82 BMW 320i running issues

Tiny
CBROWN888
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  • 1982 BMW 320I
  • 4 CYL
  • 2WD
  • MANUAL
  • 135,000 MILES
I just picked up a 1982 BMW 320i with k-jetronic that had been stored for 10 years. I have drained and refilled the fuel tanks, and put an additive to absorb any leftover water in the tanks. I have replaced the fuel filter twice, replaced the metal lines between the pump, accumulator and filter. Flushed the lines from the tank and distributor, replaced the distributor, warm up valve, injectors and temp time switch. I got the car running now but idles rough, backfires under acceleration and wont go over 3400 rpm. I checked the power to the cold start valve, wuv, idle air valve and am only getting.05v. I am suspecting the fuel pump chewed up some junk and I haven't checked the screen in the tank since I am waiting for o-rings. Any ideas?
Wednesday, November 24th, 2010 AT 2:51 AM

14 Replies

Tiny
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When you say distributor, do you mean fuel distributor or the ignition distributor?
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Wednesday, November 24th, 2010 AT 10:01 PM
Tiny
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Fuel distributor, reman
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Wednesday, November 24th, 2010 AT 10:23 PM
Tiny
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Thanks. The lack of battery voltage at the warm up valve and the possibility of the ignition distributor having an issue (read worn or in need of replacement) concerns me. If the warm up regulator is not getting power, the heating element then become inert and the heat from the engine should put it through the warm up process, it will take longer.
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Wednesday, November 24th, 2010 AT 10:36 PM
Tiny
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The ignition distributor is fine, I'm getting good spark on all cylinders, The cap, rotor, wires and plug are new. I checked compression and all the cylinders are running at between 100 and 125psi warm.
The low voltage is on the wuv, cold start valve, air slide and the temp time sensor connections. I unpluged the cold start valve cold and there is no change in the idle. I am getting fuel to it just no delivery. I also checked the lamda control unit for power going to it and none of the terminals are hot with ignition on, yet the car will not run with the lamda unit disconnected.
I've gone through wiring diagrams and cannot track down a relay for the lamda control unit. By the way the lamda unit is the control unit behind the glove box.
My past experience with older CIS benz's have an overprotection relay that supplies power to the lamda unit and fuel pump.
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Thursday, November 25th, 2010 AT 3:28 AM
Tiny
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I need to go to a friends archive to respond further. I request you come back and re-post when the O-rings are tried. Then I can look further into the issue.
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Thursday, November 25th, 2010 AT 5:34 AM
Tiny
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As to the ignition distributor, spark may be present, but the source coil(pulse generator, pn 12-11-1-276-127) inside the distributor may still be damaged or not working correctly. Have you looked at the spark output at 3400 RPM with an oscilloscope?
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Friday, November 26th, 2010 AT 5:19 AM
Tiny
CBROWN888
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Well with some business travel and the holidays over now it's time to get back on this BMW project.
Starting where I left off heres what I've done in the meantime. Pulled the in tank fuel pump, cleaned the screen, resolders the ground strap and it is now working. I tracked down the power supply to the Lambda control unit and it is now working, I have power going to the WUV, frequency valve, and idle air valve. I do not have any power to the cold start valve or the thermo temp switch. According to wiring diagrams they do not get power to the lambda unit and get power to the multi relay which I have replaced. I still have stumbling and backfire on acceration with very little RPM band.
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Saturday, January 22nd, 2011 AT 3:39 PM
Tiny
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And the O-scope readings?
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Saturday, January 22nd, 2011 AT 5:50 PM
Tiny
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Unfortunately I do not have access to an Oscilloscope and to be honest I haven't seem one in a technicians toolbox in years.
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Sunday, January 23rd, 2011 AT 2:05 AM
Tiny
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The problem seems to me to be ignition related. Mis-firing or inability to get past a certain rpm threshold is likely the coil I mentioned in my earlier post. And the Snap-on "brick" has a scope in it, lots of techs have it.
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Sunday, January 23rd, 2011 AT 5:12 AM
Tiny
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The engine revs freely without a load. I was outside just now and did a couple of items to check. When I disconnect no's 2&3 spark plug wires there is little change in the idle yet 1&4 cylinders the car stalls. So from there I checked to see that I had fuel delivery to those cylinders and pulling out the injectors. I bypassed the fuel pump relay and I am getting plenty of fuel out of those two cylinders when I move the throttle plate.
The reason I am questioning the Ignition theory is due to the fact I have consistent spark to all four cylinders.
What I will do in the next couple of days is to replace the coil, pickup, reluctor and ignition module since they are on clearance at RockAuto. Com
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Sunday, January 23rd, 2011 AT 6:04 PM
Tiny
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And MAYBE look and see if the distributor bearings are worn and allowing the shaft to move as well.
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+1
Sunday, January 23rd, 2011 AT 6:07 PM
Tiny
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Did that already. The bearings are very tight with no lateral movement.
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Sunday, January 23rd, 2011 AT 6:24 PM
Tiny
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K
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Sunday, January 23rd, 2011 AT 6:29 PM

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