Another Bmw E36 problem this time low idle

[Vince70]

I thought I would use the E36 cab the last couple of days after it’s been sitting around on the drive for the last 8 months and it started up lovely and runs nice.

But driving for about 20 minutes on some fast roads (around 70mph) and then coming to a stop it will try and stall and the idle is around 400 rpm.

I just wondered if anyone would know the answer before I take the engine apart for it never to go again.

[Parky]

As it has been standing for a while I would try some fresh super unleaded, a bottle of fuel system cleaner, and a good high speed blast first to see if that wakes things up a bit.

 

Next would be a basic service (oil and filters, plug clean, air filter in particular)

 

Then look at the throttle body and egr valves if the previous actions haven’t helped. I wouldn’t be surprised if fresh fuel and an Italian tune up doesn’t make things a bit better

[BavarianRetro]

Probably an air or vacuum leak somewhere after the MAF.

[Crispian_J_Hotson]

Engine?

[Vince70]

Sorry I forgot to mention it’s a 4 pot m43 and runs ok otherwise.

I have tried fresh Petrol and it only does it after a run to work which is about a 20 mile drive at around 60 to 70 mph most of the time.

I put new plugs filters in it etc last year about 300 mile ago.

[Crispian_J_Hotson]

Visual checks with no tools on these are the intake hose from the MAF to throttle isn't split anywhere, temp is reading at half on a warm run, tiny vacuum pipe to the fuel pressure regulator is not falling apart and oil filler cap and cover gasket are sealing correctly.

 

After that, testing for a choked idle valve, poor reading MAF and some others will follow.

 

Strange engines these, they get some weird issues sometimes, mine goes to stall when braking to a stop in reverse only- doesn't though, but they do like to be doing over 4000rpm (that's points on yer license in 5th!). I don't know of any old BM engine that likes to sit around for ages.

[binbag]

 

Check the rubber boots from the MAF to the throttle body as these tend to crack and let air in .

 

The idle control valve might need cleaning,if it doesn't make a noise when shaken use carb. cleaner to free it.

[Vince70]

Hi thanks for the help,

I just did the commute back home from work and it wouldn’t tick-over which was entertaining on the roundabouts lol.

When I got back home I disconnected the Maf and it started running perfectly so do you think it’s the Maf

It’s a weird looking Maf unit as it’s metal rather than the plastic ones on eBay for the E36 and has a plastic box on top and a different connection so I can see it’s going to cost a bit.

Could it still be something else

[Crispian_J_Hotson]

That'll be an air flow meter instead of the black plastic MAF sensor. These can be tested easily enough to show they are working correctly using a multimeter but you'll need readings to compare to. I don't have these to hand but I suppose they can be ripped off the web easily enough.

The AFM is a pretty robust unit but can go off track through wear which can also be adjusted out with a minor operation. Not really a job for a person with mallet hands if you were gifted with those.

[Crispian_J_Hotson]

Not suggesting that is the fault but here is a little insight to that strange metal box: 

 

https://www.ericthecarguy.com/kunena/common-problems-pattern-failures/51691-bosch-air-flow-meter-check-clean-fiddle

 

I became well accustomed to it on my 6 series when it blew it's own brains out. The 318 has done 177k miles with no fiddling... Yet! 

[Vince70]

Yesterday I fitted my new £8 (second hand) air flow meter and thought I had cracked the problem when it was sitting at around 850 rpm and was most pleased with myself then I went for a drive and the problem came back so I Bought a new CCV valve as it’s on its 22 year old original hoping that might help the problem and it’s due next week sometime.

 

But then I saw the problem and it was plain as day as a breather pipe (the expensive smaller one) from the fuel rail to the airmass boot had a big split in it and when I put my hand over the split the car ticked over lovely.

 

I might try BMW for the part as I’ve found sometimes they are cheaper than eBay and the dealership which is about 15 miles away drops the parts off for free which is nice of them.

 

I’m blaming it on being vain and not wearing my glasses for not seeing the inch long split in the pipe and it looks a bit of a shite to change though as it looks like lots of parts need to be removed to get to it as I think it runs under the intake manifold.

 

I might change the back breathers while I have the thing apart as they don’t look much better. I wouldn’t mind but it’s not my car anymore and my father wishes to sell it as he has trouble getting in and out the thing and it just doesn’t get used But I could buy it back if I wanted but I already have 3 cars but it’s completely rust free and original with low miles and I know I wouldn’t be able to get another.

 

On a brighter note though I cured the slight coolant leak which I was told was a bottom hose by buying a new febi expansion tank and cap while at it I gave the car a coolant change so it has some lovely blue coolant again which is a bonus.

[Vince70]

So I had a big spend today as the smaller pipe was £28 the bigger two pipes are £13 plus a CCV at £10 and a new aerial grommet was also £13.

 

Plus the expansion tank and cap plus coolant and while at it I might as well change the oil although it was only changed about 500 miles ago but it’s been in the car for nearly a year plus my other E36 is in my garage waiting for a fan spanner which never turned up on eBay.

At least I haven’t taken my Z3 apart and I guess and it works out cheaper than having a lease deal or I have to tell myself that at least lol.

 

And driving back yesterday I got a wave from someone driving an E36 which you wouldn’t get in a modern.

[The Reverend Bluejeans]

That pipe is pretty easy to change, just unbolt the upper inlet manifold. I would use a jubilee clip at each end and they can just pull off for no reason. Well, there is a reason..........

 

Put a jack under the engine and lift it - chances are a mounting is fucked, allowing too much movement and that pipe pulling off/splitting. That's the main reason the intake boots split. These are hydraulic mounts. Don't be tempted to fit a solid one. 

[Vince70]

Today I managed to fix the idle problem and I also fitted a new ccv while at it and it’s now running lovely again thanks for the help.

Also it got its new aerial base fitted and I also managed to fit a new base on the Z3 as well this weekend and put a new thermostat and housing on the Ti.

I was going to wash the cars as well but that can now wait for another day.

Plus it got a nice JVC Iphone stereo fitted which doesn’t look over the top and it only cost £28 rather than about £80 as it was ex demo.

And having a roof that works off the remote makes me a right poser down the seafront.