uenvyboykin

Ok so I get my car tuned and we pull about 15 dyno runs on it. Everytime but twice the air to fuel ratio was perfect accross the board then it goes stupid lean, I say lean but it went from 12.7 to off the charts lower and I believe that is lean. Oh and it did it everytime at 4,300 rpms or 4.3 volts on the tps sensor. We changed out a few things to see if that was the problem one was the mass air, the other was a lil computer not sure what it was but it was by my intake on my fender panal. Neither of those fixed the problem. We decieded to figure out was wrong at another date. When I got home that day I was lookin at my car and noticed a few things 1. the wire from my zex nitrous kit that tapped in my tps was worn enough to where it had open wires, i fixed that. and 2. my spark plug wires looked a lil worn not where u could see wires but there were def had lil gaps, i got those on order. Can anyone offer me any advice, or has anyone ever had this problem?

uenvyboykin

94 5.0 gt 40 alum heads port and polished, e 303 cam, 1.6 roller rockers, cobra intake port and polished, 255lh fuel pump, adj fuel pressure regulator, msd 6al box, c&l intake tube and 73mm mass air, 65mm throttle body, and i think that might be it the nitrous too but its hooked up but not functional until its tuned.

2 kwik

did you change the tps...as it should be closer to 4.6, did you guys bother to check fuel pressure when this happened? does this happen on the bottle? what plugs are you using? do you have low resist plug wires?

AdderMk2

for starters... 4300RPM's is not 4.3 volts at the TPS
ditch the C&L maf and get a real one
low numbers in the a/f ratio are RICH, not lean

and wtf are you talking about "the other was a lil computer not sure what it was but it was by my intake on my fender panal" Pictures of this item would be great

2 kwik

it's not the maf

samseed101

What was your MAF voltage? You didn't mention injectors so I can only assume they are stock. Also sound slike a 73mm Mass Air but you didn't say what it was calibrated for so again, I can only assume it's 19#. If that's the case, perhaps when you were running lean you were pegging the MAF. It doesn't take much to max one out that is calibrated for 19# injectors. Not too long ago, I was maxing out my MAF at around 4000 RPM myself. That could definitely cause lean issues.

samseed101

If he's pegging it and they screw something up then it could be.

When he said "low numbes" I gave him the benefit of the doubt and assumed that he meant "low' as in "low fuel" as in he was running 15:1 or something. Then again, I know that's not something I should assume.

2 kwik

all I know is I would not use 19's with those mods and gas

92hatchLX

MAP sensor???

I would get a different tuner dude.

uenvyboykin

sorry 24lb injectors, was not running nitrous, im runnin autolite plugs forgot the number but they are a cold plug meant for nitrous