Ka24det Idle/Tuning

[R3b]

So I picked up my car this weekend and before I got it I new there was a weird idle going on and wasn't sure why. Everything else checked out fine when driving, just the idle was pretty rough and could smell very rich fuel in the air. Ive been looking mainly at sr20 engines and information to that since I was originally going to get a s13 with a blacktop swap but they guy was a cunt and asking way to much money. I found a fairly clean, newly painted, 1992 s13 with the original ka and a turbo.

So here is the dilemma, right now I got the car to idle perfect at 950-1000 rpms by cleaning out the spark plugs which were very very very black on the tips and hardly worn out and by increasing the safc lo setting across the board by 10%. The car didnt bog at all and the smell of rich fuel wasnt in the air but a more burnt lean smell was around. What I noticed was that my air/fuel ratio was around 13.7-13.5 which was so strange since thats pretty lean. If I tried to decrease the lo setting or set all the ne's to 0% in the safc my air/fuel ratio would increase but my car would idle more and more like shit. I tried messing with the deccair setting but that didn't do much.

Thats what I have done right now to the car and it sounds strong but whats concerning is the lean air/fuel ratio and if I try to make it even the slightest bit richer the car would bog and idle like shit.

Before I did all of that ^ I initalized the safc which basically the engine reads normal off the ecu. When I did this the rpm would jump down to low as 700 and go high as 1300. It would settle down after 5 minutes but you could smell very dark and rich fuel around the car. My air/fuel gauge would also jump around with the rpm as well and would go low as high 14s and even touch sometimes 20...

I think there is also something wrong with how the previous owner has the turbo setup since if I try to give the car some foot I could hear the turbo spool but I could never get anything past 0psi of boost, the gauge only shows the vacuum pressure and when I put foot the gauge stops at 0psi. IIRC the guy told me his wastegate is set to 6psi and hasn't touched his manual boost controller to add more boost to the car.

His set up goes air into turbo with no filter, air goes into hot pipe where the BOV sits, then the air goes through the FMIC, then exits to the cold pipe where the MAF is and then goes to the engine intake. Normally I would see in setups that the MAF would be before the filter and then to the turbo. Then the BOV was on the cold air pipe on the other side of the car.

Another strange thing about the previous owners setup was that he had 720cc injectors.... Ive seen similar ka-t builds and the highest ive seen for injectors was 550. Do you think that having such big injectors is dumping way to much fuel into the engine and is running way to rich and causing to idle like shit? I think that could be an issue and also might be a vacuum leak somewhere. I dont know exactly what he asked for when he shipped his ecu to be tuned but I could give a list of all the parts he put on. Any sticky threads on tuning I should read or turbo building on a ka would help tons. Ive only found a couple basically saying setups but no details the process of installing and tuning the car for the turbo.

rs-enthalpy tune
aem wideband
s14 intake manifold
3in downpipe
thich guage turbo manifold
720cc injectors
z32maf
new water pump
new radiator
emmisions deleted
battery relocated
no egr or cat
ac was lost due to downpipe rubbing on ac line
new break master cylinder
new alternator
new starter
2 new rear calipers, pads
raceland coiulovers
full isi adjustable arms
solid subframe bushings
j30 diff
Energy suspension rack
Safc
All electronics working and not rust.

[cotbu]

13.5afr is not a lean idle afr. Contact enthalpy, and have him verify the injectors and mafs, and tell him the setup is blowthrough. Tell him you've been messing with the safc as well, but tell him you want to remove it. Also tell him, you can't stop touching things with buttons and lights.

It sounds like you inherented a shitty project.

From a Highly Tuned Note 4.5!!!

[R3b]

13.5afr is not a lean idle afr. Contact enthalpy, and have him verify the injectors and mafs, and tell him the setup is blowthrough. Tell him you've been messing with the safc as well, but tell him you want to remove it. Also tell him, you can't stop touching things with buttons and lights.

It sounds like you inherented a shitty project.

From a Highly Tuned Note 4.5!!!

Yeah I was going to contact him in the morning, I want to get rid of the safc as soon as possible and either send in the ecu to get looked over for a proper tune or look to buy a standalone and go to my friends dad who tunes and has his own shop to get a proper tune done.

The reason why I said it was pretty lean since all the threads ive seen said that afr should be 14.7 and it being a perfect number. Only when you go high throt you lean out the mixture.

There is lots of work to be done but of all the 240s ive seen in my area his ka is the healthiest and drivability of the car was 10x smoother than others. Ive been looking for around 6 months. Suspension is good, newly painted with color similar to the oem cherry pearl, interior was clean and had one small dash crack. I see a lot more potential in this than cars without ps/ac, blown engine, messed up bushings, and trashed interior.

The only issue right now is understand wtf hes done with this turbo and then clean up the engine bay, clean up the undercarriage, put in rear seats, get some other wheels, and go for an alignment, then go for a proper tune.

Down the line i'll upgrade the turbo and put in better internals and do the cliche type x body kit.

[R3b]

Bump, basically took out the safc and let the car run longer at idle car doesnt bog anymore and I have good ratio between 14.7-15.0 afr.

So idle is fine but ive narrowed down some stuff pretaining to no boost and its for sure my bov. When the car is off I can see the bov is close and when I start it up and on idle it opens up.... Also did some further inspecting im pretty sure its one of those knockoff hks bovs the guy has installed....

Im having a friend whos been messing with nissan engines forever come check the car tomorrow and I think thats my main issue for lack of boost and I also think the turbo on the car is also ebay made.

Everything else for the engine runs fine but im guessing the previous owner didnt know wtf he was doing and got the shittest parts and used random shit from his friends which explains why he has 720cc injectors in and ebay knockoff hks bov.

Im kinda bummed out but im looking forward to basically redoing the whole turbo system with a tail bov/wastegate and get a proper garret turbo locally them go and throwout the rs tune, get a standalone and then go get the car tuned on a dyno. I think the turbo manifold is fine, maf is good, wideband is good, fmc/piping is all solid surpsingly.

I basically have ka24de with a fake turbo system with half working parts and half ebay knockoffs...:picardfp:

Will keep updates but just goes to show that you really dont know exactly what someones does to the car before you get it.

[cotbu]

For the bov knockoff or not, check to make sure it's seeing a strong vacuum signal at idle and that vacuum changes to positive pressure when the throttle is opened.
Otherwise do a boost leak test, it's normal for a bypass valve to leak at idle.
Some can be adjusted to be fully closed at idle, some are not adjustable.

If you pick a bov, and you really can do without the sound it makes. A wise choice would be to choose one that has the option of recirculation.

Anyway good luck, seems like you're ironing it out!

From a Highly Tuned Note 4.5!!!

[layourke]

Down the line i'll upgrade the turbo and put in better internals and do the cliche type x body kit.http://goo.gl/tVxTl6

[R3b]

For the bov knockoff or not, check to make sure it's seeing a strong vacuum signal at idle and that vacuum changes to positive pressure when the throttle is opened.
Otherwise do a boost leak test, it's normal for a bypass valve to leak at idle.
Some can be adjusted to be fully closed at idle, some are not adjustable.

If you pick a bov, and you really can do without the sound it makes. A wise choice would be to choose one that has the option of recirculation.

Anyway good luck, seems like you're ironing it out!



There is for sure a strong vacuum signal going on, the boost gauge shows the vacuum pressure to be around 20 and when I open the throttle a bit it increase. When I get to about 4000 rpm the boost just stops at 0 and I can hear there is also a bit of turbo lag also. My buddy yesterday said that when I was revving the car the bov didnt push forward but a little bit further back inside of the housing.

Im probably going to take off the bov, get a small plate to fit over the area and just run off the wastegate for boost. 6psi without any recirculation wont be too bad for the engine or tubro till I order another legit bov.

For a boost leak test I just sprayed around with some break cleaner on all the clamps and hoses and not much happened. im going to try the soap water test and spray around the bov and around the lines from the turbo to see if anything bubbles up.

I've already look up on the whole recirculation and vta debate. I kinda like the sound it makes but im sure once I start to drive it more often id get annoyed of it and just recirculate it.

[cotbu]

You should consider a compressed air boost leak test, or smoke over any other.
Also you have to check boost under load, and yes 4000rpm and zero boost is horrible.

Some of the oem lines have restrictors in them, so under vacuum you're good, but when boost is applied it's restricted. In that case your bov will leak during boost.

You could try removing the, line from the bov and plugging it up. Too see if there's any change in boost.


From a Highly Tuned Note 4.5!!!

[R3b]

Update: Just sprayed around again for boost leaks and nothing happen as far as the engine goes and nothing bubbled up from the soapy water. I had my little brother watch the bov and he said once I put foot on the accelerator the bov would push forward like it should and then push back into the housing when I let off. My friend said the opposite lol but probably tried to mean the same thing

The vacuum pressure would stay @ 20 and only increase a tiny bit if I go past 4000rpms so im not even close to building any boost.

Im pretty sure the old owner has his vacuum lines mixed up. There is a line from the bov that goes to a t bar and that feeds into firewall side groumlet and the branches off to the left to another tbar, that branches off into the intake manifold area and then into a fuel pressure gauge. Then for the boost controller there is a line to the wastegate and at the end of the controller into a a section of the hot pipe under the bov.

Im super new to turbo on a car and tuning, me and my dad know mainly about n/a engine issues and rebuilding heads and making sure everything runs good from the engine side but we are still kinda all over the place far as turbos.


Here are some pictures and im looking up on stuff now and proper turbo setups but if anyone sees anything funky point it out.

http://i.imgur.com/GbJJ7yr.png
http://i.imgur.com/gGZOo5U.png
http://i.imgur.com/xrTZgWm.png
http://i.imgur.com/8SOJVcJ.png

[R3b]

You should consider a compressed air boost leak test, or smoke over any other.
Also you have to check boost under load, and yes 4000rpm and zero boost is horrible.

Some of the oem lines have restrictors in them, so under vacuum you're good, but when boost is applied it's restricted. In that case your bov will leak during boost.

You could try removing the, line from the bov and plugging it up. Too see if there's any change in boost.


From a Highly Tuned Note 4.5!!!

Yeah I know but I dont have a compressor around so its the best thing to do at the moment, im getting one this weekend from an family member, ill try taking the line off the bov and see if that will do anything. I dont have anything really to plug it up, is there anything I can use around my house to cover it?

[Driftwire]

Dude your cant sit there and build boost at idle just revving lol. A real quick rev to like 35 -4k and letting off should give you some slight blow off, You need to be under load to properly build boost.

I also have a KA-T

[R3b]

Dude your cant sit there and build boost at idle just revving lol. A real quick rev to like 35 -4k and letting off should give you some slight blow off, You need to be under load to properly build boost.

I also have a KA-T

You cant? I dont hear any blow even when I go that high in rpms. Ive see my other friends rev there cars have a very strong pronounced blow off sound at idle. It could be its just a really shitty ebay bov also that why I dont hear anything.

The reason why im doing all of this questioning on idle is because the car isnt registered yet and im not about to get myself flagged or even worse my car flagged for driving around without a plate/insurance.

[TheRealSy90]

I'm pretty sure you have Lean and Rich mixed up. 12.0 is save for WOT in boost, a higher number is lean, lower is rich. 15's are fine for cruising around out of boost and idling.

If the rom tune is set up for the correct injectors and mafs and setup on the engine, there is no reason to have an safc on there, and as you already found out, messing with it just causes more problems since you really don't know what you're doing.

You really should have a dedicated vacuum line for the fuel pressure regulator, with nothing t'd off of it.

The line from the wastegate actuator, to the boost controller, and then to the charge piping is perfectly fine.

Other than that, one vacuum line for the boost gauge should be all you need, there shouldn't need to be any vacuum t's anywhere.

[EnnEssEnnKAT]

Do you run the stock IAC?

[R3b]

I'm pretty sure you have Lean and Rich mixed up. 12.0 is save for WOT in boost, a higher number is lean, lower is rich. 15's are fine for cruising around out of boost and idling.

If the rom tune is set up for the correct injectors and mafs and setup on the engine, there is no reason to have an safc on there, and as you already found out, messing with it just causes more problems since you really don't know what you're doing.

You really should have a dedicated vacuum line for the fuel pressure regulator, with nothing t'd off of it.

The line from the wastegate actuator, to the boost controller, and then to the charge piping is perfectly fine.

Other than that, one vacuum line for the boost gauge should be all you need, there shouldn't need to be any vacuum t's anywhere.

Yeah what I explained in the first post I did have lean and rich mixed up but I figured it out and i'll take out the safc down the line. Im going to email the guy about the rom tune to confirm its setup for 720cc injectors. I knew the t off between fuel and boost should be separate, that looked a bit strange and will fix that up and use dedicated lines for that also.

So just to make sure, everything looks to be setup fine and since its a fairly small turbo and boost is running off the wastegate I shouldnt be getting much boost off just revving on idle?



Do you run the stock IAC?

For that im not so sure, I know he said he deleted egr and cat but not sure about IAC. I'll check now but im not sure exactly where to look. Its behind the intake manifold near cylinder 4 right? What would a stock iac have to do with anything, I did an ecu diagnostics and it shows code 55 which means everything is reading fine.

My idle is fine now after initialized the safc, so on a cold start I get to around 1300rpm which is quite high and after 3 minutes and revving the car a bit the afr and rpm straightens out in the 14.0-15 range and I get a strong idle around 900 after couple minutes of warming up. Is that normal? My dads trailblazer does something similar where on start it idles a bit high and then comes down.

[TheRealSy90]

High idle on cold start is perfectly fine, and yes I wouldn't expect to build much boost if any when just free-revving the engine.

[R3b]

High idle on cold start is perfectly fine, and yes I wouldn't expect to build much boost if any when just free-revving the engine.

Alright awesome, knowing that i think ill be good. All I need to do is get a proper bov, a garret turbo, exhaust system, electronic boost controller, and ill be set for awhile.

Another thing with the car was when I would reverse it in the driveway the rear tires would lock up, make a noise, and then quickly engage again. Im pretty sure its the subframe bushing or diff bushings. I'll jack up the car this weekend and check to see whats going on.

Hopefully my consult cable comes in and I can run some diagnostics on some other stuff.

[TheRealSy90]

Sounds like it has a welded differential or 2-way lsd to me, most likely welded, unless it's doing that while going perfectly straight? Same size wheels and tires on both sides?

[R3b]

Should I just run the boost gauge line off my bov or should I add a T in between my boost controller and wastage?

Why do some people have the boost gauge T off from the fuel pressure gauge?

[TheRealSy90]

You should run the boost gauge line off of the intake manifold or throttle body if you can, not t'd into something else. Off the wastegate won't give you any vacuum reading. And people T into the fuel pressure line because it's easy to get to, but not considered "safe" because if something happens to the line you'll have problems.

[R3b]

Where should I run it off the intake or throttle? I havent read on much doing it off there. Why would that be better than doing it near the turbo side?

There is a j30 diff in the car which is an lsd so its deffinatly not welded, ive driven my friends welded 240 and its not that.

Afaik all the wheels are the same size and the guy didnt go in for any type of alignment for the car, he just maxed out the camber on the top mount for the coilovers and thats it. He also has solid subframe bushings but I doubt that, im guessing he just has spacers. So thats why it might sound a bit noisey

[TheRealSy90]

A boost gauge ran off of the wastegate line will not give you an accurate vacuum reading. If you don't want vacuum it's fine.

[R3b]

A boost gauge ran off of the wastegate line will not give you an accurate vacuum reading. If you don't want vacuum it's fine.

I would like to have vacuum for sure, but where would I route the vacuum line from the gauge which is mechanical to the intake/throttle body?

[R3b]

You should run the boost gauge line off of the intake manifold or throttle body if you can, not t'd into something else. Off the wastegate won't give you any vacuum reading. And people T into the fuel pressure line because it's easy to get to, but not considered "safe" because if something happens to the line you'll have problems.

So after reading countless threads, hours of checking lines and looking up other vacuum lines I saw there was a closed nipple on the very underside of the throttle body. So for accurate boost readings I should route to that nipple? Then should I just use a T for a vacuum line to my bov or should just use the fpr T routing?

[TheRealSy90]

Yeah the intake manifold/throttle body fittings are where it should be ran. If you don't have three fittings available for Gauge/Bov/FPR, then you could T into one of the others if you must. Or you could drill and tap the manifold for an additional barb fitting.

[R3b]

Yeah the intake manifold/throttle body fittings are where it should be ran. If you don't have three fittings available for Gauge/Bov/FPR, then you could T into one of the others if you must. Or you could drill and tap the manifold for an additional barb fitting.

Is there a digram of the fittings? I only know of the fpr in the back, a closed nipple by the throttle and not sure where the other is.

[R3b]

Ive had my first 240sx s13 (car) for about a week and the engine is locked up.
Long story short of what I think was the cause and - checked injectors which are 720cc and looked a bit sketchy so I took them out one by one and put them back in again and instantly got knock sensor code from ecu, checked spark plugs which were still black from when I check them last weekend, took out the maf connection to look at it and looked beat up then put it back in again. Saw there was another ka24de thread with the guy having same problems and ended up being the ecu, took it out, swap there were some dry joints in the same spot as the other guys ecu and added a bit of solder to the connection, closed it up and started the car. Car idle perfect but my afr would just die completely, start at 14.7 and then go all the way to 10, white smoke everywhere infront of me since there is only a downpipe on. Switched the car off and then herd a slap/knock and car wouldnt start again.


So what I think happened was the ecu was flash tuned completely wrong and also was broken or defective and getting wrong readings, the previous owner ran 720cc injectors for no apparent reason as well and tried himself to mess with the ecu and messed up everything to fix the idle,sent the ecu to get reflashed again and ask the guy from enthalpy to richen up the mixture since it was to lean at idle and when I fixed the dry joint in the ecu, car ran super rich and idle perfect but afr would start at 14.7 and just die to around 10 and stay there no matter what, also tried leaning it out a bit with my safc and didnt even budge... Started up the car again and hear a loud slap/knock and engine wont start and cant even move it with a wrench.


Now im just destoryed and not exactly sure what to do next.

[rellik27]

Sounds like you flooded the engine, probably injector did not seat well when you reinstalled it. Take out all the spark plugs and look inside if you see gas or a strong smell its that.

[R3b]

Sounds like you flooded the engine, probably injector did not seat well when you reinstalled it. Take out all the spark plugs and look inside if you see gas or a strong smell its that.

Did this yesterday and we smelt gas is cylinder 3 and also on the spark plug. Engine doesnt start at all and sometimes shorts out all my electronics and to turn back everything on I just click the safety on the battery in the trunk.

The timing belt looks like it jumped some teeth also
http://i.imgur.com/52rQAUE.png

[R3b]

okay so update time, ive talked to a few people and for sure one of my injectors was leaking and caused my car to run rich and then basically hydrolock itself.

Orginally I though I broke a valve or rod and thats why my motor wouldnt crank or turn over but it turns out my start just blew up and stop the motor from cranking.
This is what it looks like right now.... http://i.imgur.com/pHDwDAD.jpg

Going to get some new o-rings and a starter this weekend and see if she starts up and go from there. At least now I dont have to spend money on a rebuild and get replace some general engine stuff and get other goodies :hsdance:

Also does anyone know how to drain or have an easy way to clean up the mess once I get the motor to fully turn over and get ride of all the gas in the engine?