I Just finished replacing timing chain guides and getting valve jobs done on both of heads of the 540 I recently bought to fix. Just to give you info on the car, it is a 1999 540i/6 with Dinan CPU tune, throttle body, MAF, and CAI.I bought the car with the chain off the crank sprocket and every valve bent in on the heads and found a motor with heads and two spare heads so I took the two best heads and chose to get the valve job done on those. They were pressure checked and shaved so everything is good with the heads I would think. So the problem I am having is after we put everything together we went to start it and it cranks up and dies unless I feather the gas and keep it alive, it will stay alive, but run like crap with the MAF unplugged. We swapped MAF's with a good stock one and it runs the same so we determined it wasn't that. The other things we determined that wasn't the problem is the spark plugs, vacuum leak, MAF, throttle body, timing, old gas, crank sensor, or cam sensors. So I am running out of things to check. What would be good places to check next? would fuel filter or fuel pump be relative?
oh and its throwing no dtc's. how lovely right?
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Last edited by Lelan; 04-22-2012 at 06:13 PM. Reason: Automerged Doublepost
did you pull the engine?
The reason i ask is cause you can put the flywheel on 1 tooth off and it will do what you say.
do you have a scan tool that can read live data. that may help you in determining the issue.
whats your fuel pressure?
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The filter can do that but it usually blows the fuse to the pump, happened to me when I first got the car... replaced that and it's been fine ever since.
Are you using the injectors that came with the car?
I tried to put my mod list in my sig, but it wouldn't fit.
Yes we pulled the engine and what do you mean by having the flywheel one tooth off?
I do have access matco determinator 4.0 scan tool, should that do the trick?
If so what would I look for when reading the live data?
And we were going to look at the fuel pressure tomorrow, via fuel pressure gauge. would the scan tool be able to tell me my fuel pressure instead?
And yes the injectors are the ones that came with the car
Thanks so much for all the help guys, looking forward to finding out the problem so I can have fun driving the car.
Scan tool cannot tell you fuel pressure.
The matco item isn't sufficient for your car, really, but if it will read live data, that will likely do for now.
I'd really like to know how you could get a flywheel one tooth off, too - or any way but correct.
I'd be most concerned how you determined you had no intake (vacuum) leaks. If you didn't use a smoke machine, you haven't ruled out the most likely suspect.
Were all the correct tools and instructions used for your vanos set-up?
Try looking at "Pending codes". And test fuel pressure, as 02325 says, that's crucial..
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
We checked all the vacuum lines and they looked pretty good, that's how we determined that. But I will try and get my hands on a smoke machine and we'll see what we can find there, hopefully that will be it
Yes we had all the correct tools and timing instructions for the vanos
There were no pending codes on the car, the only ones were from when we were unplugging things
So with that being said about the codes wouldn't it have to be a vacuum leak?
Thanks for helping Chris
Couldn't get ahold of a smoke machine but got a can of carb cleaner and idled the car and sprayed things down. No revs at all
So we took the manifold off and nothing seemed to be out of the ordinary.
Soo tomorrow we are going to time it.
Checked the battery and it is registering 12.3 volts. So I would say we are good to go there
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What should I look at when I am reading the live data?
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Last edited by Lelan; 04-25-2012 at 12:25 AM. Reason: Automerged Doublepost
12.3 volts is a half-dead battery; it needs to read 12.6.
You can't find intake leaks with flammables; there is no substitute for a smoke test. V-8s leak like mad, and carb cleaner won't find the common leaks..If you took the manifold off, and didn't replace every gasket and hose, you'll almost certainly have leaks now, even if you didn't before.
There's no way I'd consider ripping the engine apart to retime the vanos, if you did it with the correct tools the first time. With no indication (codes) for bad cam timing, and effectively no basis testing done, that's many steps beyond where you need to look for a poor-running engine.
Look at fuel mixture related data. If the O2 sensors indicate lean mixtures constantly, that would be a really good clue that you should do a smoke test and fuel pressure test. I'd start with those anyway.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Try swapping out the idle control valve.
edit: nevermind, you don't have one.
Question, did you also need to feather the throttle to keep it alive when you unplugged the MAF?
Last edited by DanB; 04-25-2012 at 02:38 AM.
It would stay alive without the MAF
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Left the rear intake manifold gasket off. FML
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Last edited by Lelan; 04-26-2012 at 12:21 AM. Reason: Automerged Doublepost
When you unplug the maf, you force the computer into "open-loop", meaning that it decides fuel delivery based on simplistic maps of engine rpm and temps, but not considering the feedback from airflow or oxygen sensor readings. This ONLY means that your car runs better when the computer isn't adjusting things correctly. It should not in any way be considered as indication that your maf is bad, although that's possible. This is exactly what a car with big intake leaks will do, though. Or bad primary oxygen sensors, or a bad maf.
You really need to smoke test the intake, and watch live data on a good BMW disgnostic scan tool.
If you go back to the same scanner, plug in the maf before you turn on the ignition for the scan - if the scanner doesn't show a code, go find another shop, quickly. (Because you should damned sure have codes after unplugging your maf - the codes are irrelevent, by the way.
You know a car has to run twice to set most codes in the "stored" area? Some codes will not set even then, and require more extensive driving. That's why you need live data, and "pending codes", and a smoke machine, and a good tech to run them.
Sure, you might have set the vanos timing wrong - if you didn't use the correct tools, and follow directions, you probably did. But if that were the case, you'd quickly set codes, and the car likely wouldn't run better after unplugging the maf.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Well, that's kinda an easy gasket to fix you're lucky!
But.. my question.. is how did you miss it LOL
I tried to put my mod list in my sig, but it wouldn't fit.
I have no idea how we missed the gasket cause we cleaned up the shop EVERY night and we didn't find the gasket any night so we can't even believe how we did not see it when we were cleaning it up. Just crazy, but I'm glad its running and fixed. Now time for some m5 bumpers and a new paint job, then exhaust and tinting and I'm done for a while lol
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Everyone reading this, please not how useless it is to spray flammables, hunting for an intake leak! Even this truly MASSIVE leak was missed!
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
That's because it wouldn't idle, once we got it to idle that's how we found it lol
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A smoke test does not depend on a running engine.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
I know but using carb cleaner does lol I agree smoke works better, but carb cleaner is easier for the DIY mechanic
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Last edited by bmwdirtracer; 04-26-2012 at 11:35 PM. Reason: Automerged Doublepost
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
That was all before the engine would idle... So that isn't valid anymore because we re-times the motor and it would idle after that. So then we could spray things with the carb cleaner and find the leak
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I guess you really want to go on believing that carb cleaner is an adequate leak finder. It's not, and you won't find anyone who's ever used a smoke machine who will tell you that it is. Dipstick, oil filler cap, valve cover gaskets, ccv hoses, fuel injector o-rings, bottom of the intake manifold runner gaskets , and about two dozen other places are completely immune to the spray, but smoke like mad with a smoke machine. If your leak had been only at the bottom of that plate, or the ccv plumbing incorporated in it, you could spray all day, and find nothing.
I'm really not wanting to argue with you, but this is a mechanical help forum, and spreading such wives tales is counter-productive, because it leads people to believe they've ruled out intake leaks, when they've really only fooled themselves, and so go on, searching for other culprits.
Your own quotes say that's true.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Dude above me knows exactly what he is talking about wait untill you boost it haha
I tried to put my mod list in my sig, but it wouldn't fit.
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