Name that Fuel Pressure Issue
 

So here it is. http://i272.photobucket.com/albums/j...h_P1015183.jpg

It seem to also occur while simply just cruising, but more so when accelerating...

a) fuel pressure regulator (believed to be HKS)

b) fuel pump (ebay walbro)

c) leaky pulsation damper (prob not. I didn't smell fuel, kinda does in the garage but thats norm.)

d) leaky injector

e) leaky fuel line

f) What do you think?

:beer:

Pump/Regulator/Dampner.

D and E are unlikely, but I highly suspect B.

Have you changed your filter rescently? Sometimes small things like these are overlooked. :)

No, I looked over the engine bay last night, and didn't see/smell any fuel leaks so I'll check the filter first and see if that is the culprit, then check the pump. Could it be the pump sock possibly?

Could be. I have seen quite a few issues with fuel systems clogging up with this new gas we have. The Ethanol seems to leave a residue. I would definatly check your fuel pump and sock. Maybe do a bench test on the pump to see if it is flowing properly, and make sure the filters are free of residue. Good luck. The last thing you want to do to a Rotary is run it lean.

Hmm.. That doesn't sound right.. Ethanol is a solvent, it should clean everything - even too much sometimes..
It might be possible that the ethanol has eaten away at the seals in the fuel pump, so that when it tires to pump faster to keep up, fuel starts passing by the seals. [Note: I've never seen this, but I've read about some seals in other cars not being designed to withstand the ethanol; hence this theory]

For what it's worth: my base was flooding all the time until I stopped using Arco, and started using only Chevron/Texaco/Shell/76 [Top-tier gas]

The solvent properties strip away the gum left by poorer quality gas, clogging the fuel filter.

However it still would not cause pulsing like in the video.

Oh, I should have also mentioned I don't belive the fuel pump has been rewired and I wired a switch inline, and the terminals get pretty hot... 30amp switch I think.

I'm thinking its pump realated, either voltage and/or shitty pump and/or clogged sock.

I do run premix too, not that it should affect anything negatively like that. I did drive over 150 miles before I noticed it doing this.

Thanks for the suggestions...

Honestly if you are only running 750 secondaries, buy a used FD pump. I have seen to many walbros crap out.

680cc primary, 1000cc secondaries. but I will look into other pumps if that is the problem.

Thanks

Start with what you know you need to do, rewire the pump.

Getting started. Found some 10 GA gasoline resistant wire at lowes for 10c a foot. Going to be cleaning up a bunch of other wiring. Got a Profec-B for cheap, that's going in too... Yay!

Ok, So after reading the multiple fuel pump rewiring threads I found them a little overboard and totally overkill for supplying power to a fuel pump.

So I'm simply running a new 16ga or larger wire from the 'circuit opening relay' to the fuel pump and bypassing the 'fuel pump relay and resistor' which reduces the voltage to the pump.

Quote from fc3spro.com, "On FC3S turbos, the fuel pump sees two levels of voltage depending if the engine is in boost - the "low" voltage level runs the fuel pump circuit through a resistor to drop the voltage to 9-10VDC; the "high" voltage level run full, unmolested voltage to the fuel pump. The fuel pump also sees full voltage when cranking the starter. You need to have the turbo under boost to check to see if your fuel pump is getting full voltage."

First off, 10ga wiring is totally overkill for the pump and pretty much anything in the entire car. (except a giant 1000W amplifier and subwoofers) The main fuse powering the fuel system is only 15amp, this means that a 16ga wire will be adequate according to the chart I've attached.

Why am I not rewiring as others have and suggest to do? Well I find that adding additional relays to the system is only complicating things and making more clutter and wires running around which I'm trying to eliminate. I don't think the fuel pump getting low voltage is because the connections or wiring is old, but rather the ability of the resistor to control the voltage correctly and supply the amount of fuel needed and being used.

I'll be checking voltage and amperage once everything is finished. Possibly, If I were installing additional pumps I'd probably want to add additional wiring and relays, but for my goals, a single walbro, this should be adequate and supply an unmolested 12v to the pump at all times when the car is running.

Let me know your thought and suggestions.

http://www.rowand.net/shop/tech/wirecapacitychart.htm

Nick, take note that there will be a voltage drop over a good distance of wire. I would go 12 GA to allow yourself some leeway and room to upgrade to a higher demand pump if you decide to. Good luck with your winter project.

Actually, I did end up going with 12GA. :icon_tup: Good call. Got the Dual Solenoid whatsit box mounted and vacuum lines ran and the wiring through the firewall and a 9 pin male plug wired into the gauges, fan sw, and EBC in the console. (looking nice) Also cleaned up the wiring to the 02 sensor that was crimped and taped. Soldering and heat shrinking everything.

My small pile of extra wiring, splices, and shit that I'm removing is growing. I had put gauges with wires spliced into other gauges that were spliced into wiring harness. It was a mess, I don't know what I was thinking...

This week I hope to have everything wired back up, but with Christmas almost here I'll probably have it completed and running again by 2010. And will be tuning for boost just under 1 bar. :rock:

So did you get it finished yet? If not I'm free untill X-mas day, and then after I'll be free to lend a hand if you need. just shoot me a PM W/ directions from hwy 26 and a time I'll be there.

No. But I'll be getting it done in the next few weeks. But, have you ever rebuilt a brake caliper?Anyone? My pass-rear has a torn piston boot and makes funny noises. So I gotta get that fixed too. rebuild kit is like 40 or 50 bucks.

I'll be working on it sporadically throughout the next two weeks, should be done by the 1st. I'll let you know if I need some help. Thanks!

I haven't but I use to work with hydrolics in a previous job, so I think I could do it if I took a look at the FSM. The rears are only single piston right?

Wiring is done, and it fired right up with no smoke/burning electrical smells. Fuel pressure did appear to be higher than normal when cranking. Pump was a little louder also. Will be testing further tomorrow. Although, I can't seem to find the fuel pump check connector? Its supposed to be a yellow plug near the front pass. strut tower? :dunno:

I did wire it as above. Spliced into the Main Relay bypassed the Fuel Pump Resistor and Relay and went directly to the pump using the factory spades and plugs with 12GA wire.

Fuel pump connector, rear drivers side strut tower. Removed the blue wire
spade connector from the plug.
https://cimg2.ibsrv.net/gimg/www.rx7...149f1b977e.jpg


Soldered the spade to the 12 GA wire.
https://cimg5.ibsrv.net/gimg/www.rx7...4b8f8be24e.jpg


Re-inserted spade into plug.
https://cimg7.ibsrv.net/gimg/www.rx7...345071b8b5.jpg


Main Relay Harness. On steering column. Blue wire to be removed.
https://cimg1.ibsrv.net/gimg/www.rx7...6f1f8adaaa.jpg


Soldered the spade to the 12 GA wire.
https://cimg5.ibsrv.net/gimg/www.rx7...82c30433f9.jpg

It's definitely not losing any pressure and I haven't noticed any weird fuel pressure drops. But now my Fuel pressure sits at about 40psi at idle when before it was about 37-36 at Idle. So now my tune seems to be a little rich. Hesitations when boost comes on 10.5-11 AFRs cruising. Seems to have solved my problem though. Fuel Pump has got to be running full on, definitely louder. Now gotta Drive/Tune the Mutha...

Relocated the Gauge also. A little more visible...
http://i272.photobucket.com/albums/j...123/gauges.jpg
Left to Right. Boost, AFR, Fuel Press., Oil Temp, Oil Press.

Figuring out this boost controller business now. Had it the gain/volume set to zero, and low boost set as low as possible, dropped the hammer boost spiked to ten and lost traction, way too rich tho. Set the gain to full and it seemed more stable, no spiking, albeit slower boost response. :rock:

Good shit. We both had a busy weekend. got my turbo and DP in. twin scroll removed, ported turbine inlet. but my turbo manifold had some cracks so I'll be doing it all over again..... Maybe it won't take me 2 days this time.... there were some issues. Car started back up. but I broke my ACV so I gotta buy a block off plate. and I cracked a coupler getting it off the old turbo. so I need to find a new one tomarrow. Cars still not really driveable but close. soon as I fix the vaccume leak coming from the ACV. I need to get my BOV installed next. Gonna be shooting duel flames.

Right on Jinxed. Well, let me know if you still need help of if you wanna just BS or something this weekend.

We'll have to do a cruise come spring, that loop around Portland was pretty fun (would've been better had the liquid sunshine not been around) Where did the all the pictures from that go?

Does anyone know where the fuel pump check connector is? I cannot find it.

Its the yellow plug on the passager side strut tower. I think its on the firewall side. Yeah I still need help. I blocked off my ACV and Its running like shit. I know a few things I have to fix. but if I don't get this figured out tomarrow I'm in trouble..... I may not have the turbo tighted down enough. I also have the split air pipe still installed, but I doubt that would cause any issue.

Yeah I'm down for a drive. any time. I was dissapointed in the pics from that event. its like after we did it nobody ever came back on and posted again. And I need another sticker for the T2 now.

its the yellow 2- wire connector on the main harness close to the turbo... on the passenger side.. its pretty short and hard to find, mine was covered in dirt and grease so it camouflauged with the harnesss and it was hard to find.. its on the main engine harness tho