feels like someone hit the brakes in boost ms1

Discussion pertaining to positive pressure E28s.
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BATESY
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Joined: Jul 06, 2008 8:42 PM
Location: Renton, WA

feels like someone hit the brakes in boost ms1

Post by BATESY »

So here is the story to give you guys a little back ground, just had the turbo rebuilt by Todd, k27-60trim. Car has been sitting for about a month and a bit, had some parts waiting from the motherland. Had a half tank yesterday when I got it back on the road with the new turbo. It wasnt doing it yesterday after the new turbo, although it was running wierd and what sound like pinging. Basically if you hit any boost it feels like someone is hitting the brakes the afr's are reading crazy lean. I turned to boost all the way down, I have a 13.5psi spring. I performed a datalog and only did it a couple of times so I could accually datalog this problem, dont want to damage anything.

http://www.mediafire.com/?wi3ijysjlebuu ... l66uwe0w3g

I personally think its fuel pump related, but I want some options before I jump to that conclusion. Right now it has a walbro intank only from TCD, they is not inline under the car, just a barb male to male when the old pump used to be, the filter was replaced recently but new babies die every day. Ive checked everything under the hood, no leaks air or fuel. Im running the stock 3 bar reg again. I do have a rising rate that I could install just to try out. The spark plugs are new and new plug wires.

tomorrow at work Im going to hook up a fuel pressure gauge and see what the pressure is doing under boost.

hope you guru's can help.

Chris
turbodan
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Joined: Jan 09, 2007 10:19 PM

Post by turbodan »

I can't spool the turbo car up with less than half a tank. It runs fine all the way to empty when driving normally but if I open it up in second or third the fuel apparently sloshes away from the pickup and I lose fuel pressure. I take it as a sign that the car is running well.

If filling up the tank fixes the problem, keep it filled up. These tanks weren't designed to handle strong, sustained acceleration.
BATESY
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Joined: Jul 06, 2008 8:42 PM
Location: Renton, WA

Post by BATESY »

I just filled it up and still has the problem. I just found in my garage a stock pump bosch number 0580464032 which is the stock pump for a 535i 160lph in good shape. I ran the stock inline with the walbro intake before and it worked great but I removed it due to the pump dieing and never put one back in. I did notice that I have a longer then normal crank right now. Going to pull the tank pump out tomorrow and check the hose between the housing and the pump. also install this bosch stock inline and see what happens.If that doesnt fix it then Ill probably try swapping in my rising rate and adjust it to stock and not connect the vaccum line to it to run like a stock fpr.
clongo
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Post by clongo »

The walbro could be your issue. How old is your pump? How did you wire it in?
T_C_D
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Post by T_C_D »

A fuel pressure gauge would be a good idea.
BATESY
Posts: 428
Joined: Jul 06, 2008 8:42 PM
Location: Renton, WA

Post by BATESY »

Im going to try that today. Pump isnt to old, couple of years tops. Im guessing that the little rubber hose between the pump and the housing broke or has cracked open. I brought in a stock inline today as well. going to do some trial and error. should be fun. I'll let you guys know later how it goes
clongo
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Post by clongo »

Keep in mind that you can't pull fuel through a Walbro pump like you could with the stock in tank pump. So if the Walbro has a torn rubber boot or is faulty it will still cause your lack of fuel pressure even with the stock pump installed (assuming fuel pressure is the issue or something with the pump is at fault.) I found that out the hard way when i killed my first Walbro pump.

How did you wire the pump? Did you connect the wires directly to the tabs at the top of the fuel pump assembly? Or did you splice it using BMW connectors with BMW heat shrink? The BMW heat shrink doesnt respond well to fuel and will actually swell up submerged in fuel.

What fuses are you running? Plastic or ceramic? I have also had issues with using plastic fuses for the fuel pump because they tend to melt and loose connection in the fuse box.
Brad D.
Beamter
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Post by Brad D. »

FWIW, I ran fresh wiring to my pumps with a dedicated fused circuit. I used the original pump wiring to switch a relay located in the trunk of the car. Works great with far less current draw through the factory ceramic fuses and ensures I have maximum available voltage to the pumps.
clongo
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Post by clongo »

Brad D. wrote:FWIW, I ran fresh wiring to my pumps with a dedicated fused circuit. I used the original pump wiring to switch a relay located in the trunk of the car. Works great with far less current draw through the factory ceramic fuses and ensures I have maximum available voltage to the pumps.
I thought about doing something very similar. Did you power it straight from the battery?
Brad D.
Beamter
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Post by Brad D. »

clongo wrote:
Brad D. wrote:FWIW, I ran fresh wiring to my pumps with a dedicated fused circuit. I used the original pump wiring to switch a relay located in the trunk of the car. Works great with far less current draw through the factory ceramic fuses and ensures I have maximum available voltage to the pumps.
I thought about doing something very similar. Did you power it straight from the battery?
Ya, I ran a fused circuit right from the battery.
BATESY
Posts: 428
Joined: Jul 06, 2008 8:42 PM
Location: Renton, WA

Post by BATESY »

Image

Found it. Motherfucker. I had the feeling. Put a pressure gauge on it. ran at 28psi idle and 20psi when driving down the street. made my own adaptor using 8mm line and 12mm. basically put the 8mm line inside the 12mm and clamped it down. Works perfect. probably will never brake again.


Image

Thanks for all the replies and help

Chris
BATESY
Posts: 428
Joined: Jul 06, 2008 8:42 PM
Location: Renton, WA

Post by BATESY »

I bought my whole setup with housing used from Todd, hot wire to stock connector and the other the housing.
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