chris190

Greetings!

I'm new to this forum and I have some trouble with my engine after installing the pacesetter LT headers.

I hooked up my diablo sport predator and the codes I'm getting now are P0171, P0174 and P0300. The smoke that comes out of my exhaust looks more black.... the tips of the exhaust are dark black so to me it looks like it's running too rich.

Initially... On the first start up when I completed this job I connected the battery and started it and no issues... no codes and the engine seemed to be running fine...(no black smoke).

Now after running it for about 30 min.... it's running rough and it shakes when I try to accelerate around 2-3k rpm. I can drive it but it seems like it has not enough power.



This is what I did to the car:

-Installed the pacesetter LT and used the factory manifold 3 layer steel gaskets.

-Installed new O2 sensors on the front (on the long tubes) and replaced originals with these sensors: NEW BORG WARNER BWD 4W OXYGEN SENSOR
(one of the original broke when I tried to take it off the stock manifold.

-After long tubes I have 3" Thunderbold Cats then a flowmaster (8" tube) reducer from 3" to 2.5".

-Next in line is exhaust coming on the sides. (between the diameter reducer pices and the side pipes I added a small section where I welded the original rear o2 sensors. (so the ones in the front are after marker.... the ones in the rear are the stock ones).

The codes I get say it's too lean but it looks like it may be too rich idk.

What would be the first thing I can adjust in the Predator to make i a bit better.., the LTFT ? and which way you think?

Also is it very bad to drive it like this? .. I drove to work (11 miles) the first time today) and I just want to drive it back home to do more research and tuning with the Diablosport.

Any help would be appreciated..

Thank You

Chris

eaglegoat

It's reading lean, so it's dumping extra fuel and causing it to be rich. I don't know anything about those o2 sensors. If send them back and replace with stock. You need a real tune. Good luck.

eaglegoat

And no I wouldn't drive it like that.

chris190

Thank You for the answer.

Do you think it I can try to tune in the LTFT or WOT or anything with the air/fuel mixture to make the computer put in less fuel for the time being .... just so I can drive it back home without any anxiety? maybe that's all I need ?

If these cheap after marker primary o2 sensors are crap (i know i should have bought OEM)... I can get OEM ones meanwhile.

Also can the code P0300 (missfires) be the result of running too rich?

Thank You again!!

eaglegoat

You can try to tune it with trims, but it's a practice I do not ever advise. You'd be better off commanding open loop and babying it home, no more than 1/4 throttle etc. Yes your p0300 is from rich misfire. Don't let this thing idle too long either.

2xLS1

iTrader: (25)

Shouldn't set lean codes with just LT headers if everything was done correct. So you shouldn't have to change anything with the Diablo to prevent the codes. Something you did is causing the fuel trims to go more than +20% and that is the percentage of fuel the PCM is adding to what it thinks it should use to achieve stoich. The added fuel is fouling the plugs and could me causing the misfires or the misfires could be real because of cracked plugs or loose plug wires dumping unconsumed air into the exhaust driving the trims +. Each scenario could cause the other problem. I've never seen or heard of Borg Warner O2 sensors. Not saying they are junk but I've only ever used AC Delco or Bosch. Not sure if front O2s reach the relocated bungs on GTOs with LT headers. If they don't, did you use extensions or did you cut and splice the O2 wires? If you have to drive it just unplug the front O2s and disconnect the battery to reset the trims. It will stay in open loop until you figure out what the problem is.

chris190

Hi,

I used extensions (wires that came with the pacesetter headers) . I connected the wires and used heat shrinking tubes over the connection points so they are not exposed.... I hope nothing got shorted and I put them next to each other...like some wires to penetrate the shrinking tubes? or whatnot.

I suppose a next step would be to check the voltages on them or maybe I can use the Predator to check for that? (haven't done that before but I can look into it) .

I forgot to mention I also did a tuneup when I did the headers. New MSD wires and new TR5 plugs gaped at 0.42.

By open loop do you mean ..let's say cut the signal wire or all wires from the front o2 sensors and run it like that so the computer won't know what to adjust?

Either way what I'm understanding is even if with aftermarket front O2s if they are running properly and because more away from headers now with long tubes it should still NOT throw off the fuel/air mixture that bad where I have no power and engine is acting weird..shaking if I keep the gas pedal steady and sometimes it felt like the idle was going low around 500 rpm..kinda like trying to die.

I also read somewhere of any vaccum leaks... didn't see any hoses off or anything like that under the hood that I can tell.

Thank you guys so much for all this help... never head this car run like this and it's scarring me.... hopefully it's just a tune or o2s

chris190

Also can I use the original OEM rear o2 sensors and put them in the front? so I don't buy new ones? cause then I can delete the rear o2s alltogether....maybe that's an option.

eaglegoat

I've seen this happen a couple times on GTOs with pacesetters. They are a huge pain in the butt. You can double check for an exhaust leak at the header flange, also recheck that all your plug wires are seated.

Your problem is most likely that the headers moved the o2 location.

2xLS1

iTrader: (25)

Depends on if they use the same plugs front and rear. Some vehicles do, others do not. And using real extensions is not the same as cutting and splicing the O2 sensor wires. There is a chance you crossed some wires and or introduced resistance in the wiring. I don't believe you can permanently turn off DTC codes with a Diablo Preditor. Monitor the O2 viltages with the Preditor. They should be oscillating between 100 and 900 MVs.

2xLS1

iTrader: (25)

I disagree. Just moving them does not cause misfires and fuel trims that cause 171 and 174 lean codes.

chris190

I sure hope so is just the relocation of these sensors.

I checked the plug wires and all good ( I know I felt like 2 clicks for each wire end when I installed them)

I just put back the stock tune from the Predator for now and I started again for a few seconds... exhaust sounds more poppy now... did one rev and still a bit black smoke.


If there is an exhaust leak at the flange of the header I would see it or hear it right? would it have to be big enough to see or hear it to throw out codes like that?.. I looked around with the engine running but couldn't see any.

I guess I will leave the car at work for today and will bring my jack tomorrow to lift up at work to see if I can either change to new OEM front sensors or cut the wires to create an open loop and try to drive slow like that back to my home garage.

2xLS1

iTrader: (25)

No need to cut any wires. Just unplug the front O2s and disconnect the battery to reset the trims. If it still misfires in OL, you likely have cracked plugs or they are fouled from the added fuel. And why run TR5s with such a small gap? Run TR55s with a .055-.059 gap. If you need longer wires for the O2s to reach, buy real extensions with a plug on each end.

eaglegoat

We can agree to disagree. I'm pretty sure I have the logs from one still on my laptop at home. I've seen it more than once on a GTO.

This reminds me that I need to email hptuners about adding the o2 proportional and integrator delay to the 06 OS.

eaglegoat

After you reloaded the stock tune you need to reset the fuel trims.

You may not be able to hear/see any leak. Once you heat cycle the headers you should recheck torque or the bolts. It might not be at the flange it could be at mid pipe.

Like he said, just unplug the sensor. Make sure you're using only good quality parts/pieces from here on out. If you can't do it right, don't do it. It's not worth the headache.

chris190

ha .That makes sense to disconnect the sensor instead of cutting the wires.... don't know what I was thinking lol..

Honestly I got the plugs a while back .. I see now many people use the TR55 so maybe I can change to those too. I know the tr5 come gaped at 0.39 or 0.40 and so many mixed opinions about the gap size which I found out is suppose to be lower than tr55s so went with 0.42

I will buy the real extensions and OEM sensors if I need to tomorrow... thats a good advice in order not to mess with wires. thank you!!

chris190

Thanks man! ... and yea I will keep in mind to buy good parts... that was a wrong decision to get after market o2 sensors where I have to splice and connect wires..deff not worth the headache.

chris190

Here is a vid I made after I put back the stock tune and ran the car for a few min.. I see only (2) o2 sensors appear to show voltages which increase with temperature it seems.

https://www.youtube.com/watch?v=r7ry...ature=youtu.be

btw I thought that when you would flash it back with the stock tune it would also reset the fuel trims but I suppose that's incorrect. Only way to reset those is to disconnect the batter right?

and sorry for the vertical video!!

eaglegoat

Not sure if the diablo had that feature or not. I know hptuners didn't automatically reset the trims when you flash a calibration.

2xLS1

iTrader: (25)

Your STFTs go to +50% almost immediately. I'm going to guess the O2s that read 0v are the fronts and are miswired with their outputs shorted to ground.