Odd No Fuel Issue, help!

[90 DGRZ]

***UPDATE*** (read update post bottom of page if you have already read this first post)

s13 with sr.

Alright guys bare with me, this might be long to explain, but i'm desperate, so here goes.

Lately i've had odd issues where when i'm WOT, the car just completely stops responding, as if it runs out of gas. It just "cuts" fuel and i have to wait 2-3 seconds for it to come back through the lines. as i'm blipping the throttle frustrated with the problem, you can hear the throttle body sucking for air but no fuel. a couple weeks back, i changed out my fuel filter and the problem went away, in mid-drift/straight line WOT.

Today at the track, the dreadful problem came back from the first session. The problem ONLY now occurs in left/right drifts, straight line WOT is okay.

so i began to troubleshoot all throughout the day with NO success.
i had a full tank of gas to start the day.
-pulled the pump and took out the broken baffle in tank that may have possibly been causing shorts by touching the pump. -ran next session, Fail.
-pulled z32 pump and replaced with a friend's stock fuel pump to see if it was a pump issue. ran next session, Fail.
-Pulled driver side wire harness, patched a few "exposed" wires hoping maybe the fuel pump signal wire was the culprit, tucked higher away from tire, ran next session, Fail.
-Finally checked the smallest things like the fp wires, lines, ecu connection, nothing.

By this time, it was the end of the day. the ONLY thing i can think of now is that ... maybe the fuel filter has kidney stones already after this short amount of time? When i pulled the pump, it was apparent that the pickup was bare with no screen to filter.


I'm stumped, and i can't test it out anywhere but the track, so ANY input as to what it might be, i'll try to knock out to eliminate that problem.
thanks guys

[90 DGRZ]

...anybody??

[wow-thats-a-cool-car]

I had that same problem w/ my KA remember you drove it. It was the wires in the wheel well maybe recheck them? I have no ideas

[GSXRJJordan]

Not your fuel pump.

Most likely your MAF wires. I've seen similar problems a couple times - what MAF are you running? Do you have the clip that holds the connector to the MAF? Are any of those "exposed wires" MAF related?

When the ECU senses a problem with the MAF, it shuts down for a second, giving you the situation you're describing. Sad truth is, if there's a problem with fuel, the ECU usually doesn't know about it until it's too late - methinks your problem has nothing to do with fuel.

[wow-thats-a-cool-car]

o ya my friend kam grounded his maf and it made a huge difference

[626 FC3S]

haha sounds like you got my curse !!!

[90 DGRZ]

Not your fuel pump.

Most likely your MAF wires. I've seen similar problems a couple times - what MAF are you running? Do you have the clip that holds the connector to the MAF? Are any of those "exposed wires" MAF related?

When the ECU senses a problem with the MAF, it shuts down for a second, giving you the situation you're describing. Sad truth is, if there's a problem with fuel, the ECU usually doesn't know about it until it's too late - methinks your problem has nothing to do with fuel.

i'm just running the stock maf, and no i dont have the clip, it's held tightly with zipties tho, lol. it's not shaking loose or anything....
it only seems to happen while under load, mostly WOT mid-drift IIRC.


???

[GSXRJJordan]

Make sure the MAF wire you used is the OEM shielded grey stuff. The MAF signal is very sensitive 0v-5v, and most likely what's happening is the MAF is max'n out and jumps voltage, which causes the ECU to shut down.

This happened to me in 4th gear when I used to have a KA-E MAF (which worked fine on a redtop) - I'd max out the flow, reading jumps from max 5v -> 0v, and the engine dies for like 1.5secs. Then it comes back like everything's gravy.

Start by checking your ground to the MAF.

[90 DGRZ]

UPDATE
Alright guys, back from an unsuccessful track event today, and here's the update.

It happens almost anytime i'm in full boost. usually in mid drift, stand still burnouts, and immediately after kicking the clutch. Now......to test, when it would cut out, i would pull out of gear, floor it and leave it WOT, and whereever the rpm's drop to (usually 2-3k range) it just kind of stays there as if i'm 1/4 throttle or something. i can hold it there for however long i want, and will stay lingering around the 3k range....until....

...once i let off, and let the rpm's drop down to 1-1500k,(basically near idle) full fuel returns.

the whole day i was changing what it could have been, on TOP of everything already done mentioned in first post.

-changed FPR
-added ground to MAF
-re-grounded battery in a better location
-unplugged ECU and made sure no bum wires, etc.
-and plugged up a couple vacuum lines etc that most likely wasn't the problem, but i'm now desperate. it's VERY frustrating.

what's next? TPS? ECU?

please help.

[wickedjester]

if u can get ur hands on another ecu try swapping that out. to me it sounds like the ecu is cutting fuel


if it was a maf / tps problem it would effect straight line wot as well


also check the ecu mounting

[Blackparade]

chuck, check ecu mounting, make sure its secured/grounded correctly. If i were you i would recheck the wiring to your fuel pump. if you want to completely eliminate your wiring, then make your own wiring to the fuel pmp. completely seperate harness complete with switch fuses and relay. i think this is your problem.

[90 DGRZ]

if u can get ur hands on another ecu try swapping that out. to me it sounds like the ecu is cutting fuel


if it was a maf / tps problem it would effect straight line wot as well


also check the ecu mounting

i'm sorry this is so confusing. but it also cuts during stand still burnout, and straight line WOT. basically whenever it wants, sporadically. sometimes it doesn't do it, most other times it does. every time in the higher 6-7k rpm range.


chuck, check ecu mounting, make sure its secured/grounded correctly. If i were you i would recheck the wiring to your fuel pump. if you want to completely eliminate your wiring, then make your own wiring to the fuel pmp. completely seperate harness complete with switch fuses and relay. i think this is your problem.

i'm not sure if it's the wiring, because the fuel pump doesn't cut off, it's still on, hence me being able to keep the car on after cutting out, leaving it WOT but lingering around 3k for however long i keep my foot there.

also, i checked the ecu earlier today, but i'll recheck when i have more time.

[Om1kron]

sounds like a power issue, what kind of battery are you running?

[dkwasherexd]

maybe your injectors are stuckk? or maybe the egi fuse is bad?? or something is shorting out. Do you have any extra plugs hanging anywhere? maybe it melted and is shorting out. That happened to me and my fc stalled on the freeway. Or it could be your secondary injectors are not firing...

[Jdm.I.Am]

I had this same kinda problem with my 180sx with stock fuel pump an maf, changed the maf to z32, and changed fuel pump to walbro 255 and z32 fuel filter and problem went away. hope that helps.

[let5l1de]

hey chuck. i thought you would have had this all worked out by now. the problem just seems so inconsistent.

Well it sounds like you have worked with almost all the problematic fuel possibilities. So I would start to move away from the fuel system unless you have reason to believe something is not performing up to standard.

Next is the electrical system. First and foremost, you should have at least 13.5v and as much as 14.5v while rpm is above 2k. This will ensure adequate power supply for the complete system. Also check to make sure all ground is properly secure and in oem locations.

Faulty coil or coils may throw the computer into limp mode for a sec or 2 for recovery of signal. Try checking all wires here for good connection. Swap all the coils with another sr that runs right to eliminate the coils from the problem.

CAS failure at bearings and or sensor/pickup (not truck) will also cause misfires and erratic operation at higher speeds throwing the computer off. I have a CAS you can barrow.

Check your injector connector pins for any corrosion and clean as needed. Very gently, bend the metal pins to promote good contact withe the injector connectors/harness.

Spark plugs are cheap. Buy a new set of plugs and gap them to .030" for now. The smaller size gap will void the possibility of spark blow out at higher rpm due to higher boost #'s if not stock. You can always increase the gap after the problem has been solved.

Anyone else feel free to toss in your :2c:.


gl with your troubleshooting.:kiss:


Parts I have that you can barrow for testing.

SR (not KA"E") MAF
SR Throttle body
SR CAS
MultiMeter

if you cant get it solved before the next event, I'll try and help you out.

[S13cl9kid]

hope u fix ur problem bro