Lean at wot

[Ttype6]

So should i also switch my maf? i have one... there arent any leaks or holes and the translator is set how the manual says for the tt chip on on on off and both dials at 0

Record a log first.

 

[Mr.Spool]

So should i also switch my maf? i have one... there arent any leaks or holes and the translator is set how the manual says for the tt chip on on on off and both dials at 0

Shouldn't hurt it

 

[SCOOBY DOO]

I mentioned earlier that the ECM does its thing from the data the 02 sensor sends it...and Eric says the reading looks dead, and I agree. Why not swap in a new Denso 02 sensor. I think you said you don't even know how old it is.

 

[Eric Stage I]

I just looked at one of my old logs and it shows right around 100 grams at a similar pressure and rpm.

Thanks for double checking. I was trying to look through some old logs also, to see what “normal” is.

 

[Ttype6]

I mentioned earlier that the ECM does its thing from the data the 02 sensor sends it...and Eric says the reading looks dead, and I agree. Why not swap in a new Denso 02 sensor. I think you said you don't even know how old it is.

The O2 was unplugged in that log. In the other log,the O2 is very active.

 

[TireFryer]

File after resetting ecm and plugging in the narrowband sensor. fuel pressure set to 46 psi line off. Still lean but i did see the fuel gauge rise as i got into a little boost. Should i try my spare maf i have? It looks like the maf is reading 100 at 6 psi and about 50 at 1 psi... so like half of what it should?

 

[Ttype6]

Should i try my spare maf i have?

Yes,but it would be nice if it had the screen installed. Does your current maf have the screen? Is this a 3.5" maf? Did the engine run better? Any sputtering or laying down?

 

[TireFryer]

It runs great its just so lean. Current maf has a screen. I ran my spare screenless maf in my 87 and it ran great also. It doesn't sputter or buck it just kind of lays over when it gets lean.

 

[Ttype6]

It runs great its just so lean. Current maf has a screen. I ran my spare screenless maf in my 87 and it ran great also. It doesn't sputter or buck it just kind of lays over when it gets lean.

It's definitely lean. Have you measured them to see if they are 3.5" diameter?

 

[SCOOBY DOO]

From the initial log I'd swap the 02, but that's just me.

 

[TireFryer]

here is the log from the other maf without the screen

 

[TireFryer]

yes they are 3.5

 

[Ttype6]

Well,that all looks better. Did it feel better? It looks like power went away at frame 3241 either by losing battery voltage or a power wire shorting to ground. Look at your chip settings to see if they all returned to default.

 

[TireFryer]

I actually shut the car off then keyed it on a couple times and forgot to stop recording. It seemed to be a little better. I think ill replace the narrowband like scooby doo said but maybe ill take one more log with the narrowband unplugged and see what happens

 

[Ttype6]

Did you simply turn the ignition of and then back on at frame 3241?

 

[Ttype6]

I actually shut the car off then keyed it on a couple times and forgot to stop recording. It seemed to be a little better. I think ill replace the narrowband like scooby doo said but maybe ill take one more log with the narrowband unplugged and see what happens

The narrow band is simply telling us what the air/fuel ratio is. We also have the wide band backing it up. If the narrow band was bad and the cause of the problem,it would not have been so very lean when you got into the throttle while it was disconnected. The MAF did show an improvement. It's the one thing that has caused an improvement. nothing else has.

 

[Ttype6]

Thanks for double checking. I was trying to look through some old logs also, to see what “normal” is.

oops,my engine is 273 cu. in.

 

[Mr.Spool]

I still cant get to the file,but your in good hands

 

[TireFryer]

i think ill throw on a return line and see what happens..

 

[Ttype6]

i think ill throw on a return line and see what happens..

The reason I had you bump the fuel pressure up to 46 line off is so that when you put the line back on the pressure will fall 5-7 psi. You should check to make sure this is happening. It should be, because we know that it will get down to 39 according to your earlier test. The reason that we want it to do this is so that when the engine is running with the line connected,the pressure will be in the 39 to 41 psi range. As soon as you open the throttle and the vacuum falls,the pressure will rise instantly. this is what it was not doing before you increased the pressure. The computer program is plotted with the assumption that the fuel pressure will rise when you open the throttle and it adds the appropriate amount of fuel for that scenario. If the fuel pressure doesn't rise when the program thinks it should,there wont be enough fuel injected and it will go lean. When you replace the return line,you will be able to adjust the fuel pressure down to 42 line off. The computer will adjust the fuel delivery at that lower fuel pressure based on info from the O2 sensor,and just like now,the fuel pressure will rise when you open the throttle. Everything that is happening now will happen in the same way and you will still be lean by the same amount at a lower fuel pressure. The line won't fix your problem because something else is causing it. Again,the MAF is the only thing that has caused an improvement.