Back on the E30 scene with my 1991 Neon green cab

[BobIzYaUncle]

Hi all, I'm fairly new to the site. I originally posted up couple of months ago on the hunt for an E30. Well, finally I'm there. A few weeks ago I took a drive down south and paid a pretty penny for a 1991 J Reg Neon Green Cabriolet 318 in lovely condition only covered 105k miles.

Has had a good quality paint job in the past but underneath is solid with no welding. Has a manual roof which I was told come like it from factory but I'm not 100% convinced. Roof is in excellent condition also.

There is a tapping from top end of engine which I'm suspecting is cam wear, this will be a winter investigation job. The 1st weekend I had her, I took her into work and for waxoyl treatment and total underseal.

She will be drystored with runs out on dry weekends. My plans are just to perfect it even more to get her up to my standard.

From what I've seen so far, the following will be done.

Front upper roof seal worn
Roof storage compartment seal worn
Cam / tapping noise investigated
Slight engine stutter through revs and idle
Fuel and temp gauge tempermental
No engine 'check' light
Drivers seat bolster worn
Audio upgrade
Convert aerial to auto electric
Repair cracked dash
Wheel referb
Suspension overhaul
Rear duff overhaul
Retrofit obc
De-tint windows

The above is in no particular order and no timescale set. Mostly will be done over winder months so can enjoy throughout rest of the year.

I will post some photos up once I've worked out how to

[Brianmoooore]

Welcome to the club! What you have is a 'run out special' model - the last of the E30 cabs, which were 1.8i engined. in neon blue or neon green (I have a blue one). The main difference between this and 'ordinary' cabs was the special interior trim, which is unique to these cars, so it needs looking after, and you will devalue the car if you fit ordinary trim.
Cabs with electrically and hydraulically operated roofs exist, but most by far are manually operated. It's so easy and quick to raise and lower, that power operation is just an unnecessary complication.
There's no engine check light because UK cars weren't fitted with one.
Fuel and temp gauge - check the brass nuts on the back of the cluster case that hold the two gauges in place.
Tapping noise is the hydraulic self adjusting tappets. It was BMW's first attempt at these, and it wasn't too successful. The problem doesn't really affect performance or do damage, so the choice is either to live with it or replace them about every 60,000 miles. A change of oil spec. can sometimes quieten them a bit.
Aerial should be electric, so wiring should be there. (plain red and plain white wire. Aerial make is Horstman (?)
Engine stutter - look for air leaks between the AFM and the throttle body, usually as a result of perished rubber bits.

[flybynite]

Drivers seat bolster worn

Yes, worth keeping that car original, if anyone will have a matching original bolster it will be Brutus on here

Aerial make is Horstman (?)

You have been doing too much house-building Brian

Convert aerial to auto electric

Hirschmann , get an AUTA 2050

[Brianmoooore]

Aerial make is Horstman (?)

You have been doing too much house-building Brian

You could be right! Done absolutely nothing else since March.
Horstman, of course, is the heating programmer I screwed to the wall. At least I got the first letter right!

[BobIzYaUncle]

Excellent. I appreciate your input and information. Really appreciated. I will post my progress as I go

[Acaciastrain360]

That’s a sweet cab dude! Love the upholstery!!

[BobIzYaUncle]

That’s a sweet cab dude! Love the upholstery!!

Cheers mate
I've since removed the tint off the windows and replaced all the bulbs in the dash

[martauto]

Lovely looking cab you have there mate , hell of a colour and the interior as well .

Mart.

[BobIzYaUncle]

Little update, I've only gone and got the 6 disc CD changer working,

The car is fitted with a period correct pioneer sterio which has a cassette player upfront and a 6 disc changer in the boot. When I select the changer, I get and error message on the display. Upon first looking at the changer I thought 'yeah, it's had it'. The changer wouldnt eject the CD cartridge so guessed there was an internal problem. I remove it from the boot and stripped it down to find a CD stuck preventing the cartridge from being ejected. Approx 2 hours of tinkering and its fully functional and working. Realy happy with that. Now time for the new electric aerial to be replaced before refitting. Pics to follow at the weekend

[BobIzYaUncle]

And another update....
Since the previous update, I've reinstalled the 6 disc changer only to find it won't eject the cartridge in the vertical position, works OK when horizontal. Not end of the world as I don't use the car much only for odd ride out so will stack the cartridge with 6 good cd's which will keep me going for a while.

I've installed a new auto electric aerial and cleaned out the boot.

Today's job was to replace the air metre as the top had been cable tied on where I can only imagine someone previously has been playing! I've removed the idle speed control valve for cleaning and it is now running smooth and power restored. Really happy.

I'm on the look out for design neon green back seat so I can use the material to repair my drivers seat. I'm sure it'll be a tough find but I'm in no rush.

[BobIzYaUncle]

I thought the new air flow meter and cleaning the idle Air control valve sorted the running issue but seems not. Went for a drive to Newark yesterday and the slight surging on hard acceration and cruising speed is still there. On my way back trying to get a feel of it, I was thinking it feels just like the engine is constantly switching between lean and rich mixture. I thought maybe the lambda is reading incorrectly or very sensitive so unplugged it. Thinking this will make ening run on default values. One doing this I've discovered, it seems a fairly new lambda, so guess this car may have had this issue a while. With it disconnected, the surging goes, but noticeable loss of power and slight misfire lower end of revs however idles smoother and not as lumpy. Anybody have any ideas. I'm going to also post this in technical section.

Thanks in advance

[Brianmoooore]

M40 ECU doesn't substitute a default lambda signal like the M20 does.
Does your AFM have a potentiometer on the side of it, under a plastic stopper?
If so, remove the wiring cover over the engine loom on the bulkhead, and look for two grey/black wires near where the loom branches off to the engine, which have a plug and socket on the end of them respectively. Plug the two together, and this connects the potentiometer on the AFM to the ECU to provide a substitute lambda voltage. Adjust the pot. for a CO value of between 0.5 and 1.0% .
A lambda sensor that switches slowly is usually one that is failing.

[BobIzYaUncle]

M40 ECU doesn't substitute a default lambda signal like the M20 does.
Does your AFM have a potentiometer on the side of it, under a plastic stopper?
If so, remove the wiring cover over the engine loom on the bulkhead, and look for two grey/black wires near where the loom branches off to the engine, which have a plug and socket on the end of them respectively. Plug the two together, and this connects the potentiometer on the AFM to the ECU to provide a substitute lambda voltage. Adjust the pot. for a CO value of between 0.5 and 1.0% .
A lambda sensor that switches slowly is usually one that is failing.

Thanks for the post mate, no mine doesn't have the have loom or the potentiometer on the side. It's doing my nut. Think best bet is to lob it on the gas analyser and see what current Co is

[BobIzYaUncle]

Here goes an update on the running issue

1. Done some investigation and found few vac air leaks to fuel regulator and idle control valve. Sorted those, only minor and didn't make much difference.

2. Refitted the old afm and it ran terible. Adjust the potentiometer by 4 Teeth counter clockwise which made the idle smoother but big dip on hard acceleration. So scrapped that and refitted the new one.

3. Checked the C101 connector for water ingress which was OK.

4. Checked the throttle position switch. Confirmed working on open and closed throttle but not on wide open throttle so will need to remove the throttle body to adjust and retry otherwise suspect faulty TPS.

5. Started unplugging and checking other connectors. Found one 3 pin plug under the intake manifold which had really dirty connection on pin 1. See pic. Not sure where this connector goes to or what's its for but the engine cuts out and does not restart when disconnected.



6. Located the blue temp plug temp sensor under the intake manifold, difficult to access but disconnected it and checked resistance which was around 560ohms when warm. I think the resistance should be lower than this so going to replace anyway as it seems to be the original sensor.

7. Found even on cold start, engine idles around 7 to 800 rpm drops to around 650 to 700 when warm. Not much difference. unplugged the idle speed control valve while the engine was still running (when warm) and with some revs I prevented from stalling and it idled normally without any more intervention! So I then unplugged the afm, again I had to keep revs up for a few seconds but then allowed to idle and it idled normally with the afm and icv unplugged! Is this normal?

8, with engine warm and running, I unplugged the o2 sensor, this slightly changed the engine tone but had no other effect.

9. Whilst engine running, I unplugged ht leads one at a time just to check if any cylinder had a different response than any other but no, they all seems to reponde the same.

10. Reinstalled everything and took for a test drive. Idle seems much smoother, only bit of lump every once in a while but still around 650 to 700rpm. Acceleration still same and hesitant with the slight surging feel, not smooth. I would say its the best now than it had been but still not right.

My next task then I think is to replace the coolant temp sensor and adjust TPS. I'm also going to test o2 sensor and icv resistance.

Will update once done, if anybody had any other ideas from what I've done please give me a shout.

Cheers

[BobIzYaUncle]

Update,

Carried out some more testing.
Found an air leak from the grommet sealing the ICV to the inlet manifold. Sourced a new one from BMW and fitted it, sorted that.

Whilst engine was idling, I used a screwdriver on the injectors to listen to them operating. Only to find, when I touched the electrical connectors on cylinder 4 and 3, it began misfiring, so I worked the connectors on and off in attempt to make a better connection, which it did. Stopped misfiring and didn't miss a beat whilst I wobbled the connectors again.
There was viable oxidisation on injector 3. With the evidence of oxidisation I've found on 2 connectors now, I think it'll be best to fully removed the loom and check everything over the winter months I won't be using it.

I checked resistance of the coolant temp sensor which was just under 100 when hot and just under 1000 when cold. We'll out range compared to hanynes manual so will be replacing that also.

Finally, checked the oxygen sensor, again out of range when warm so got a new one on order. Producing 0.1v at idle and 0.5v at 2,000 rpm which is very much on the low side.

Been a test drive and it's running much better, I put this mostly down to the bad connection on the injectors. I will update again once fitted the new sensors but won't be for a while

[Brianmoooore]

The corroded pin in the plug in your last but one post is for the injectors (I think). A fibre glass contact cleaning pen (like an old type propelling penil, but with bunch of glass fibres instead of graphite) is good for cleaning blade contacts, and silicon grease is good for keeping them clean.
Your blue sensor appears to be out of spec., but it's too early to condemn the O2 sensor. It can't respond correctly if the fuel mixture is out of limits.
As I've just posted in another thread, I'd trust a second hand genuine blue sensor much more than a cheap new one.
In response to 7 in your list, the AFM produces very little signal at idle, so the engine should start and idle almost normally with it unplugged. I say 'almost', because you are unplugging the inlet air temp. sensor as well, so the ECU will think the incoming air is cooler and denser than it is.

[BobIzYaUncle]

The corroded pin in the plug in your last but one post is for the injectors (I think). A fibre glass contact cleaning pen (like an old type propelling penil, but with bunch of glass fibres instead of graphite) is good for cleaning blade contacts, and silicon grease is good for keeping them clean.
Your blue sensor appears to be out of spec., but it's too early to condemn the O2 sensor. It can't respond correctly if the fuel mixture is out of limits.
As I've just posted in another thread, I'd trust a second hand genuine blue sensor much more than a cheap new one.
In response to 7 in your list, the AFM produces very little signal at idle, so the engine should start and idle almost normally with it unplugged. I say 'almost', because you are unplugging the inlet air temp. sensor as well, so the ECU will think the incoming air is cooler and denser than it is.

Great info. Cheers