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-   -   Intermittent loss of power (http://www.318ti.org/forum/showthread.php?t=43176)

john318isau 04-20-2017 03:06 AM

Intermittent loss of power
 
On a couple of occasions over the last two weeks my car (M44 with DASC) had lost power for about 10 seconds. There doesn't seem to be any consistency as far as it happening at certain engine temperature or whether under load.

Fault code was showing some camshaft position sensor errors, so I bought a second hand genuine part but had the same issue and same error.

The problem did start after I washed the engine bay, although I'm not sure whether this is related or coincidence.

It also started after I started smelling fuel in the engine bay. I replaced some old cracked fuel hoses and found a loose hose clamp which improved this but there is still a small fuel smell. I thought when the car lost power last time that I could smell fuel strong while driving.

Is this a limp home mode? Any other possible causes for CPS error codes? Any help greatly appreciated.

maverick 04-20-2017 05:11 AM

Are you running the rising rate fuel pressure regulator setup from Downing? Could the regulator be acting up causing a fuel pressure fluctuation and also possibly the source of the gasoline smell?


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john318isau 04-20-2017 06:06 AM

Quote:

Originally Posted by maverick (Post 384658)
Are you running the rising rate fuel pressure regulator setup from Downing? Could the regulator be acting up causing a fuel pressure fluctuation and also possibly the source of the gasoline ?

Yes,I have the RRFPR.

I don't have anything to check fuel pressure, but maybe I need to get that checked.

Dr Shuffles 04-20-2017 03:16 PM

How long has it been since you fixed the sketchy fuel hoses? If it's been a while and you can still smell fuel, then there's another leak somewhere. If you can't find a leak in the engine bay or underneath, then maybe pull up the back seat and check the lines to the fuel pump.

A while back, I was having some mysterious engine problems - turned out it was the fuel pressure regulator. And at one point, the increased pressure caused one of the fuel hoses to pop off. A faulty FPR is definitely a possibility.

So I would find the leak, and check the fuel pressure.

john318isau 04-20-2017 10:35 PM

Quote:

Originally Posted by Dr Shuffles (Post 384661)
How long has it been since you fixed the sketchy fuel hoses? If it's been a while and you can still smell fuel, then there's another leak somewhere. If you can't find a leak in the engine bay or underneath, then maybe pull up the back seat and check the lines to the fuel pump.

A while back, I was having some mysterious engine problems - turned out it was the fuel pressure regulator. And at one point, the increased pressure caused one of the fuel hoses to pop off. A faulty FPR is definitely a possibility.

So I would find the leak, and check the fuel pressure.

I replaced two of the rubber fuel hoses in the engine bay a week ago. There is a third one that I didn't change as it looked okay, but maybe I should change.

I have a spare fuel rail so I could try another FPR, although not the RRFPR.

I ran the car today with the camshaft sensor disconnected to see how it would drive. Aside from a slightly worse idle, it drove fine, and did not seem down on power.

john318isau 04-23-2017 12:06 AM

Can anyone tell me what the procedure is for checking fuel pressure for a DASC equipped M44, and what the pressure should be?

john318isau 05-01-2017 10:51 PM

The problem happened again last night.

This time the car lost power and there was some banging noise from the engine bay, not sure what (can they back fire in the intake system?).

I pulled over but the car started running normally then.

The problem is intermittent, and has only happened within ten minutes of driving home from work. It has strangely never happened on my way to work.

I took the vacuum hoses off both fuel regulators and can smell fuel in the hoses. I ran the engine with the hoses disconnected but can't see any fuel coming out. Probably not the right way to test them though?

I had a spare fuel regulator so I've put that on to see if it makes a difference.

I was thinking of blocking the vacuum hoses to the RRFPR and the super charger bypass to disable the super charger. Is that worthwhile?

This morning the car would not start at all. Maybe the FPR I put in is faulty. There was some banging or popping going on in the engine bay when trying to start it.

maverick 05-02-2017 12:28 AM

Possible misfire issue and you said it showed up after you washed the engine. Check very closely for a fault in the ignition system. Wires, coils, plugs etc.

Also with the RRFPR the hoses need to be watched closely as the pressures get up there to compensate for the extra fuel required by the boost and the last thing you want is a fuel fire.


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andakn 05-03-2017 03:14 AM

You said you washed the engine bay, did you take out your spark plug boots and make sure their is no water down in the head grounding the spark plug

john318isau 05-03-2017 03:42 AM

Quote:

Originally Posted by andakn (Post 384794)
You said you washed the engine bay, did you take out your spark plug boots and make sure their is no water down in the head grounding the spark plug

The intermittent stalling did happen the day after I washed the engine bay, but I did have a fuel leak which seemed to start quite a few days before I washed the engine bay.

I had covered many electrical parts in plastic bags before washing so it may just be a coincidence. I also checked the spark plugs out and there was no water.

I suspect that I have a fuel pressure issue which may have caused the leak.

The car is now not starting at all when cold in the morning. Yesterday it started fine in the afternoon when it is a bit warmer. Not sure if the temperature is the cause or just coincidence.

I put my spare fuel pump in last night and it ran fine but wouldn't start this morning. It just cranks and cranks and starts popping and banging inside the engine bay.

andakn 05-03-2017 03:49 AM

Check those spark plug holes and replace the plugs if their corroded.

maverick 05-03-2017 04:24 AM

Where do you live? Is the car stored inside or out at night when this is happening? What's the weather been like? Still think you are having an electrical/ignition issue.

john318isau 05-03-2017 05:08 AM

Quote:

Originally Posted by maverick (Post 384797)
Where do you live? Is the car stored inside or out at night when this is happening? What's the weather been like? Still think you are having an electrical/ignition issue.

Australia - in a colder part of Sydney (can be about 5C/40F in the morning).

Could be electrical/ignition.

I was presuming fuel as I can smell fuel and had a fuel leak.

One thing I do have is an intermittent cam sensor fault code. I switched to a used cam sensor I bought now but it shows the same fault code. Not sure if it is faulty too or if there is something causing it to appear as this fault code.

So far I have tried fuel pressure regulator, fuel pump, swapped fuel pump relay, changed rubber fuel lines, fuel filter was replaced a few months ago.

maverick 05-03-2017 11:14 AM

Of course I can't say for sure but my guess is that there is moisture getting into the ignition system some place. One place that I recently heard when all the other normal places turned out okay was the coil pack. Looked good but when swapped was the problem. If I remember correctly that problem appeared after an engine cleaning as well.

Go through the ignition system is my best advice. The absolute last thing you want with a blower is a through the intake backfire.

john318isau 05-03-2017 11:32 AM

Thanks for all the advice. I will see if I can try another coil.

Tonight I got it started, took a lot of cranking, and eventually started with some throttle. Ran very bad and would stall if left to idle, but after it warned it seemed to run okay.

I pulled off a few things to check, and one thing I did find was that at first I couldn't blow through the PCV. After a bit it did seem to free up and I could blow through it.

I have a catch can fitted before the PCV and I emptied it and out came a reasonable amount of oily liquid, the consistency was closer to water than oil. Photo attached.

I put in a spare PCV and bypassed the catch can but will need to try it in the morning to see of it made any difference.

http://autos.johnavis.com/blog/uploa...n-contents.jpg


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