m50 starts but dies

[89_525i_PhoenixAZ]

I just purchased a 93 525i m50 and the kid I bought it off of said that the head gasket was bad. I got the car home and noticed that half of the exhaust manifold was not bolted to the head and the other half was bolted but did not have the gasket in. I reattached the exhaust with the gaskets in place. The car will start up and run for a while and then when I give it gas, it dies out. It will not start again until I pull the relay for the fuel pump and crank on it for a while and then I put it back it when the car starts up but then it will do the same thing and die out when you give it gas. Does anyone have any ideas of what could be going on?

[whiskychaser]

I just purchased a 93 525i m50 and the kid I bought it off of said that the head gasket was bad. I got the car home and noticed that half of the exhaust manifold was not bolted to the head and the other half was bolted but did not have the gasket in. I reattached the exhaust with the gaskets in place. The car will start up and run for a while and then when I give it gas, it dies out. It will not start again until I pull the relay for the fuel pump and crank on it for a while and then I put it back it when the car starts up but then it will do the same thing and die out when you give it gas. Does anyone have any ideas of what could be going on?

Not clear why you are trying to start it with the fuel pump relay out as that stops the pump working. You normally jumper the relay pins to get the pump to run (engine off) and then test the fuel pressure. Should be 51psi. If the engine runs OK with the jumper in, you know your relay is shot. Fuel pressure with engine running should be about 46psi. I'd be taking a close look at the FP relay and the throttle position sensor

[Tiger]

I would change out the crank position sensor first. Buy direct from dealer... the aftermarket one are junk.

[89_525i_PhoenixAZ]

it seems like the engine keeps getting flooded for some reason. I can take out the fuel pump relay and crank it forever and finally it seems it will burn up the gas and then start allowing me to through the relay in real fast for it to stay running. It will then idle for a minute or so and then the idle will drop even lower and a trans program message will come up and it will die out failing to start again until I crank and crank it without the fuel pump relay in it

[whiskychaser]

it seems like the engine keeps getting flooded for some reason. I can take out the fuel pump relay and crank it forever and finally it seems it will burn up the gas and then start allowing me to through the relay in real fast for it to stay running. It will then idle for a minute or so and then the idle will drop even lower and a trans program message will come up and it will die out failing to start again until I crank and crank it without the fuel pump relay in it

No offence but you need to go about this methodically. Checking your fuel pressure will prove if you have too little - or too much pressure. In the latter case the fuel pressure regulator could be stuck shut but I doubt it. You can also pull the injectors and run the pump to see if they are leaking. If yours is a US model do the stomp test and see what codes you get. I CAN tell you that the idle control valve also supplies the tranny ecu with a signal so if your idle drops and you get transprog this could be the reason. Equally this could be spurious. The engine ecu will tell you if the ICV is REALLY playing up. HTH

[whiskychaser]

This is new - post a reply to a thread and its there but no listed. Curious

[Tiger]

It is there... you just need to refresh your screen.

[Tiger]

Ahh! I see what you mean... after you post, you get a blank white page!@

[whiskychaser]

Ahh! I see what you mean... after you post, you get a blank white page!@

Yeah, and your answer is there but not listed?:D But there are engineers at work as we speak so its probably sorted now

[89_525i_PhoenixAZ]

I did the stomp test and got a 1-2-6-1

[whiskychaser]

I did the stomp test and got a 1-2-6-1

Info I have says that means you are not getting a signal from the engine ECU to the fuel pump relay socket to turn the relay on. That could be a break in the wiring from the ECU or the ECU output is fried. Are you getting a voltage at one of the smaller relay pins when you crank? If not, the good news is you WONT get a signal if the crank position sensor is duff. Try replacing that as Tiger suggested. I'd also put in a new FP relay just to be safe

[89_525i_PhoenixAZ]

I think it threw that code because I was pulling and putting the pump relay while trying to start the car.

So I changed the Fuel Pump, the fuel pump relay, the crank shaft position sensor and the throtle position sensor but still have the same symptoms, any suggestions?

[whiskychaser]

I think it threw that code because I was pulling and putting the pump relay while trying to start the car.

So I changed the Fuel Pump, the fuel pump relay, the crank shaft position sensor and the throtle position sensor but still have the same symptoms, any suggestions?

Yep. You still need to prove the fuel pump runs properly and gives you the correct pressure by jumpering the relay slots. If that's fine, you then look for the voltage from the ECU that turns the relay on. But you have got rid of a lot of potential problem areas so you have to be close! Keep at it and dont let it get you down:)