Help Examine My Datalogger Results!!

[StreetThisDSM]

This was a 2nd gear pull. The car was midly warmed up. Here are the results:

Air Temp - 137 deg
Throttle Pos - 99%
Coolant Temp - 204 deg
o2 Trim - 100%

Fuel Trim Hi - 117%
Fuel Trim Mid - 100%
Fuel Trim Low - 139%

RPM - Knock - Timing - o2 - Inj. P/W

3718 - 0 - 26 deg - .84v - 7.95mS
3906 - 0 - 25 deg - .86v - 9.49mS
4125 - 0 - 23 deg - .86v - 11.03mS
4375 - 0 - 21 deg - .88v - 13.33mS
4468 - 0 - 17 deg - .90v - 15.38mS
4687 - 0 - 18 deg - .90v - 17.44mS
5031 - 0 - 19 deg - .90v - 18.72mS
5250 - 0 - 19 deg - .90v - 19.74mS
5343 - 0 - 21 deg - .92v - 18.97mS
5531 - 0 - 21 deg - .92v - 19.23mS
5687 - 1 - 21 deg - .92v - 18.21mS
6165 - 15 - 17 deg - .92v - 16.92mS
6281 - 19 - 16 deg - .90v - 17.18mS
6437 - 18 - 14 deg - .92v - 13.33mS
6562 - 18 - 12 deg - .94v - 15.64mS
6625 - 25 - 14 deg - .92v - 15.64mS
7000 - 24 - 09 deg - .94v - 11.79mS
7093 - 24 - 09 deg - .94v - 14.62mS

I have been getting some bucking and jerking in the higher rpms. Usually 5500 rpm and higher. It almost feels like fuel cut to me. I have owned the car for about 2 weeks now. Since then I have replaced the plugs with the NGK BR7's and a new fuel filter. The wires looked ok, but I will be replacing them sometime here in the future.

Minus the mbc and K and N air filter and modded air box, the car is 100% stock when it comes to performance. I have the boost set at 15 psi. When I datalog in 3rd gear. I build a lot more knock then what I got from this 2nd gear pull. When the car is cold, it runs way better then if it was to be on for 20 minutes or so.

Please help give me ideas here. I am going to order a Walbro and re-wire the fuel pump in the next week or so. I think that will help me out some.

 

[CanadianTSi]

Turn down the boost abit

 

[StreetThisDSM]

Turn down the boost abit

Even If I turn down the boost, it still bucks and jerks in the higher rpm. Its the worst in 3rd gear.

I'm hoping the Walbro and re-wiring of the fuel pump will help. Also once I get it e-checked the catalytic convertor is coming off and a testpipe is going on.

 

[StreetThisDSM]

O and I always run 93-94 octane fuel

 

[CanadianTSi]

So you've changed the plugs and wires and your still bucking...Have you checked for boost leaks??

 

[StreetThisDSM]

So you've changed the plugs and wires and your still bucking...Have you checked for boost leaks??

I haven't changed the wires yet. I will be buying some NGK's here real soon. I have no checked for boost leaks yet. That is something I will be doing soon.

 

[1fast97gsx]

you're running too lean and the boost is too high. Your timing should go down and once you hit boost it should smoothly increase... yours does the exact opposite. Richen it up a little and/or lower the boost. Check for boost leaks asap .. something is not right don't keep driving like that!!!!

 

[StreetThisDSM]

you're running too lean and the boost is too high. Your timing should go down and once you hit boost it should smoothly increase... yours does the exact opposite. Richen it up a little and/or lower the boost. Check for boost leaks asap .. something is not right don't keep driving like that!!!!

I don't think its running to lean at all! .90 is = to 13.2:1 air/fuel, which is perfect. My plugs were nice and tan like they should be. There may be a boost leak, but I haven't been able to find it yet. The car runs like a freakin champ and doesn't buck or jerk at all when it hasn't fully warmed up or been driven for 20 minutes or so. I think heatsink is killing my performance.

 

[Tarantula]

Yep heat sinking.... With 137 F air temps plus 15 psi compression of air, your intercooler is heat soaked and you are knocking. (Obvious from your log) If you don't have the manifold heat shield, put one on. Shield your filter from the rest of the engine. You are on the right track in replacing the fuel pump. I would have to agree with turning down the boost and checking for leaks.

 

[CanadianTSi]

13.2:1 is to lean under boost, you want to be around 11.5:1...beside you can't tell your real A/F Ratio without a wideband.

Change your wires and tigthen all your connections.

 

[mitch83]

13.2:1 is to lean under boost, you want to be around 11.5:1...beside you can't tell your real A/F Ratio without a wideband.

Change your wires and tigthen all your connections.

to help you understand a bit more what he means by not being able to tell A/F without a wideband. When you go into wide open throttle the ecu dosent really use the O2 sensor to make fuel corrections so the O2 is pretty irrelevant at WOT.
mitch

 

[StreetThisDSM]

Ok thanks for all the help guys! I am still very new to DSM's. I have spent the last 3 years knowing everything there is to know about MX-6's and Probes. Now its time to learn something new

 

[mitch83]

Good choice
mitch

 

[frontdriver]

Boost leaks seem to be the #1 tuning problem. Also, check your base timing and make sure it's not too far advanced. The datalogger thinks your base timing is 5*BTDC unless you correct it.

 

[StreetThisDSM]

Well I figured out that lack of fuel was my problem haha. My cheapo boost gauge that I bought the car with doesn't read right. It is about 3 psi off. So when I was thinking it was at 15 psi, it was actually at 18 haha. I turned it down, so now it should be at 15 psi. WOOOW does the car feel better. I want to get back to the track and see what it runs now. My 14.4 was with it jerking and hesitating and set at 18 psi.

Thanks again everyone!!

Time to order the walbro and re-wire the fuel pump. Then I can run 18 psi hehe