Problems leaning out. Please help!

[Terminator2003]

Lately my car has been throwing the CEL. I hooked up my Diablo handheld and checked the code. The system is running lean.

So anyways, I did some data logging and kept an eye on the voltage. I replaced both the battery and alternator within the last month. Voltage is staying around 13.4-5. I did a few WOT pulls and some regular driving. Once I reviewed the data log, I saw that it dipped into the 12s a few times with the lowest point being 12.6V. The highest the voltage read was 13.6V.

That being said, I don't think the alternator is the issue. I wondering if you guys think my fuel pump is crapping out? What other suggestions could you give me?

The weird thing about it is, every time the CEL comes on, I'm just cruising at low RPM....no WOT pulls at all. It has come on 3-4 times in the past week.

Couple notes, I have a 2.8 upper pulley and a tune. I recently just changed the spark plugs to some fresh TR6's.

Anything else I should check through the data log? Or other ideas? Any help would be great! Thanks

 

[lxhatch302]

You need more Than 12 volts at wot. I had the same problem with mine and alt was bad

 

[Terminator2003]

You need more Than 12 volts at wot. I had the same problem with mine and alt was bad

So you think that since it dipped to 12.6V that it is indeed the alternator again? Before I replaced the alternator last month, I ran data log and the voltage was dipping into the 10s for voltage. So I knew right away that it was the alternator.

And remember, the CEL seems to always come on at cruising speeds. Not at WOT

Anyone else have input? Thanks

 

[2003_svtcobra]

Try putting a bigger pulley on it to slow it down!

 

[Terminator2003]

Try putting a bigger pulley on it to slow it down!

Thanks, I guess I could give that a try. Metco makes a few different sizes from 3.2" to 4". What side would you guys suggest? Does it really matter?

Also, do you guys think this is the cause? Are the stock fuel pumps known to have issues? My car has 36k on it.

Thanks for the help!

 

[2003_svtcobra]

i put a 3.2 on mine. because my voltage would drop off to 12.4 around 6k once i put the bigger pulley on it. it fixed it

 

[03cobra#694]

Check for vac leaks, especially around the intake.

 

[Terminator2003]

I'm still pretty stumped about this issue It seems to do it when I'm just cruising and not during WOT pulls.

My car also completely died a few times when down shifting. Would this suggest a vacuum issue?

Any help would be great! Thanks

 

[Terminator2003]

Well I'm confused even more now. I took off the "custom" tune, put on the Diablo "pulley tune octane 91" and within an hour of driving the car, the CEL light came back on.

I read the code and once again the "P0174 System too lean" came on.

Like I said before, I data logged and it did dip down to 12.6V for a split second. My alternator is 1 month old. Do you think it could be on its way out already?

What about the fuel pumps? Are the stockers known to shit the bed? Could they be causing this problem? I checked for vac leaks but didn't find anything.

Any help would be greatly appreciated.

 

[03cobra#694]

OBD-II Trouble Code: P0174 System Too Lean (Bank 2)

 

[hotcobra03]

code

are you only getting 1 code? or both 171/174

 

[Terminator2003]

OBD-II Trouble Code: P0174 System Too Lean (Bank 2)

Thanks! I'll give that a try

And yes, it is just throwing the one code (P0174)