This #$%^&*@ car! long post

[repenttokyo]

I wouldn't suggest diving into your vanos if you don't know what you are doing or how to set it. Rule the cheaper stuff out first. Do you have the stock chip in there?

Before my S38 M5 transplant I had an M50tu with M3 cams, S50 valve springs, injectors, 2 custom chips, larger MAF, lightweight flywheel, 3.46 diff, custom intake, etc. I had a new vanos put in after it was making noise and sticking. Do some more research and you might have to take it in to a professional.

One thing about the fuel pump and filter, fuel pressure can build up in the lines on idle. Once that pressure is released, a clogged filter or bad pump will need more time again to build the necessary pressure. Also, if a coil did go bad, sometimes it can take the ecu with it. Seen it happen several times. With a bad coil, bad ecu, fuel filter/pump, or vacuum leak can all give the same symptoms. What are your MPGs? What does the exhaust smell like? Any fuel smell from the engine bay? Does it get better once warmed up? When colder outside? How do the spark plugs look? Any transmission hiccups ever?

Also, at times when a tank goes almost empty, the pump picks up sediment at the bottom of the tank. It clogs the fuel filter. I have seen this happen a few times.

Tip: If you decide to change the fuel filter, take a sharpie and write the date and mileage on it before installing.

i have a question for you: After having had both in your car, which do you prefer : the modified M50, or the S38? Taking into account the difficulty of installing both setups.

That leads me to my second question: How hard / expensive was it for you to install your S38? Was it worth it as an upgrade?

[632 Regal]

so new gaskets might fix the remaining vacume leaks? That'd be a sweet deal!

UPDATE for those following my misery
The surge I attributed to leaking reused intake gaskets was due to the hose at the carbon canister purge valve being disconnected. Found this while examining all the hoses for what size to order.
Problem is now far better after sealing up potential but undetected leaks at the fitting for the pressure regulator hose fitting on the intake and intake air temp sensor and of course the disconnected hose.
I've looked at nearly everything yet overlooked something.

[Ross]

The latest for anyone still following. Stumble remains off idle. Intake gaskets not changed becuase no matter how much stuff is sprayed around them there is no change to idle.
A 570 mile road trip on premium fuel with a fair amount of over 3000 rpm running combined with crawling in construction zones delivered >23 mpg and pipes look nice so I'm otherwise happy with state of tune.
Back to suspecting idle control valve. Has anyone here had a similar plight due to IAC? Mine is clean and ohms out nearly identical to a new one.
I hate $100 guesses so am looking for someone who's been there.
It's best described as a stutter, a couple of tiny little hesitations just off idle, more noticeable while driving but still there if just a free rev in neutral. Many wouldn't even notice it.
Who thinks IAC valve?

[bmwpower]

Did you change it out yet?

Place your hand over the valve when the car is running. Do you feel the valve "stutter"?

[Barney Paull-Edwards]

Only an idle thought,buy a can of ethyl/Easy-start and get spraying.You swear there is no air leak but it seems one of the only things left! Revs go up there it is.

[Ross]

Wow. How did this get resurrected?
No. I never changed the idle valve and spraying all sorts of combustible things everyhwere a vacuum leak could be netted nothing.
The car has been parked since the GF has taken a liking to the E39. While some ding repairs were being done last summer the battery got run down with the doors open most of the day and the dent man listening to the radio. This effectively performed a computer reset and when I took it around the block a few times all seemed well. Perhaps it needed to unlearn all the bad values aquired before all the other work was done.
I need to give a little exercise nd see if it's really fixed.
Wasn't it me who started a thread about following up a while back? Sorry guys.
This car is surplus now and I really ought to dispose of it as sitting in the diveway for months on end isn't doing it any good.
Anyone who want a touring let me know. The front bumper cover has been replaced for anyone following this cars posts.