new motor is in need (running lean)

[ka-t 300]

Well I put my fresh forge built motor in last weekend and I can't figuire out why it's running lean . I need some ideas . vacum is at 21.5 hg or 550 mm hg and don't see any signs of a vacum leak. i have a jwt ecu that worked fine for 2 years . I had to run my apexi afc up to +40 to get it to idle at 16 on my wide band lol. timing is set at 20 btdc spot on. I can probably supply more info if needed, but i guees i need to know what else to check or what are other possible causes for this . every thing worked fine when i pulled the old motor out. the tps is not the same one though as i did not use the same intake manifold , I used another one that i did the emmissions removal on.

any ideas ? need advise kat gods lol

[ka-t 300]

wow no ideas ?

[ka-t 300]

wow no ideas ?

[j-z]

ive got an idea.... did your new pistons lower the compression ratio?

[ka-t 300]

lol yeah called jwt about that , said that would not effect afr's it would only let you change the timming curve to be a little more aggresive.

[ghx407]

Low fuel pressure or hidden leak in the vacuum lines or intake tract is all that comes to mind for now...

Have you diagnosed the new TPS?
Modified by ghx407 at 2:17 PM 5/21/2009

[ka-t 300]

going to try to this weekend , i'm just trying to get a list of thing to check for that could possibly cause this such bad 02, sensor, tps, iacv, ect. i'm just not sure of what all to check for but i wnat to try and check every possibility out this weekend. i'm stumped right now because all was good the other motor in there. lol

[ka-t 300]

well I put a scanner on it only have 8 codes lol here they are need to know which one would cause the lean issue and witch not to really worrry about .

p0120--- tps circut malfunction

p1441---malfunction control aux emmision control

p0105 ---map circuit mal function

po443 ---evap

p0325 ---knock sensor circut malfunction

p0446 ---evap emmision controll system

p1445----malfunction control emmission system

p1105 --- malfunction control air metering devise

any comments appreciated .

[480sx]

Some of your ish is effd up. You need to fix that ish if you want that effing thing to run. Go through your FSM and go through each of those codes, find out which is relevant and which isnt. Ill give you an off the top heads up.

I = Important F = Forget about(unless you need an emmisions check then your screwed)

P0120 - IP1441 - FP0105 - FP0443 - FP0325 - IP0446 - FP1445 - IP1105 - ??? check that one out for sure.

[ka-t 300]

apexi neo says maf input at idle is 1.12 v fsm says should be 1.3 -1.7 ( .2 v out of spec.)

apexi neo says tps is 3.9 v fsm says it should be .3 - .7 ( in spec. ) .

so i assume that the voltage is to low for the ecu to pick up or its reading a lower volt than spec so it is not injecting enough fuel thus it is running lean. does this sound right ?

[480sx]

K. Unless you wrote something wrong, you have a problem that your not aware of.

You say your TPS voltage is 3.9 at idle, when closed? That would mean you have a bad TPS. Like you said.. The fsm says it should me DECIMAL POINT 3 - .7. Its 3.9.

Your maf is questionable, if its giving you a code you should just replace it though.

[DevilMB3017]

Just an FYI, I'm pretty sure those two things are the same section of the motor harness.

I happened to have a knock sensor issue and a TPS issue at the same time before. It seems to be becoming a common occurrence. You might want to check out your harness, it's the section by the fuel rail that leads to the TPS and knock sensor on KA24DEs.

[ka-t 300]

[QUOTE=480sx]K. Unless you wrote something wrong, you have a problem that your not aware of.

You say your TPS voltage is 3.9 at idle, when closed? That would mean you have a bad TPS. Like you said.. The fsm says it should me DECIMAL POINT 3 - .7. Its 3.9.

Lol my bad on the decimal I double checked it its .39 not 3.9. I'm leaning on replacing the maf. I know that they are known to go out. thanks .

[480sx]

Your situation with the maf makes sense as far as running lean goes. If its measuring lower than the lowest FSM limit it might be just gumed up. You might wana try buying some MAF cleaner, spraying the crap out of it and driving it. Then using the maf cleaner again, and seeing what your left with.

You can take the element out of the housing to clean, which is good, just dont touch or damage the element. Simply spray that ish on there following the directions.

Picking up spare mafs is always a good idea.

[ka-t 300]

well after 5 months later lol, i resolved this issue since it is cooler now to work outside, thought it would post what the problem was just for future info for everyone. I noticed on my apexi neo that my ig. voltage was 11.8v so i checked the batt. it was no good , replaced it , still 11.8 v ,pulled the alternator to go have it checked as i was getting ready to leave i noticed a spot on the alternator that was a connection for a 2 wire connector that didnt remember pulling the connector off. so i went out to the car and looked for it and found it it was a little hiddin in the rest off the wires. the point of the conection on the alt. faces straight toward the inner fender well so you cant see it from the top or the bottom wich is why i over looked the problem till i pulled the alt. out. i put the alt. back in hooked up all the connections and bam 13.7 v this fixed all the lean issues i was having. any way i was pissed and happy as hell at the same time lol. the moral of the story is these cars have to have the right voltage to run correctly. some one told me you have to have at least 12v but have not verified that yet in the fsm. any way some info you my fellow ka-t friends

[ka-t 300]

Well it was still acting sort of lean but was running good then heard some squelling sounds . thought it was blow off valve started to replace that while i was at it checked shaft play on turbo and uh ooooo loose , looked in the compressor housing and could see where the wheel had been rubbing on the housing. so checked oil feed line for restiction and it had a piesce of rubber stuck in the restrictor, so what we have here is oil starvation for the turbo. well as some of you may remember i was looking into ball bearing turbos about a month ago, didnt get one how ever i have replaced the turbo with a new one. while i had the down pipe out i noticed that there was carbon marks leaking through my v-band joint witch is is located right before my 02 sensors , so in short part of my running lean problem was probly due to that exhaust leak right before my o2 sensors.

Any way wanted to point that out as some thing to check for on lean issues. got new turbo blow off valve installed fixed exhaust leak , connected alt. connector , broke it in for 500 miles and boosting 18 psi now.

thats true ka-t = blood sweet and beers (and money) lol.

I love it though its running great. trying to fig. out how much boost you can run with just 93 octane though ?

[WDRacing]

I ran 15 psi from a T4 with 93 octane and the proper amount of timing retard on boost. Which is about .5 per psi after you reach 4-5 psi of boost. So for 15 psi you're looking at about 5-7 degree's of timing retard on boost.

Or you can use water injection and leave the timing

WD

[ka-t 300]

I ran 15 psi from a T4 with 93 octane and the proper amount of timing retard on boost. Which is about .5 per psi after you reach 4-5 psi of boost. So for 15 psi you're looking at about 5-7 degree's of timing retard on boost.

Or you can use water injection and leave the timing

WD

well i have a jim wolf tune so timing is not the issue. i just thought that still you can only go so far with just 93 octane. im running 17 psi now. but i have another question though about how much whp would that be with .43 ar 57 trim turbo ?

[WDRacing]

To many factors to think about, but a safe bet is 350ish