Ok well i got the car pretty drivable up intill about 50% throttle. Idels is not bad it goes from 14.3 to 15.3 or so. I went a head and put the z32 in and it made tunning a lot more easy. Well the olny problem I got right now is when it hits about 5psi it goes to bucking. i look at a data log when this happens and it and the air fuel looks ok right around 11.4 during and before the bucking starts! Now this Z32 maf is a good working maf it came off my running Z yesterday. So ill just have to fine another one for my z. But what could make it start bucking or dying out?

 

Hey, sorry I didn't get to your message. I keep forgetting that my email is still down so I don't even know it when I get a pm.

If you're having issues after boost, I'd check for some boost leaks. That could also cause some idle issues. What are you doing with the PCV system? All hooked to the intake, partial hooked to intake, or all vented? If you have some vented and some on the intake that can definitely cause issues as well (its essentially a vacuum leak with that setup).

 

Hey Mark! My pvc is all vented. I can check for some leaks tommorow but right before the 5 speed tore up I had stock injectors and it would boost all the way. But after driving it some tonight the only gear it will make over 5psi with out bucking and cuting out is 6th . It will just keep pulling in 6th and go to full 9psi.

 

I sent you a PM. It might possibly be your MAF or just a HUGE boost leak and the motor is just way overcome with fuel

Just a guess though

-matt

 

*update* I did how ever notice that in first it will buck when it hits 3psi and 2nd at 3 psi and 4th and 5th it will go up too 5 before it starts tpo cut out or buck and 6th it will not buck at all. the turbo can fully spool.

 

What rpm is it at when it can boost up to 9 psi in 6th gear? How about in the other gears? Starting to sound potentially like a MAF problem, like matty mentioned.

 

I say about 3500 in 6th

 

I can data log it. If someone can tell me how to send it for them to look at

 

i remember reading something about a s/c kit with similar problems. the owner simply twisted the maf in the pipes to face a different direction and it fixed the problem. dunno if this has anything to do with your setup !

 

That really has nothing to do with his problem. Turning the Z32 MAF on a Supercharger setup with help in a Loopy idle problem that was occuring. He is Turbo

-matt

 

Im looking at some data logs now and it seems to happen at 5000 in 1st and 4000-4300 in all other gears! Air fuel dont show to go lean or rich at the time. its right at 11.1-11.6 before and during time. The airflow seems to still be reading during the whole time not jump around too much.

 

Hmm... maybe its spark related... still though, I would think the a/f ratio would change. What wideband setup are you using?

 

zt-2 zeitronics

 

Sorry I missed your call earlier, I fell asleep hard, didn't even hear the phone ring.

You might try watching the wideband unit itself in real time and see if you notice any changes, maybe even let it buck for a couple seconds or so. If the a/f ratio isn't changing... something very, very weird is definitely happening.

One thing I didn't consider was ignition timing. Maybe the timing is somehow getting off because it doesn't really sound like a fuel issue if the a/f ratio is staying constant like that.

 

well I got to go buy a another Maf for the Z any how so im going to try another z32 on the max to see! I have watch it on the data log and watch it in the car when it bucks the air fuel seems to stay at around 11 or so.

 

ok well I was ridding today and blew a intercooler coupler off so while im going I said let see if it will happen with no boost present. So i floored it and it went all the way through the rpms with no problems. So the bucking or cutting out only happens under boost!

 

so when it buck's theres no change in a/f? wat else can you monitor? timing, air flow? What tuning device are you using? In my case, I had the emanage blue ignition harness wired up and gave me alot of problems, under boost it would buck n hesitate with no change in a/f, i thought it was spark plugs, so i gaped them smaller, same thing. So i hooked up the ignition back to stock and car has been running perfect ever since. So it was ignition related maybe my ignition chip on the emanage is bad. but that was my experience. how much boost u get when this happens?

 

im using a eu! Before I changed maf and injectors I had no bucking issue. I looked for boost leaks but have not been able to find any

 

I have the same exact problem.

Today I installed RC 440cc injectors in my car (4.5 gen V2 SC 3.6 pulley.) When I get to about 4300 rpms it starts to buck badly in any gear. Maybe a lil later in the higher gears, but sometimes it'll break through the bucking and boost. I'm gonna be installing a wideband in about a week or two...for now I have a vafc2.

I'm thinking since we both are having this problem its an injector issue? I installed them correctly (spliced in the new harnesses)...could it be I installed them in the wrong order....does that matter?

 

What gap you guys have your plugs at? are they 1 step colder?

 

Nah I still have stock plugs. Im going to change them today!

 

I have one step colder NGK's gapped to .036

 

Stock plugs with stock gap? hmm that dosnt sound like a good thing. Maybe your getting spark blowout under boost. I think i have mine gapped at .030, i have a thread with some info on this that some guys posted like neal and i think stephenmax, saying they have gapped all the way down to .025 with no problem.
So try n do that see if u still get the same problem. both of u

 

im going out to the car and try the new colder plugs now with a .32 gap ill let you know how it turns out when i get done!

 

Please, let me know how it turns out. I had this problem very small and only sometimes....after I put the injectors in it's much worse.

I'm gonna pull the codes today....

I'm also gonna check the coils. I was also told it might be a TPS problem...? Someone mentioned I can mess with the TPS via VAFC2...which I don't believe. Can anyone shed some light on the subject?

 

You can use the V-AFC 2 to check the TPS voltage/percentage and manually adjust it on the throttle body so that it gives the correct reading. I had an S-AFC 2 on my car and it made adjusting the TPS extremely easy using it like that.

 

ok well I not really sure now because I changed the plugs and one did have a a small hair line crank in it. But the first time out boosting after changing the plugs it spooled right up to 12.5 psi and dam near snatched me into the ditch at the same time the maf popped lose from its pipe. well I stopped and put it back on and the problem was back. So im not sure if the Maf was moving at the time it was building and reading differant so thats why it went up all the way or what. BUt I got to drive about and hour to go get my new
z32 maf so ill let you know after I install it and see

 

Yeah, that's what I heard about the coils. Try taping up the coil with electrical tape over the crap. Wrap it up a bunch of times.....keep me informed. When I get off work I'm gonna mess with my Coils...pull codes, and adjust the vafc see if anything happens....

 

Your setup sounds rigged and slapped together. Intercooler couplers popping off....Maf pops loose... and yet you can't find a boost leak?

Get some silicone couplers and T clamps if you don't have them already. Secure all your charge piping first, then go from there.

 

hey I tried PMing you but you never responded...can you please leave me positive trader feedback for the ignition coils i bought from you? i left you positive feedback already.

thanks

 

I have all t bolt clamps on my set up. I had just one or two couplers that were not the best. the maf kept coming off on the smooth side. SO I have took it off and made it some what rough now it has stay on all the way up to 14psi on the way home from charleston to get maf.

 

UPDATE** I put new z32 on tonight with no luck the car still cuts out. It not really just like bucking its kinda like a fuel cut you would get on subrau, and supras. It just dies out the higer the gear the more boost it will let you make before it cut and in 6th gear Iv been all the way up to 15psi and it would not cut.

 

Thats the exact feeling I get....

I checked the front coils (keep in mind im a 3.5). They looked perfect, I'm gonna check the back in a few days. I also was thinking that my problem is at 4300 isn't that around when it goes to open loop? Could that have anything to do with it? Your setup is bucking at a lower rpms correct? I'm just trying to think out loud...I'm gonna see if I can grab a maf...

I just find it nuts that when it bucks/cuts or whatever...sometimes if I stay punched it "breaks through" and I can pull like crazy. Can you get past the point when it bucks 95turbo?? Anyone else have any suggestions??

 

What are you tuning with? This is the exact same problem I had when i had the emanage blue ignition harness hooked up. it would misfire/buck/hesitate w/e it was but if i left it at WOT, it would just break thru the hesitation and eventually start pulling hard up top. Now, i assume the most misfire/hesitation you guys are getting are around the 4### rpm range, which leads me to belive this might be a timing issue. Maybe ecu is pullling alot of timing? Maybe your getting spark plug blow outs?

 

Yeah thats possible but Im not sure why it worked before I put the injectors in. the car would boost up fine. ALso if I hold mine it does not clear up it will keep bucking and cuting out! but if I let boost fall off it will go right on.



As you can see the red lines are rpms the yellow is timming and the other flater yellow is air/fuel. the pink line is boost.

 

I'm just using a VAFC -2 .....getting a wideband in about a week.

I had it tuned a little on a dyno...the vafc setting is pulling fuel in the lower rpms.....not sure if thats advancing or retarding the timing. I mean it boosted fine before the injectors....

I didnt have a chance to pull codes, so we'll see what happens when it goes today. I'm gonna see what else I can troubleshoot....I'll also check the TPS settings on the VAFC. But what would cause a change in timing just by adding the injectors?

 

That log looks fine, you can def notice some disturbance up top. Are you retarding any timing? I remember, one of the turbo guys told me once that when they advanced timing too much that they would get this same problem. Either way, if it didnt do it before at the same boost it shouldnt do it now. I know its a PITA but looks like your going to have to remove the injectors and put the old ones back on, to see if it still does it.

 

im running stock intill about 8 psi then pulling 1degree and 2 at 10
But this normaly start to happen well before 5psi in 3rd gear and around 3psi in 2nd in first it will go to 5000 then start its **** all other gears other than 6th it will happen around 3800-4100

 

What a/f ratio were you at with the old injectors?

 

11.5 at about 7psi and they were at 96-100% duty cylcle they were 290cc from the dek