Idle Problems after ka-t swap....

[rn240sx]

Well, we just got the motor put in, wired up... It cranks up fine, but once it starts up, the idle is really bad and the motor shakes like a washing machine, and wants to die but doesnt that easy. Eventually it will drop down far enough and die out. No smoke out the tail pipe either.. I can smell the richness too... I can hit the gas pedal and rev it up and it smoothes out a little, but not perfect, but better than when its idling..I looked at the fuel pressure gauge and it reads 43 psi solid the entire time is was having really bad idle.The motor was in my previous 240sx that was totalled out. And YES the motor is fine cause I drove it home that night of the wreck and it drove and idle'd fine and even boosted ok...During the down time, I went FROM 370cc inj TO 555cc nismo injectors, FROM stock maf TO Z32 maf, had the jw ecu re-tunned. Thats about the only changes i made to the motor. This reminds me the very 1st time that I put my turbo setup on my ka motor, it did the SAME idle problem BUT had WHITE smoke out the tail the entire 5 miles home from the shop. I got it home to diagnose, shut her down, looked at it for a while and cranked it back up and VIOLA..... it idle'd like SMOOTH as can be at 800 rpm and never had a problem again until now.I disconnected the Z32 maf and double checked the wiring to make sure i had the right wires spliced together (according to jwt) so it was right. Im not sure why its idling this bad but if anyone has any clue's, please let me know...

ThanksRobert98 240sx ka-t

[UltraRed2$0sx]

I think stock fuel pressure should be about 34psi with a vaccume source, and around 43 without one.If you can smell fuel, probably running too rich. If its not the fuel pressure check the o-rings on the injectors. One time putting my 480cc's one of the o-rings messed up (the small on teh bottom of injector) and the car wouldn't stay on for nothing, unless i reved it up, also shook like a dishwasher, lol.......Hope this helps, good lcuk

PauL

[rn240sx]

Well there brand new injectors with brand new O-rings from nissan. The O-rings I purchased were from a 96 300zx TT..They both went on fine for each injector, i seriously doubt that one of them broke off... BUt i guess right now i have nothing better to do, so i will pull them out and double check them..

OK, I JUST GOT BACK AND CHECKED ALL 4 INJECTORS AND ALL THE O-RINGS ARE IN TACT AND NONE ARE BROKE OR TORE OFF.....
Modified by rn240sx at 11:50 PM 11/20/2004

[Structure240sx]

if you tighten the injector caps a little too much it can shred the o-rings. if its taht bad you would see some raw liquid fuel coming out of the tailpipe or some soot with it.

if its not that i think its running very lean. i have a wideband on my car and whne the engine is started after being completely cooled down it will idle very rough til it warms up slightly. or i play with the safc to smooth it out.

you can be idling at 9:1 afr's and it will purr like a kitten

[rn240sx]

The only changes that I have done to this motor is the 248/248 cam setup, 550cc inj, Z32 maf and jwt ecu upgrade...Other than that this motor ran fine in the other S14 i had.. It sat for 5 months, but other than that, there should be nothing wrong.

I checked the maf wiring 3 times with the jwt web site and its right. I checked the ECU wire changes also 3 times and its correct. I pulled the injectors and checked both O-Rings and they are all in-tact. I dont know where else to check...

[UltraRed2$0sx]

When i got a Z32 MAf and a Tomei plug, i tried following their instructions for wiring and never got it work. After double checking a few times i just wired it color to color and it worked perfectly. I dont know if JWT's instructions are to wire the MAF wiring color to color.Try that if you have it wired otherwise.If its not fuel related then it should be the MAF, either bad wiring or faulty MAF.

PauL

[S14tat]

i think its probrably a bad MAF. do you have a SAFC? this way you can check the voltage of the MAF or just to see the air flow %. this will give you a idea. if the wiring is correct your air flow should be at around 3% at idle. and it there is a bad connection, it would go hay wire and it can go as high at 70% just idleing which explains why it runs soo rich.

[skatanic28]

whats your boost gauge reading at idle? your fpr isnt seeing vac for some reason, maybe vac leak? are you running a recirc'd or dumped BOV?

[rn240sx]

Well while the motor is ON and running for the short amount of time, the boost gauge reads 0-5 inches and bounces around with the motor until it stalls out. Also my fuel press gauge reads 43 psi solid which is way too much. Ive been told that its a vacuum leak. If it "IS" a vacuum leak, then where is it, the manifold... Intercooler... IC piping..?? Who knows and how do i tract that down..??

[andrave]

pressurized your piping with a few psi from an air compressor, that should help you target your leak. also, how is your IACV hooked up?

[skatanic28]

alrite sounds like a vac leak for sure. i dont believe it would be an IC piping leak, because that shouldnt affect manifold vac. check all vac lines going to bov, wastegate, boost gauge, fpr. see if there are any obvious problems with them. ive seen people use smoke/fog machines to track down vac leaks before, anyone else familiar with that?

[klattr1]

possibly distributor installed incorrectly? (off a tooth?)

[marshun]

a neat way to find a vac leak is to spray soapy water on your vac lines. makes it easy to see visually.

[NateDogg]

I vote for cams. I bet they're off. Use the JWT install instruction on their webpage. Makes it easier.

[rn240sx]

Ok, I changed out both intake manifold gaskets and the idle is MUCH better BUT not perfect. Now it sounds like a mustang with lumpy cams..However the motor does idle and stays on without stalling out..While I had the motor at idle, i went to the maf and un-plugged it, and the motor stalled right out..My vacuum gauge still reads 2-4 inches and my fuel pressure dropped to about 41 psi from 44 psi.

I just put these 248/248 cams in and on the intake side i did move it back 4 teeth, so now the cam lobe's aim away from each other and that intake side is a TINY but off from the exhaust side which is what people have said when u use the 248 ex cam on the intake side.

The distributor was NEVER removed, nor touched during the cams installation. I still think its a vacuum leak so tomorrow im gonna pull the bov and boost gauge vacuum feeds off the manifold and seal them off to see if the idle gets better.. By the way my wastegate boost feed comes off the compressor itself.

Thanks guys

[klattr1]

i agree with natedogg then.

its too much of a coincidence that you just put in those cams and you think the intake cam is slightly off. i know someone that put in their cams wrong and they were getting similar vacuum numbers.

[rn240sx]

Well, its NOT a vacuum leak.With a new upper and lower intake manifold gasket and bypassing the intercooler and the IC piping, i still have bad idle problems...

We pulled the valve cover off to check the cams to see if they were lined and they were..!! We had the #1 piston at TDC and both front cam lobes were aiming away from each other as they are supposed to.. We did the same for the #4 piston at TDC and the cam lobes were pointing away from each other so the cams are aimed right...BUTHere is where the problem is. While we had the #1 psiton at TDC, we noticed that the Main Crank pulley TDC mark was NOT under the needle...!! The TDC mark was at 11 O-clock position where its supposed to be around 2 o-clock ish....So, thats where my problem is. I just dont know how this chain skipped a tooth or more while we did the cams.

[IvanAtSPRacing]

I would guess it to be the cam install or the distributer being off a tooth or two. BTW, how do you install cams without pulling the distributer? You risk misaligning the distributer, breaking the distributer, breaking the cam, etc.

Quick check to see if its the cams that are your problem would be a compression test. See if your getting really low or really high (but consistant) compression readings from all four cylinders. Cams not being phases correctly will show here. If everything is money, then I would go for the distributer timing.

[rn240sx]

Well guys, its done. Both cams were installed on the exhaust stroke of the #1 piston. The ASP pulley we have has the timming Marks marked in the WRONG PLACE..!! So, we did the old fashioned method to find TDC at the compression stroke and realized that both cams were wrong. We got them fixed and now they are correct. The car starts up, but now it has a slight mis-fire to it, my vacuum gauge now reads 16-18 inches. Also when i hit the gas pedal to rev it up once and release, the motor will stall immediately once the idle drops down..Now we have to figure out what is causing these problems. Im just happy that we got the cams in right and that its now idleing..!!

[klattr1]

well, im glad its right now.

[Structure240sx]

yea me too. that was bothering the hell out of me that one night i was tryint o help ya out.

[andrave]

yeah how the hell did you change the cams without removing the dist? wasn't that a total *****?

[p00t]

http://jimwolftechnology.com/w...E.PDF

cam install intructions, upper cover and dist arent touched.

[rn240sx]

UPDATE:

The mis-fire issue has been fixed. All that was needed was an MSD ignition box.Apparently 615cc injectors will dump more fuel at idle in comparisson to the stock 270cc injectors. This added fuel at idle is causing my mis-fire simply because the ka's stock ignition is not strong enough ignite that extra mixture at idle alone..!! Once I go WOT, then the spark is amplified and it is able to ignite the mixture, BUT not at a 100% burn, but enough to a point that no mis-fire is felt under boost...I then installed this MSD box and the mis-fire is GONE and i probably gained about 30 hp just with this box..!!

NEXT UPDATE:My stalling problem when i shift to N from any gear. Well, EVERYONE claims that it was due to my bov dumping to atmosphere..Well, I just dumped $150 at the local performance shop to have them fabricate a recirculation method for my bov. They knew right off the bat what they had to do because they have done it b4 on other maf controlled cars..So, guess what..... IT DIDNT WORK..!!Im still stalling when i shift to N from any gear at any rpm, whether im IN boost or OFF boost.And YES, they did it right. They went FROM the bov and routed the pipe back to the INTAKE side of the turbo AFTER the maf sensor... ( basically between the maf and turbo)

I told u guys that this was not the problem but i wanted to try it out for the hell of it, just to see if i was wrong. And i was right.. $150 down the drain and im still stalling out...

Any more bright suggestions...??

[MaxType 240]

1. You said you had 555cc injectors. Where did the 615cc come from?

2. Is the JWT ECU tuned for Z32/555s or Cobra MAF & 50lbs?

3. Please tell me you have a SAFCII to lean out JWTs programming, improve your idle, and set decelerating air function?

Jesse

[rn240sx]

I have the Newest model NISMO 555cc inj which have been flowed tested to 615cc inj. My jwt ecu is programmed for the Z32 maf and the 555cc inj (but jwt knows about the newer nismo inj and he asked me if i had the new ones or the older style one's, that way the program was tunned to the correct flow rate)I have the sfc 2 but its not tunned yet. Im waiting on the dyno run and my wideband O2 so that I can tune it. As far as the dec-air function, it did not work. I had one guy on freshally go thru it with me like 4 posts long and it would not work for anything. When i was tunning it to the idle, the motor would respond like it was supposed to, but when i got out to test drive, it stalled out at every light and every stop sign. I gave up on it eventually.

Now to the stalling problem:All the blame is toward the jwt ecu programming. We all know that the jwt ecu is not the best tune in the world. But it works its purpose. All their concern is toward WOT and to make sure that the motor stays "HAPPY" under full boost. But under idle, thats another story.

Their 370cc inj program has the smoothest idle simply cause your only running 370cc inj vs stock 270cc inj. The same amount of fuel is dumped at idle speed, therefore the idle is smooth and we can run OPEN atmposphere bov without having any stall out issues.

The 555cc (50lb) AND the 740cc inj (72lb) inj programs however are not so good at idle. Why, well cause their program for some reason ADDS more fuel at idle. They have not corrected or maybe even figured out how to maintain the same amount of fuel flow as the stock ecu does on the stock 270cc injectors. (maybe they dont care, who knows) Being that these larger inj programs ADD more fuel at idle, this causes the mis-fire and irratic idle problems. Why, well cause the STOCK (S14's internal coil) ignition is not strong enough to ignite the fuel mixture from the added fuel dumped at IDLE only. This causes a slight mis-fire at idle. When u get a large enough mis-fire the motor will dop idle down far, then the IACV will try to compensate, then the motor will raise back up, another mis-fire will occur and the idle will drop back down, and this entire cycle will continue unitl the motor drops down far enough to stall out...Now, when u hit the gas pedal to raise up the rpm, the ignition will amplify and ignite MOST of the mixture to a point that u will not FEEL any more mis-firing. However the ignition is still not strong enough to ignite 100 % of the mixture, even at WOT..

The only cure to fixing this rough idle and to KEEP the jwt ecu prog is to get an MSD ignition box... OR just dumping the jwt ecu and going stand alone with a better ignition system.

I went with the MSD ignition box and it stopped the mis-fire, my idle is now smooth as can be, and i felt a nice huge gain in power at wot.

Next: the stalling issue at stop lights and stop signs was also directly related to the extra fuel at idle and because i was running open atmosphere bov. Being that all the air was dumping out WITH the added fuel dump, the ignition had no chance to keep the motor alive..So i just recirculated the bov and that fixed the stalling, now since then the motor has NOT stalled one time..!!

The rough idle was figured out by one of the ka-t.org guys that ran into the same problem and it took him weeks to figure it out. He is one of the few guys that r putting down 500+ rwhp.The stalling issue was figured out by a member on freshalloy who happened to read my post. Apparently my greddy type S bov needs to be internally modified to run as a recirc bov..

I dont know how these guys figure this out, but they did and i thank them all...!!!!!!!!!!!!!!! And to think that I was ready to sell this freakin car cause i was so fed up with these problems...

Ok, thats enough on my end...