Hey guys,

Just bought a 98 kouki with a manual swap. Car didnt start without being pushed and dropping the clutch but Ive fixed that. I installed a turbo and Im having an issue with idle while cold but also/or if I rev the car up and let the rpms drop it will die, also if at a cruising speed at 3ish grand holding steady the car will seem to lose power and slowly drop to 1000 rpms if i dont give it more gas or let off...like it bogs out or something. I have timing at 20 degrees...

The car will rev fine and holds 20lbs vac at idle, seems to boost to 10lbs ok but feels a bit sluggish... I boost tested my lines and found a few leaks which I fix, ive also replaced the coolant temp sensor (ecu), cleaned out the air idle control valve, and the O2 sensor but havent had any luck. My turbo kit is below....

gapped plugs at .030
t3/t4
walbro fuel pump
z32 mafs with a 90 bend going into turbo inlet
38mm external gate
BOV not hooked up (to make sure its not leaking)
880CC Delphi injectors w resistors (need to redo these)
jyg fuel rail w external FPR at 39 psi
FMIC
R.S Enthalpy Rom Tune with jumper harness to S14

My next thought is knock sensor?

Any help would be wonderful.

Zak

if it picks up a LOT of power at 5k ish try the knock sensor and or wiring

Ok, Ill swap one out that I have already from another engine. Couldnt hurt to rule it out...

Z

I was going to say O2, but if you swapped that dude out already...

Does it buck at all or just seem to lose power?

Hey WD,

The car will buck a little bit when you start to accelerate slowly (like from a stop) but once above a couple grand it will accelerate fine (seems like it surges). Then if you are in, say third gear, and at a steady 3 thousand rpms the car will slowly drop rpm like you either flooded the engine or fuel cut (engine bogs). But, if i give it the slightest amount of gas it will accelerate ok but the power doesnt seem 100 percent at 100% throttle. If I let off the throttle to like 90 to 95% it feels like it pulls better than full throttle.

Power-wise, Im comparing it to a high horsepower ls6 which may be skewing my perception of power.


Zak

You don't happen to have a wideband do you? Ever adjust the tps? It may be out of wack.

Na, no wideband...I actually swapped out the tb w another that i had and i get the same result. Maybe they are both bad...haha

Man, this is a friggin odd problem. I've had some trouble when the ecu was in closed loop while cruising at around 2800 - 3200 and it would shudder and buck a bit, until I gave even a little throttle input, then it would smooth right out until I was just cruising again. This repeated until I bought a cheapy one wire O2 from Napa. Never had a problem again.

I know you said you checked for vacuum leaks and whatnot, I had a buddy that had a coupler with a cut in it. We troubleshot that whore for a week because we couldn't see the cut until you pushed on the intercooler pipe. The boost gauge even showed decent vacuum at idle.

Just shooting in the dark...

Also, unless you're running 20psi or so, the LS6 comparison is a bit unfair...lol.

Ill do the leak test again and see if i can pull/ push the couplers to possibly create a leak. I havent looked at the ecu for codes yet, do you think it would be an issue that would throw a code? I was thinking about contacting RS Enthalpy and asking to see if they would do a check on the ecu for free or a small fee.




Here is the other ride, procharged...if you wanna buy it WD....



Z

A procharged, LS swapped FD...Why are you even bothering with a S14? I have been in love with the FD since it's inception. I was a pubic hair away from trading my Skyline for one when I was over on Oki back in the day. It was a bright silver Efini...I cry a little when I think about it.

The FD is a timeless classic.

I have to ask...how much?

WDRacing wrote:A procharged, LS swapped FD...Why are you even bothering with a S14? I have been in love with the FD since it's inception.

The FD is a timeless classic.

I have to ask...how much?

wow I dont think you will ever be happy with the kat's power in comparison.

Pull the codes your self. Its worth a shot. My knock map/sensor is removed/disabled and my ecu keeps getting the code. Enthalpy is pretty good... but electronics can be lame from time to time.

drive around a little before doing the boost test to warm everything up.

what kinda bov?

oh and get a wideband. I see some money, 300 bux wont hurt you that bad and it can save you more.

neverlift wrote: Pull the codes your self.

oh and get a wideband.

This

Ive owned a KAT before which was my first real turbo car but didnt have these issues. It was back when Structure and Fiznat were on the boards which was yeeeears ago....

Ill do the code thing as well once I get some time.

WD, I know you wanna buy it! Im selling it for 30 grand. I dynoed at 560 rwhp @ 10 lbs of boost.

It's been a long time since Tony and Fiz have been on the boards...ahh the good ole days.

I just acquired a camper and conversion van, so any vehicle $$ I may have had is gone. Good luck selling her though.

Ive noticed on the forum searches no one really updates as to what an issue was so Im going to make sure I see this problem through, if I solve it....

New info, I checked the codes right when i got home and got 55 which is all good. I cleared the code then went for a drive and then rechecked and ended up pulling code 34...knock sensor. could this be causing my issue?

I also have noticed that this bog issue will occur when i try to hold the rpm, any rpm that is. So rev to 3 grand and hold...slowly and steadily it will bog down, I tried holding it at 6 grand and the same thing....

What do ya think? That makes me feel like its a tps issue but maybe it goes hand in hand w the knock sensor...i dunno.


Z

The knock sensor isn't registered after 5k. However, if the ecu thinks the sensor is bad it may f the timing tables entirely. Not really sure there. I do know that when the ecu registers knock it pulls out tons of timing.

Not holding any rpm is just crazy, even if the tps was wrong it would still run. It would just not run optimal. I've had my tps settings royally f'd and still drove the car without any of your insanity. I dunno man. Email Enthalpy and see if he has any idea's. Could be the daughterboard inside came loose or something, you could check that yourself as well.

After that, time to break out the multimeter I'm thinking.

your knock sensor may be bad but thats not the issue, the knock map stops making changes even if the sensor or reading is fubar at 5000~5400 rpm.

run it one more time and pull the plugs, my car would foul out when I had a bad daughterboard connection. I got a brand new board from moates that was doa, they swore it was still good, but it fried as in visible smoke, the chips. Same ecu and header new board bam start first try.

Was the motors ignition timing set per fsm? I had ~somewhat~ similar issues when I had a tooth retarded on the dizzy. car ran like pecker and would die off at pretty much any rpm unless I feathered.


Good luck man keep at it.

Hey,

Ill swap out the knock sensor and do a check. I did set the timing per FSM and Im pretty sure its right, my timing light is showing about 19-20 degrees but its jumps a little back and forth...if it was retarded would I still be able to hit the 20 degree timing like I am?

Ill have to work on it this weekend when I have enough time to trouble shoot different things.

Ill also try to email RS Enthalpy and see what they have to say.

Zak

well yeah if the car didnt actually go into timing/idle set mode you will get a faux reading. I just put 8* at the dizzy back into my motor. Explains the excessive glowing turbo/mani. I knew ,well I thought I knew it was spot on. Nissan eccs can be emo sometimes.

If its in set mode it should not really be jumping around unless rpms are swaying pretty bad.

So I have another update.

I was working w the car today and took it for a drive after I retested for boost leaks. I have noticed that once the car warms up a bit the rev to a rpm and hold works and is constant. It wont rev, hold for a sec, and then slowly drop like it does when the car is cold. Also, when the car is nice and warm I will shut off the car then try to restart it...wont restart. It take about 10-15 min before it cools off before it will start again.

I havent gotten a respons from RS Enthalpy either, maybe on vacation?

Zak

cts related it sounds like, possibly an issue with the tune if the scales were overlooked or forgotten.

maybe an issue with the resistor pack/injector setup? for some reason I don see that being a shelf tune, so he just might need to make a few changes.

Whats CTS exactly? I can say that the resistors on the injectors are done pretty crappy...i wanted to redo them but havent bought a box to wire them up.

CTS = Coolant Temp Sensor

Ok, i was guessing but wasnt sure... I did replace that but I should check to see if the wire is cut or something down the line going to the ecu.

What would possibly cause the non start after the car is nice and warmed up? any idea there?

Z

the cts is normally the reason a warmed up ka wont start

Alrighty,

Ill check voltages tomorrow...and report back.

Z

well that didnt work as well as I had hoped. I followed the thread that tells how to check the CTS and was only able to verify that i get 5 volts when the ignition is on...

Im not really sure what this means or how to use my volt meter to check this, can anyone dumb it down for me?

"Use a Multimeter to measure across the sensor (with the connector removed)."

I did change my knock sensor to rule that out, the original one looked pretty bad so Im glad I got that squared away.

Still havent heard from Enthalpy either. Ill try to email or call tom I guess.

Z

you need to measure the resistance across the terminals of the sensor(its the horse shoe looking thing on the meter that does ohms) I cant recall the numbers you want off the top of my head but its in the fsm.

Nissan knock sensors are by design crap, IMHO. Yes they work but they are poor in quality, I cannot say I have pulled one off that looked good(cracks)

Measuring across the terminals means put one lead (black) on one of the sensor tabs, then the other lead (red) on the other little senor tab?

I have the Ohm readings that they should be from the CTS thread that Im going to use.

Ill check tonight.

Z

yep thats it