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StealthJPL 01-11-2013 03:30 PM

Rich Fuel/Gas smell from exhaust!
Hey guys. It has been a while since I have visited Bimmerfest and I forgot about how helpful it has been in teaching me about BMWs. I have recently put my Bimmer under the knife a few times and have been very successful thankful in part to this forum. I also have thanks for a BMW mechanic that works at a DIY hobby shop to thank as well. I wanted to get two opinions on my Bimmer about a problem that I have. Last October 2012, I took my 1987 BMW 325es to a car wash and sprayed down the engine after I had changed out the timing belt and water pump, which is how I came about joining Bimmerfest. After I sprayed down the engione, something got wet and the engine started running really rough. It got so bad that my CAT turned cherry red and I started smelling a really rich fuel mixture coming from the tail pipe. At first I was told that it was my throttle body housing but after checking that over I found nothing wrong with it. Yesterday, January 10, 2013, I changed the spark plugs (.30 Gap as per the manual) O2 sensor, rotor, wires and distributor cap. All of the mentioned maintenance was recommended because of the fuel smell. Unfortunately, the smell is still present and I do not know what to do next. I would like to get started in making this car my project toy, but as long as there are problems present I cannot focus on the toy part until I can get her running correctly. Does anyone know what the problem might be? After spending this much on my car, I really do not want to spend any more until I know exactly what is wrong with it. I am going to take it to the hobby shop tomorrow and ask the mechanic about it but I would really like to have two opinions to follow. The one thing I have noticed is that a lot of focus is on the fuel injectors. Maybe that is the problem, and I am going to ask the mechanic tomorrow about it. Sorry if this post is in the wrong section. I did try to follow the proper posting procedures. Thank you all in advance. BMW SPECS: 1987 325es 3.7 Li 6 cyl SOHC.

downhiller 01-11-2013 03:37 PM

fuel pressure test. sounds like the fpr is bad.

StealthJPL 01-11-2013 05:28 PM

What is an FPR? I am unfamiliar with mechanical acronyms.

hornhospital 01-11-2013 07:33 PM

Fuel pressure regulator. It's on the end of the fuel rail. Has a vacuum line going to it, and a fuel return line running back to the tank. It bleeds off excess fuel pressure back to the tank at low speed. If it fails it puts full pressure to the injectors even at idle, and the engine runs way rich.

StealthJPL 01-11-2013 07:47 PM

Thanks. I will look into this tomorrow morning. That actually sounds plausible and makes more sense then the CAT going out.

Nick323 01-15-2013 02:39 AM

Water destroying a FPR ?
You hose down the car and the FPR goes bad ???
Either I read this wrong or Beemers are more "interesting" than I thought :confused:
Normally I would think that if Water causes a problem it would most likely be a elecrical problem.
If it is not firing on a cylinder, you will also dump raw fuel into the exhaust :wow:
The honeycomb in your cat will absorb the fuel & cobust it, causing the comforting red glow ;)
We have a lot of 4X4's burning down here, due to some fool "tuners" enrichening the mixture and then getting the cat to get hot enough to ignite the grass that is stuck between the cat & its guard :violent:

downhiller 01-15-2013 06:00 PM


Originally Posted by Nick323 (Post 7314215)
You hose down the car and the FPR goes bad ???

if you take away what he did and use it as a normal "i was driving then noticed....." situation. the washing could be irrelevant and be a sole coincidence. maybe he blew a vacuum line off, maybe it just decided to die. ive seen crazier things.

7pilot 01-18-2013 07:24 AM

You probably have water trapped in the connectors of the engine harness.
They will dry out eventually but may leave deposits in the connector which will cause corrosion and bad connections.
I would recommend that you get a can of "Water Displacer 40", disconnect every electrical plug on the engine harness, and flood with the WD40.
Major targets would be C109, the TPS, the CPS, the CTS, The main and fuel pump relay sockets,the ICV plug.
You may also want to disconnect the fuel injector plugs and clear the water out of them.
Don't forget to dry out the distributor cap/rotor with a clean dry rag sprays.


BigBoy740il 01-20-2013 08:50 PM

+1. 7pilot is absolutely correct. E30s are prone to connector corrosion. Clean all connections with CRC electric connector cleaner, let air dry and reconnect. Make sure you address the circular connector below the throttle body. That's the one for the fuel injectors.

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