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1994 318is starts for asecond or two then shuts off immediately. or wont start at all

10K views 10 replies 5 participants last post by  jamesjohn012 
#1 ·
I have a 94 318is bmw... will not start, and if it does, it shuts off immediately. Checked the fuel pump by removing the rear seat and when the key is turned to start i can hear the fuel pump kicking in to pump the fuel. So I know that that as well as the relay is working... Also, needed a coil pack anyway so I replaced it with a new BMW one.

I will check the fuel filter.... for water??? Is there anything else I need to look at. should I clean the "Idle Control Valve" of check for anyother sensors Please... need insight.... And yes, there is gas in the tank....
 
#3 ·
not yet, I'll see if I can give it a cleaning just to see if that helps...Thanks! I'm used to working on 7 series, but not the little 4cyl. I thought I'd ask around the people who have these 3 series. By reading around this site, it seems that this is a common issue with these cars. I'll check the MAF. before ripping off the intake manifold to get to the ICV. I Did notice the other night that I didn't seem to have a spark in #2 or #3 cyl. maybe bad cables or just bad everything. Thanks for your help...
 
#4 ·
I had the same problems with the same car same year, It was off and on for a while. I checked the Throttle position sensor, and spark plugs. engine ran like Shi+ during this time. Turned out to be bad wires for me. I replaced them and had a steady idle and everything. If not that then check the intake hoses .
 
#7 · (Edited)
well, after checking everything else I took out the DME unit, (which is the car's computer for controlling...Air, fuel mixture, and spark) just to check it out. Due to the poor water drainage design of the compartment where it is stored, If there is a major downpour or if you go through a high pressure wash then water will quickly fill the "much Too Small" drainage holes below the windshield cow and therefore will run right into the compartment where the car's main computer is. This is a known problem with this particular car.

When I removed the computer it looked fine, but when I took the cover off and removed the circut board it became very odvious that water had indeed fried the board. it was rusted, and there was a powdered coating of corrosion on the terminals. The dealer will hit you for around $1223.00 for a new one. then you have to have it programmed; however, You can find them on ebay already programmed for a few hundred bucks with a warranty.
The faulty computer explains why there was no spark at all in the two cylinders (since the cables and plugs are all new, and the fuel filter, pump and relay were all good) and also why it allowed too much voltage to go into the coil frying it.

jameskeith
 
#10 ·
Jameskeith here with some interesting things about the "car won't start issue or car stops running and won't start again until engine cools down"

What Is a DME Relay?An AC coil relay, similar to the DME relay-photo courtesy of Wm Seán Glen at Wikipedia.org. The Digital Motor Electronics (DME) relay unit is used on many Porsche and some BMW models. This is actually a double-relay-in-one component. The main relay is used to fire the DME control unit (computer), while the secondary relay gives power to the fuel pump and heater element inside the oxygen sensor. Failure in the injection system is usually related to the DME relay, but some technicians seem to have found a solution for it.
.Significance
You can find the DME relay used on Porsche 944, 924 and 968 models. BMW uses this relay for its 1992-1995 BMW 318I E36, 1991-1992 BMW 318IC E30, 1994-1995 BMW 318IC E36, 1991-1995 BMW 318IS E36, 1995-1995 BMW 318TI E36 and 1991-1992 BMW 318I E30 models.
Function
The primary circuit within the relay control unit carries a very small amount of voltage and amperage, which runs through a small coil. This primary current is used to control a much larger current on the secondary path with another coil installed. This secondary current is then used to switch on the fuel pump.
Identification
The DME relay is a small cube of about 1 inch that may be located under the hood in the engine compartment, inside the fuse and relay box under the driver's seat or inside a fuse box, hidden under the dashboard. The relay itself may be marked with the legend DME-relais on top.
Considerations
Problems starting your car, the engine dying while driving down the road (but able to start after it has cooled down) are common problems associated with the DME relay, which may be reaching the end of its life. This may be due to breaking solder joints inside the unit--the most common cause--or an internal diode failure.
Prevention/Solution
Auto technicians recommend basically two ways to deal with a DME relay. First, you can carry a spare relay in your glove compartment, ready to be installed whenever the unit fails to avoid being stranded on the way home; second, reinforce the solder joints on a good or failed unit. Steve Grosekemper, shop foreman for Dieter's Motor Sports, recommends adding solder to the joints in the relay's circuit board to keep the heat from breaking the connections. Keep in mind that a diode in the primary circuit may also be the cause of a failed relay. This diode can be removed and replaced with a new one found at most electronic auto parts stores.
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Read more: What Is a DME Relay? | eHow.com What Is a DME Relay? | eHow.com
 
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