Vacuum leak diagnosis suggestions

[O'Rattlecan]

Vince, can you water it down for me? I sit in a cubicle and do debits and credits in a banking system.

What do you mean "fuel trims?"

Ryan

 

[blacksnapon]

the pcm adjusts injector duty cycles to add or subtract fuel as noticed by the o2 sensors.that is the fuel trims.

 

[O'Rattlecan]

Hi Vince,

I'll get this exhaust buttoned up as soon as the dang headers arrive (downside of ebay sellers, they don't ship as fast). Do you think it's worth putting on a new HEGO sensor while it's all apart?

Ryan

 

[blacksnapon]

Hi Vince,

I'll get this exhaust buttoned up as soon as the dang headers arrive (downside of ebay sellers, they don't ship as fast). Do you think it's worth putting on a new HEGO sensor while it's all apart?

Ryan

Can't hurt. After all that's where the pcm realizes if you're lean or rich.

 

[CowboyBilly9Mile]

f your truck cam into my bay, fuel trims are the first thing ] look at. sft (short fuel trim) is the adjustment that the pcm makes fir immediate "repairs" LFT is the adjustment made for larger problems.

Excellent suggestion and explanation of SFT and LFT here and downstream, but how can he look at those on his EEC-IV system without spendy equipment?

 

[O'Rattlecan]

Note: computer is from a 1995 F150, so it's not an OBD II system.

Ryan

 

[blacksnapon]

Note: computer is from a 1995 F150, so it's not an OBD II system.

Ryan

AH, yes, EEC4, gotta love it. Without extremely spendy equipment, you can't get into the data stream.

 

[O'Rattlecan]

Exhaust is getting done today or tomorrow or something. The shop owners cut me a deal because we're friends, but because of it I am low on the customer service totem pole.

Turns out I had a little leak somewhere on the fuel neck that made them nervous to weld. So it got shelved a couple days until they had enough time to pull the tank when welding the exhaust in.

So close................... yet.......... so far.

Ryan