So recently i have been having this weird problem when i only cruising down the road. I recently did a m106 swap with the 745i fuel pump and everything. only till recent has it been doing this, while cruising on the freeway or on a road with barely any throttle it will feel like it slacking on fuel, i dont think its a misfire because the tach isnt erratic at all, i thought i might be the fuel pump so i filled my tank up and nothing. i didnt how ever replaced the high pressure pump under the car when doing the swap just the intank one. the wierd thing is i have these puck looking things that i never removed from the fuel lines in the engine compartment here a pic:
there on the both line on the fuel rail, dont really know what they are, but there bmw parts....i dont know if i supposed to remove them when doing the swap. i looked on a couple of friend e28's and the e23 i pulled the motor out of and non of them have these funny puck thing, i dont know what they are....i was thinking about removing them and going from there. need some other opinions.
BATES
ps sorry for my terrible grammer.
Last edited by BATESY on Jul 23, 2009 12:30 AM, edited 1 time in total.
I don't think the 745i in tank pump is going to do much. I believe it is just another low pressure "lift pump" just like the one you removed from your 535i and isn't going to supply any more fuel. If you want to upgrade, install a Walbro or TRE performance pump in its place.
what about replaced the stock 535i high pressure pump under the car with the 745i one??? i didnt really think about replacing that when doing the swap.
Instead of replacing it with a 20 year old pump, get a Walbro GSL392 inline pump. It will outperform the old 745i pump in every way and not break the bank.
Like Brad points out, replacing the pump is a very worthwhile upgrade.
I think you should also add a "tee" fitting with an 1/8npt tap to the inlet side of your fuel rail, in the hose and buy an inexpensive fuel pressure gauge. This way you can monitor fuel pressure to verify if you really are losing it when driving when down the road.
So got off early today and got the car up on the old hoist and replaced the old fuel pump with the one from the 745i which looked pretty new, i also replaced the fuel lines which had those fuel dampers on it from the hard lines to the fuel rail....seems to run better. i havent had a chance to drive it long enought to say the problem is fix....the other thing i found that sucks about the m106 is the afm is a totally different part number then any other m30 i have seen or have in my tool box if anyone needs a regular m30 afm i have two of them in great shape and both havent been tampered with.
It is a totally different AFM and uses a 0-10VDC output and has a second stage in the wiper for measurement under boost. The stock M30 AFM is a 0-5VDC output and isn't interchangeable.
Really,
I need to see one of these. That sounds really intriuqing?
RussC
Big Bronze Rim wrote:It is a totally different AFM and uses a 0-10VDC output and has a second stage in the wiper for measurement under boost. The stock M30 AFM is a 0-5VDC output and isn't interchangeable.
Big Bronze Rim wrote:It is a totally different AFM and uses a 0-10VDC output and has a second stage in the wiper for measurement under boost. The stock M30 AFM is a 0-5VDC output and isn't interchangeable.
The output voltage is just a matter of whats going in. The NA B34 AFM would work, but probably quite poorly. Both should read about the same wide open though.
I think I've seen the second stage thing somewhere else. Its a small, straight metal spring that adds extra resistance towards the fully open position right?
I thought the vac line going to the dme is what it used to fuel under boost. Mine has that extra spring tab, but how can that measure any boost, let alone from 1psi to the next?
grsmonkey wrote:I thought the vac line going to the dme is what it used to fuel under boost. Mine has that extra spring tab, but how can that measure any boost, let alone from 1psi to the next?
If you have the AFM on the compressor inlet it can work, as long as you have the AFM spring tight enough not to peg open before maximum flow occurs. The vane type AFM is designed to measure air volume, its just oblivious to changes in air density.
yea that why i thought the afm wouldnt work...one ending in 022 and the other a stock m30 i think ended in a 027. at least its not that problem because i would think trying to find a m106 afm would be a total bitch and the dealer wants 800 bucks.....$%#
grsmonkey wrote:I thought the vac line going to the dme is what it used to fuel under boost. Mine has that extra spring tab, but how can that measure any boost, let alone from 1psi to the next?
on the m106 using its motronic it has the knock sensor and boost box seperate from the ecu. thats were my vaccum line from the intake manifold runs into and senses boost levels. its a bitch because if i hit 9psi it cuts fuel
i need to pick up the boost limit chip delete and have somemore fun.
so finally something has failed other then the high pressure fuel pump. the car is running SUPER rich, if i even rev it up it just blows out black crap.....i changed out the engine temp sensor and nothing....im leading towards the AFM the only problem is where to find a AFM ending with 022. i dont know what other cars in the US come with such a AFM so need some help. if anyone has any other opinion please let me know. I cant even really drive the car barely idles, seems like its just flooding the thing. thanks much
funny enough I found out that the fuel pressure regulator was bad...I was at work and checking everything, i pulled the plugs and they were completey soaked in gas...put some new plugs in NGK bkr6es that i have seen some of the m30 turbo guys run. Car started and died again...for some reason i didnt check the FPR and tapped it with my screw driver and heard a click, restarted the car and i could only idle and not rev. picked up a new and BAM good a new. Test drove it and seems all good.
Good to hear you sorted it out. The heat range 6s should be fine for low boost (1 heat range colder than stock). If you increase boost any I would bump up to a 7. I've had no issues in over a year and a half (fouling, misfires, etc) on the same set of BKR7Es, but I've got a fresh set the next time I do a "tune up" on the car.
what boost range are these good for...i can only go max 10psi after the chip so im not expecting anymore then that. as of right now im only at 6 to 7psi
I ran a set of bp6es on my 535i at 20 psi with no ill effects. I ran those same type of plugs on my 745i at 9psi (when it would actually do it) with no problem there either. Get the chip and turn that thing up! If you don't know where to buy them, David, ecartoys on this board, hooked me up.
IMO best plugs to ever use on a M106 are Bosch W6DP0. They are the original plugs in the Alpina motors as well as Porsche and Ferrari. The only bad thing about them is the price and that they are kinda hard to find! But they sure are worth it!
If you're using a FMU would changing the pump to a 255 vs stock require any tune adjustment? I am thinking not since off boost the FPR would maintain fuel pressure and under boost the FMU would also, but I want to be sure.
