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-20% LTFTs What else?

Booba5185

Booba5185

New member
Hey guys, I've been chasing small problems with my car, an oil leak, exhaust leak, and such. At the beginning of it all my LTFTs were -10%, 02 sensor is a Denso about 2 months old. Now they're at -20% at idle and around the same at 2500 RPM, STFT's are ~10-15% at 2500 RPM and hoover +\- 3% at idle. I've tried different MAF sensors I have (3, all cleaned) and nothing changes. I do get 1-3* of KR climbing a hill in cruise control, and I can hear a slight clatter from the valves, although I think the oil leak fix took care of that. I typically run ethanol free gas, and I put Techron through the tank a few weeks ago as well. FPR doesn't seem to be leaking. I'm pretty much at a loss here...what do you guys think?
 


I would check around the EGR tube that bolts to the rear exhaust manifold, also if your still running the stock throttle body is the honeycomb part still inside??
 
From what I have read the kr while climbing a hill is cause by the torque converter and is completely normal. My car does this as well.
 
I am running the stock throttle body, but the screen is removed. I'll check the EGR stuff tomorrow, however I am curious how it would cause a rich condition?

I am running a GT torque converter, so it is a slightly higher stall. This didn't happen before my new transmission.
 


That screen is put there for a very good reason and by removing it you could harm your engine. Sooooooo put it back or face your engine wrath
 
99+ throttle bodies especially the screen you took out helps straighten airflow for a better maf reading
 
Screen is back in, but I haven't driven or started it yet. Long day at work, but I might head back out there tonight and take it for a spin. It'll kinda be bitter sweet if this fixes it all. I'll be glad it's fixed, but irritated that I broke it in the first place. I swear, I'm never reading anything on ZZP's website again.
 
Its not as dramatic on 97-98 style tbs but the maf table needs to recalibrated when you mess around with it. And you have no way to tune...its best left alone
 


I've got a 2000 so I never shoulda messed with it. I'll still check the EGR and such tomorrow. I ran and passed a smoke test a month or two ago and passed, so I believe I don't have any vacuum leaks. Those wouldn't cause a rich condition though.
 
You shouldn't see a 20% change from a maf screen. If you did it would usually be leaner and less noticeable at higher flow points.
 
That's kinda what I'm thinking. It will help, but I think there's something else going on. What? I have no idea. If I had a stuck injector it would cause a misfire or something, right? I've gotten no misfires at all.
 
Misfires show as lean. Exhaust leaks show as lean. Vac leaks show as lean...

Having negative trims is uncommon in modded cars to say the least... if it was me I would check fuel pressure.. fuel injectors... and if I had a goofy pcm tune setup for a ported tb or different maf sensor.
 
Stock tune, but I do have a fuel pump rewire. I also have the 2 speed **** bypassed via the relay pin. I'll drive down to Oreilly's on the test drive today and rent the fuel pressure testing kit. Short of clicking, how else should I check my injectors?
 


Other than making sure they are stock injectors... best way to see if they are leaking is to check the fuel pressure and see if it drops without the pump running.
 
Yea, it's bit me in the ass before, the alternator booster (diode). Another problem causing "mod." Anyways, I just made a lunch run in the car, and the LTFTs are down to -10.7% at idle, and dropping slowly (like LTFT's do) it was at -9.4% when I shut the car off. Under light acceleration it's still up to -20.7% though.
 
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