Please help my e30 wont start
Moderator: martauto
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Chris1990318i
- E30 Zone Newbie
- Posts: 9
- Joined: Fri Aug 11, 2017 11:00 pm
Hi i have a h reg bmw e30 318i. It cranks over but will not start. Iv replaced the fuel pump relay. Fuel pump. But there is no power getting to fuse 11. Iv jumped the relay and the pump turned on but still nothing. I have spark on all 4 spark plugs. I i dont hear the fuel injectors working as if they have no power. Please help me. Thanks
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Chris1990318i
- E30 Zone Newbie
- Posts: 9
- Joined: Fri Aug 11, 2017 11:00 pm
Forgot to mention i also replaced the cps today and still nothing.
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
Moving this to "tech help", where it will get seen.
Are the tips of the spark plugs wet with fuel after a cranking session?
Are the tips of the spark plugs wet with fuel after a cranking session?
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
You say in your OP that there is no power at fuse 11. Do you realise that the fuel pump relay only switches on when the engine is rotating? It would be very unusual for you to have sparks at the plugs and for the relay not to switch on.
If you did not realise this, and the fuel pump is working when the engine is turning, it does look like the injectors may not be getting power. They are fed with power via the 5 pin DME relay, near the fuel pump relay, on the bulkhead, which should be switched on by the ECU when the ignition is turned on.
Check that it clicks when pulled out of its socket with the ignition on, and again when it's plugged back in.
It can be bypassed, for testing purposes, by connecting wire links between pin 30 and both 87s of its base.
If you did not realise this, and the fuel pump is working when the engine is turning, it does look like the injectors may not be getting power. They are fed with power via the 5 pin DME relay, near the fuel pump relay, on the bulkhead, which should be switched on by the ECU when the ignition is turned on.
Check that it clicks when pulled out of its socket with the ignition on, and again when it's plugged back in.
It can be bypassed, for testing purposes, by connecting wire links between pin 30 and both 87s of its base.
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
M40 DME relay has two 87 terminals.
The centre one has a red/blue wire which goes to the ECU, and sometimes a red/yellow if your car is a later one with ABS.
The outer 87 has a thin red/white wire and a thick wire which may be either red/white or plain red.
The thin red/white feeds the coil of the fuel pump relay. The other end of the FPR coil is earthed by the ECU in response to pulses from the crank sensor. You have sparks, so we know that CPS is supplying pulses to the ECU, and that they are being processed to feed the coil. They should also be integrated to supply a constant zero volts for the FPR. It would be very unusual for just this part of the ECU to fail.
The thick red or red/white is about six inches long, before it reaches an internal splice in the loom. The three wires that go on from this splice can vary in colour, but all go to the connection box that's fitted on the side of the engine, under the inlet manifold. The one we are interested in goes to the injector loom plug, which is on a very short lead from the box, and is unusual in that it's a flying male plug. AFAIK, it's the only one of this type that appears on any E30, except for those with head lamp wipers, etc.
I've seen looms with the correct coloured wire of red/white, brown/white and brown/yellow going to this plug, and I've seen looms where all three wires are plain black.
If the fuel pump does not power up when the engine cranks, and the injectors aren't firing, the common link between them is the red/white output from the DME relay, so the first test has to be to pull out the fuel pump relay, switch on the ignition, and see if there is 12 volts between the red/white wire (pin 85 or 86, depending on how it's connected) and a good body earth. This needs to be checked with a 12 volt bulb of at least a few watts. A meter will give a misleading result.
The centre one has a red/blue wire which goes to the ECU, and sometimes a red/yellow if your car is a later one with ABS.
The outer 87 has a thin red/white wire and a thick wire which may be either red/white or plain red.
The thin red/white feeds the coil of the fuel pump relay. The other end of the FPR coil is earthed by the ECU in response to pulses from the crank sensor. You have sparks, so we know that CPS is supplying pulses to the ECU, and that they are being processed to feed the coil. They should also be integrated to supply a constant zero volts for the FPR. It would be very unusual for just this part of the ECU to fail.
The thick red or red/white is about six inches long, before it reaches an internal splice in the loom. The three wires that go on from this splice can vary in colour, but all go to the connection box that's fitted on the side of the engine, under the inlet manifold. The one we are interested in goes to the injector loom plug, which is on a very short lead from the box, and is unusual in that it's a flying male plug. AFAIK, it's the only one of this type that appears on any E30, except for those with head lamp wipers, etc.
I've seen looms with the correct coloured wire of red/white, brown/white and brown/yellow going to this plug, and I've seen looms where all three wires are plain black.
If the fuel pump does not power up when the engine cranks, and the injectors aren't firing, the common link between them is the red/white output from the DME relay, so the first test has to be to pull out the fuel pump relay, switch on the ignition, and see if there is 12 volts between the red/white wire (pin 85 or 86, depending on how it's connected) and a good body earth. This needs to be checked with a 12 volt bulb of at least a few watts. A meter will give a misleading result.
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Chris1990318i
- E30 Zone Newbie
- Posts: 9
- Joined: Fri Aug 11, 2017 11:00 pm
Ok thanks ill give it ago. The car is a massive resturation project.
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Chris1990318i
- E30 Zone Newbie
- Posts: 9
- Joined: Fri Aug 11, 2017 11:00 pm
Hi i jumped the dme relay 30 and both 87 and the car nearly fired up but then just carries on cranking. Then if i leave it for a little bit it nearly starts again then just carries on cranking. It smells abit strong of fuel in the engine bay when it does this. The car has been standing for 10 years. But i ive replaced the fuel pump and relay and the fuel filter. Cheers
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
Check that the fuel smell isn't a leaking hose. The hole can be so small that the jet of fuel coming from it is almost impossible to see, and you can only find it by visually working back from wherever the fuel is landing.
If it's been standing for 10 years, then it's possible that the injectors are stuck. The fuel left in the system will have turned to gum in that time.
Remove the big hose between the AFM and the throttle body, and spray something like carb. cleaner into the TB while cranking the engine. An improvement on this, if you have such a thing available, is what I've done on occasions such as this. I have a blowlamp, powered by a 3.9Kg red propane bottle, from which I remove the jet in the torch and fix the torch so that it feeds gas into the TB.
By adjusting the gas flow, it is possible to get the engine to start and run, and I've even moved cars a few hundred yards under their own power using this arrangement.
Hopefully, with the injectors being powered at running speed, they will free up, you will be able to turn the gas off, and the engine will continue to run.
If it's been standing for 10 years, then it's possible that the injectors are stuck. The fuel left in the system will have turned to gum in that time.
Remove the big hose between the AFM and the throttle body, and spray something like carb. cleaner into the TB while cranking the engine. An improvement on this, if you have such a thing available, is what I've done on occasions such as this. I have a blowlamp, powered by a 3.9Kg red propane bottle, from which I remove the jet in the torch and fix the torch so that it feeds gas into the TB.
By adjusting the gas flow, it is possible to get the engine to start and run, and I've even moved cars a few hundred yards under their own power using this arrangement.
Hopefully, with the injectors being powered at running speed, they will free up, you will be able to turn the gas off, and the engine will continue to run.