Roush Stage 3 running lean???

[RoushStage_3]

First post on S197 forum but have been using y’all for years!!! I recently bought a 2007 Roush Stage 3 and about 4 weeks ago I recieved a cel for running lean bank 1 & 2 so I put in a new MAF and the problem persisted. Seems unresponsive when not in boost. Then I put in an off road x pipe. Took it to my mechanic and he put an AFR gauge on it or something and said my fuel trims were way off and suggested I get a dyno tune to fix the fueling. But I’m still convinced there is an underlying problem that would need to get fixed before I drop $400 on a dyno tune. Keep in mind I had the cel BEFORE I installed the x pipe. Thanks!


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[msvela448]

What do you mean by a new MAF. Did you replace the MAF sensor itself and keep the same intake tube... Or did you change the intake tube to something else. Was the MAF a stock FORD part? Did you put the exact same sensor back in? Or did you "upgrade" to something different?

All of the above things can have a PROFOUND effect on your tuning.

Why did you replace the MAF? What pushed you in that direction in the first place?

Does the car have the stock Roush Stage 3 tune? Or has someone modified it?

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[CammedS197]

Datalog. But I'd check your 02 sensors. What does the AFR read?

 

[JJ427R]

Datalog. But I'd check your 02 sensors. What does the AFR read?

I had a similar on my Roush and it was a bad 02 sensor as this person stated. Replace that first. Also had similar code when I changed plugs and one of my coil packs connectors was not on completely.

 

[RoushStage_3]

What do you mean by a new MAF. Did you replace the MAF sensor itself and keep the same intake tube... Or did you change the intake tube to something else. Was the MAF a stock FORD part? Did you put the exact same sensor back in? Or did you "upgrade" to something different?

All of the above things can have a PROFOUND effect on your tuning.

Why did you replace the MAF? What pushed you in that direction in the first place?

Does the car have the stock Roush Stage 3 tune? Or has someone modified it?

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I replaced the MAF sensor with factory Delphi. Car was bone stock when I bought it.


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[1950StangJump$]

In my opinion, get it dyno'd. You don't know what tune is on it now, and it may or may not be safe for the car's modifications. For all you know, the original owner "demod'ed" the car before sale but didn't adjust the tune.

Once on the dyno, the tuner should be able to give you some ideas on what the underlying condition is causing the cell -- whether a hardware issue or just in the tune

 

[RoushStage_3]

In my opinion, get it dyno'd. You don't know what tune is on it now, and it may or may not be safe for the car's modifications. For all you know, the original owner "demod'ed" the car before sale but didn't adjust the tune.

Once on the dyno, the tuner should be able to give you some ideas on what the underlying condition is causing the cell -- whether a hardware issue or just in the tune

Probably will, the 2.49 pulley and 90mm idler just came in from Brenspeed today so I’ll probably get then tuned together at the same time


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[msvela448]

If your Roush was bone stock there should be no reason to do anything to the tune. (On the surface). Roush's tune will be the absolute best option for all around driving and power. With the factory tune it should run well whether in sub-zero conditions or in desert heat, racing or cruising, all day, every day.

The lean A/F condition / code, with the car in 100% stock form, was due to something else, possibly a vacuum leak letting in unmetered air, a failed O2 Sensor, maybe a bad MAF. But there are diagnostic trouble codes for failed O2 and Failed MAF. So if you get a check engine light it is important to get the codes by going to a local auto parts store and having them read the car through a scanner connected to your OBD port. (unless you have a programmer already... More on that below).

Once you start modding the car... Changing exhaust pipes, deleting cats, larger intake tubes, s/c or crank pulleys, etc... You will might need an adjustment to the tune. Some changes are minor enough that the computer can compensate, but it can only adjust so far before it thinks that something is wrong and turns on the check engine light.

Now combine a possible pre-existing issue with the addition of modifications and it makes it very hard for any of us to help you without very specific details.

The A/F shouldn't be way off with the little things you've done. There has to be more to this. Did you or anyone else change the pulley on the supercharger or crank? Did you change the air intake tube? Those specific mods are very likely to cause a lean condition due to the increased air flow into the engine.

Did the car come with a handheld tuner? If so... Then someone has already changed the tune. And you can read the DTC's yourself and post the codes you are getting.

We can get to the bottom of this.

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[RoushStage_3]

If your Roush was bone stock there should be no reason to do anything to the tune. (On the surface). Roush's tune will be the absolute best option for all around driving and power. With the factory tune it should run well whether in sub-zero conditions or in desert heat, racing or cruising, all day, every day.

The lean A/F condition / code, with the car in 100% stock form, was due to something else, possibly a vacuum leak letting in unmetered air, a failed O2 Sensor, maybe a bad MAF. But there are diagnostic trouble codes for failed O2 and Failed MAF. So if you get a check engine light it is important to get the codes by going to a local auto parts store and having them read the car through a scanner connected to your OBD port. (unless you have a programmer already... More on that below).

Once you start modding the car... Changing exhaust pipes, deleting cats, larger intake tubes, s/c or crank pulleys, etc... You will might need an adjustment to the tune. Some changes are minor enough that the computer can compensate, but it can only adjust so far before it thinks that something is wrong and turns on the check engine light.

Now combine a possible pre-existing issue with the addition of modifications and it makes it very hard for any of us to help you without very specific details.

The A/F shouldn't be way off with the little things you've done. There has to be more to this. Did you or anyone else change the pulley on the supercharger or crank? Did you change the air intake tube? Those specific mods are very likely to cause a lean condition due to the increased air flow into the engine.

Did the car come with a handheld tuner? If so... Then someone has already changed the tune. And you can read the DTC's yourself and post the codes you are getting.

We can get to the bottom of this.

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Codes are p0174 and p0175. Care didn’t have a tuner when I bought it and as far as I know it’s stock everything. The x pipe was installed after the CEL came on. My mechanic looked but couldn’t find a vacuum leak and checked the fuel pressure to but said that the short and long term fuels trims were off.


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[msvela448]

Something isn't right with those codes... P0174 is a Bank 2 (driver side) too lean code while a P0175 is a bank 2 (driver side) too rich code. I've not seen both of those codes come up together. It should be one or the other.

The P0174 points toward an O2 sensor (on the driver side), or a vacuum leak. The P0174 should be from the "upstream" sensor closest to the engine.

If you are truly getting both codes then you might have burnt / shorted wires on the driver's side upstream sensor.

I can't emphasize enough that you might have a vacuum leak. One of the frequent culprits is the little cap on the T fitting near the brake booster. (Roush may or may not have that cap on the T, depending on their use of the vacuum lines for the bypass valve of the supercharger). That T fitting and cap is located very close to the driver side header on the firewall (about 10 - 12 inches above the collector) and it gets pretty hot, and thus dries out and cracks.

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[RoushStage_3]

Something isn't right with those codes... P0174 is a Bank 2 (driver side) too lean code while a P0175 is a bank 2 (driver side) too rich code. I've not seen both of those codes come up together. It should be one or the other.

The P0174 points toward an O2 sensor (on the driver side), or a vacuum leak. The P0174 should be from the "upstream" sensor closest to the engine.

If you are truly getting both codes then you might have burnt / shorted wires on the driver's side upstream sensor.

I can't emphasize enough that you might have a vacuum leak. One of the frequent culprits is the little cap on the T fitting near the brake booster. (Roush may or may not have that cap on the T, depending on their use of the vacuum lines for the bypass valve of the supercharger). That T fitting and cap is located very close to the driver side header on the firewall (about 10 - 12 inches above the collector) and it gets pretty hot, and thus dries out and cracks.

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My mistake p0171 and p0174 !


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[msvela448]

P0171 and P0174 are indeed both upstream O2 sensors reading a lean condition. This is very likely a vacuum leak and not a bad O2 sensor because it is unlikely that both sensors would be bad at the same time.

If you are 100% certain there are no vacuum leaks, and 100% certain the pulleys for the supercharger haven't been changed, and 100% certain the factory Roush intake tube is installed with the correct MAF.... Then I would suspect the tune is in fact off.

Like someone else suggested, are you sure the previous owner didn't de-mod the car (put all the factory stuff back on) but failed to change the tune file?

Also like someone else suggested...a datalog, or at least posting a few numbers, might also help us diagnose it. I'd be curious to know what the numbers are for your STFT and LTFT on both banks. High positive LTFT numbers also can point to a vacuum leak.

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[RoushStage_3]

P0171 and P0174 are indeed both upstream O2 sensors reading a lean condition. This is very likely a vacuum leak and not a bad O2 sensor because it is unlikely that both sensors would be bad at the same time.

If you are 100% certain there are no vacuum leaks, and 100% certain the pulleys for the supercharger haven't been changed, and 100% certain the factory Roush intake tube is installed with the correct MAF.... Then I would suspect the tune is in fact off.

Like someone else suggested, are you sure the previous owner didn't de-mod the car (put all the factory stuff back on) but failed to change the tune file?

Also like someone else suggested...a datalog, or at least posting a few numbers, might also help us diagnose it. I'd be curious to know what the numbers are for your STFT and LTFT on both banks. High positive LTFT numbers also can point to a vacuum leak.

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Previous owner probably didn’t have time to de mod it cause it was reposed by the bank lol. I’m gonna try to get ahold of my friends SCT handheld and see if I can get some data logging. At the time I don’t have a handheld myself. I’m pretty sure my mechanic said my LTFT was like 23 or 27? If that helps.


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[nawagner]

Agree with those that have mentioned vacuum leak. Check the caps on back of the supercharger at the elbow. They get old and crack.

 

[Marble]

Codes are p0174 and p0175. Care didn’t have a tuner when I bought it and as far as I know it’s stock everything. The x pipe was installed after the CEL came on. My mechanic looked but couldn’t find a vacuum leak and checked the fuel pressure to but said that the short and long term fuels trims were off.


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Unless he is a tuner, he will not understand what the fuel trims are supposed to be for a blown motor.

 

[redfirepearlgt]

Reading this reminds me of the classical mistake made when reconnecting O2 sensors after a clutch job, or LT's or OR pipe mod is done. The O2 sensors get connected backwards. Causes one side to go lean and the other side to go rich. May wish to first check this as you have no idea what the previous owner did to the car prior to selling it.

As for the following statement: "...Roush's tune will be the absolute best option for all around driving and power. With the factory tune it should run well whether in sub-zero conditions or in desert heat, racing or cruising, all day, every day".

The Roush tune is compromised of many nanny protection strategies that fail to unleash the full potential of the packages. A decent dyno number can be generated for bragging rites. But when it comes to putting that to the ground under track conditions the car will be inhibited from doing so. Proper tuning by a reputable speed shop like VMP, PBD, Lund, LITO, or AED will unleash the potential of the 2300TVS packages and create a completely new car to drive and enjoy at a whole new level. Sorry devoted Roush owners. I am speaking from first hand experience. After seeing the light personally I have gone on to enlighten others. Those who I have helped remove the Roush-colored-glasses and see the light have also learned and expressed their gratitude and no longer suffer from this phenomenon. I refer to this cleansing process as "De-roushing". PRAISE THE MAKER!

 

[JJ427R]

^^ Roush is conservative on their tunes as they have to be, they are a production automobiles, same as the Shelby GT500's and GT350's. There is a lot more to be had out of those as well. How about Challengers, Corvettes, Camaros.....

I just get sick of the singling out of Roush and like they are the only ones who are conservative on their tunes or their tunes are so terrible. Once again it's a production automobile covered by a factory warranty, and once you modify it by one of the other places you listed you void that warranty, same as the other production autos I listed. Any of the tuners you have listed offer any warranty? That's my point....

Would I recommend the factory Roush tune for the OP's car, absolutely not, especially since he knows changes have been made, Since he is upgrading the pulley's I'd put the pulleys on and get it on a dyno to eliminate any questions....

 

[Pentalab]

^^ Roush is conservative on their tunes as they have to be, they are a production automobiles, same as the Shelby GT500's and GT350's. There is a lot more to be had out of those as well. How about Challengers, Corvettes, Camaros.....

I just get sick of the singling out of Roush and like they are the only ones who are conservative on their tunes or their tunes are so terrible. Once again it's a production automobile covered by a factory warranty, and once you modify it by one of the other places you listed you void that warranty, same as the other production autos I listed. Any of the tuners you have listed offer any warranty? That's my point....

Would I recommend the factory Roush tune for the OP's car, absolutely not, especially since he knows changes have been made, Since he is upgrading the pulley's I'd put the pulleys on and get it on a dyno to eliminate any questions....

Well Roush did do a few goofy things a few years back per VMP....+ what I was seeing on my aeroforce gauges. Like AFR up to 12.5 :1 and timing pushed forward to a whopping 29 degs. Starting around 09, Roush shut off the knock sensors. The oem Roush M90 tune left me under whelmed, no big deal, but with KS shut off, timing pushed way too far ahead, and timing a tad on the lean side, it was time to get the tune tweaked.... at least turn the KS back on. The Roush 2011 /2012 / 2013 cars had bad tunes in em. They ran pig rich. A few folks on the Roush forum had their cats clog up...and subsequently lost an engine. Several of em video recorded the eng start up at idle..and it was horrid. That took several months to sort out, with dozens of trips to the dealer, and Roush reps coming out to the dealer. It wasn't a few totally isolated cases either. In the end it got sorted out. Then when cars started going out of warranty, folks started getting tunes from VMP / JDM etc. Back then, Roush's 'tune dept' basically consisted of one cubicle.

If you added LT's, bigger TB, etc, Roush would not provide for a new tune. Back then, you sent roush the entire ECU, they sent it back to you...with the roush tune. You are correct though, they have to make their tunes conservative, to comply with their warranty.