M52....now running and idling well BUT....FINALLY SORTED!!

Post Mon Oct 17, 2011 9:54 am

My M52 conversion is installed, running & the car moves under it's own power. BUT, it runs like a pig - I have posted a video on another thread of the running issues. Looking at all the advice I received from helpful zoners, I took the M50 inlet manifold off & checked/replaced all of the vacuum pipes and checked all jubilee clips were tight. Everything went back together very carefully and it still runs and idles badly - like it's not firing on all cylinders. I then removed all spark plugs, cleaned them up & checked gaps etc before replacing them. No difference.
The only other thing I can mention is that when the car is running/idling if I obstruct the air inlet (no air filter attached yet) partially with my hand then the revs pick up and it runs better for a bit. When I move my hand it usually dies.

Please help me - I have run out of knowledge/skill and am now completely despondent about the whole thing. I've spent ages and a small fortune to get this far and the car still doesn't run like it should. A can of petrol & a match are looking like a good option at the moment as I'm so p1ssed off with it!

Post Mon Oct 17, 2011 10:17 am

Can you get any fault codes out of it?

Post Mon Oct 17, 2011 10:26 am

I cured all of my M50 running issues by replacing the engine/frame earth....it appears that the ECU is very sensitive to voltage change.

Post Mon Oct 17, 2011 10:40 am

^^^^^
Thanks. Checked the earth that was already in place - all good, but added another on the other side of the engine bay for good measure!

Post Mon Oct 17, 2011 1:03 pm

Sounds like ICV problem, remove it and check the insides are free and move easily

Post Mon Oct 17, 2011 1:12 pm

Would that explain the bad running at higher revs Dan? It sounds like it's running on 3 or 4 cylinders up to about 4k rpm then clears and revs OK. This improves as the engine warms up and it starts to run better.
Once this is sorted then I have the rest of the niggles to sort - no temp reading even though I've just fitted and wired the brown M20 sensor in and the rev counter has suddenly decided to stop working!

Post Mon Oct 17, 2011 5:34 pm

maf260 wrote:Would that explain the bad running at higher revs Dan?

Yes

I'v just had a problem with mine,
couple of days ago it sounded like it was running on 4,
tried to cut out on idle,
done all the checks,
coils, plugs, maf,
then looked at the ICV and there was a masshoove split in the pipe that goes from there to the inlet boot,

replaced pipe and now it's good again,

so it could be worth checking around that area,
pull the ICV off and give it a good cleaning/soak with carb cleaner

Post Mon Oct 17, 2011 5:39 pm

^^^^^^^^^^
Thanks.

I've just checked and/or replaced all of the vacuum hoses and bought a brand new inlet boot from the stealers (nice & cheap!) so it shouldn't be pipework, but will check to see if anything's come adrift when refitting.

I'll also take the ICV off and give it a thorough check & clear out.

Beginning to regret the conversion right now. Nothing more frustrating than putting all this work in & it not running properly. I have very limited automotive skills - amazing I have got this far!

Post Mon Oct 17, 2011 7:43 pm

Might sound daft but...................

It is on the right way yeah??

Post Mon Oct 17, 2011 9:50 pm

maf260 wrote: Beginning to regret the conversion right now....

not when its up and running right you wont

my m50 was to the point where fire would be the only resolve but when it fired up and ran it all seemed worth it, and to boot its not even rolling yet lol

have faith mate!

Post Mon Oct 17, 2011 10:13 pm

craigieeb wrote:Might sound daft but...................

It is on the right way yeah??

I would say it is, but something I should also check. Please advise on the correct way so I can check. IIRC the ICV has an arrow at the top somewhere indicating the flow?

Post Mon Oct 17, 2011 10:21 pm

Ermmmm....
yeah lol

there is an arrow on it,
I think it points towards the inlet manifold and not the inlet boot

it's one or the other :lol:

Post Mon Oct 17, 2011 10:30 pm

deanocool wrote:
maf260 wrote: Beginning to regret the conversion right now....
not when its up and running right you wont

have faith mate!

X2 I have been where you are, but once it drives properly you will GRIN from ear to ear!

Where are abouts are you? Maybe a localish zoner could have a look for you. A second pair of eyes often helps.

Andy

Post Tue Oct 18, 2011 9:16 am

craigieeb wrote:Ermmmm....
yeah lol

there is an arrow on it,
I think it points towards the inlet manifold and not the inlet boot

it's one or the other

OK! Not sure that helps!!

Post Tue Oct 18, 2011 9:40 am

Arrow indicates the direction of airflow, so points to the inlet manifold

Post Tue Oct 18, 2011 11:39 am

maf260 wrote:
OK! Not sure that helps!!

OK!

Post Sun Oct 23, 2011 9:45 pm

Update time -

I took the ICV off (it was fitted correctly!) and gave it a thorough cleaning & soaking with carb cleaner. Checked all the vacuum hoses again to make sure there are no air leaks. I refitted the ICV and it seemed better - still not great but better. I let the car warm up and it ran really well, idling nicely and revving easily with a dab of throttle. I took the car for a short drive up & down my road and it still spluttered, but not as badly as before. I then left the car for a while and came back later to restart it - it ran horribly again.
I am at a total loss now of what I can do/fix/check. The car seems to run better when warm, but it still feels like it's holding back.
Oh, and the brakes are absolute shite even though I have bled them 3 times now!
I really hope this will all be worth it as I can't stand even looking at the damn thing at the moment!

Post Mon Oct 24, 2011 1:34 am

I feel for you on the brakes, it took me many a time adjusting the pin for them to work ok, and even now I'm not 100% sure they should be how they are but they still seem to stop well. Might just be paranoid!

Assuming you've been around the bay with the carb cleaner checking for air leaks, is the oil breather ok from the rocker to the intake boot?
As I recall from your other threads you've pretty much done everything I'd have thought it was, which is mainly checking coilpacks out, spray with some WD40 and change plugs possibly.
Is there no chance of you plugging it in somewhere to diagnose the issue? There a guy around my area that'll come to yours, plug in his reader and tell you the problem for £30 although I get trade price. If you replace or fix what he says is wrong and it doesn't resolve it he'll come back for free and do it again.

Post Mon Oct 24, 2011 11:25 am

Brakes are the least of my worries if I can't get the thing to run properly. Felt like giving it a good kick as I walked past it today.

Post Mon Oct 24, 2011 6:35 pm

Feel for ya mate. When I first got mine running it ran like crap, I had -
- one knackered coilpack (well it kind of melted cause of some wiring damage).
- Earth problem - ran extra earth to block & ecu case, back to same point as main loom earths.

Then it ran great then for quite a while till one day it started runnng like crap again, that turned out to be the O2 sensor wiring had chafed and was shorting out. In that case unplugging it make it run fine again so that pointed me in the right direction that time.

I can't find your vid now but from what I remember it didn't sound like a coilpack problem, that would be a regular misfire like du-du-du-du-du-du-du. Yours sounds like either the mixture or the timing is going way way out, but not completely bonkers which would be either MAF or TPS or a wiring / electrical fault of some kind, or low fuel pressure maybe? That's the problem really there's so many things that *could* be wrong... someone who could see the live data from the ECU would be ideal.

I can't remember if you've tried it with the MAF & Lambdas unplugged but if it smooths out at all it gives you something to go at.

Hope you sort it.

Post Mon Oct 24, 2011 10:15 pm

I haven't run another earth to the ECU case yet, so that must be worth a try. Where is the best place to take a decent earth connection from? Somewhere under the dash area?

Post Tue Oct 25, 2011 9:06 pm

My ECU is mounted on a little bracket where the battery used to be, I think this was partly my problem in that my new mount didn't have much of an earth through it. All the earths except the mount arm on the other side go to the little tab thingy on the strut top.

Post Tue Oct 25, 2011 11:29 pm

check ur crank sensor

Post Sat Oct 29, 2011 6:07 pm

Fitted a new cone filter today as I didn't have one. Whilst I was there I unplugged the MAF sensor plug. The car picked up revs slightly and runs much better. I can rev cleanly through the range without it spluttering (only stationery, didn't drive it anywhere). So, this points to the MAF being faulty? Does this mean a new/replacement one or can it be 'fixed'?

Post Sat Oct 29, 2011 7:59 pm

I think a new or second hand one is your only option really, is there perhaps someone with a 328i that can swap to see if that is the fault?

Post Sat Oct 29, 2011 8:04 pm

Have you blanked off the nipple on the plastic connector that plugs into the inlet manifold, the pipe then comes from there to the icv.........

http://i9.photobucket.com/albums/a95/re ... old005.jpg

Stolen from Lee

Post Sun Oct 30, 2011 10:34 am

^^^^^^^^^^^
Yes, that's blanked off. When I was going through everything I bought a brand new plug from the stealers as the clip had broken on the old one. Not expensive, but still slightly satisfying even though nobody will ever see it!
I'm going to drive the car a little today to see how it runs & drives with the MAF unplugged. Then I need to hunt for a replacement so I can know for sure if that's my problem.

Post Mon Oct 31, 2011 9:01 am

Took it for a quick drive up & down the road yesterday. Runs like a dream and idles really well. Didn't give it too much of a bootfull as it wasn't fully warmed up. This is great news, except for the fact that the MAF sensor is unplugged. I don't intend driving this car much/at all over the winter, but if I do start it up whilst it's laid up will it do any damage by not having the sensor connected. Clearly I need to find a replacement MAF, but just wondering in the meantime.

Post Wed Nov 02, 2011 8:32 pm

maf260 wrote:Took it for a quick drive up & down the road yesterday. Runs like a dream and idles really well. Didn't give it too much of a bootfull as it wasn't fully warmed up. This is great news, except for the fact that the MAF sensor is unplugged. I don't intend driving this car much/at all over the winter, but if I do start it up whilst it's laid up will it do any damage by not having the sensor connected. Clearly I need to find a replacement MAF, but just wondering in the meantime.

i got a maf off ebay it was a tenner. i expect you will do equally well at a scrappy

Post Sat Dec 24, 2011 3:21 pm

Update - bought a replacement MAF from BSS325i and it now runs very sweetly indeed!