I just had my JWT ecu reprogrammed to the bb turbo setup, 370 inj, higher redline, speed limiter, etc. yadda yadda.... and I've noticed that they run a real conservative fuel curve, and when I drive around the car sorta hesitates under WOT. (kinda feels like
turbo lag) then all of a sudden it'll boost. I cant seem to figure out whats going on here, and I'm hoping somebody could shed some light on this one for me.... btw I have stock maf, z32 fuel pump new wires, plugs, gutted cat, and a 3 inch exhaust. It also backfires like crazy.

What fuel pressure regulator are you running?

might be a good idea to keep your lower tps voltage to .45 That is what worked with me when i had 370cc , also i ran a larger plug gap .35 since boost was low .

Originally posted by Low612
might be a good idea to keep your lower tps voltage to .45 That is what worked with me when i had 370cc , also i ran a larger plug gap .35 since boost was low .


.035 is the stock gap just to let you know .036 would be larger. Beside everyone seems to think the the smaller the gap the better but you are wrong if you think that. You want the biggest gap possible that you can run before fouling (missfire) occurs, because you want to introduce the biggest spark possible so idealy if you could run .050 that would be great but when altering the gap size for high performance ignition modifications, never go more than +/- 0.008" from the stock setting because the gap surfaces between the ground and the center electrode may not be parallel for larger changes. Higher compression or boosted engines generally require a smaller plug gap and a HIGHER IGNITION VOLTAGE. If I were boosting like 8 psi on a stock DET I woldn't change anything if I were boosting 10 psi maybe I'd run a gap of .032.

My guess is the backfire could be partially due to the gutted cat. The hesitation could be due to misfire which could be too big of a plug gap. I would try gapping down to .030 as it's the easiest thing to try first.

Khiem

they're already gapped to .030...I'll have to check my tps voltage....

02 sensor maybe?

Are you sure you gapped your plugs right? Come by later and we'll check that TPS voltage and your plugs.

also, did you get the 9.5:1 CR program or the 8.5:1 CR program?

I got the 8.5:1 cr....also I just checked the plugs (denso iridium)
and they were fouling, fuel was glazed on them leaving a shiny brown residue....time for some bkr6e's. The quest for no hesitation continues......

shiny brown sounds more like oil than fuel. do they smell like anything?

fouling usually ends up with large dry, brown deposits.

you on the SoCal SERCA list sean? this kind of thing would be pounced on there, though not in a constructive manner. its great! :D

The plugs wreek of fuel....here's what I'm ***** do...first i'll swap back in the bb ecu and see what happens, if the problem persists then i'll just have to get some new plugs, new 02 sensor, and check the tps voltage and see what happens....if it solves the problem, then I'll switch back to the JWT ecu and see how it runs. Now if the problem comes back with the JWT ecu, then I'm pretty sure it could be an injector leak because it smells like fuel under the hood when the engine is running and the car's hesitation is getting worse. The hesitation occurs between 3000 rpm to about 3500 rpm. we'll see......

all four plugs or just one?

This is my experience with denso iridiums , my car ran funny with them. i was boosting 8psi with a t-28. When i switched back to ngks the car ran much better. I noticed the car ran richer and rougher.

Originally posted by unlucky
02 sensor maybe?

That was it!!!!! I was running a bb o2 sensor with my jwt ecu:rolleyes:

So be reading this im assuming you cant do this huh?Run a bb o2 with your jwt ecu? I had no clue and have been posting my troubles on this forum for 3 weeks now.If this is true you cant do it then how or what o2 can you use?My stk one dont fit into the holw in the turbo elbo it is to small.D

So be reading this im assuming you cant do this huh?Run a bb o2 with your jwt ecu? I had no clue and have been posting my troubles on this forum for 3 weeks now.If this is true you cant do it then how or what o2 can you use?My stk one dont fit into the holw in the turbo elbo it is to small.D

So be reading this im assuming you cant do this huh?Run a bb o2 with your jwt ecu? I had no clue and have been posting my troubles on this forum for 3 weeks now.If this is true you cant do it then how or what o2 can you use?My stk one dont fit into the holw in the turbo elbo it is to small.D

So be reading this im assuming you cant do this huh?Run a bb o2 with your jwt ecu? I had no clue and have been posting my troubles on this forum for 3 weeks now.If this is true you cant do it then how or what o2 can you use?My stk one dont fit into the hole in the turbo elbow it is to small.Do i need to get a different sensor form anouther year vehicle?

you have to make another bung (threaded hole)in your downpipe
so that a stock sr20 bosch 02 sensor will fit......bb 02 sensor=bb ecu.......your stock oem ecu, Jwt turbo programmed=n/astock o2 sensor....they have to be compatible or else you'll run funny. Hope that helps:)