So I'm really hoping to get this fixed quick because I'm scheduled to get on the dyno this next Saturday with a local BMW group.
I have a 1989 325i with an M30B35 swapped in from a 1988 735i. It has a custom 3" intake with a big K&N air filter, a full 3" stainless, catless exhaust with an E.A.T. performance chip.
I have been running the car for a while with a 1990 325i rusty speed-holed accident repaired POS chassis without any real major issues. Even bleeding the coolant went fine and it never ran hot until the stock fan died.
With the swap to the new minty California chassis however it blew a fuel pump fairly quickly when the alignment shop had it. I figured that since the car sat for a few years with the PO it was just caused by a pump that got cruddy and tired so I swapped it out with a replacement pump and went on my way. The rest of the year it seemed to be ok but I didn't drive it much and the exhaust is pretty loud.
Well, this year after the 20 feet of snow melted and it was finally un-timelocked from the localized glacier I decided to charge up the battery and get the parts moving again. It was running a little rough but after getting some fresh premium in things were smoother and appeared to be ok.
After dropping a friend off at a shop to pick up his E34 535i we had a "spirited" run back on the freeway and I had instantly noticed that over about 5,000 rpm power just dropped off like a rock. It was almost like it was rev limited or something like that where my speed would only slowly creep up. Once I shifter and got below that range it kicked back in and started accelerating again. My rev limiter is at 6800 on the car and before it has never had this issue and ran hard until about 6k and I'd shift around 6500.
First, does anyone have an idea why the power would be dropping off past 5k? I've never experienced anything like this before in any of my E30s.
Second, has anyone experienced fuel pumps dying with this swap before? The odd thing is that when I start it up it seems to run fine but after a couple minutes it makes the classic buzz/hum/whine/squeal/imgoingtodiesoon sound the fuel pumps make when it's on its way out. I've had some noisy ones and some on their way to death ones but they always make the noise all the time. This one works fine when it first starts up and then makes the noise. Even if I just stop for gas quick and fill up I get back in the car and it won't make the sound for a couple minutes. This is the same one from the old 1990 chassis that ran fine before. Do I just need to suck it up and buy a brand new pump from BMW for $300?
Third, even when running under 5k the car seems to be running a bit slower than normal and a bit off. I just got done modifying my 2012 Mazdaspeed 3 and right now it's putting out about 310hp at the crank so it's pretty quick. Previously with the old chassis and with just an intake on the Speed3 the 335i kept up with the Speed and it was a give or take as to who would win. With the new mods I sort of wrote it off as being just slower than the Mazda but now I'm thinking that maybe with this power issue there is something else going on. Is the M20B25 stock fuel pump enough to keep up with the motor pressure and flow wise or do I need to swap to the E34 or maybe an aftermarket fuel pump? Are the stock fuel pressure regulators different between the M20 and M30? Do I need to upgrade the fuel injectors or possibly the pump to support the mods with the E.A.T. chip?
Thanks for any input, I'm really hoping to get this resolved asap so the car doesn't fall flat on it's face on the dyno. There's some big six haters there.
I have a 1989 325i with an M30B35 swapped in from a 1988 735i. It has a custom 3" intake with a big K&N air filter, a full 3" stainless, catless exhaust with an E.A.T. performance chip.
I have been running the car for a while with a 1990 325i rusty speed-holed accident repaired POS chassis without any real major issues. Even bleeding the coolant went fine and it never ran hot until the stock fan died.
With the swap to the new minty California chassis however it blew a fuel pump fairly quickly when the alignment shop had it. I figured that since the car sat for a few years with the PO it was just caused by a pump that got cruddy and tired so I swapped it out with a replacement pump and went on my way. The rest of the year it seemed to be ok but I didn't drive it much and the exhaust is pretty loud.
Well, this year after the 20 feet of snow melted and it was finally un-timelocked from the localized glacier I decided to charge up the battery and get the parts moving again. It was running a little rough but after getting some fresh premium in things were smoother and appeared to be ok.
After dropping a friend off at a shop to pick up his E34 535i we had a "spirited" run back on the freeway and I had instantly noticed that over about 5,000 rpm power just dropped off like a rock. It was almost like it was rev limited or something like that where my speed would only slowly creep up. Once I shifter and got below that range it kicked back in and started accelerating again. My rev limiter is at 6800 on the car and before it has never had this issue and ran hard until about 6k and I'd shift around 6500.
First, does anyone have an idea why the power would be dropping off past 5k? I've never experienced anything like this before in any of my E30s.
Second, has anyone experienced fuel pumps dying with this swap before? The odd thing is that when I start it up it seems to run fine but after a couple minutes it makes the classic buzz/hum/whine/squeal/imgoingtodiesoon sound the fuel pumps make when it's on its way out. I've had some noisy ones and some on their way to death ones but they always make the noise all the time. This one works fine when it first starts up and then makes the noise. Even if I just stop for gas quick and fill up I get back in the car and it won't make the sound for a couple minutes. This is the same one from the old 1990 chassis that ran fine before. Do I just need to suck it up and buy a brand new pump from BMW for $300?
Third, even when running under 5k the car seems to be running a bit slower than normal and a bit off. I just got done modifying my 2012 Mazdaspeed 3 and right now it's putting out about 310hp at the crank so it's pretty quick. Previously with the old chassis and with just an intake on the Speed3 the 335i kept up with the Speed and it was a give or take as to who would win. With the new mods I sort of wrote it off as being just slower than the Mazda but now I'm thinking that maybe with this power issue there is something else going on. Is the M20B25 stock fuel pump enough to keep up with the motor pressure and flow wise or do I need to swap to the E34 or maybe an aftermarket fuel pump? Are the stock fuel pressure regulators different between the M20 and M30? Do I need to upgrade the fuel injectors or possibly the pump to support the mods with the E.A.T. chip?
Thanks for any input, I'm really hoping to get this resolved asap so the car doesn't fall flat on it's face on the dyno. There's some big six haters there.
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