Lean sr20det and stalling

[Russo]

Hey guys I'm trying to finish up my first sr20 swap in my s14. It's a s13 blacktop sr. The car runs great when it's cold but when it warms up it starts running very lean 18:1+ it idles fine until you give it gas. Even a short blip of the throttle will make it fall on it's face.

It then proceeds to shake violently until it finally dies. I'm honestly stumped with this one I've cleaned the iacv, replaced the maf and honestly don't know where to go from here.

I suppose it could be a bad fpr or something fuel related which would make sense as why I'm running lean. I also put in a walboro 255 and a 300zx tt fuel filter

Any insight from you guys would be great. I really appreciate it

Forgot to mention is seems to run better with the cts unplugged but I literally just replaced the cts with a new one
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[Russo]

bump, nobody?

[nismoman]

do you have a fuel pressure guage? and are you sure the fuel lines didnt get reversed when you hooked them up to the rail? how much voltage do you have at the pump?

[Russo]

do you have a fuel pressure guage? and are you sure the fuel lines didnt get reversed when you hooked them up to the rail? how much voltage do you have at the pump?

I don't have a fuel pressure gauge the fuel lines are hooked up correctly and I havent checked the voltage at the pump. Also in limp mode with mafs unplugged it runs nice and rich. if fuel pressure were an issue wouldn't this not be the case?

[Silvia716]

It could be your o2 sensor or coil packs/spark plugs I just finished my swap and it was doing the same thing I changed my plugs and lines and she's running good now still running lean tho but I'm wating on fed x on my o2 sensor but that stopped her from cutting out

[Russo]

it has new plugs but i'll check them maybe all the running weird messed up the plugs. The killer is this car has to be runnin in 11 days so it can get outa this house

[Silvia716]

I would check the gap it should be .036

[Polked4G63t]

sounds like a vacuum/boost leak to me, anyone else?

Swing by the local hardware store with $15'ish. Coupler, pvc cap, and screw-type valve stem...oh yea, windex.

[Big Zee]

boost leak would't kill it right away, but it would cause the face falling.

check all your couplers like Polked4G63t suggested and your plugs, and try a different maf with someone that has a running sr and see if that helps, if it does your runnning the wrong maf, ( seen silvias with sr's not run on the sr maf and had to switch to a ka-e one to make the dammed thing run ) if that be the case get the number ont he top of the maf and try to find a maf with that code and hook it up.

is your bov vented or recric'd ? when you try to rev will it rev then stumble or fight for any kind of rev ?

last up is double check all your wiring. if it was a professional harness great, if you did it, make sure its all been soldered and shrink wrapped, all the right wires are going to the right place

[Russo]

i've checked all my couplers and they all seem tight, probably make a boost leak tester today or tomorrow

i ran the sr maf and then swapped it to a ka sohc maf same story

harness is wiring specialties

the bov is atmospheric

it revs up great, no stumbling. on it's way down it falls on it's face.

even if I don't rev it until the bov opens it still struggles

[murffy]

yup yup check all ur cuplings bro and try get a fpr it helps check if ur getting enough fuel to ur injectors
the spark plugs are very important also my sr had same problem and when i check the plugs they were for a sentra and they were the wrong heat the bk7e frm ngk do the job legit either the (ix) iridium or the copper ones which are like 2bux each at autozone or napa
gl bro

[Russo]

i regapped the plugs to .036 and it runs a little better, still running lean though I'm sure I have some vac leaks, got 14 inches of snow comming tomorrow so probably no progress to come soon. If any of you guys wanna check out the whole build I have a thread on preludepower

Other_ Russolude's not a Prelude don't kill me build thread. 56k=fail - Preludepower.com (http://www.preludepower.com/forums/showthread.php?t=334389)

let me know what you guys think.

also still looking for a reason i'm still stupid lean at idle

[Russo]

alright the engine still shakes violently and searches for idle but only when the car is warm

[HYPNOTIK]

Check all your fuses.

[coup-emonster]

Check all your fuses.

Doubt its fuses haha but check everything..what stumps me is that your saying that when you disconnect the maf..it runs good..did you get a new maf? Or used maf? Maybe its faulty..is it a stock maf? And if your positive it works..then id check the harness to see is there is anything wrong there..and finally worst case id say your ecu is the culprit..sometimes if your maf is wired wrong..a false ground could fry your ecu..trust me happend to mee when I wired a z32 maf in my rookie days haha the ecu smoked up!! Haha and smelled like the little toy trains hahahah..but yeah good luck bro hope this helps.

[Russo]

Doubt its fuses haha but check everything..what stumps me is that your saying that when you disconnect the maf..it runs good..did you get a new maf? Or used maf? Maybe its faulty..is it a stock maf? And if your positive it works..then id check the harness to see is there is anything wrong there..and finally worst case id say your ecu is the culprit..sometimes if your maf is wired wrong..a false ground could fry your ecu..trust me happend to mee when I wired a z32 maf in my rookie days haha the ecu smoked up!! Haha and smelled like the little toy trains hahahah..but yeah good luck bro hope this helps.

the stock sr maf had the same effect the "new" (used) ka sohc maf the wiring harness is made by wiring specialties so thats good. Unless someone has a good sr20det maf on long island somewhere, idk lol

[sidedrifts13]

Adjust your Tps

[WhiteNgold]

stock/healthy sr has -20psi at idle.... if not then u have either a timing issue or boost/vac leak. check ALL grounds in harness especially the one from pass side fuse box. check the basics first. it dont hurt to check

[Russo]

it has ~20psi of vac at idle. all my grounds are good i'll recheck them today anyway i'll break out a can of carb cleaner and try again for some vac leak tests my tps is also set for .45v when thottles closed

[bakerzduhzen]

place the motor at tdc and check your cams and chain location.

[Russo]

place the motor at tdc and check your cams and chain location.


i've checked and double checked that already it's right on

[gmorcos37]

Sorry for bumping an old thread but I am having similar issues. Did you ever figure it out?

[240pimp]

mine was running like crap, and we found out it was a bad coilpack. Runs great now!

[CraftHell]

Anyone figure this out? im having the same issues and i read it points to not having a recirculating bov, or get a tune. motor thinks the air is there and placed the fuel and spark but when the time comes its not there and it falls on its face.. hence it will run great wide open and such but when you put the clutch in it idles down real low or even dies..
i have a new tomei fpr, idle vacuum is -20 at idle and new coil packs installed, walbro 255, tial atmospheric bov, and im having the same issues and cant figure it out..
i changed the fuel filter, plugs, coolant temp sensor, checked for leaks,.. only thing i havent looked into is the iacv and tps.. not sure.. any way to clean them without taking it apart?

[adey]

Bump for a user with a similar problem!

Links to the youtube video of the issue:
https://www.youtube.com/watch?v=vlDRKj5kZh4

AFs are all over the place, although it seems to lean to the lean side (har har). yet, sometimes it will go down to super rich! Maybe a pinched injector O-ring?
Checked all the vac hoses that I have (not many) and re-tightened all intake/IC/throttle piping...
checked MAF wiring, seems to be no issue. startup is strong and instant, the damn thing just won't idle!

Holding the throttle still and trying to keep constant RPMs doesn't work -- the rpms will hit whatever I'm aiming for, and then within a second the revs start to fall, even though my foot is stable on the gas.

Since the video I installed a Tomei FPR and set to about 3.3 bar, it made no difference.

Details:
1998 S13 blacktop sr20det
S15 T28 dual bb turbo
Z32 MAF
Stock Compression
Nismo 555cc injectors
Walbro 255lph fuel pump
HKS wastegate actuator
Tomei exhaust manifold
Tomei adjustable fpr (small)

[Kingtal0n]

Bump for a user with a similar problem!

Links to the youtube video of the issue:
https://www.youtube.com/watch?v=vlDRKj5kZh4

AFs are all over the place, although it seems to lean to the lean side (har har). yet, sometimes it will go down to super rich! Maybe a pinched injector O-ring?
Checked all the vac hoses that I have (not many) and re-tightened all intake/IC/throttle piping...
checked MAF wiring, seems to be no issue. startup is strong and instant, the damn thing just won't idle!

Holding the throttle still and trying to keep constant RPMs doesn't work -- the rpms will hit whatever I'm aiming for, and then within a second the revs start to fall, even though my foot is stable on the gas.

Since the video I installed a Tomei FPR and set to about 3.3 bar, it made no difference.

Details:
1998 S13 blacktop sr20det
S15 T28 dual bb turbo
Z32 MAF
Stock Compression
Nismo 555cc injectors
Walbro 255lph fuel pump
HKS wastegate actuator
Tomei exhaust manifold
Tomei adjustable fpr (small)

looks like it needs tuning. You never mentioned what ecu is in it.

If you are incapable of tuning whatever it is yourself, go back to the OEM injectors/maf/ecu first, and re-check your wideband's report.

The reason I suggest this is because the problem you see there could be any number of things, including but not limited to,
1. bad maf (probably not)
2. bad wideband (doubt it)
3. exhaust leak (unlikely)
4. air/boost leak (very unlikely, but check pre-turbo for a leak, for sure)
5. fuel pressure issue (due to regulator/pump, also unlikely)
6. injectors are not actually 550's
7. injector lag time is wrong in the computer
8. other stuff

Most of it is unlikely, however by swapping back to OEM parts and verifying the idle is back to "normal", you would eliminate most of it as potential sources, and you can focus on the real problem: the computer (or injector size)