SR20DET Help!

[z31andreww]

Hello all! I have been a lurker here for probably about 6 years now, i've owned an sr20det s13 hatch before, almost 4 years ago, so i went and got myself another 90 s13 hatch with an sr20det (s13 blacktop)! I am so happy to be back in an s-chassis. SSOOO, i got this car by trading my Audi A4 (p.o.s) for it, the kid had the s13 for about 4 months before i got it, He knew really nothing about the car other than what the previous owner had listed on the ad. He didn't know what chip it was running, if the bottom end of the motor was built, the exact brand of turbo on the motor, drove it daily for 4 months with a "fuel pump issue", he didn't know what he was doing it seems. So i've been driving the car for 2 days now, which i know isn't much but it should theoretically have the same setup my last s13 did with the exception of cams and a 6 puck clutch, so i have an idea of how the car should run, idle, boost, and drive. When i got it, he let me know the fuel pump (Walbro 255) may need to be replaced, because it can't always hold idle. I found this odd, the pump should either work or not at all. So now, i believe there is another fuel issue i am chasing.

When the car is cold, it runs decent. Idles at about 1400 rpm (which i don't like), but pulls good through the rpm range and cruises nicely. When the car is warm, it usually can not hold it's own idle, so i will have to keep my foot on gas lightly to keep it idling. Yesterday i was leaving work, let the car idle (when it was cold) for about 10 mins at the most, and it was able to hold idle the entire time. Right when i started driving away, it seemed almost like it's getting flooded? , through first and 2nd gear it kind of struggled to get going, almost like a misfire, until it gets up to about 3000 rpm then it starts driving good and normal. Once i stop and get going again, same thing. Spat and sputtered until (it seems like?) all cylinders were igniting. I know i don't have "bad" plugs based off how it runs at about 3000 rpm, Cold it be the fuel pump? could the pressure be too much or too little? Should i even think about replacing plugs or coils? can re-gapping the plugs do anything? Any help on this would be much appreciated! I just can't think of where to start.

Please help me NICO!!

[PapaSmurf2k3]

What is the mass airflow setup like? What you're describing almost sounds like a boost or vacuum leak.
If you have a blow off valve that vents to atmosphere, it could be open during idle, blowing off metered air.
Inspect your piping and couplers for all of that.

[PapaSmurf2k3]

Oh and welcome to NICO, you 6 year creeper stalker!

[z31andreww]

Thank you man! I have always loved following build and tech threads, finally got myself another Nissan!

I did notice one of the 4 wires going into the Cam position sensor looked chewed and gnarled, going to re-pin it tonight hopefully.

But here are mechanical specs i know so far:
Blacktop S13 Sr20
Tomei 256 poncams
2871 spec JB Turbo
Stock Ecu, with chip
z32 maf
660cc DENSO/Sard injectors
Type S Recirculationg BOV
Walbro 255
Greddy catch can
Mishimoto Rad
Adjustable FPR (unknown brand)
Turbosmart dual stage boost controller

Me and a buddy were looking at it last night, we were thinking the same, Boost or vacuum leak, we went over all hoses and couplers last night, found a small leak on the coupler directly after the maf in front of the turbo, closed that leak up then drove it, didn't seem to do too much unfortunately. When it does decide to idle and not stall out, It was idling about 1400 rpm. After i drive easy, no boost for like 10 15 mins, i was able to get it to idle at 800-900r rpm (which is where i want it to be), but that only lasts so long (maybe 2-3 minutes) before it will start hiccuping again.

I am doing my best (very best) not too boost for now until this is figured, it is hard (love boost) but i can manage lol

Thanks for the help PapaSmurf!

[PapaSmurf2k3]

Do you have access to a wideband O2 sensor? It would be good to see if you're running rich or lean.
Maybe you can try adjusting the fuel pressure up and down to see if it helps or hurts, just to point you in the right direction.
Have you checked ignition timing?

[z31andreww]

It does have an o2 sensor, looks really ragged honestly though, I don't have an OBD 1 scanner either. I honestly believe i am running rich, because it smells like pure gas, and i get smoke out the tail pipe when i start it after it bogs itself out.

The FPR on the car seems to be working, it does have gauge, i will check exact pressure it is showing. i have not messed with it yet, i wanted to be sure i could make it home last night lol. Do you think it could be getting too much fuel to cause this? I was thinking of checking wiring on the fuel pump, and maybe getting more direct power to it? Could be a bad coil pack?

I have not checked timing yet, i was going to do so either tonight or this weekend.

Just drove it out to pick up some food for lunch, did not boost, and it did not bog itself out at all. I could cruise to a light, throw it in neutral beforehand, and it was sitting idling between 1000-1400 rpm. It runs like this when cold, but it still was doing it on the way back after 15 mins of driving and temp was up. So no boost, idles decent. After boost, no idle.

[PapaSmurf2k3]

Yeah check fuel pressure. I wouldn't think your fuel pump is messed up if you're getting plenty of pressure.
It seems like the tune on the car is really unknown, so it's wise to stay out of boost until you can monitor the fuel while driving. You either need to beg/borrow/steal/buy a wideband O2 sensor, or bring it to a dyno shop.
Getting fuel closer during idle and normal cruising will be as simple as adjusting your fuel pressure (down, from what you're describing), but that might lean out your map under boost. So tread carefully.

[z31andreww]

Thanks for the advice man, I'm gunna drive easy til I figure this all out. Doing my best to get a wideband o2 sensor, am going to check fuel presure, and possibly have my local import shop do a smoke test, and try to see if they can see what tune it has. I'll definitely keep the thread updated!

[z31andreww]

So i have been tinkering with the fuel pressure, (treading lightly as you recommended PapaSmurf) and found that if i adjust the idle screw on the iac valve down about a full turn, and adjust the fuel pressure down from about 3.9 bar to about 3.7 bar, it seems to idle much nicer and doesn't jump around as much or bog down as much. It still does have an unsteady idle, but maybe jumps 2-400 rpm rather than the 6-800 it was doing before. Does it seem like I'm heading in the right direction? Should i maybe try just readjusting idle through idle mode? Before adjustments, vacuum would be around -19,20 while idling decent, when the idle jumps it would go down to about -10 vacuum until it caught up with itself again and went back to -19,20, now after adjustments it is still idling between -19,20 and the spikes bring vacuum to about -16,17 before heading back to -19,20 when it catches up with itself. I did find a bolt broken off my exhaust tail pipe, fixed that. fixed the hole i found in a pcv hose going to my catch can, capped off a small opening going to atmosphere on my blow off valve, and also sprayed some carb cleaner in the iac valve to try and clean it out. I am still trying to find a wideband o2 gauge i can afford so i can watch my afr. Is there anyway anyone can give me some insight on where fuel pressure should be according to the mods my engine has? I know the Walbro pump brings it to about 52 psi, and with my AFPR it looks like it was at about 3.9 bar (56 psi) before i adjusted and is currently sitting at about 3.7 bar (53 psi). I want to be sure i can still hold boost, only boosting at 10 lbs and want to keep it there for street driving. Please help me master tuners!

[PapaSmurf2k3]

Stock fuel pressure is around 40 psi.
And yeah, it sounds like you either have a vacuum leak somewhere, are blowing off metered air that you still can't see (while idling), have your fuel pressure set incorrectly, or have a bad IACV.

[z31andreww]

I have the pressure set now at about 46 psi, the Walbro 255 lph i read on the interwebs ran at 52 psi, is that not true? Or am i holding pressure back somehow with my AFPR? Should idle be more like 40 or more like 52? IAC valve has been cleaned out, seems to adjust well, i can notice idle changing on the slightest turn of the adjusting knob. It now idles at about 1100 rpm now, still jumps between 1300 rpm. Sometimes it does drop down to like 8-900 rpm, and at times has bogged itself out. Could this just be the cams looking for more fuel? Any idea on where idle should be at with this setup? I have looked and looked for vacuum leaks, none really found mrore than what i described before. Any problem spots or areas that sr20's like to leak? How can i check the Blow off valve to see if it's blowing off metered air? It does not always idle like crap, mostly after driving for more than half hour-ish or after boosting around a bit. I also noticed last night my dual electric fans are never coming on going to wire those to have constant power on both fans, keep it as cool as possible.

Thank you so much for helping me out here!

[PapaSmurf2k3]

The fuel pressure regulator sets the pressure, not the pump. Assuming the map is like stock, you should be more like 40 psi of fuel pressure at idle instead of 52. Again, in order to really know which way you need to go, you need a wideband O2 sensor. It sounds like you really should get one so you know whats going on both at idle, and while driving/boosting/when you're having a problem.
Idle should be around 800-900 rpm when warm.

[z31andreww]

I am going to get a wideband O2 sensor lol i can't stand driving this car like this! Thank you for all the help PapaSmurf!

[z31andreww]

So got my innovate wideband afr gauge! Super stoked, looks like a solid product for sure. So i got it as we all know to read my afr ratios and see if i can get the car running decent BEFORE taking it to a shop, which is still my goal. I found out today the electric fan motors on my dual electric radiator fans may be blown, as i was not able to get either one to turn at all when connected to direct power, may take it to a shop to get those checked out because i really am not the best at electrical..lol but heres where the afr gauge comes in. I bought the innovate lc1 controller and db gauge, intending to use 1 o2 sensor in the stock location. So first question, I read the sensor should be more than 24 inches away from the turbo, but my tomei downpipe has the bung maybe 4 inches away? Is it a horrible idea for me to use that bung? 2nd question, can i run 1 sensor and splice into my stock ecu for narrowband readings and be safe or should i just make a new sensor bung specific for the afr? Like i said, i really really hope to keep the sensor in the stock location, how would this be possible? Also, do you know which wire off the stock ecu would need to be spliced into to give narrowband signal? I have read around, can't find a solid answer. Please help, i dont want to start cutting and running my car with this new sensor and gauge until I'm sure!

[z31andreww]

Found out for my ecu (62) it is the white 19 wire.

[PapaSmurf2k3]

I'd leave everything as is and run the wideband stand alone.

[z31andreww]

So i have not gotten the Wide band installed yet, hoping to get it done either tonight or this weekend, and i can't wait for that to happen!

But, last night i was driving home from work, and my car started running like crap. As i came around a corner, i gassed out of it like anyone would do into a small amount of boost and right when it actually hit boost, it just sputtered and had no power at all. Just after, i tried to venture into boost slowly, and i was able to climb rpm's but if i got on the gas hard (big boost) it just sputtered again. I pulled over to do a quick inspection, and nothing seemed out of the ordinary, nothing was unplugged, i didn't see any loose couplers, no leaks or anything but i noticed a loud ticking noise. First thought it was an injector, sounds like the type of clicking an injector would make. Another thought, was maybe a valve hitting to valve cover? Or the timing chain? It still seems to drive okay in low rpm's, idle is rough however. Another thing i noticed after this went down, was that the fuel pump has not been priming the system prior to cranking, as it usually does (takes about 10 seconds before turning off and then i crank). Tonight i am going to check for boost leaks and vacuum leaks, and i am waiting on a vc gasket to come in before i pull the valve cover off this weekend to inspect. Also thinking about getting a new walbro fuel pump to replace mine. I am still chasing the idle problem, with it not staying at a consistent rpm, idling between 8-1400 rpm. Any other ideas on what this could be? Could i maybe be misfiring? What should i check? Is it okay to drive the car in the meantime out of boost completely? Does it sound like a fuel issue? Just looking to get some more expert insight, this car is my daily driver i need to figure this out quick!