bccentaur3

#1

I've had my car tuned twice and will get it tuned a 3rd time when I come around to getting the water injection kit. Well since the tune, I'll be cruising like normal and the car jerks. My rpms don't drop or anything, but the car just jerks. Is this caused by the spark plugs at all? Could this be an electrical issue?
O yeah, I get a lot of back fire too. Everytime I down shift and sometimes when I slow down in gear. Now what is this caused by?

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98 Celica gt red- totaled deer94 Celica st black DD (bad weather beater)- totaled deer95 Celica gt silver- chassis sold88 Celica All-Trac (Burned to a crisp)94 Celica gt white (sold)In need of a rust free chassis!!!!

lagos

#2

Part of the problem is that the safc is not very good at par throttle tuning. The other part of the problem is that whoever tuned your car, probably only did the high throttle map on a dyno.
You should buy a wideband and try to tweak your low throttle map.... but even then youll never get things perfect, unless you invest in a standalone or at least an emanage ultimate.

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15PSI - 30MPG - Megasquirt Tuned

bccentaur3

#3

Thanks for the fast reply. I guess I will save up for an emanage ultimate. Why pay for a wideband and still not run prefect when I can buy the ultimate and run nearly perfect.

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98 Celica gt red- totaled deer94 Celica st black DD (bad weather beater)- totaled deer95 Celica gt silver- chassis sold88 Celica All-Trac (Burned to a crisp)94 Celica gt white (sold)In need of a rust free chassis!!!!

lagos

#4

you kind of want both so that you can monitor and log things on the street and then make adjustments on your own.

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15PSI - 30MPG - Megasquirt Tuned

FunkySR

#5

>

QUOTE(lagos @ Mar 30, 2008 - 6:45 AM) [snapback]659642[/snapback]

>
Part of the problem is that the safc is not very good at par throttle tuning. The other part of the problem is that whoever tuned your car, probably only did the high throttle map on a dyno.
You should buy a wideband and try to tweak your low throttle map.... but even then youll never get things perfect, unless you invest in a standalone or at least an emanage ultimate.

yes you are so right. I reached the end of the safc's capabilities yesterday. I am now saving for emanage ultimate.

6strngs

#6

what exactly causes the jerking? Is it that the SAFC is altering the MAP sensor signal so much that the ECU thinks you are decellerating and shuts off the injectors like it does during decelleration? cause when mine bogs I see my wideband go way lean (too lean to register a number) like it does during decelleration. that's my theory.

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94 GT - Sold -------- 69 Pontiac Lemans - Sold88 Alltrac - Sold ---- 04 WRX - Sold00 GT-S - Sold ------ 91 Miata - project/drift car95 GT - Sold -------- 96 GT - New Daily Drive

lagos

#7

>

QUOTE

>cause when mine bogs I see my wideband go way lean (too lean to register a number) like it does during decelleration.

Thats normal. All cars cut fuel to basically nothing when you let off the gas.

Safc is just not a good way to tune for bigger injectors. It tries to fool the ecu to think that its seeing more/less air, but at the end of the day, the ecu is still going to do what it wants to. You also only have a very basic low/high throttle map and nothing in between.

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15PSI - 30MPG - Megasquirt Tuned

bccentaur3

#8

well am I actually suppose to have a low throttle map at 20% and a high map at 25%? someone told me that that setting is way off.

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98 Celica gt red- totaled deer94 Celica st black DD (bad weather beater)- totaled deer95 Celica gt silver- chassis sold88 Celica All-Trac (Burned to a crisp)94 Celica gt white (sold)In need of a rust free chassis!!!!

rjbibeau

#9

did MAP use a wideband with your tune Will?

bccentaur3

#10

Yeah they did. But I have also been told that their wideband is off. To be honest I don't even think Alex tuned my low throttle setting as good as he did the high throttle. Thats why I'm going back one last time.

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98 Celica gt red- totaled deer94 Celica st black DD (bad weather beater)- totaled deer95 Celica gt silver- chassis sold88 Celica All-Trac (Burned to a crisp)94 Celica gt white (sold)In need of a rust free chassis!!!!

presure2

#11

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QUOTE(bccentaur3 @ Apr 2, 2008 - 11:27 AM) [snapback]660822[/snapback]

>
Yeah they did. But I have also been told that their wideband is off. To be honest I don't even think Alex tuned my low throttle setting as good as he did the high throttle. Thats why I'm going back one last time.

if your just doing WOT throttle dyno runs, they cant tune the lo throttle maps.

IIRC my throttle settings were similar to those you posted (i cant remember the exact %'s) my reasoning is, that anytime your in boost, you dont wanna be on the lo throttle map, which in theory should be alot leaner.
from watching the safc, i could see that at anything over ~25 or so % throttle, i would make boost. so, i set the hi throttle map to ~ 30%, so that anytime i would go into boost, i would be using the hi throttle map, while still being able tune the lo throttle map fairly lean.

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Former Team 5SFTE pro member ;)13.6@108MPH, 5SFTE Powered

bccentaur3

#12

So do you have a wideband to tune with?

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98 Celica gt red- totaled deer94 Celica st black DD (bad weather beater)- totaled deer95 Celica gt silver- chassis sold88 Celica All-Trac (Burned to a crisp)94 Celica gt white (sold)In need of a rust free chassis!!!!

presure2

#13

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QUOTE(bccentaur3 @ Apr 2, 2008 - 8:23 PM) [snapback]661017[/snapback]

>
So do you have a wideband to tune with?

no, i tune by smell.

j/k
yes, i have a wideband.

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Former Team 5SFTE pro member ;)13.6@108MPH, 5SFTE Powered

rjbibeau

#14

ohh ya rotten egg smell

bccentaur3

#15

Manny, you're a funny guy... NOT!!!!! Like I would've believed that.

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98 Celica gt red- totaled deer94 Celica st black DD (bad weather beater)- totaled deer95 Celica gt silver- chassis sold88 Celica All-Trac (Burned to a crisp)94 Celica gt white (sold)In need of a rust free chassis!!!!

rjbibeau

#16

he's got the nose of a wideband!