3rd Bimmer in the fleet : '81 733i. PHOTOS

[maxthegearhead]

Hello everyone.

I have just purchased my 3rd car and my 3rd bimmer, an '81 733i 5 speed.

Almost no rust on this car, bought from Queens NY. She sat since 2005.

Grey with a blue pinstripe and tan interior.

Non running, she has spark. I suspect massive vacuum leaks and 10 year old fuel.

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I will update this thread as I make progress!

[TicoVW68]

Looks like a solid start. My 3rd BMW and my most recent purchase is a '78 733i and it has become my favorite one to drive. It had been sitting for some time and the fuel pump was stuck. Cleaned up the pump and she fired right up. Good luck!

[StevenHenriksen]

Very cool to find a 5 speed car! Good luck getting her sorted out

[Hit Man X]

Looks fun... I would lay money on seized fuel pumps. I found a Carter for the intank, P76800 and needs the STS-1 sock. About $40 for a working lift pump.

Pull the plugs and soak the cylinders with that foaming oil, Sta-bil makes it. Dump the crank case, fill with cheap Supertex 15/40 Diesel. Crank it with plugs OUT and verify you have oil squirting out of the oil spray bar on the head.

Once that has been done, toss in a fresh set of plugs. Shoot some Bill Cosby in a can down the TB and see if it sounds okay. If it has knock or a weak hole, I would just part it.

[coolvegase34]

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[maxthegearhead]

Looks fun... I would lay money on seized fuel pumps. I found a Carter for the intank, P76800 and needs the STS-1 sock. About $40 for a working lift pump.

Pull the plugs and soak the cylinders with that foaming oil, Sta-bil makes it. Dump the crank case, fill with cheap Supertex 15/40 Diesel. Crank it with plugs OUT and verify you have oil squirting out of the oil spray bar on the head.

Once that has been done, toss in a fresh set of plugs. Shoot some Bill Cosby in a can down the TB and see if it sounds okay. If it has knock or a weak hole, I would just part it.

Thanks for the advice! I will certainly do that before attempting to start. I'll diagnose fuel pressure before springing for it though as I'm on a shoestring budget at the moment, but thanks for the part number, that'll save a lot if the old pump is bad, which in all likelihood it is.

[maxthegearhead]

Update! I checked for oil coming out of the cam oilers and there is an abudence. The spark plugs were fouled so I cleaned them and put them back in. Verified spark again. Won't start on the starting fluid. Someone appears to have loosened the distributer and messed with the timing. Compression test results in my next post.

[maxthegearhead]

1. 150psi
2. 170psi
3. 160psi
4. 156psi
5. 176psi
6. 90psi

Spark plugs are crap and need replacing

[maxthegearhead]

Another update: got her to start on starting fluid, started with a vengeance! The timing was completely out of whack. I had to turn the distributee about 30 degrees to get her to even fire. Now i am going to focus on the fuel system, to see if we can get her running on her own gas.

[maxthegearhead]

Fuel pumps replaced, can hear them running and have pressure at the rail. I tested for injector pulse and got around 500hz pulse while cranking. Injectors do not seem to be firing, I listened to them with a screwdriver and hear nothing and I smell no gas coming out the exhaust.

The only replacement injectors I coul find were $180 at the dealer or $60 on ebay. Is there a more economical option?

Thanks guys!

Here's an interior pic to motivate y'all
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[poopin04]

Fuel pumps replaced, can hear them running and have pressure at the rail. I tested for injector pulse and got around 500hz pulse while cranking. Injectors do not seem to be firing, I listened to them with a screwdriver and hear nothing and I smell no gas coming out the exhaust.

The only replacement injectors I coul find were $180 at the dealer or $60 on ebay. Is there a more economical option?

Thanks guys!

Here's an interior pic to motivate y'all
20191116_195833.jpg

I know someone in Brooklyn who can rebuild them if you want to go that route.

[BONDOSPECIAL]

I'm sure the injectors could use a cleaning, but they are probably not your no-start problem. Last year, I started a car w/ Bosch multiport FI (a 1975 Opel) that had sat since 1983 and it ran surprisingly well. Fuel injectors can tolerate sitting a long time and still work fine. I also wouldn't expect all of the injectors to be dead together.

[Hit Man X]

Figure out that 90psi on No 6 before you dick with the car more. Time for a leakdown test.

[maxthegearhead]

Simply cleaned the fuel injectors with a rust removal formula and they were firing again! After putting everything together the car sputtered to life. Misfiring, but running.

[maxthegearhead]

With a couple of used parts and some more elbow grease, the 7 is coming along. She starts at the turn of the key now. I am going to set the ignition timing to factory specs tomorrow. Once I get the brakes sorted, it'll be time for the first real shakedown at speed!

[maxthegearhead]

A few updates. First and foremost, I hope everyone is doing well in this difficult time. Now on to the 7.

Compression has improved now that the engine has run for some time. I measured 135 PSI up from 90PSI on cylinder 6.
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Engine runs alright, although I suspect the injectors could still use some cleaning. Not to worry. Now that the engine has been timed it's running even better!
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PS, I'm looking for name suggestions!

[TowJamma]

Great work. Another one saved.
That is some tenacity on your end.
Names are kind of personal, IMO, for me to recommend. We call my 1980 Schtinkie due to the exhaust pipe emissions.

[maxthegearhead]

After laborious injector troubles, and the prospect of having to replace every single rubber part of the mess of vacuum and injection air control elements, I have decided to put the L Jet aside for another time.

I unceremoniously removed the intake piping and injectors, and gave the cylinder head a cursory clean.
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Intake manifolds from a carby M30...
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Next on the list is dual Weber 32/36's with water chokes!

[TowJamma]

Well now, those are nice.
And some kind of spark box for the distributor?
Keep us up to date on this.

[Kenneth1948]

Max, I sure don't want to damp your enthusiasm regarding the installing the Webers. I considered doing this with my '84 which has a problem with the Motronic which I can't solve. However there are a number of things to consider. The ECU controls a lot of functions. It is expecting input from the AFM and other sources. If you just unplug things I think you may have driveability problems with ignition, idling etc. I would recommend keeping the L-Jet parts so you can put it back together if you need to. I had an '81 5 - speed (same color) and had to replace a lot of the injector plumbing etc and yes, it's a lot of work but at least you're working towards a known result. They run very well and the Getrag 265 is an excellent transmission. Wish I still had it but rust got the better of it. Good luck whatever direction you choose to go, John Kenneth

[maxthegearhead]

Max, I sure don't want to damp your enthusiasm regarding the installing the Webers. I considered doing this with my '84 which has a problem with the Motronic which I can't solve. However there are a number of things to consider. The ECU controls a lot of functions. It is expecting input from the AFM and other sources. If you just unplug things I think you may have driveability problems with ignition, idling etc. I would recommend keeping the L-Jet parts so you can put it back together if you need to. I had an '81 5 - speed (same color) and had to replace a lot of the injector plumbing etc and yes, it's a lot of work but at least you're working towards a known result. They run very well and the Getrag 265 is an excellent transmission. Wish I still had it but rust got the better of it. Good luck whatever direction you choose to go, John Kenneth

I will be keeping all the L Jet the parts for a rainy day. Luckly L Jet distributors are independent from the fuel "computer!" The Getrag 265's reputation is legendary and this one shifts beautifully.

Well now, those are nice.
And some kind of spark box for the distributor?
Keep us up to date on this.

As I said above, L Jet distributors are independent so I can just keep that for now. I may end up going with some kind of more modern system if I find it for a good enough price though.

[maxthegearhead]

Carbs installed!
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