M20B20 Stalls, sputters, hard to start.

[sierra9260 4]

I have an E30 320i that has just gone from bad to worse. When I bought her the oil was heavily over filled and I had to take about 2 litres out to get it back down to normal. All my air flow meter and TB was soaked in oil. Its still all through the intake manifold. I've done my best to clean everything out.

The car takes ages to start, often works when I press the gas pedal rapidly while turning the key. It dies usually when at the lights idling after the engine has heated up. When put into gear it loses power and usually dies and sometimes won't start again until its cooled down.

I bought a new ICV for it as it had some oil inside and the idle was playing around a bit. I've replaced a leak the exhaust manifold gasket was causing and I have a few ideas on where to go from here.

It seems the spark is good and the pressure on the fuel rail is adequate (although untested) I'm assuming now its either the Crank Shaft Position Sensor or the Throttle Position sensor. It's been to a mechanic and had a fault code reader which gave nothing. I used to assum it was the fuel pump but I replaced that. I'd love to put my finger on what is actually causing this.

On a side note the car runs much worse now I replaced the manifold gasket. It doesn't like the gas pedal being pressed at all and often just dies.

Appreciate the help guys

[yng_750 247]

C191 PLUG

i had very similar issues with a m20b25,

turned out it was the big round plug dead center under the intake manifold was faulty.

Happens to heaps of them, often you can see corrosion on the contacts though in my case it looked good but was poked.

it has about 7 wires which run to the water temp sensors and the injectors.

When one of the ground wires fail the front or rear 3 injectors lose power.

i tested by taking the intake off and removing the fuel rail. i hooked the injectors back up and turned the car over, front three injectors squirted fuel about 30cm into the air, rear three shot it a couple of meters high, i cut the plug out and crimped in bullet terminals, fixed the issue.

I had another engine that was running well but the plug looked average so i cut it out and used terminals again, made a big difference to fuel economy as all injectors were firing the same.

So in my opinion worth fixing for the $10 cost of terminals as problem or not its probably on its way out

here is the pic of where to find it,

http://t3.gstatic.com/images?q=tbn:ANd9GcT...oFilo_VYJ2i_7_L

and what the loom looks like when removed from the car.

http://pixelpusherz.net/E30/harness1.JPG

easier to do with the intake off but can be done with the intake in place which means you dont have to replace gaskets etc.

Would highly recommend using proper ratcheting crimping pliers if doing it with the intake still on.

[Allanw 1051]

C191 PLUG

i had very similar issues with a m20b25,

turned out it was the big round plug dead center under the intake manifold was faulty.

Good idea - It is a really common problem spot.

It wasn't fitted on early cars, so no problems with them.

On Dads E30, it had a very very slight missfire - only once every couple of months, and only like a single cylinder missfired. On the Advice of Brent from Betta Motor Works up here, we cleaned it up (this was probably 10 or 12 years ago!) and it's never done it again since. Just on the weekend I cleaned it again, as I was poking around and saw it sitting there and though "Why not?"

It's worth giving it a clean anyway with some decent contact cleaner and then a corrosion inhibitor. I use either Wurth or De-Oxit (which we use on Medical Electronics with great results). If the contacts are iffy, either replace them, or hard wire it.

[RAH 6]

I dont like the sound of it being over filled by 2 litres of oil. Id make sure that the manifold is clean an that the injectors are clean. Overfilled engines can blow the oil back thru the entire system and cause all sorts of issues.

Ive seen the mess that overfilled oil can cause. Check that out and make sure that isent the cause.

[sierra9260 4]

Thanks for the help guys but it wasn't the C191 plug... I took that all out and although didn't get a photo it looks like the whole things was nearly brand new.. as well as the plastic box that houses the wires and connects to the injectors.

Next I guess I will start doing some proper testing as my cables and connections look a bit stodgey.. I've heard that the cranks shaft position sensor also gives these symptoms if its faulty?

Cheers

[euroitalian 60]

Engine management temp sensor can create these symptoms. (Blue 2 pin sensor in t/stat housing)

If you check the resistance across the pins it should be approx 2.9Kohm cold, and resistance should fall as temp rises.

[Etwenty1 45]

Thanks for the help guys but it wasn't the C191 plug... I took that all out and although didn't get a photo it looks like the whole things was nearly brand new.. as well as the plastic box that houses the wires and connects to the injectors.

Next I guess I will start doing some proper testing as my cables and connections look a bit stodgey.. I've heard that the cranks shaft position sensor also gives these symptoms if its faulty?

Cheers

sounds to me like tps. If you can't hear it clicking on and off its a good bet. If you remove the inlt man you will have to deal with the oil vent tube which can be testing.

Long cranking can also be cap and or rotor

[albert72 0]

Engine management temp sensor can create these symptoms. (Blue 2 pin sensor in t/stat housing)

If you check the resistance across the pins it should be approx 2.9Kohm cold, and resistance should fall as temp rises.

Been having the same sputtering issue as well. I've just tested mine with the engine still warm and came up with 100 ohms which is way off based from this info I got from the web

Model: 325i, 325is

Connector color: blue

Temperature Resistance

14+-4 F (-10+-1 C) 8200-10500 ohms

68+-2 F (20+-1 C) 2200-2700 ohms

176+-2 F (80+-1 C) 300-360ohms

Will test again tomorrow morning when the engine is stone cold

[sierra9260 4]

I cleaned the magnetic crank sensor as it was completely saturated in globby gritty oil and then got a jump start this morning as the car has been sitting for a while... It took about 2 cranks when it had enough juice and just fired into life... I was amazed as this has been a very seldom thing with my e30. I will keep working on things over the weekend but I've finally bit the bullet and I'm taking to an auto electrician on Monday. Hopefully that will avoid any ambiguity and o can just get straight to the problem causer.. I'll keep you posted.

[Etwenty1 45]

I've finally bit the bullet and I'm taking to an auto electrician on Monday.

I would go to an experienced independent bmw workshop rather than an auto sparky.

You may end up with a new set of HT leads and coil and no improvement.......

Did you dismantle and clean/check your tps?

Edited June 29, 2013 by etwenty1

[sierra9260 4]

That is a good idea, the only one in the hawkes bay region is Jeff Gray and i can't afford to spend a bomb on them. Also i know i am very close and have already spent so much time trying to fix this... that said it may be more beneficial to have money well spent on a technician who won't waste my time.

yes I didn't find anything much untoward apart from a bit of oily/moisture around the connecter plug which i dried and cleaned off... When the car fired up today it happily went to 5k rpm and beyond. does that mean i could rule out a spark problem and fuel delivery issue?

I'll continue trying to clean things up this weekend. I did pull that temperature sensor in the thermostat housing out and it was pretty globby and horrible in it. Residue from the coolant was all over it. i don't have a multimeter handy so that was more of a reason to send it off to the sparky.

[albert72 0]

That is a good idea, the only one in the hawkes bay region is Jeff Gray and i can't afford to spend a bomb on them. Also i know i am very close and have already spent so much time trying to fix this... that said it may be more beneficial to have money well spent on a technician who won't waste my time.

yes I didn't find anything much untoward apart from a bit of oily/moisture around the connecter plug which i dried and cleaned off... When the car fired up today it happily went to 5k rpm and beyond. does that mean i could rule out a spark problem and fuel delivery issue?

I'll continue trying to clean things up this weekend. I did pull that temperature sensor in the thermostat housing out and it was pretty globby and horrible in it. Residue from the coolant was all over it. i don't have a multimeter handy so that was more of a reason to send it off to the sparky.

Just replaced the temperature sensor (blue plug) this morning, resistance of the old one was way off. idle is now smooth at 600 rpm. Hopefully car will consume less petrol now since previous idle was between 700-800rpm

[Etwenty1 45]

That is a good idea, the only one in the hawkes bay region is Jeff Gray and i can't afford to spend a bomb on them. Also i know i am very close and have already spent so much time trying to fix this... that said it may be more beneficial to have money well spent on a technician who won't waste my time.

yes I didn't find anything much untoward apart from a bit of oily/moisture around the connecter plug which i dried and cleaned off... When the car fired up today it happily went to 5k rpm and beyond. does that mean i could rule out a spark problem and fuel delivery issue?

I'll continue trying to clean things up this weekend. I did pull that temperature sensor in the thermostat housing out and it was pretty globby and horrible in it. Residue from the coolant was all over it. i don't have a multimeter handy so that was more of a reason to send it off to the sparky.

[sierra9260 4]

Just replaced the temperature sensor (blue plug) this morning, resistance of the old one was way off. idle is now smooth at 600 rpm. Hopefully car will consume less petrol now since previous idle was between 700-800rpm

Sounds good mate, was it a brand new one? How much did it set you back? I took the radiator sensor out and one of the thermostat ones... (Most definitely should have got both out) and cleaned all the clumped up cooling fluid off it then flushed my cooling system... Interesting thing was the car idled at a nice level pace with a lot less play than usual.. Could be going down your road a bit there. This problem could be a myriad of small things. The main issue is still taking that gas pedal of after revving the car and it struggling to get back to idling.

Edited June 30, 2013 by sierra9260

[albert72 0]

Sounds good mate, was it a brand new one? How much did it set you back? I took the radiator sensor out and one of the thermostat ones... (Most definitely should have got both out) and cleaned all the clumped up cooling fluid off it then flushed my cooling system... Interesting thing was the car idled at a nice level pace with a lot less play than usual.. Could be going down your road a bit there. This problem could be a myriad of small things. The main issue is still taking that gas pedal of after revving the car and it struggling to get back to idling.

Around $25, there's the bosch and tridon brand. Went for the bosch ones. Funny thing is, idling is now all good but car now tends to hard start when engine is warm or after long drive. Might be the coil going bad or something else

[Etwenty1 45]

The main issue is still taking that gas pedal of after revving the car and it struggling to get back to idling.

remember when you throttle off the TPS clicks and the idle is then controlled by the ICV, and vice versa when you throttle on. Check the TPS is clicking off as the throttle closes (you do this with the car off and just listen for the click) TPS may need adjusting or the ICV may need cleaning out.

[sierra9260 4]

So its been in the best auto sparky's shop for nearly a week, went down there today and the car is still running like clogged up toilet. They replaced that blue plug mentioned but no change. He's played around with ICV and throttle position sensor but apparently they are still stumped. Sounds like everything they've tried I could have told them wouldn't work :/ but they know best... I wanted it to go to a shop so compression, spark and fuel could have been ruled out then sensors tried. what fun

[sierra9260 4]

remember when you throttle off the TPS clicks and the idle is then controlled by the ICV, and vice versa when you throttle on. Check the TPS is clicking off as the throttle closes (you do this with the car off and just listen for the click) TPS may need adjusting or the ICV may need cleaning out.

Sorry I've been using my phone and didn't notice this thread has an extra page now so I didn't see your comment.. I will give that a go if and when I get the car back.

[Etwenty1 45]

So its been in the best auto sparky's shop for nearly a week, went down there today and the car is still running like clogged up toilet. They replaced that blue plug mentioned but no change. He's played around with ICV and throttle position sensor but apparently they are still stumped. Sounds like everything they've tried I could have told them wouldn't work :/ but they know best... I wanted it to go to a shop so compression, spark and fuel could have been ruled out then sensors tried. what fun

But at least you have eliminated Battery, earthing points, alternator, HT leads, Coil, and the ICV now .....right?

Sounds like they have no idea and are trying random stuff. If you have mate with an e30 swap the ICV's over and see if that makes any diff.

Poor idle is one of the most common e30 probs and there are plenty of sticky's around (this forum and other) that will take you through. Most are easy DIY's including a compression test and the electrical ones can be done with a $20 DMM.

Edited July 4, 2013 by etwenty1

[sierra9260 4]

But at least you have eliminated Battery, earthing points, alternator, HT leads, Coil, and the ICV now .....right?

Sounds like they have no idea and are trying random stuff. If you have mate with an e30 swap the ICV's over and see if that makes any diff.

Poor idle is one of the most common e30 probs and there are plenty of sticky's around (this forum and other) that will take you through. Most are easy DIY's including a compression test and the electrical ones can be done with a $20 DMM.

Finally finished with my car. They said its got them beat?? They said it has a small leak somewhere when they ran compression tests. But said its not enough to cause the car to do what its doing and they also said the oil which was overfilled could have been mostly water... however there are no other signs of water mixing with the oil to my knowledge and since I emptied it many months ago it hasn't filled back up it has stayed at a constant level. Any way ive already wasted too much money and time on this M20B20 I would rather spend the money I have spent on gaskets and garage work on a new M20B25... I am going to have an ask around this site for one and just swap it out if its possible. I think thats the best option and I'll get some more power while I'm at it. Thanks for the help everyone

[Etwenty1 45]

Finally finished with my car. They said its got them beat?? They said it has a small leak somewhere when they ran compression tests. But said its not enough to cause the car to do what its doing and they also said the oil which was overfilled could have been mostly water... however there are no other signs of water mixing with the oil to my knowledge and since I emptied it many months ago it hasn't filled back up it has stayed at a constant level. Any way ive already wasted too much money and time on this M20B20 I would rather spend the money I have spent on gaskets and garage work on a new M20B25... I am going to have an ask around this site for one and just swap it out if its possible. I think thats the best option and I'll get some more power while I'm at it. Thanks for the help everyone

I hope they charged you nothing for fixing nothing.

Shame you cant find someone to sort it, at least then you would have a "good / running" m20b20 to sell for ?? like this;

http://www.trademe.co.nz/motors/car-parts-...n-612693761.htm

[e30ftw 394]

remember when you throttle off the TPS clicks and the idle is then controlled by the ICV, and vice versa when you throttle on. Check the TPS is clicking off as the throttle closes (you do this with the car off and just listen for the click) TPS may need adjusting or the ICV may need cleaning out.

Completely off topic, But thanks to reading this I managed to fix a little idle issue on my e30 touring, Found the TPS was full of oil and stuffed so went to pick a part and grabbed one from an e30 that was clicking and replaced / adjusted now my idle is mint.

Might pay to check you can hear the TPS click when you close the throttle? I used to have a fluctuating idle that would die when cold, or drop too low and die sometimes because it had dropped to low to fast.

Edited July 12, 2013 by e30ftw