered everything. If anyone has an idea what I should check...?

Thanks

Post Thu May 22, 2014 12:55 am

Sorry, pretty long post. Anyone had this before or know any reasons for this?

Post Thu May 22, 2014 9:12 am

did you change the 2.0 airbox for the 2.5 one?

Post Thu May 22, 2014 9:16 am

Check the blue temperature sensor as a first step:

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

Try spraying WD40 or similar around the inlet manifold gasket with the engine idling; a brief increase in idle speed indicates a gasket leak.

Post Thu May 22, 2014 10:12 am

Yes I bought a new 2.5 afm and airbox from Byron. I haven't checked the blue temp yet. For some reason I find all things to do with the blue temp sensor a bit daunting. Just for some info...my temp gauge never goes over half way since this problem started happening, Its usually just on the first notch. I'll try the blue temp sensor on my lunch break. Thanks!

Post Thu May 22, 2014 10:25 am

Also, my ECU seems to have a small high pitched wine at certain throttle positions. Is this normal or is it the ECU struggling with something?

Sorry, might be a stupid questions, do I disconnect the battery before testing the pins on the ECU loom for the blue temp sensor?

Post Thu May 22, 2014 10:41 am

Not normal for an ECU to make any noise at all! Are you sure it's not the OBC gong in the trim panel below the steering column doing it?

Post Thu May 22, 2014 12:44 pm

I don't have an obc gong in the trim panel. It does seem to come from the ECU. only when I slightly press the accelerator. I have my 2.0 ecu and after pay day the end of the month I'll be in touch with you for a chip.

Anything else that could be making a noise? It is an electrical noise, i think....

Post Thu May 22, 2014 12:52 pm

It could possibly be a component such as a diode or capacitor within the ECU breaking down under load.

Which ECU do you have, e.g. 0 261 200 173 or 380? The 380 was reknowned for blowing diodes in the idle control circuit, so it could be that...

Post Thu May 22, 2014 12:59 pm

I'll check when I'm on my break. For some reason I think it's a 380. would that affect it when I press the throttle? The symptoms do seem to go away at higher revs...

Post Thu May 22, 2014 1:12 pm

Well, if it is a 380 and has blown idle circuit diodes, then yes, it would create the issues described.

Post Fri May 30, 2014 12:46 pm

No I was wrong. its not a 380 ECU. The symptoms seem to be worse when engine is warmer, and once I get into higher revs it doesn't seem as bad. Could a simple air leak be causing this? I have checked thoroughly and couldn't find anything. I've taken the leads, and a few other bits like the ICV from my old engine as I know these were in good order and will swap these to see if that helps. Could it be the blue temp sensor? Any help with be appreciated. Just need to get this sorted now!

Thanks

Post Fri May 30, 2014 1:25 pm

Speedtouch wrote: Try spraying WD40 or similar around the inlet manifold gasket with the engine idling; a brief increase in idle speed indicates a gasket leak.

Post Mon Jun 02, 2014 10:34 am

Did this over the weekend. Sprayed every around the manifold and intake. No change in idle speed. Found a loose bolt on the distributor cap, so there was a bit of play. It could came away from the block only about a mm if I pulled it. Could this have affected it? My temp gauge doesn't reach half way either, it always stays just around the 11 mark.

Thanks for all the help so far.

Post Mon Jun 02, 2014 10:56 am

A loose dizzy cap bolt won't help, but I doubt it would cause the issues described.

Many E30 temperature gauges only show around 1/3 - 1/2 of the way up in normal conditions.

Post Mon Jun 02, 2014 11:52 am

Right ok. That's good to know. Could the issues be caused by a blocked fuel filter? Or bad injectors? Will change the filter and I was planning on sending my injectors off to be cleaned anyway.

Post Mon Jun 02, 2014 11:54 am

Both good ideas that certainly won't cause any harm and may well improve the situation.

Post Wed Jun 04, 2014 2:00 pm

On the way to work this morning. Engine constantly sputtering with loss of power. Temp gauge suddenly decided to go towards the red (didn't go in the red). Idling around 400-500 mark. Pulled over on a country lane to let someone pass, stalled, then wouldn't turn over. Smoke coming from the engine bay. I let it cool down and it finally started again so I could drive it to somewhere that was safer to stop. A bit of smoke coming from the exhaust. There was a flow of rain water going under the car and a trail of multicolored patterns in it. Couldn't spot a leak but it was raining so there were drips from multiple locations. Head gasket gone? Or worse, head cracked?

Post Wed Jun 04, 2014 2:04 pm

Sounds bad. Check the coolant reservoir for signs of oil in the water, and under the oil filler cap for mayo/water.

Post Wed Jun 04, 2014 2:13 pm

Checked both. All seems normal.

Post Wed Jun 04, 2014 2:14 pm

coolant in the expansion tank very low even though it was topped up a day or two ago.

Post Wed Jun 04, 2014 2:38 pm

I would do a compression test - all six cylinders should be reading roughly equal pressures of 170-190psi.

You could also whip the spark plugs out and check they are all a light tan colour; if they are very clean, this may indicate water getting into the combustion chamber(s) and steam-cleaning the plug tips.

Post Wed Jun 04, 2014 3:00 pm

Ok, I'll check the pugs after work and try and do a compression test. If it starts, would it be ok to drive it about 3 miles to my garage if the temp gauge stays where it should?

Post Wed Jun 04, 2014 3:10 pm

Post Wed Jun 04, 2014 3:16 pm

Ok brilliant. Thanks for all your input! really appreciate it!

Post Thu Jun 05, 2014 10:45 am

Filled it with fresh coolant yesterday so I could get it home. Took three stops over 4 miles due to over heating. Found steam coming from the front metal coolant hose going to the bottom of the rad. Anyone know the part number for the metal hose? Can't seem to find it on real oem.

Thanks