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E21 (1975 - 1983)

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Old 08-13-2009, 12:42 AM
bimmerzilla bimmerzilla is offline
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Location: Payson Arizona
Join Date: Jul 2009
Posts: 3
Mein Auto: 1988 bmw 325e
fuel problem!!!help Plz!

I have recently picked up a 1980 320i i have spark and air so fuel is my issue and im not familur with there injection system the car has sat for a few years and i'm pretty sure theyy might be plugged ? please help im not sure where to start really i looked up a diagnostic of the fuel system and it seems there is a start vavle injector in the manifold and the regular injectors whats the best way to go about getting my baby some juice lol
i have a e30 325e that i recently rebuilt but the m10 to the m20 is almost night and dayy
thanks guys
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Old 08-31-2009, 02:45 PM
xuismE30 xuismE30 is offline
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Join Date: Apr 2009
Posts: 8
Mein Auto: E21 & E30iS
i have the same problem, i think its might be the fuel distributor..
i replace the spark plugs wire fuel pump,fuel filter and sender and the distribtor too, got it timed after words and problem still not sending fuel..
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Old 06-11-2010, 11:13 AM
marks82 marks82 is offline
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Location: Toronto, Canada
Join Date: Jun 2010
Posts: 8
Mein Auto: '82 320i
Hi Bimmerzilla. Does the car start at all?
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Old 06-15-2010, 02:06 PM
davidgoerndt davidgoerndt is offline
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Location: Orlando, Florida
Join Date: Jun 2010
Posts: 4
Mein Auto: 1982 320i
If it's been sitting for long, you might have rust in the tanks also the fuel pump in the tank has a screen on it another source for a problem. First thing would be to have a look in the fuel tanks and see what's there. The K-Jet system needs pressure to work so any leaks will be a problem. Injectors can clog also. Like I said lots of potential problem areas to check.
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Old 06-17-2010, 08:54 PM
galaxyflier galaxyflier is offline
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Location: Saratoga Springs, NY
Join Date: Apr 2010
Posts: 35
Mein Auto: 1981 320i (E21)
The first thing to check is the fuse for the fuel pumps. This fuse is forward-most fuse on the left (driver) side of the fuse block. I have had this fuse go bad in the past and when it does, the car stops dead instantly. I now replace the fuses once a year whether they look good or not. I drive into New York City every so often and don't need a fuse to corrode up half way through the Lincoln Tunnel.

Anyway, having ensured that the fuse is good, you should hear the fuel pumps come for about two seconds and then stop when you turn the key to ON. This will tell you that the fuel pump relay is functioning properly. The relay receives pulses from the distributor which enables the fuel pump to operate. The main purpose of this type of set-up is to turn off the fuel pump in the event of a major collision. In a crash, the engine will stop which causes the relay to lose the pulse input from the distributor which cuts power to the fuel pumps so they don't cause or feed a fire. When you turn the key to ON, there are no pulses from the distributor so the pump runs for two seconds and stops. If you turn the key to ON and don't hear the pumps run, this relay could be the problem.

A broken wire to the pump could cause the pump to not operate, also. For troubleshooting purposes, you can by-pass the relay with a jumper wire. There are four prongs on the relay. Install the jumper into the relay socket between the slot closest to the front of the car and the slot that is next to and perpendicular to it. This will enable the pump to run continuously with the key in ON. Now if the pump doesn't operate, you can put a test light on the pump terminals and check for power at the pump and trace the wiring as required. If the main pump runs but seems abnormally noisy, it could mean the pump is on the way out and probably isn't providing sufficient pressure (>80 psi). When my pump went bad, this is what happened and the car ran, but would not maintain highway speeds or climb steep hills. But, if the pump seems to operate normally, the next obvious step is to check the fuel filter. If the car has been sitting for a while, go ahead and replace the filter.

Another problem could be the fuel accumulator, which is located next to the main pump near the right-rear wheel. The accumulator maintains system pressure when the car is not running so pressure will be available for starting. It also provides steady system pressure from the fuel pump and dampens any pressure fluctuations from the pump. When you get into checking fuel pressures, you will need the proper gauges for troubleshooting the K-Jetronic system. I think you get them from Bavarian Autosport for less than $100. (www.bavauto.com). Good luck. Hope this helps.
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