Wot Leaning out

M

Murt TTA

Condoms prevent minivans
Joined
Feb 25, 2002
I am having a problem leaning out in the top end at about 80 mph and over my o2 numbers just seem to drop to about 650 then it starts to knock so I let off.

Stock turbo, thdp, adjustable regulator, 50 lb injectors, turbo tweak chip for 50's 20 deg/18 deg. It started leaning out with this combo so I replaced the intank pump w/ a walbro 340, new fuel filter, and stainless lines because the line broke changing the fuel filter. I tried adding a little boost to a bout 17 lbs, lowering the boost all the way down to 14. Boost is holding constant with no creep in 3rd. Plugs are gapped properly at .035.

I also have been running the reccomended fp of 43 line off, I also have adjusted that up and down a few psi. I put a fuel pressure guage ran it to the hood and when the 02s are dropping the fuel pressure is staying constant at about 58-59 w/ line on. I also tried adding 20 % fuel w/ the turbo tweak chip but that didn't help.

Swapped out MAF meters, the Maf reads 255 with no drop out.

Battery voltage is staying constant at about 13.4-13.5 at Wot.

I am running out of ideas here. I am thinking about putting back in a set of stock injectors and another chip if I cannot figure this out...

any ideas appreciated.

thanks
 
This is strange since you added 20%, and had fuel being delivered, but had no change in O2's - wonder if you already have the 50's maxed out?
 
Blown&Injected said:
This is strange since you added 20%, and had fuel being delivered, but had no change in O2's - wonder if you already have the 50's maxed out?
Click to expand...

i dont think so since hes only at 17 psi, i ran 37#s with 17psi with no problem. i was thinkin maybe a volume issue? hes got pressure.
 
hotwire kit was installed as well at the same time the fuel pump was upgraded with no change in the o2 numbers...

93 octane gas is being used also.

I am thinking of putting the stock injectors and stock chip back in to see if there is any change if I can't figure anything out..

3" thdp, no cat, hooker exhaust, K and N filter cleaned recently. o2 sensor is a delco purple wire, not sure on age, but it seems to be bouncing back and forth.

I am going to get direct scan hooked up and see if i am missing anything over the scanmaster...
 
Murt TTA said:
hotwire kit was installed as well at the same time the fuel pump was upgraded with no change in the o2 numbers...

93 octane gas is being used also.

I am thinking of putting the stock injectors and stock chip back in to see if there is any change if I can't figure anything out..

3" thdp, no cat, hooker exhaust, K and N filter cleaned recently. o2 sensor is a delco purple wire, not sure on age, but it seems to be bouncing back and forth.

I am going to get direct scan hooked up and see if i am missing anything over the scanmaster...
Click to expand...

Post a log file and lets have a look.
 
johnnyttype said:
i dont think so since hes only at 17 psi, i ran 37#s with 17psi with no problem. i was thinkin maybe a volume issue? hes got pressure.
Click to expand...

AGREED

just looked and a stock turbo with 50's

WOW! can the simple O2 be that far off? I know the WBO2 is much better but damn man, maybe another O2 sensor is in order???

Mine has been eating Sunoco Blue so....
 
UPDATE:

I took the car out for spring, did some spring cleaning. Got a new ac delco o2 sensor in the car, Just took it out for some WOT blasts and the o2 numbers are just dropping off under 700 then it starts to knock a little so I let off this is at about 85-90mph or so 16 psi, 93 octane, 50's , same combo as before. I still haven't hooked up a directscan but I will get getting a beater computer to check it out soon...

How do I check my fuel pump flow even if i have pressure? Maybe I have bad injectors? I used the lucas cleaner...

I also have the typical header crack, but its not huge.

BLM numbers look fine at idle and WOT.

The car seems to run ok with no misses / popping / or stuttering at idle or WOT. Maybe a bad ground? I relocated all my grounds to the intake manifold instead of the head but everything looks secure.

I might throw a set of stock injectors and fpr, I am outta ideas.

any insight appreciated.
 
As long as you have pressure at WOT, you still have volume. How much knock are you seeing? Try turning the fuel pressure up and see what it does.
 
I've turned the fuel pressure up, even added 20% in the TT chip and it will just run rich -- 850 or higher 02's, until it eventually leans out up top...
 
IC stock?, have you cleaned it out? could be force feedng a bunch of old oil inside from inside IC or the front is full of bugs
Maybe false knock? does it jump in numbers or climb?
make a run then check plugs?
Air restriction IE filter?
gap plugs @32

Hmmmmm
 
front mount intercooler - no oil residue, or cooling issues:rolleyes:

air filter is a K and N cone filter cleaned about 300-400 miles ago, I guess i could try re-cleaning it again can't hurt... Plugs are gapped at a tight and are not old.

Knock is increasing, starts to climb .2 , .7, 1.5... then off comes the foot...

Its really puzzling, I am going to have to get the directscan for more info I think.
 
did it start doing this after you cleaned the filter?..

only reason I ask is when i did the K&N oil treatment it coated my maf and threw everything out of whack, I was chasing things and tossing parts at it when all along I greased up my inards with k an n oil
 
You have a good head scratcher going on. I'm surprised that adding 20% more fuel didn't change the blm's.

I'm throwing out thoughts..

Have you tried unplugging the computer and let it re-learn?
What do the plugs look like?
Any chance the fuel filter was put on backwards affecting flow?
Were your grounds on the intake before or after the injector/TT chip install? If before the injector/TT chip, was it running correctly then?
+2 on a Log File

Steve
 
I actually changed the longblock, the stock one had a miss and it turned out to be low compression on one cylinder and I had a 87 T that I parted out w/ a good running stocker. I drove the car before it was parted it there didn't seem to be any leaning out or these problems on the other car.
 
I've swapped a spare ECM, spare MAF, spare coil pak/ module.. all with no success since I had the spare parts car...

I've reset the ecm to relearn to no result.

I'll double check on the fuel filter to see what way its going. Or i'll just change it again at this point who knows.
 
Might want to get those injectors flowed if you swap them for the stockers to see what they flow. Could have some debris in them, also check out the injector harness. Hell, the chip could be burnt for the wrong injectors, email the chip maker to look up the chip's part # and see what injectors it's burned for.

50's, hotwired 340 and 20% on top is a ton of fuel for 17psi and a stock turbo.

Curious what your injector duty cycle is during a WOT blast?
 
Not sure what my inj. duty cycle but I'll get it when i hook up the direct scan. Chip is a Turbo Tweak according to what was written on the chip, but anything is possible.

Plugs looked okay last time I pulled it. Wires are Russ Merritts custom wires. I'll try to get a laptop w/ directscan on it, check the fuel filter, and pull the plugs again.

Inj. harness looks okay from a visible inspection.:rolleyes:
 
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