Was getting tuned today, everything up to vtec is perfectly tuned an running great. However once it crosses over into vtec the motor just seems to start choking and falls on its ***. Can't figure out the problem at all. Anyone have any ideas?

Turbo Setup:
Max Rev manifold
Tial 40mm Wastegate
t3/t4 60 trim
2.5" downpipe
2.5 to 3" test pipe
3" Thermal exhaust
650cc RC injectors
AEM EMS

 

i think the plugs are toast. i'm sure ur timing is right, just check for tune up parts first

 

plugs are perfectly fine and timing is as well

 

This is an interesting thing. My car did the same damn thing, but is a single cam. Ended up being my LMAs. Does it feel like it falls out of vtec?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">This is an interesting thing. My car did the same damn thing, but is a single cam. Ended up being my LMAs. Does it feel like it falls out of vtec?</TD></TR></TABLE>
so thats what your problem was? Get it all fixed now? I bet the car is pulling strong with that cam

 

its a stock head i don't see how the lma's would play into it at all but thanx for the help .........please someone help

 

need to figure it out today...someone please help!

 

you got a LOT to learn if youre tuning AEM by yourself. thats the reason its bogging...needs to be tuned man.

 

yea thanx for the vote of confidence its being tuned by an aem authorized tuner but we are all at loss as to wut the problem

 

usually if the car bogs when VTEC is activated that menas that VTEC is set too low. try increasing the VTEC rpm and see what happens from there

 

that shouldn't matter, if the fuel values are set appropriatly. This may be the case with a stock ecu and fuel maps. But I would imagine that if he has a professional programming it, they would not have missed doing this. This is how i'd go about solving the problem. Ask yourself what happens when vtec is activated? If in open loop, new fuel table is looked up. Oil pressure drops for the solenoid to push pin closed. It has to be related to either of these two. Confirm that these are working correctly and if there operation is impacting anything else.

 

I would start by disabling everything you can, like VTP and coolant checks. Just to make sure you are "dropping out" of vtec some how. Recheck CAM timing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">I would start by disabling everything you can, like VTP and coolant checks. Just to make sure you are "dropping out" of vtec some how. Recheck CAM timing.</TD></TR></TABLE>

yea, could be a tooth off by chance...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Andy R &raquo;</TD></TR><TR><TD CLASS="quote">that shouldn't matter, if the fuel values are set appropriatly. This may be the case with a stock ecu and fuel maps. But I would imagine that if he has a professional programming it, they would not have missed doing this. This is how i'd go about solving the problem. Ask yourself what happens when vtec is activated? If in open loop, new fuel table is looked up. Oil pressure drops for the solenoid to push pin closed. It has to be related to either of these two. Confirm that these are working correctly and if there operation is impacting anything else.</TD></TR></TABLE>

i tuned a turbo B16 with R cams and first tuned the car with VTEC disabled:mid 11's a/f ratio. then i tuned the car with VTEC set low, like at 3K rpms and tune the VTEC fuel maps: mid 11 a/f. I then set VTEC to engage at 5K rpms and after doing a few WOT pulls on the street to check out everything, the car would bog once VTEC hit then clear up about 500rpms later. after the street tune we went to the dyno to fine tune the car. the graph showed that power was falling when VTEC came on at 5Krpms. (the primary lobes were still making power up to 5K). we then set VTEC to 5600 rpms and the car didnt bog once VTEC hit. it was constant power

 

i ahve the same problem.

 

I have the same problem on my b16 also. My vtec is set at 5.5 and it still bogs. I only did a couple of slow pulls to see if vtec kicks in before i get it tuned(i have a basemap right now at 8psi). Before vtec, it pulls great. Do you guys think it could be due to the thick(.054) head gasket and type r cams? Sorry, i dont mean to steal your thread but its kinda odd that we have the same problem. Also, plug gap at .40 is too much?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">usually if the car bogs when VTEC is activated that menas that VTEC is set too low. try increasing the VTEC rpm and see what happens from there</TD></TR></TABLE>

100% your problem, well maybe 99%. ive also noticed that sometimes the a/f will dip rich for like 200 rpms right around vtec xover, i havent been able to work it out (probably because i run a free software program), but that might very slightly be the case. id go with the vtec being too low.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ek99 &raquo;</TD></TR><TR><TD CLASS="quote">I have the same problem on my b16 also. My vtec is set at 5.5 and it still bogs. I only did a couple of slow pulls to see if vtec kicks in before i get it tuned(i have a basemap right now at 8psi). Before vtec, it pulls great. Do you guys think it could be due to the thick(.054) head gasket and type r cams? Sorry, i dont mean to steal your thread but its kinda odd that we have the same problem. Also, plug gap at .40 is too much? </TD></TR></TABLE>


.40 is way to much. your probably blowing the spark out, cutting power resulting in the bog or maybe bucking that you have. start with like .030 or .028 and go down. youll probably wind up at .028 or .026, especially if you are only running 8 psi

 

wow, .26 or .28. So far i retarded the cam gears to compensate for the thick head gasket and i gaped the spark plugs to .30. The good thing is that it improved things and in first gear it pulls like crazy all the way to 7k+(i didnt want to take it any higher). But in second and third it still bogs when it hits vtec but not as bad. Should i raise vtec higher than 5.5? I'm using bkr6eix-11 plugs and i'm not sure if their the right ones. Also, when it bogs in second or third it kinda makes a sound like the wastegate or bov stays open. Kinda like a loud wind noise. i will try to gap the plugs down a little.

 

try the bkr7e-11's.


dont take offense to this, but your sure that your just not spinning tire and then when you upshift you dont have the mph going and cant make the boost(less motorr load) or you are just loosing rpms?

in 1st and 2nd gear on the street i spin to the redline and it doesnt get a chance get my mph up to where it should be and consequently when i first catch traction it bogs out

 

this may be completely wrong for your circumstance, but this same thing happened to me and it turned out that the VSS came unhooked somehow....once i hit VTEC, the car just puttered and started losing power....does your speedo work??

 

I'm pretty sure i'm not spinning. Even in first gear, it just puts you in the seat and does not spin. Just when i hit vtec in 2nd and 3rd it feels like it sits there for a while and then it starts to pull to redline. I know what you are talking about though. My last turbo ls did that where in 1st and 2nd would spin and then it would bog in 3rd. My speedo works so i dont think that has anything to do with it. Its a 99 em1 and everything worked great before the turbo, so its definitely turbo related and most likely tuning. Now all i gotta do is find someone in North Carolina to street tune my car.