I recently acquired a 91 735 and it has a few problems.
It doesn't want to rev right, seems like something is holding it back.
I just emptied the cats tonight, they'll go back on tomorrow, next I have to try and see if the mufflers are somehow plugged. Not getting much out of the tailpipes.
I am also wondering if there is anything the security system can do to limit the throttle in these cars. I do know that the electric door locks have been disconnected because the doors wouldn't unlock. I haven't been able to find anything on disabling the system entirely. I never lock my cars anyway, keys are usually in the ignition. The guy I got it from said he was told there were a couple pins he could cross to defeat the system, maybe kill it(?) but he couldn't remember which ones and he was afraid to short the pins. Anyone know which pins and where I find them?

Instead of emptying cats and mufflers:
have you done your basic homework such as changing the distributor cap and rotor, changing plugs, checked fuel pressure and changed fuel filter and airfilter, checked for air leaks in intake system, checked for air leaks in vacuum system, checked indle control valve, checked AFM mechanically and electrically and so on.
Do you have the Bentley repair Manual for the E32?
If not, invest in one.
The security system either kills the engine completely or not.
Do you have EML? If so, does the EML light come on when you have the ignition key in position 2?
Does the EML light go off after 2 seconds then? If not, your car will run in limpmode.
Did you do a stomp test to get fault codes?

Procedure is on my website below.

Yor locking system is controlled by the GM. I assume that your microswitches are broken.
See here
http://bmwe32.masscom.net/
wiring diagrams
http://shark.armchair.mb.ca/~dave/BMW/e32/
search this site
http://www.bimmerboard.com/forums/e32/
If you have EML and the EML light does not come on at all when you start the engine for about 2 seconds, then let me know.
Then you have a special EML problem. But easy to solve if you know how.

OK, a little more history will help explain the exhaust. The car was in a section of road that got hit with fast rising water. The water came up over the bottom of the doors. I know that the car locked itself, the windows wouldn't roll down and she couldn't get out. Had to crawl out thru the sunroof.
The computer under the rear seat has been changed due to that. The car never did let the doors unlock after that. We had a hell of a time getting in it. So that's when the door locks were disconnected.
The car was driven for a while after it was flooded but then it started having problems, he played with it until he got PO'ed with it then it sat, that was sometime in '04.
A couple of weeks ago he told me to get it out of his driveway. It does start easy enough, just has a hard time running up, cut holes in both cats and muffler and that helped some. There is barely any exhaust coming out the tailpipes. I drove it home but getting it beyond about 2200 was nearly impossible. The engine sounds fine and sitting with no load you can rev it as long as you do it smoothly and don't try to step it down. In that case it will cut out completely and quit if you don't let off.
All the basic stuff has been checked or changed as far as I know but I'm unsure what some of those initials stand for.
Got over 30 years experience building/repairing cars but no BMW exp I'm afraid.
No idea if there is EML, I'll look. What's it do?
Stomp test? Brings to mind a few things, none of them having to do with cars tho. I didn't see this on your site, what am I looking for?
AFM? No idea.
Idle control valve sounds like something I could probably check if I knew where it was and what to check for.
Where do I find these codes?
As for the manual, I intend to get one if I can get this thing to at least run down the road half decent, if not it will likely go to the crusher. Not gonna blow the money they want for a manual if it's gonna cost me $3 grand to fix a cheap car. I don't mind putting a few bucks in it but it's gotta stay within reason.
How do I check the fuel pressure on this thing? Where do I look (didn't see the fuel rail) and what should the pressure be? I have a gauge set but I'd be willing to bet this has a fitting I don't have, had that problem with a Jag.

Thanks for all the info so far, I do appreciate it. Your site in particular is full of good stuff. I've got one back door that still won't open. That will be left till after it's running tho. And the wiring diagrams always come in handy.

Don't think I had seen the Bimmerboard one yet but I really don't like those ones that use the list format, to damn hard to make sense of them sometimes.

Thanks again, R.

o.k., some basics
AFM = air flow meter
idle control valve, AFM are here
http://paulaxford.com/bmw730i/images/eng_sensors.jpg
cleaning AFM is here
http://paulaxford.com/bmw730i/index.htm


stomp test is on my website under
Procedure for Acquiring Flash Codes from your BMW
http://www.europeantransmissions.com/Bulletin/DTC.BMW/bmwcod.pdf

EML explained:
http://www.bimmerboard.com/forums/posts/102319/

So: if your throttling valve has a bowden cable for the throttle, it has no EML.
If the throttle valve has a motor at the side and no bowden cable, it has EML.
That is the easiest to check it out.

Fuel line comes up from driver side at the firewall
http://www.e32fixes.com/results.asp?method=show_fix&fixid=3

use this to see the details
http://www.realoem.com/bmw/select.do


Fuel pressure for the M30B35 engine (M30 straight 6) is 3 bar plus /minus 0.6 bar. That is without the vacuum control. Testing:
http://bmwe32.masscom.net/sean750/fuel_pressure_regulators/FuelPressureRegulators.htm

Thank you much for the info, I'll get on this later this evening. Gotta get some stuff done right now.
Too much to do and not enough time!!
Thanks again, R.

BTW I know it doesn't have a throttle cable so I guess EML.

EDIT*** EML light comes on, goes out after a couple of seconds (without starting, didn't notice it when it was running before, don't recall any lights except check engine). Guess that's right?

Oh yeah, is there any way to shut the blower fan OFF? That thing is annoying. Seems like it will go low but never off.

If EML:
when you switch the ignition into position 2, does the EML light in the cluster light for about 2-3 seconds and then go off?
That is very important, if it does not light for 2 seconds and then go off, the car will run in limpmode.
http://bmwe32.masscom.net/johan/eml_bulb/eml_bulb.html

If EML:
when you switch the ignition into position 2, does the EML light in the cluster light for about 2-3 seconds and then go off?
That is very important, if it does not light for 2 seconds and then go off, the car will run in limpmode.


Yep, that's exactly what it does.

Just did the code thing, only one I get is 1222 and that seems to cover a lot of ground. Guess I'll have to get the exhaust back together and see what happens.

OK, had a little time to play with it and this is what I have found so far.
The intake tube between the AFM and the throttle body was split half way around at the clamp on the throttle body end, couldn't tell till I pulled the AFM off.
Was wondering how much this would effect things.
Any idea where I could get one of these?
It still acts like there is a bad throttle position sensor (I assume it has one). If you gently run it up the R's will come up without much fuss but if you hit the pedal quick or even not so quick, (just a little more than slow will do it) it just cuts out, just like you turned the key off.
Right now the AFM is off and it runs the same as it does with it on.
Now that I think about it it's almost like it's getting too much air?? Maybe because of the intake tube? Would this really have that much effect on it???
I don't want to start buying un-necessary parts just to figure out which one is bad. The closest dealer that could put it on a machine is nearly in Pittsburgh and I don't even want to think about driving it that far.

The intake tube you might get at
http://www.bmaparts.com/
or www.autohausaz.com
call patrick at BMA, even if it is not on the list they might be able to get it.

Such an air leak in the intake system has a big influence on the engine performance. Check ALL rubber parts in the intake system, also the vacuum hoses which go under the intake.
Throttle position sensor should be cleaned at first, maybe that helps.
http://paulaxford.com/bmw730i/images/eng_sensors.jpg
http://paulaxford.com/bmw730i/index.htm

"Maybe because of the intake tube? Would this really have that much effect on it???"
Yes

try to tape it for the time being with some strong tape to seal it.

I'll give what you've got listed there a shot. Thanks a lot, I really appreciate it.

Here is a pic of the vacuum hoses underneath the intake, that is not shown on any drawing. Make sure that they are connected and not brittle
http://s71.photobucket.com/albums/i155/shogun_bucket/?action=view&current=whichhose.jpg

Thanks, I'll be sure to break out the mirror and give them a look too.
After some more playing around today I am beginning to believe my biggest problem is fuel. To be a little more specific, old fuel. This car has sat since 04 and the fuel stinks of varnish. I thought it was nearly empty so I dumped ten gallons in it hoping it would thin it out enough. We only managed to get a majority of the fuel in it until it started coming out the neck. So I fear it didn't thin it out enough.
My next venture after checking the afore mentioned stuff I will drain the fuel tank, change the oil filter and if that doesn't clear it up I suppose the next thing will be pulling the injectors and cleaning them.
Is the plug on the tank bottom a drain or is it something else?
It's hard to explain what I was doing to come to this conclusion, it had to do with playing with the throttle pedal. I was pushing it quick and holding it instead of letting off. It would barely stay running but if I just held the pedal still it would eventually catch up, cough a few times and rev up but it didn't quit. And it really stinks from old fuel.
Again, thanks for the help. The wife is starting to believe she'll never actually drive this thing. lol

The fuel tank has a drain bolt at the bottom, but you won't get out all fuel. Because the bottom is not even.
http://www.realoem.com/bmw/showparts.do?model=GB43&mospid=47359&btnr=16_0012&hg=16&fg=05
Since the car stood there for so many years, I assume that inside the tank there is corrosion, rust and at the bottom a lot of stuff which blocks the fuel pump, filter inside the tank, and the fuel filter outside under the car above the rear axle. If you want to make it perfect, remove the tank and clean it (wash it) thoroughly. It is not too difficult, see the above pics.
Remove the fuel pump from inside the trunk, then lift the right rear of the car up with a jack, remove the rear wheel, remove the plastic mud guard inside the rear wheel and then you see the ventilation system for the tank and the expansion tank.
http://www.realoem.com/bmw/showparts.do?model=GB43&mospid=47359&btnr=16_0113&hg=16&fg=10
Get new fuel hoses and replace all those hoses, the old ones will be brittle or hard as stone.You will also need new hose clamps, the BMW ones are one time use style.
Before you losen the 2 straps underneath the tank, you have to remove the rear bumper. That is also quickly done.
http://www.bimmerboard.com/forums/posts/302868/
fuel pump removal
http://bmwe32.masscom.net/sean750/fuelpump_replacement/Fuelpump.htm
http://bmwe32.masscom.net/maxf_website/gauge.htm

Thanks for the info, I'm sure that will save me a lot of time. This might have to wait till next week tho, got some other stuff that needs done.

Just wondering if anyone knows if you can get a key cut somewhere other than BMW. The dealer wants way more info than they need and my key for 3 days plus somewhere between $50 & $150. A little steep in my opinion for a non coded key.
I manage to break the end of this stupid POS switch blade key, all I want is a normal key, no fancy garbage.

Keys:

also happened to me that the lower part (metal) of the switchblade broke where the key stub goes in.
No need to buy a complete new switchblabe, the lower section can be bought separately, and luckily that is the cheaper part of the switchblade :buttrock
http://www.bimmerboard.com/members/q/original/Switchblade%20Remote%20Part%20Nbrs.jpg

If you have a decent equipped locksmith, he can make you some copies if you bring to him the key blanks. Actually I bought 2 keys from a Ebay dealer in Hongkong for less than 10 $, here are a lot
http://search.ebay.com/bmw-blank-key_W0QQ_trksidZm37QQfromZR40


Use the BB E32 board for such info, has just been discussed there again
http://www.bimmerboard.com/forums/e32/

Never thought about ebay for key blanks, guess I'll have to call around to some locksmiths and see if I can find one that can cut it.

BTW the switchblade part of the key was already broke (the hoopie part was broke in half) and the unit itself is pretty much junk too.

Thanks, R.

found something about fuel tank rust/cleaning on the E23 forum of RF:

Dirty fuel tank adventures (long)

Message: I had posted several times last year about troubles I was having with my '81 745i fuel system. The fuel pressure would gradually start dropping under load and the pump get noisier - classic symptoms of obstruction somewhere. The tank had rusted out while the car sat in storage so I had put a new fuel tank on three years ago, but hardly ever used the car. One problem was that the feed line from the tank was pinched between the tank and trunk floor, and I fixed that.

I have not run a transfer pump since 1994 and with two pumps sucking (large one for main, original pump for extra injectors and nitrous system) there was never a suction-side problem. But to make 100% sure this wasn't the problem, I bought a new Walbro 392 pump (255 lph) directly in the tank. Since I was changing filters so often, I put a Fram changeable-element filter under the hood which made it easy. There would sometimes be some light-brownish "silt" in the filter canister when changing an element. Looking down into the tank with a flashlight looked clean on the bottom. And every time I thought I had it fixed, after taking it out to back roads and making a few full throttle runs, the lack of fuel would come back.

It got worse as the tank level dropped, but as long as I kept it above 3/4 full I could drive around town without problems. The fuel pressure would gradually start dropping under load and the pump get noisier - classic obstruction symptoms. Filling the tank to the top would temporarily cure it. But this was misleading - the fuel level was only indirectly responsible...

Recently I had to take the car on a 200 mile (each way) trip. After about an hour of running it started dying in the middle of nowhere. So I pulled over, shut it off for a minute, and before changing the filter decided to try restarting. It ran perfectly(!) for another half hour, then started dropping pressure again. Eventually on the return trip the intervals were down to less than 10 minutes. I got pretty good at turning the key off and pushing the clutch in, counting to ten, and firing back up, all while driving 60 mph :)

So my mental lights have finally come on - crap in the tank was being sucked up into the pickup sock and eventually plugging it. When shutting the engine off, the crud would fall back to the bottom of the tank until the fuel circulation picked it up again. That's what misled me about the fuel level in the tank - since it was shut off while refilling the pickup would clear! And keeping it full made the concentration of crud less so the time to clog was longer.

Today I dropped the tank, having bought a fuel tank sealer kit from POR-15 (www.por15.com). I used the electric pump to drain the tank just about dry into cans (through the filtered side so the gas is clean). There was an unbelievable amount of rust and crud in there - the first "Marine-Clean" rinse came out solid-brown like chocolate milk! So much for my "new" tank... The second was much better. Now I'm finishing up the "Metal-Ready" phosphate prep stage, and after rinsing plan to duct-tape a hair dryer on low heat to the tank neck and let it bake for a couple of hours. After that, the sealer. (It's got to be bone dry for the sealer to stick, and that would take several days without forced air).

I've used this kit before on two of my tractors, a 1965 Ford truck, and a '73 Mercedes diesel with rust pinholes in the tank, and if the directions are followed to the letter it works beautifully. The body and frame of the Mercedes rusted away after six salty-road years but the tank was still shiny and clean inside and never leaked again. No connection to manufacturer, etc.

Anyway, as someone once said, when you eliminate the impossible, whatever remains, however improbable, is the answer.

-Charles
'81 745i currently tankless
'85 745i

Guess I better shove a mirror down in there and look around a bit. If it has any rust in it I suppose I'll drop it and seal it. I have some red tank sealer here that will seal just about anything.

P.S. - Where do you find time to dig all this stuff up? :urtheman
I couldn't get this much info from a service manual:biglaughb:clap

Hi Nitetimes,

I have very similar issue to the one you experience with your BMW. When I'm on the road and press the gas pedal, the car behaves unresponsively. I can see the R's going up but the car itself is not moving forward as expected. I'm wondering could this be a problem with the transmission?

--Ivan

The best is always to get a readout on a fault code diagnosis machine. Good invested money and saves time.