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Damn fuel trims, guys I searched!

oldman

DSM Wiseman
9,794
190
Jun 21, 2003
Dayton, New_Jersey
kams1gsx said:
my o2 has been bouncing around from like 0 to.37 to.6 and only gets to .89 at full spool,also turbo light comes on and off,what the hey? OMG
That is normal but what is a turbo light?
steve said:
Yes, cycling. The voltage should cycle back and forth between say 0.3v and 0.7v (your numbers will vary) at idle, low throttle driving and cruising.
 

kams1gsx

Proven Member
52
0
Feb 19, 2005
lower lake, California
At least i thought it was a turbo light,its the one that kinda looks like a carosel thingy to the right of the check engine light.I dont know, ive only had my dsm 4 a few months.
 

eclipsegsx1736

Supporting VIP
1,600
37
Nov 11, 2003
Los Angeles, California
Coolant fluid is low.
 

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SiX_BoLt

Probationary Member
25
0
Apr 28, 2005
Morganville, New_Jersey
best way to tune is to lean it out until u get little knock and then richen it up a little. Timing is important too

My problem with the fuel trims is that i cant get my low fuel trim at idle to get to 100%. I turn the idle clockwise and that doesnt help. Idle actually increases. I thought idle increases when leaned out? Same applies when turned out counter-clockwise. Any help or link to tuning with the MAFT would be great help thanks!! :dsm: :talon: :laser:
 

dsmsucks

Proven Member
660
4
May 14, 2005
Rochester, New_York
Okay guys I was out today messing with my car and I noticed something. I broke my damn boost controller. :mad:
I was wonder would that have something to do with the ruff idle. I should be getting my o2 in a 2morrow or wednesday
 

oldman

DSM Wiseman
9,794
190
Jun 21, 2003
Dayton, New_Jersey
Depending on how it's broken and where you're tapping as pressure source for the mbc.
 

oldman

DSM Wiseman
9,794
190
Jun 21, 2003
Dayton, New_Jersey
dsmsucks said:
Im was using the joe-p mbc. I broke the adjusting nob off. As for pressure source was using the wastegate and bov line
You will have to make the determination whether the broken knob is allowing air to enter/leave the system. If so, tapping the BOV line means you have a vacuum/boost leak and will effect your idle as well as the BOV. One of few reasons why it's best to leave the BOV line alone and tap from the compressor/J-pipe instead.
 

dsmsucks

Proven Member
660
4
May 14, 2005
Rochester, New_York
oldman said:
You will have to make the determination whether the broken knob is allowing air to enter/leave the system. If so, tapping the BOV line means you have a vacuum/boost leak and will effect your idle as well as the BOV. One of few reasons why it's best to leave the BOV line alone and tap from the compressor/J-pipe instead.
Yeah I started the car up today. I could feel air leaving the bov line. This upcoming friday I will have a new denso o2 and spark plugs. Im going to see if any of this made a difference in fuel trims. If not, that means its the ecu :mad:
Will keep you updated oldman!!
 

turbo2086

Proven Member
200
7
Jun 8, 2005
Eau Claire, Wisconsin
Okay here is another problem. Think its probably the same as the other guy. Didnt want to make another thread on it.

I replaced my O2 sensor, then stopped getting readings at idle a few months down the road. Before it cycled. Replaced the sensor for free, from the manufacturer, I said it was a broken warmer. Same thing. On my MMCD my fuel trims are all at 139% and dont seem to really change at all, not matter what rpm I'm at. However the o2 will get readings while cruising. Think its a whacked ECU also? :(
 

dsmsucks

Proven Member
660
4
May 14, 2005
Rochester, New_York
Well guys it wasnt the o2 sensor?! The car continues to run rich. I even took backed out the screw and took out the lower and side honey combs(nothing OMG )Im just going to throw back on the stock stuff(1g mas and 450cc injectors
 

steve

DSM Wiseman
14,856
1,718
Feb 3, 2002
Boulder, Colorado
Is the ECU still reading 2.5v on O2-R?

When you unplugged the sensor and still read 2.5v I tried to suggest that it was a ECU problem not a sensor problem. Putting the stock stuff back in isn't going to fix the problem.

Steve
 

dsmsucks

Proven Member
660
4
May 14, 2005
Rochester, New_York
steve said:
Is the ECU still reading 2.5v on O2-R?

When you unplugged the sensor and still read 2.5v I tried to suggest that it was a ECU problem not a sensor problem. Putting the stock stuff back in isn't going to fix the problem.

Steve
Yes the ecu does still read 2.50 at the o2r. What I dont understand is that I put on the following and (2g mas, 550cc, supra sidemount) and the car ran good until one moring?
Guess I have to replace the ecu then :mad:
thanks steve!!
 

steve

DSM Wiseman
14,856
1,718
Feb 3, 2002
Boulder, Colorado
What's to understand? Stuff breaks all the time and rarely gives any notice.

Like I said back on the 27th, it sounds like the EMI filter for the O2 sensor has failed.
Since the ECU is seeing a rich signal from the O2 sensor it's pulling as much fuel and it can driving the fuel trim to it's limit and making the car run lean.

The EMI filters are a pain to replace but they can be. It's cheaper than another ECU.

Steve
 

dsmsucks

Proven Member
660
4
May 14, 2005
Rochester, New_York
steve said:
What's to understand? Stuff breaks all the time and rarely gives any notice.

Like I said back on the 27th, it sounds like the EMI filter for the O2 sensor has failed.
Since the ECU is seeing a rich signal from the O2 sensor it pulling as much fuel and it can driving the fuel trim to it's limit and making the car run lean.

The EMI filters are a pain to replace but they can be. It's cheaper than another ECU.

Steve
Pulling a rich signal? Dont you mean pulling a lean signal so thats why its runing lean? :)
 

dsmsucks

Proven Member
660
4
May 14, 2005
Rochester, New_York
All I have to say is STEVE IS THE MAN!!! My car is 100% better, idle, fuel trims, ect. All you 1g guys with stuck fuel trims and other ecu problems, take business to steve. Check his home page out!!!!

Now I have a new problem! Okay now when a 1g gets the 550cc/2g mas comb the car runs rich at idle right? Why does my car run good when I go +5 on the safc but in order to get fuel trims low to l00% I have to go down on the afc to -23 before it reads 100% Now what bothers me is when I do this the car doesnt rev to good. Only revs good when I go +5 on the safc but the fuel trim low reads 81%?!?!
 

turbo2086

Proven Member
200
7
Jun 8, 2005
Eau Claire, Wisconsin
Well here is my the status of my fuel trims LOL... I reset my fuel trims, and put an UNHACKED 1g mafs on. I have o2 readings at idle now! My fuel trim low shot back up to 139% within 20 miles or so. My fuel trim M is at 101% and after a lot of WOT my fuel trim H is at 108%. Again o2's cycle at idle!

I got the new version of MMCD (one that shows o2f on 1g's) Mine reads 3.47v. Which is not the 2.5volts I read up there^^^ This mean I'm still really lean?
 

steve

DSM Wiseman
14,856
1,718
Feb 3, 2002
Boulder, Colorado
turbo2086 said:
I got the new version of MMCD (one that shows o2f on 1g's) Mine reads 3.47v. Which is not the 2.5volts I read up there^^^ This mean I'm still really lean?

No like it sais above you have to use the O2-R parameter because O2-F in MMCd is logging the wrong ECU parameter.

Steve
 
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