View Full Version : Engine cuts in and out only on the freenway. Not the common 3k hesitatio.

02-14-2008, 07:18 PM
SR20 red top
apexi neo
walboro pump
manual boost guage @12psi
and an AEM truBoost which isn't hooked up. Just powers on.

Okay so I'm driving at night: headlights on heater on. Get on the freeway. I'm in 5th @ around 2500 for about 15 minutes, so my foot is barely on the pedal. The car just dies (like gas pedal is unresponsive), then 2-5 seconds later gets right back up. I go into 4th (cause by this time my speed has dropped), give it more gas, cutting still happens in and out. It does not happen at lower speeds at all, never had a problem in 3rd or lower, throughout rev range.

What's weird is the truboost. which normally reads -20 to -18 (remember it is not hooked up) will start reading 1.20-3.34 ish. There is no fuel smell. It doesn't backfire when it starts back up again, which makes me feel like it's a fuel problem. Also, I have a a/f ratio gauge and it will just dimly flicker red (rich [*EDIT it's actually lean not rich my bad guys]). That's fishy cause when it goes out of the gauge's range it'll just turn off. When it starts back up again, the a/f ratio goes crazy. It'll sweep through from rich to lean back to rich then back to lean like 4 times before it starts running okay or cuts again. I just check the ECU and got code error 55, which is no malfunction.

I know that this is similar to a common problem, however the symptoms don't match. Anyways my question is should i garage this? It doesn't seem like the other problems that i search around for, IT’S NOT THE HESITATION AT 3000RPM, which only occurs when accelerating, this happens when my speed is constant.

probable problems
-fuel pump problem <although it has a walboro this was my first guess
-Some sort of electrical problem. (this is my suspicion due to the TruBoost changing, I did accidentally short when i was jumping someone else's car. I have no idea what i should be looking for if it is a electrical problem)
less likely problems
-dirt in CAS (above 30% hesitation)
-dead coilpack - (this tended to show up at only above 30% throttle, not while cruising)
-spark plugs (will tend to run rich, so I don’t think this is it and checked already)
-vaccum lines (checked)
-oil starvation

See i searched.. but zilvia is organized so badly, these are the threads with the most relevance.

^the first response scares the shit out of me. (oil starvation)

What are your opinions? Will i do more damage by continuing to drive it?

02-14-2008, 07:32 PM
You have a walbro, but do you have a FPR? My buddy had the same problem only gave it a little gas then bogged like you hit a brick wall. He put in a walbro but no FPR, installed the adjustable FPR and all was good.

02-17-2008, 01:51 AM
yeah check on the fpr/get one

02-17-2008, 02:02 AM
you should ditch the 'rich/lean' gauge and get a wideband kit :wackit:

02-17-2008, 02:32 AM
This is kinda off, but im having the 3k issue on a ka24de. Ive checked all the basic wiring, vac, maf, plugs, wires. searching really hasnt been much help since this seems to mostly happen to SRs. Any other ideas besides over pressure in the fuel? I have a new stock fuel pump.

02-17-2008, 07:07 PM
o hullo nic. how is project mermaid?

yeah i should, right now it's just a light show :tweak:.

so yup i don't have a adjustable FPR, i'm getting one from a buddy who's parting out his old SR setup. Will not having an adj FPR create a lean or rich condition? Cause uh funny story red actually means lean on the a/f gauge :-/ oops. It's a new car.

02-17-2008, 07:17 PM
ya i have a fpr and that happened to me b4. my car all the sudden had no throttle response so i pulled over and it shut off. i poped the hood and my fpr gauge broke and it was leaking all over the fucking place.

make sure ur not leaking gas from engine bay


02-17-2008, 09:57 PM
hahah let's see did my swap in 02. it's been down for various reasons probably close to two years of that time. daily driven like a 16year old moron the rest. never once had an FPR on it.

number of times fuel was the problem?


02-21-2008, 10:28 PM
Alright well i tried to install the adjustable fpr i got from my friend. Didn't really work, let me show you why.

yes what a stellar piece. $10 from a good friend

Except this!! weak-sauce. The adjustable one could not seal. I had it real tight, but I guess that little O-ring wasn't sufficient to seal the fuel compared to the stock fpr's male extension. So I still haven't installed it. Now I'm going to my processes lab and I guess i'm going to lathe out a replacement for that piece that connects to the fuel rail.

Btw i know it's for an sr, i got it off my friend's sr. i don't know how he got it to work on his..

I'm sorry it took so long to get an adj fpr. I'll update when it's installed and if the problem persists. Btw, just driving around town for the past week the problem has not occurred (but no freeway driving yet)

*edit ya fuc me i didn't know that s13 has a different fuel rail than the s14 and the fpr end is different on both. So I definitely have to machine something.

02-23-2008, 11:39 PM
got a CAD file done, now i might just load this into the school's CNC machine if my professor lets me we'll see. Otherwise I'll just make it by hand.

Also, if you need this file let me know it's in NX5 (worst program ever) It'll adapt an S13 fuel rail to 5/16" fuel line.

*EDIT 3/27

so there's no point in updating this, nobody should care. Minus the fact that steeles was right, it was not a fuel problem. I machined the part out, and then tried to fit it, didn't fit, went to lathe it down a bit more, ended up destroying the piece, so I could either re make it or order the nismo piece.

However, luckily my friend noticed my Apexi Neo was reading a 0% correction factor when at low throttle. Therefore, that highway crusing meant that I was running at low throttle (untuned), pumping more air than the ECU thought was going in. Thus running a lean setting. (hence the a/f gauge going to lean)

I'm unfamiliar with what the ECU does when it senses a lean setting. Does it shut everything off? Or is that the Neo shutting everything off? From what I've heard is the low thro map extends up to 80% is some cases, it depends on how it's tuned. inbetween like 30-80% is a mix of high tho, and low tho, therefore it wouldn't turn back on until it decides to idle or hit the high throttle map.