Empire087

I have been having issue with hard starts, but usually it idles correctly.

baube

the "open" valve cover with a filter doesn't help for sure

I can see my a/f going lean only by opening the oil cap at idle

Empire087

Ok i have some videos, hopefully they do an ok job showing what the fuel pressure is doing. It is indeed losing pressure.
Heres the car crusing, it does go to about 13.1 or so after being off the throttle a while. This is with almost zero pedal pressure, as its low rpm
https://www.youtube.com/watch?v=5rgwy_LUHfQ
This is the problem happening.
https://www.youtube.com/watch?v=qTQzgU6x8Ww
and here is showing that if i shut the car off the problem goes away(temporarily)
https://www.youtube.com/watch?v=pkOX4M6AJPw

R_34

How much volts do you have at the pump ?
The hose going from the plenum to the fpr is not leaking under boost ?

Empire087

The battery is wired directly to the pump, and the ground directly to the chassis. Using a relay as the on/off.

Kingtal0n

So you've narrowed it down, good. Next step would be to pinch the return line shut (clamp it closed) and see if fuel pressure skyrockets, and stays there.

Also check the regulator make sure the vacuum hose is connected and functioning.

If you clamp the return line shut, and fuel pressure still drops / stays low, then your pump is bad, or there is a major clog between the pump and rail. given the intermittent nature it is more likely pump. Checking the voltage is advised but somewhat unnecessary, since the fact the pump works at all indicates that there is some connection (at least 8+volts IMO), and a wire so small that it would not support pump activity would just burn or the pump would stop all together. In other words, if we run any car battery down dead, just leave the headlights on all day. When its dead, let it sit a while, then run the smallest wire to the rear of the car and still notice there is probably at least 8volts.

cotbu

how is that relay controlled? can you do another test, just cutting off the relay and powering it back on to see if it changes anything.

if you ever ran the pump dry, I would consider replacing but after that test. lol

I only ask because I couldn't see, if pressure went to zero when you did the key off, while rolling. You moved the camera as I was watching the gauge. I think you got it figured out though.

Sent from a Highly Boosted Note 4!!!

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LoverTechnologies "Half Broken Things!"

Empire087

Already still having problems, except i found out that those gauges your rent from the auto parts store suck. After returning to autozone to bring them their gauges back, that essentially just got stuck on zero after a while :/. During that drive after changing the power source for the on signal for the relay, the problem came right back as usual. Shutting off the car would temporarily fix the problem. So i borrowed the same gauge form oreileys and that one showed things working right for a little while, and then slowly got lower and lower until it didnt move right anymore and got stock on like 20 psi until i bleed it. The problem still persist after all that, and i switched over to a different fpr to try and fix the problem.

Ok i checked the voltage at the batter 13.8v, and then checked the voltage at the pump it was 13.3/4 volts. This was taken using the pumps ground. with the gauges acting the way they did i clamped the return line and it seemingly made no change in the gauge. I couldnt however tell if the fuel pressure went up.

Cotbu, the fuel pump is like 2-3 weeks old and ive never driven past 1/4 tank. Im wondering if im on my second dud. I will try and cut the power tommorrow and see if that makes a difference. Also You wanted to know if my ecu will throw a maf code, it indeed does.

Just trying everything, im getting beyond frustrated.

Empire087

Alrighty rehooked up the gauge, with the original fpr im getting about 40 psi at idle and around 50 with the vacuum removed. I used a jumper to bypass that relay and just run 12v direct from the battery.

Empire087

Brand new pump, and a rb25 fuel pressure regulator still has the same problem.

cotbu

Still having issues? Have you looked inside the ecu yet? Can you tell me if you have a daughter board inside with socketed chips or if you are able to remove the board from the ecu?

I'd like to try to richen up the transition area of the map only and see if you still end up leaning out.
That could be a last resort if you prefer, cause before that I would rewire the whole swap, double checking the work.
Systematically eliminating things as the cause.

Sent from a Highly Tuned Note 4.5!!!

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Empire087

Yup still having the same issue, but i did remove the ground from the harness and ground it right by the tank for the fuel pump. It seemed like it took longer to lean out. Im also running pig rich cruising 12:1 afr, max of 10.5/6 wfo it actually bogs sometimes its so rich wjen you lay into it. And it settles around 13.8 afr at idle. While warming uo theres also a pretty bad miss that goes away forr the most part once above 140 degrees.

My ecu is rom chipped, but i did try an r32 a/T ECU and the problem followed the ecu.

Kingtal0n

you didnt need to change the fuel pump until you clamped the line shut, as instructed above, you are making more work for yourself by ignoring procedure

Empire087

Ok, heres the thing though. The parts store fuel pressure gauges are junk, I couldnt even start to try and trust one after fucking with those things over 5 days. I understand what your saying make sure the fpr is good, however to my knowledge a fuel pressure regulator either works or it doesnt correct? Even so i took two that are proven working and replaced my stock one with both of those. One off a ka24e, and one of a rb25det. my problem still persist, The pump was under warranty it was worth a shot for 25 minutes of time to change it out. The fact was i had to make the pump physically stop running to get any kind of pressure back potentially pointed towards a faulty pump.

Empire087

Ok definetly green relays, today while i was out for a drive after it started breaking up a little that it wanted to die when i came to stops. And it came really close one time and then the problem again temporarily went away. I didnt have to restart the engine anything the rpm just got really really low. Thoughts?

Empire087

Ok so i did clamp off the return line and the pressure does increase to about 90 psi. However if i rev it, then the fuel pressure drops off incredibly fast and falls well below 20 psi. So this would point at the pump correct?

Kingtal0n

I thought you changed the pump?

1. unplug the vacuum hose from the fuel pressure regulator, with the engine off, and run the fuel pump. Write down the pressure.

2. run the engine with the regulator vacuum hose connected. At idle, the fuel pressure will be lower, by about 6-8psi (for engine vacuum around 12-15" Hg).

3. When you "stab the throttle" or "rev the engine" the fuel pressure should return momentarily to the fuel pressure from #1, as the engine vacuum drops back to 0" Hg (0psi).

4. After you let off the throttle, the engine vacuum shoots to 18-22"Hg and the fuel pressure should now drop below what it was in #1, and then gradually settle back to where it was in #1 at idle.


Clamp the fuel pressure line and go for a drive- See if the fuel pump can deliver enough fuel to keep the engine rich, and keep fuel pressure high. 90psi is hard on fuel system components but it should be fine for a quick test. You just want to prove that the pump is unable to supply the demand. e.g. If I SEE 90psi of fuel pressure at 12psi of boost and 6000rpm and I SEE that now the air fuel ratio is much much lower, then I KNOW the pump is able to supply for the demand, and I can direct my attention to the computer or elsewhere.

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Empire087

It does all those things listed 1-4. pressures are 39 psi at idle(21 psi vacuum), and 46/47 no vacuum pressure. And yes if i downshift while cruising and pull more vacuum it will drop 2-3 psi more than it was at idle.

Kingtal0n

ok so what about #5, clamp and drive

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https://tinyurl.com/turbo240