IntegraTypeR

iTrader: (1)

Hi guys,
i am going through an issue that i am trying to fix for a long time. Whenever boost kicks in my fuel pressure drops so bad my AF goes extremely lean. good thing hondata has the lean protection option. Here is what i did and still couldn't fix the issue:

1- changed fuel lines completely (-6an) with new 255HP walbro fuel pump with the sock style filter (used to run a 044 inline with the walbro intank, but removed the 044 so i can simplify in analyzing the issue)
2- installed Vanjen clamping system since i had a few leaks at the charge pipes and went with vanjen so i can minimize such possibility
3- removed intake manifold, fixed/welded a small leak i had on there, surfaced the flange and checked for flatness with a straight edge and installed a new OEM intake manifold gasket
4- did a compression test and came back with 185,185, 183, 181 psi
5- did a leak down test while positioning each piston to TDC and did it in the same order as in doing a valve adjustment 1/3/4/2. all pistons showed 20-25 % leak, which is good on my gauge being in the green zone
6- fuel pressure rises when VAC gradually increases and reach to 0, but once boost starts to kick in i can notice the fuel pressure dropping more and more
7- replaced TB gasket
8- set hondata fuel pump test option on so i can keep the pump running while engine is off and then applied pressurized air (35psi) from an air compressor directly to the FPR. without boost the fuel pressure stays 43-45psi at the fpr and as soon as i apply 35psi i notice my fuel pressure gauge goes up to around 90 psi and stays there even if leave the compressor running for 10 mins. pump does sound different when compressed air is applied to the fpr, but thats normal because of the fuel pressure increase
9- replaced aeromotive with a new internal filter
10- installed mechanical fuel pressure gauge at the aeromotive fuel filter and seems my fuel pressure reaches 80-90psi of fuel pressure. i hope its clear so in other words i'm getting 38psi of fuel pressure with the vac hose on (base was set to 43.5psi with vac hose off) and at the same time the fuel pressure at the fuel filter is reading 80-90psi
11- check fuel tank by opening the fuel cap and there is no vac or pressure build up
12- monitored ect and it seems to stay 202F when cruising and no boost applied. as soon as boost starts to kick in the ect temp goes a bit high to 204-206F when the engine see's a lean AF
13- oi l temp is good i think 180F
14- my boost gauge reads fine and i can see my WG spring boost value when full boost kicks in, but hondata lean protection option interferes
15- did check the ID1000 injs if they leak by applying compressed air to the intake manifold (test was done with the intake out of the engine head) and its was leak free
16- checked the voltage using a multimeter to monitor the fuel pump voltage and it seems voltage is stable at 13.7v all the time. It even stays that voltage even when the fuel pressure drops

my setup is:
build b18c block, ported b16 head, CTR cams, arp studs, new OEM dist, new OEM spark plug wires, gt35r 0.82ar, Vanjen racing clamping system, 3 inch DP, walbro intank 255HP fuel pump, -6 feed and return, weldon 120psi FPR, BDL fuel rail, ID1000 injs, Aeromotive fuel filter, two fuel pressure gauges (mech one before the aeromotive fuel filter and second one which is my main reference is at the fpr)

summarized issue:
1- fuel pressure drops when boost starts to build and goes down to 20psi.
2- my ECT goes above normal as i think its normal since the engine is see-ing a lean AF when boost kicks in, but when i cruise a bit the temp goes down

questions:
1- what could be the issue? would like some hints!
2- thinking of doing a turbo boost test while engine is shut off (applying compressed air at the turbo inlet and see if i'm getting any leaks. what areas should i check when i do the test? coolant cap, oil cap, vac hoses, wg, bov, charge pipes, intercooler, turbo compressor and turbine side, fuel tank while cap is removed....if there are any more areas to look for a boost leak please let me know
3- my brakes are good, but i'm starting to think that i might be having a leaking brake booster! is that possible?

by the way i'm sorry for the long post, but i wanted to provide the reader with the full story so it becomes clear.

Turbo-LS

iTrader: (4)

What wiring do you have for the fuel pump ?

pingaturbo

i recently had an issue with this too, contact Whitfield Racing they do all the work on my car, and they were able to fix the problem. i would explain it but don't know how, one more thing they are closed Sunday and Monday. If not looked Jason Whitfield on Facebook.

IntegraTypeR

iTrader: (1)

i have a 70amp relay connected to the walbro pump (the reason why i went with 70a is cause i attended to hook two fuel pumps 044 and 255hp walbro to the same relay instead of running two relays). now the relay has the stock fuel pump singal, +12v from bat, gnd, and output connected correctly. if you think its a relay then its NOT as the voltage stays stable at the relay output even when the issue happens! replaced my new walbro with another new walbro and problem is still there!

Turbo-LS

iTrader: (4)

Ok just wanted to be sure you had the properly sized wiring

Muckman

iTrader: (2)

It sounds like this issue occurs at any boost pressure. Once you go above 0psi MAP the FP decreases, is that correct? I think that rules out any supply/demand issue.

I didn't see that you mentioned anything about the FPR vac hose in your troubleshooting list. How is the vac line connected to your FPR? What is it T'd off? You mentioned possible leaking brake booster. Is your FPR connected after or before the brake one way check valve?

SOHC_MShue

How much power are you making and how much boost? Its very possible that your pump is just crapping out and not able to keep up with flow demands in boost.

IntegraTypeR

iTrader: (1)

yes fp decreases when boost goes above 0 psi ! the fpr gets a vac ref that is tee'd between the boost gauge and intake manifold, but now i replaced all my old vac hoses with new ones and distributed out a dedicated vac hose to the BOV and fpr while the source from the intake is shared by the boost gauge and wg side port. still no luck. sprayed more soap and still cant find any leaks around my vac hoses. about the brake boost i dont think it matters if it leaks or not as the check valve on the brake booster hose was checked and was fine. that check valve makes sure no pressure reaches the brake booster. another thing my vac block is tee'd between the brake boost check valve and intake manifold which am sure is 100% right

I did mention about the fpr vac if you read above i supplied the fpr with pressurized air from an air compressor to verify my FPR is in a good functioning condition and it is thats with turning the pump constantly on so the total fuel pressure! it seems to be functioning correctly and stays stable even if i leave the pump/compressed air on for 10 mins!

Here are more tests i did today:
1-blocked the charge pipe right before the throttle and used a boost leak kit where i applied 25psi of pressurized air (engine shut off that is) and noticed i had some minor leaks around the welds of those vanjen fittings. then i started noticing a hissing sound from some where.....looked and sprayed water/soap everywhere with no luck. as soon as i open the engine oil cap i notice the sound is coming from there and with an additional sound of something bubbling/boiling kind of a sound. it made me think that my turbo is leaking pressure from the inlet into the oil return line and it was!!!! is that normal? i did remove the return line and noticed that there is air blowing from the return line (used my fingers to verify by plugging and unplugging the return line).
2- replaced all vac hoses and checked my brake booster check valve and seem it still is working fine
3- kept the rad cap off to see for any bubbling and there was nothing during the test
4- did a pressure test (184 / 180 / 186 / 182)
5- did a leak test (20% / 15% / 16% / 24%). all where in the green zone of my leak tester
6- checked wg dump tube during boost test and wasnt leaking
7- checked bov and no leaks
8- checked intercooler and no leaks


questions:
1- it sound to me my turbo oil seal is some how shot since it leaks boost into my oil return line. i made a few calls and some rep today told me its normal for the oil return line to bypass air....hmm!??!!??
2- what else can i check?

IntegraTypeR

iTrader: (1)

i street tuned the car yet and right now i'm running off a 14psi wg spring. i could guess power is nothing more than 400whp

Turbo-LS

iTrader: (4)

Your running a motor in tuned up to 14 pounds of boost seriously wtf

IntegraTypeR

iTrader: (1)

sorry i street tuned the car using a wideband and timing is conservative and dist is adjusted

wantboost

iTrader: (2)

There's just so many variables and potential issues that could be compounding each other so it's truly hard to diagnose over the internet

Have you checked the bypass on the pump? It could be faulty

Another way is to clamp the return line off and see how much pressure you can generate (generally whatever the pump bypass is set at) then crank the car and see what it drops to at idle. Then drive it a bit and see how far it dips. That will tell you if it's the pump real quick.

IntegraTypeR

iTrader: (1)

if i open the wg apart would that tell me something? i am just worried that i see nothing being damaged in there and my boost is still leaking from there?

if the wg leaks then i should see damage inside the wg??????


what else can i check? i'm loosing boost and fuel pressure!

wantboost

iTrader: (2)

Drop in boost = drop in pressure above base pressure....

Muckman

iTrader: (2)

Forget my brake booster questions. I was assuming you had T'd off that hose.
Can I just see a picture of the vac line on the FPR?

You've tested the FPR by manually pressurizing it and FP holds fine.
The only difference on the street is either the boost reference isnt making it to the FPR OR you are consuming fuel faster than it can be pumped, which is unlikely.

I don't think you need to be street testing with any boost. Use a smaller wg spring or pull it out entirely. You said it behaves the same at 0psi so lets prove it.

IntegraTypeR

iTrader: (1)

agreed

IntegraTypeR

iTrader: (1)

i will open the wg apart and see whats happening inside

IntegraTypeR

iTrader: (1)

update:
guys i didnt open the WG and decided to fix the leaks i had on my car first. Now i can verify that my turbo, intercooler pipes, intercooler, throttle body, intake manifold are not leaking anymore. when the engine is shut off and if i pressurize 25psi of air from an air compressor at the turbo inlet my boost gauge read 24-25psi and now i have no leaks. I checked the system by spraying water/soap on the pipes during the boost test. I took the car for a ride and made sure my VE table is extremely rich to prevent a lean AF mix. Boost kicks in early now and my boost is stable now! thats good news, BUT my fuel pressure still drops. here are the thing i can verify are in perfect condition:

1- Turbo
2- intercooler pipes
3- intercooler
4- intake manifold (tested it outside the engine and checked injectors for leaks too)
5- throttle body
6- bov
7- WG

now in conclusion my turbo system is in a healthy condition and i dont need to check my WG spring or valve seat since boost is stable and stays at the wg spring rate!

Questions:
why is my fuel pressure dropping when boost start to kicks in? could the ecu be the issue? if yes how would it correlate to the issue?

other conclusions:
1- AF mix goes lean when fuel pressure drops. if its a closed injector i should expect an increase in fuel pressure and a lean mix (not in my case) and if the injectors are fully open then i should expect a drop in the fuel pressure and AF mix will be extremely rich. now its neither of the above, so my Injectors are good.
2- fp vac source is a clean NON Tee'd line which is directly from the intake manifold. my boost gauge is a direct line from the intake too! its simple if my boost gauge is see-ing 12psi then my fuel pressure should be base + that 12psi! but no i notice a drop as soon as boost starts to kick in and drop is extreme once full boost occurs. for everyone's information fuel pressure drops down to 30psi and prolly more if i keep my foot full on the throttle
3- using a single walbro 255HP intank pump that i replaced twice using a brand new kit and new sock. checked the voltage during the fuel pressure drop period at the pump and voltage is stable at 13.7v
4- fuel lines and fuel filter checked again and no kinks, bends or signs of being clogged


what could it be? i'm going mad

m4xwellmurd3r

im no expert on the matter but I googled up other makes and models having the same issue (it happens a lot it seems) so the one thing I can suggest is to try another fpr and see if you continue to have the issue.


Posted from Honda-tech.com App for Android

IntegraTypeR

iTrader: (1)

i did try replacing my weldon fpr to my old good working aeromotive a few months back and fuel pressure still drops BUT that was when i had boost leaks. i will try it again today to see the results with the boost leak issue eliminated and see how it goes

IntegraTypeR

iTrader: (1)

ok i just turned the pump on from hondata using the test output option while the engine is off and pumped 30psi of air into my turbo inlet. my intercooler pipes are leak free and my boost gauge shows 29-30psi of boost and my fuel pressure is 71-72psi. my base is 43.5psi and since boost is 30psi so on paper the fuel pressure should be 73.5psi. so in my case this shows that my fuel system is fine, but once i take the car for a drive fuel pressure drops. FYI the test was done for 15mins so thats a long period i know and the fuel pressure stays where it should be all that time during the test while engine is shut off. when engine running my base fp is 43.5psi and i'm boosting of the wg spring which is 12psi right now and see 30psi of fuel pressure when full boost kicks in where it should have been 43.5+12= 55.5psi

guys i need help and suggestions on what to check or do?

questions:
1- could it be a bad ecu?
2- could it be a blown intank fuel pump hose?
3- bad alternator that cant provide enough current? FYI voltage is 13.27v at the pump when full boost kicks in (checked using a multimeter when driving)!

help help help

Turbo-LS

iTrader: (4)

Hmmm. Stock tank with stock vent? Maybe vent is clogged?

IntegraTypeR

iTrader: (1)

stock tank and the stock vent still goes to the stock blue/white check valve which is right above the tank right to the front in the engine compartment where i installed a normal air filter to keep dirt away

can i try removing the check valve completely? is that a bad idea? if the vent is clogged then why the issue is not there when engine is shut off (during boost/pump test) and shows up when the car is running?

IntegraTypeR

iTrader: (1)

running a single walbro intank 255HP pump.i'm see-ing 43.5psi of fuel pressure at the fpr during idle and 80-90psi of fuel pressure right before the fuel rail/fuel filter at idle. is that normal?
i installed a mechanical gauge before the fuel rail/fuel filter there as requested by a member on here to see what fuel pressure i'm getting before the fuel rail/fuel filter.

m4xwellmurd3r

whoa that Is not normal. thats showing a massive restriction. I dont think you should ever be seeing double the pressure before the filter, maybe a little, but not that much!

that would explain why you see a drop under load. supply> demand. without running or at idle demand is very low, so ypu wont see a drop even with nasty restrictions till you ramp up the demand.



Posted from Honda-tech.com App for Android