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Discussion Starter #1
My husband is on the side of the road right now with my 1990 535i. He said he tried using cruise control a couple times (which I've never done) and suddenly it acted like it ran out of gas.
No code came on. Trying to figure out quickly if he can somehow reset the computer by disconnecting a certain fuse. Has anyone experienced this?
P.S. There's plenty of gas.

Thanks.
 

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Change the fuel pump, dme (that's the ecu), abs and o2 sensor relays to new ones.

Change the crankshaft position sensor to a brand new one.

Change or rinse out your fuel filter in water and run 2 gallons of diesel together with 14 gallons of regular (the diesel goes in first on an empty tank) through your fuel tank, do this for 3 consecutive fillups, and then once every 3 months. This keeps your injectors clean.

Change to a brand new OEM fuel pump.

Have someone check the reserve cranking charge and cold cranking amps on your car's battery with a digital meter designed for this purpose and replace it if its getting too weak. Check the reserve cranking charge once every 12 months, and once every 6 months once your battery is more than 4 years old.

Have someone hook up an ammeter to your battery and check the normal and fast idle amps being generated by the alternator, to see if its in good shape. If its not, rebuild or replace. Don't think twice about it.

Pick up a spare DME for your car from Ebay. Its only like $60 or less shipped and can be resold easily later for the same price if you sell your car. Test the DME on your car, and then keep it in your trunk (bubble wrap it) as a working spare. Btw all the old relays you change out should be kept as working spares.

Check your fuse box to see if everything is normal, and have a whole bunch of new fuses at the ready.

Get the Bentley manual and read it 3 times within the first 3 months of possession to familiarise yourself with it.

Once you've done all of the above, you would have taken care of most of the common no-start problems in our car. Your baby will not leave you stranded anywhere.

The other thing you should do for total peace of mind would be to get a new radiator cap, a new brass bleed screw, new upper and lower radiator hoses, a new water pump and a new thermostat. Change all these out. Only change out the radiator if you were having mysterious coolant loss problems before this. If you want absolute peace of mind, then change the huge octopussian coolant hose that runs under the intake manifold (525 m50 engines only). This is a big job as it involves removing the intake manifold, so its a good idea to change the camshaft sensor, the two coolant sensors on the cylinder head, the fuel hoses connected to the front and rear of the engine, the crankshaft position sensor (mentioned earlier and much easier to change with the intake manifold off) and finally, have your starter rebuilt - it will give out at some point and its easily accessible with the intake manifold off. Now this is for a 525 which I realise is not your car but you should seriously think about it as well.

When you remove the intake manifold and disconnect sensors and switches, label them clearly to ensure that you reconnect the right ones back again during reassembly.
 

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Discussion Starter #4
I got the BMW to a Mechanic Friend and he was unable to get it started after installing a New Fuel Pump. I did some researching on here and went to his garage to check the Crank Position Sensor.
When I got there I found that the Sensor Next to the CPS was Dangling down in front of the Motor. After looking all over I found a Picture of the Plug/Sensor that had been ripped out. It says in the Bentley Manual that it is The CYLINDER IDENTIFICATION SENSOR. It is the one that is in The Picture Below from the Manual marked E.

#1 If this Sensor is Not Connected will it cause the Car not to Start?

#2 I Looked for this Part on The Internet and No One Sells a Cylinder Identification Sensor. What is the Proper Name for the Part?

#3 Where does other end of the Sensor Attach to the Motor?

Any Help or Pix would be greatly, greatly appreciated!

Steve



 

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I got the BMW to a Mechanic Friend and he was unable to get it started after installing a New Fuel Pump. I did some researching on here and went to his garage to check the Crank Position Sensor.
When I got there I found that the Sensor Next to the CPS was Dangling down in front of the Motor. After looking all over I found a Picture of the Plug/Sensor that had been ripped out. It says in the Bentley Manual that it is The CYLINDER IDENTIFICATION SENSOR. It is the one that is in The Picture Below from the Manual marked E.

#1 If this Sensor is Not Connected will it cause the Car not to Start?

#2 I Looked for this Part on The Internet and No One Sells a Cylinder Identification Sensor. What is the Proper Name for the Part?

#3 Where does other end of the Sensor Attach to the Motor?

Any Help or Pix would be greatly, greatly appreciated!

Steve



The cylinder identification sensor(correct name) should be attached to the #6 spark plug wire, actually the #6 wires runs through a coil which is the sensor. The engine will run without a plug wire running through it. I've never tried disconnecting it at the harness like you've shown. Plug it back in anyway.
Most common no spark cause on that engine is a dead crank position sensor. Sometimes you give it a smack and it will come back but don't expect it to last long if it does.
Alternately perform the overhaul(roadside no less) suggested above.

The cyl. ID wire is typically sold with a set of spark plug wires, cut rate brands don't include it so it's often just left off.
 

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Not familiar with the m20 I'm guessing that thats the camshaft position sensor. It controls fuel injection. The Cylinder Identification sensor I thought was also called knock sensor there are two on 93 m50 and later engines.All sensors are ,hard wired to the ECM or engine computer.
 

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Not familiar with the m20 I'm guessing that thats the camshaft position sensor. It controls fuel injection. The Cylinder Identification sensor I thought was also called knock sensor there are two on 93 m50 and later engines.All sensors are ,hard wired to the ECM or engine computer.
No cam sensor or knock sensors on M20 or M30 which in question
 

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I think your camshaft position sensor is busted Rinpiels. And I doubt your cylinder identification sensor is a big deal if its not usually included in cheap ignition plug wire packs.
 

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I think your camshaft position sensor is busted Rinpiels. And I doubt your cylinder identification sensor is a big deal if its not usually included in cheap ignition plug wire packs.
Please elaborate on the M30 camshaft sensor.
 

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Discussion Starter #12
So, I replaced the CPS with a brand new one and it still doesn't start. Just turns over. So far,

The Fuel Pump Replaced with New
The CPS Replaced with new
The Fuel Filter, checked and clean.

Any advice would be greatly appreciated!

Thanks!
Steve
 

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Hello Steve from another Steve. I’ve been away from the forum for a while but hope that I can provide some assistance. I am not as familiar with the M30 as I am the M50, so my recommendations will not be very specific.

BTW, do you have the Bentley manual? If not, I highly recommend that you obtain one either by purchase of a hard copy or download the PDF version which can be found by a search here on this forum.

For a gasoline engine to operate, you need air, compression, fuel and spark. It is unlikely that your intake is blocked (air) or that you lack compression. So that leaves spark and fuel.

I tend to approach no-start problems by ruling out fuel delivery problems first. You have replaced the pump, so that is ruled out. You indicate that the filter is clean, so that too is ruled out. You do not indicate whether or not you have checked the fuel pump fuse or the fuel pump relay.

Anyway, check the fuel pump fuse and the fuel pump relay. If those are okay, then you can do the following to check to see if it is a fuel delivery problem. Get a can of starter fluid. While someone is trying to crank the car, spray a 2-3 second burst of starter fluid in the intake. If the car fires and runs momentarily, then you have confirmed that you have a fuel delivery problem. A word of caution, don’t run the engine long (i.e. more than a second or two) on the starter fluid. It is very hard on the engine. Once it fires up, you have the information you need. If the engine still does not start, then you likely have a no-spark situation, but it is not confirmed at this point. You need to proceed to diagnosing the electrical system.

Since you replaced the CPS (which is a very common fail item), then you can rule that out. Fortunately, you have a car with actual spark plug wires. You can check for spark in a couple of ways. Pull a plug wire, insert a known good spark plug in the plug wire, ground it on a metal portion of the engine or chassis and have someone try to crank the car. If you are getting spark, it should be obvious. You can also hook up an old fashioned timing light to one of the plug wire, have someone try to start the car and see if there is a flash of the timing light. If so, then you have spark on that particular wire. If not, then you likely have no spark.

There are ignition items involved in the M30 (such as cap, rotor, etc.) that are not on the M50, so again, I’m not nearly as familiar with the testing procedure. If, after checking all of the ignition components, you still have no spark, then the DME may have gone bad. You can usually find one used at a salvage yard for $30-50 or on EBay for $60-100.

I hope this information has been helpful. Let us know how it goes.

Steve
 

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. You said this started when using cruise control. On my car its like a second throttle cable right next to the regular cable. could this of failed or affected the throttle body or petal cable catch, intake valve or any other vac hose around it.
 

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Discussion Starter #15
Hello Steve from another Steve. I've been away from the forum for a while but hope that I can provide some assistance. I am not as familiar with the M30 as I am the M50, so my recommendations will not be very specific.

BTW, do you have the Bentley manual? If not, I highly recommend that you obtain one either by purchase of a hard copy or download the PDF version which can be found by a search here on this forum.

For a gasoline engine to operate, you need air, compression, fuel and spark. It is unlikely that your intake is blocked (air) or that you lack compression. So that leaves spark and fuel.

I tend to approach no-start problems by ruling out fuel delivery problems first. You have replaced the pump, so that is ruled out. You indicate that the filter is clean, so that too is ruled out. You do not indicate whether or not you have checked the fuel pump fuse or the fuel pump relay.

Anyway, check the fuel pump fuse and the fuel pump relay. If those are okay, then you can do the following to check to see if it is a fuel delivery problem. Get a can of starter fluid. While someone is trying to crank the car, spray a 2-3 second burst of starter fluid in the intake. If the car fires and runs momentarily, then you have confirmed that you have a fuel delivery problem. A word of caution, don't run the engine long (i.e. more than a second or two) on the starter fluid. It is very hard on the engine. Once it fires up, you have the information you need. If the engine still does not start, then you likely have a no-spark situation, but it is not confirmed at this point. You need to proceed to diagnosing the electrical system.

Since you replaced the CPS (which is a very common fail item), then you can rule that out. Fortunately, you have a car with actual spark plug wires. You can check for spark in a couple of ways. Pull a plug wire, insert a known good spark plug in the plug wire, ground it on a metal portion of the engine or chassis and have someone try to crank the car. If you are getting spark, it should be obvious. You can also hook up an old fashioned timing light to one of the plug wire, have someone try to start the car and see if there is a flash of the timing light. If so, then you have spark on that particular wire. If not, then you likely have no spark.

There are ignition items involved in the M30 (such as cap, rotor, etc.) that are not on the M50, so again, I'm not nearly as familiar with the testing procedure. If, after checking all of the ignition components, you still have no spark, then the DME may have gone bad. You can usually find one used at a salvage yard for $30-50 or on EBay for $60-100.

I hope this information has been helpful. Let us know how it goes.

Steve
DME Where is this Located At?

Anyway, check the fuel pump fuse and the fuel pump relay.

Where is The Fuel Pump Fuse Located? Is It Number 29?

Which one is the Fuel Pump Relay?

By The Way, your advice is simple and clear and I appreciate it very much. I am not used to working on Fuel Injected motors. MY passion is a Suzuki Samurai Offroad vehicle that I have sunk tons of cash in that is carbed and I can pretty much, fix anything on it. This BMW is alot more sophisticated and I am not experienced with it. Thanks!

Steve
 

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DME Where is this Located At?

Anyway, check the fuel pump fuse and the fuel pump relay.

Where is The Fuel Pump Fuse Located? Is It Number 29?

Which one is the Fuel Pump Relay?

By The Way, your advice is simple and clear and I appreciate it very much. I am not used to working on Fuel Injected motors. MY passion is a Suzuki Samurai Offroad vehicle that I have sunk tons of cash in that is carbed and I can pretty much, fix anything on it. This BMW is alot more sophisticated and I am not experienced with it. Thanks!

Steve
FP fuse is # 23 in the main fuse box located on the driver's side (Per Bentley manual for the US Version) of the engine bay in the box in the corner just aft of the shock tower and at the corner of the windshield. While in there, take a good look at all other fuses. The lid for the box should have a table showing which fuse powers what device and what amperage the fuse should be. The lid just pops off by lifting the plastic tab at the front of the box. It will then hinge up and the tongs on the hinge side can be disengaged from the box.

The FP relay is in the same type of box on the opposite side of the firewall. There are 3 relays in a row and the middle one should be the FP relay. This box has to be removed by loosening 4 Phillips head screws (they do not actually come out).

As an FYI, you can try the trick with the starter fluid before you check the FP fuse and FP relay. In fact, it can be the very first diagnostic test that is done when a no-start situation arises.

Check your PM in a few minutes for an early Christmas present.

Steve

Edit: Forgot to mention, the DME is in the same compartment as the FP relay. That's a last resort replacement type of thing though, so you should have plenty to work on and diagnose prior to considering replacing it.
 
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