SR20DET Fuel Delivery Issue? Need HELP

[rps13sh]

OKAY, i have a S13 SR Blacktop that's having some issues which i cant seem to figure out right now.

My setup:S13 SR with S15 turbo, stock SR injectors (purple) R32 Skyline Fuel Pump, stock intake manifold, stock fuel rails, stock fpr, Z32 fuel filter, AEM EMS tuned to 300whp 300tq @14psiAEM Methanol Injection Kitall the bolt ons, dp, testpipe, 3" catback, etc.

Now the problem is, the cars been running perfectly fine for a while now but very recently my car would start up fine but sound like a subaru and i have very little power. Turbo spools, bov goes off, i get BOOST but engine feels like its running on 3 or less cylinders so i checked the coil packs, i tried replacing the injectors, changed the injector rings, what else... changed the spark plugs. Still the same, BUTTT when i drive it around and get on the highway for a bit then its perfectly fine. runs fine, boosts fine. and i can get back on local streets and the car seems fine. Obviously somethings going bad but i dont know how to pin point it so i thought maybe i can get some feedback from you guys that will help me in my process.

I have a NISMO FPR so i ordered a FPR gauge today so i can check my fuel pressure. Also ordered some 555cc injectors because my tuner said i needed bigger injectors to get more power, but i was fine with my 300whp so i didnt bother to change them earlier on. any ideas on what i can do on the meantime please feel free to post your 2cents.

THANKS IN ADVANCE GUYS.

[Justin35ll]

Well yes you need bigger injectors to make more power, adding the injectors won't make power you'll also have to turn up the boost.Adding bigger injectors is to compensate for more boost being added to the cylinders.

As for your problem it seems like it's an intermittent problem as u said u drove it on the highway then got back to town and it felt fine. Well the only thing I can tell you to do is when is IS missfiring again, don't go out and drive it. Open the hood and pull the injector connectors off 1 by 1 until the one you pull off DOESN'T change the idle.

Then you will have pinpointed the cylidner missfire and will be able to go from there. Either find the fuel or spark issue

[rps13sh]

yea i tried all that before but it didnt help.

i unplugged each injector and noticed only #1 was giving no response when unplugged. i tried changing the injector with a spare, still got no response. i then checked the plug, it sparked fine. so i tried another injector, same thing, no response or not much that i can tell. i then took out ALL the injectors and replaced all the rings. placed them back in and still same problem.

so yea it does run fine after driving on the highway for a little bit. but always on start and if i only do local drives it runs like s***. could something be clogged? i dont know. i wont get my fpr gauge till after the holidays, but when i get that, ill install my nismo fpr ive had laying around for a while, change out all my fuel lines, fuel filter was recently replaced with a brand new z32 so wont be changing that. 555cc injectors will go in and then ill have to get it re-tuned.

[otterman]

Check your knock sensor. If your knock sensor is going bad the car could be retarding the timing, which is why it seems like a slug sometimes.

My roommate and I had the exact same problem you're having with our cars when the knock sensor started to go bad.

Try putting a 1mega ohms resistor into the clip that connects the wiring harness to the knock sensor. Now they car will think your knock sensor is good. Those resistors are cheap as hell too, like pennies.

If that works then you just saved yourself a bunch of time and money trying to figure out the problem.

[rps13sh]

hmm... if it was my knock sensor, wouldnt my EMS retard my timing and make my car run more rich? cause when i have this problem i notice that my car runs more lean. even at idle, from a regular 14.3 it goes up to 16. and it stays on the leaner side when driving unless i floor the pedal than it goes down to 11's.

[rc1honda]

Sounds like your maxing out your injectors. 300hp on 370cc injector is pushing beyond 100% duty cycle.

If your always pushing your injectors they are going to crap out on you quick. Also get a real FPR. Nismo ones are crap. Get a aeromotive one and call it a day.

The AEM should have a diagnostic screen for you to look at and check for any faulty sensors. Check it out and do what you need to do to fix it.

Also leave the 550cc injectors at the store. Get the 740cc injectors and tune it to 300hp if thats all you want. That way you injectors will never be maxed out and will cause a nice rich state in full boost.

I really don't see how your motor has not fried the rings yet. And your tuner should of never of tuned so close to the edge of injector failure. You need a lot of fuel for 2.0L motor to safely produce 300hp.
Modified by rc1honda at 12:25 PM 12/31/2009

[otterman]

hmm... if it was my knock sensor, wouldnt my EMS retard my timing and make my car run more rich? cause when i have this problem i notice that my car runs more lean. even at idle, from a regular 14.3 it goes up to 16. and it stays on the leaner side when driving unless i floor the pedal than it goes down to 11's.

Yeah, you might be maxing out your injectors. If I was you, I'd try the resistor in the knock sensor. There's been so many times when I've spent money trying to fix a problem when it was something super simple.

[rps13sh]

i guess the methanol really helped cause it ran fine for a while. i have a good feeling its my injectors too. i really didnt think id need more than 555cc cause i wasnt planning on going over 300whp. im getting reconditioned subaru injectors which are super cheap compared to aftermarket. flow tested, with new rings and all. ill check the knock sensor by unplugging it and i guess ill have to replace the injectors to find out what the deal is. thanks for your input guys, ill keep you guys posted.

[rps13sh]

ok here's an update. right now we pinned down the problem as a leak in the intake manifold. which could be cause by me not changing the gaskets the last time i took it apart because i couldnt find anyone who had them instock so i just put some gasket maker and called it a day. that's in the work but i do need bigger injectors so now the question is, do i stick with sidefeed or go top feed?

what are the benefits of going topfeed? and what are the benefits of going sidefeed with an aftermarket rail like JWT or circuit sport? it looks to me like top feed injectors a little cheaper than sidefeeds. i dont know. can i get some feedback on that please?

[240life]

Im using deatwerks (excuse the spelling) 740cc side feed injectors, and a NISMO fpr. I run 21psi all day and my afrs have been great all year. I think for your power goals you would be fine with a similar fuel set up. Do some research on companies and pick the one that best suites you. Some people don't like the injectors I got but like I said no issues with them all season running alot closer to 400whp then 300.

[sudo]

cause when i have this problem i notice that my car runs more lean. even at idle, from a regular 14.3 it goes up to 16. and it stays on the leaner side when driving unless i floor the pedal than it goes down to 11's.

Sry for thread jack...but I am having this same problem on my s14 sr20det. It all started when I installed my nismo fpr w/ gauge...when i increase fuel pressure the gauge would jump back on forth really fast...and the fuel lines would pulse??? the only steady pressure it can maintain is between 20-25psi before it starts to ping back and forth again......has ne1 ever had this issue??

Same symptoms as the op...under normal driving, car runs lean at 16-17afr with light throttle until i floor it then it then it goes down to 11's

help...Ive never experienced this w/ a fuel system?? nismo fpr and fuel lines pulsing?? everything was fine before i installed the nismo fpr...unless its just a defective fpr...but so far most everybody to talked to said nismo's fpr are good...

sry for the thread jack again, but i figure someone on nico couldl prolly help me out.....sum1 shed some light plz!!!
Modified by sudo at 12:33 PM 1/28/2010

[otterman]

what are the benefits of going topfeed? and what are the benefits of going sidefeed with an aftermarket rail like JWT or circuit sport? it looks to me like top feed injectors a little cheaper than sidefeeds. i dont know. can i get some feedback on that please?

It's easier to find big injectors if you're running top feed (1000cc+ injectors). They're also easier to put into the rail.

If you're wondering what's cheaper... by the time you get your top feed set up done you'll have spent more money then just buying side feed injectors.

The SR rail can handle just about any size side feed injector you put in it. I'm not even sure if there is SR sidefeed injectors big enough to max out the rail.

[rps13sh]

so what's the difference between topfeed and sidefeed injectors? im guessing topfeed is better somehow cause everyone "upgrades" to top feed. but why?

[otterman]

so what's the difference between topfeed and sidefeed injectors? im guessing topfeed is better somehow cause everyone "upgrades" to top feed. but why?

This

It's easier to find big injectors if you're running top feed (1000cc+ injectors).

[OM3GA]

Word

Get 740cc Tomei, Nismo or HKS sidefeeds, put them in the stock rail and call it a day. I thought about upgrading to the other rail but there really is no need. The stock rail flows incredibly good, although the saturation is supposed to be a little better in the CS style rail i still wouldnt go with that one over the OEM.