nyc86zc

Ok here's the story. I have a d16a1, ZC head, HMT kit running 10psi, fuel controlled by a SDS EIC, and just recently I turned the boost up to 13 psi. The cars has been hauling *** for the past two years it's been boosted. I replaced the fuel pump and filter within the past three years. I do not have any fuel upgrades on the car anywhere, stock injectors, FPR, pump, rail, etc. For the past month the car has been hesitating and progressively been getting worse in the upper rpm range before I hit boost(when my fuel management system kicks in) and I've just been overcompensating by adjusting my SDS EIC (fuel management unit) to deliver more fuel earlier, which has helped. If i didn't give it more fuel the A/F gauge would go dead lean and the car would feel like it hit a brick wall.

Well last night it was getting really bad. The car was stumbling on it's face the whole night and sputtering when not in boost. So, i made it home in one piece. I go out there tonight and start to see what's going on with it, checking lines etc. and everything under the hood seeems kosher. Then I hop back in the car and I hear the loud whining from behind my seat. It's the fuel pump whining really loud but it's still maintaing 20 psi on my Fuel pressure gauge mounted on the filter. If i unplug the FPR line it doesn't move, it's still at 20 psi.

Whenever I've heard of people having a fuel pump go on them it's just gone out all at once. There was no warning etc. This one is making a loud *** whine, which it never did before.
Is the filter clogged or the pump failing?
Any options to upgrading an external fuel pump in an 86 crx si?
TIA

dewme5

fuel pumps normally go slowly, it's just people don't pay attention until its too late.

I have a snap on vantage, with a low amp probe. (i'm a mechanic by trade, not a tech/parts changer) Monitoring the amp draw to the fuel pump, I can actually see the electrical signal of the electric motor, and the power it takes to rotate the pump. There are typically 6 vanes inside a High pressure fuel pump, and some of yours are worn out. at no point with a normal fuel system, should you be running 20psi. even with a clogged fuel filter, your pressure would overcome the block, until your fuel demand overcame the flow past the blockage. Subjecting your fuel system to 13psi of boost is going to take it's toll. time to pay up. May as well get one that will support just a little more hp. don't go crazy with a 255l/h unless you need it.

chinoy

So if he shouldnt get the 255 l/hr which one should he get ?

Tom-Guy

Go 255 lph, there are no repercussions except extra fuel flow when you need it.

Ron, if you make sure the fuel pump is a positive displacement type (like Walbros are) you can run two in parallel for increased flow. Keep in mind , alta single Walbro 255 HP (high pressure) pump has been known to support 550 whp although that's maxxing it out.

chinoy

What do you mean by Positive displement JD?

Im thinking the mistake I made was replacing my 6 PSI pump with a EFI pump.
I should have kept both.

BoosTedZSix

20 psi is insanely low

Tom-Guy

Positive displacement, like a roots blower.