Running lean and detonation

[Kong76]

Been having detonation issues after installing the FRPP2 kit a couple months back. Plugged in my scan tool and saw that my STFT and LTFT are both positive at 3 and 8%. The stft2 and ltft2 are around the same. I have checked for vacuum leaks over and over minus taking it in for a smoke test. I have bought 4 new 02 sensors to replace the sensors to see if that is the issue. I have not found the time or patience to put them on yet. I have no CEL's but the car is running off and the exhaust gases are quite strong on startup.

I have read way too much on fuel trims the past couple days and my head hurts. Like to solve this problem myself but I have no issue paying the money to get it resolved and out of my hair. Any of you guys run into similar issues?

 

[usgiorgi]

What octane fuel are you running? I assume since you're in CA, 91?

Try adding some octane booster to see if the detonation goes away.

 

[Kong76]

What octane fuel are you running? I assume since you're in CA, 91?

Try adding some octane booster to see if the detonation goes away.

Yea 91, been trying different gas stations. I have been using Boostane periodically but didn't want to have to rely on it due to the manganese and cats. I have an e85 station about 15 min away that i can try a few gallons to a tank of 91. The boostane did seem to help. Kit says I can run 91 and if thats not the case, kit has to go. I think its a lean condition issue somehow.

 

[usgiorgi]

Have you tried cleaning your MAF sensor?

 

[Kong76]

Have you tried cleaning your MAF sensor?

Not yet, the kit was installed a few months ago and came with a new sensor for the gt350 intake. I will give it a cleaning and go from there. I was doing some more testing and this might not be a vacuum leak but instead a fuel delivery issue. Sounds like I have some work to do as far as testing fuel pressures, smoke test etc. What a mess.

That boostane has some pretty nasty stuff in it. Coated my spark plugs orange. God knows what my cats are like.

 

[accel]

Been having detonation issues after installing the FRPP2 kit a couple months back. Plugged in my scan tool and saw that my STFT and LTFT are both positive at 3 and 8%. The stft2 and ltft2 are around the same. I have checked for vacuum leaks over and over minus taking it in for a smoke test. I have bought 4 new 02 sensors to replace the sensors to see if that is the issue. I have not found the time or patience to put them on yet. I have no CEL's but the car is running off and the exhaust gases are quite strong on startup.

I have read way too much on fuel trims the past couple days and my head hurts. Like to solve this problem myself but I have no issue paying the money to get it resolved and out of my hair. Any of you guys run into similar issues?

Quote from another site:

Normally, STFT and LTFT should be plus or minus 8 from zero. If STFT and/or LTFT are more than about +10 or higher, it indicates the engine is running LEAN. Negative numbers (-10 or more) indicates the engine is running RICH. A lean fuel condition can be caused by:

* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (try cleaning the injectors)

* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

 

[ice445]

8% is up there. Minor vacuum leak or injector thats flowing poorly is my guess. See if you can pull up the misfire counter for each cylinder to try and narrow down which is the problem.

 

[Kong76]

8% is up there. Minor vacuum leak or injector thats flowing poorly is my guess. See if you can pull up the misfire counter for each cylinder to try and narrow down which is the problem.

At freeway speeds both

8% is up there. Minor vacuum leak or injector thats flowing poorly is my guess. See if you can pull up the misfire counter for each cylinder to try and narrow down which is the problem.

8% is up there. Minor vacuum leak or injector thats flowing poorly is my guess. See if you can pull up the misfire counter for each cylinder to try and narrow down which is the problem.

It was at +10 ltft on freeway. Stft at freeway speeds is 0 which is good. Just cleaned the maf and no change. Ill pull up each cyl but I don't have any codes.
The fuel trims have to be plus or minus 25 to throw a code. I can tell power is not what it use to be and like I said the pinging is concerning.

 

[Kong76]

no clue why it quoted three times sorry.

 

[accel]

At freeway speeds both



It was at +10 ltft on freeway. Stft at freeway speeds is 0 which is good. Just cleaned the maf and no change. Ill pull up each cyl but I don't have any codes.
The fuel trims have to be plus or minus 25 to throw a code. I can tell power is not what it use to be and like I said the pinging is concerning.

Myself I reinstalled PP2 two times, detonation is there. I'm thinking of giving it another try. I had oil catch cans on both sides of the engine, but now I think that I should remove them and try just OEM hoses. Who knows, maybe aftermarket OCC hoses do suck some air. Another item to re-check is throttle body.

How many times can one re-flash ECU with the tune? Do not want to fry it if I do this too many times...

Also, anyone knows of some gasket material I could apply in addition to supplied with PP, but still be able to remove later?

 

[Kong76]

I attempted O2 sensors today. Upstream pass side is a nope. Downstreams i can reach but dealership broke the tab off the connector and cant seem to get it apart. Must have done that when replacing the tranny a few years ago.

Ill move on to fuel pressure check and smoke test for the time being.

 

[mustangpegasus51]

What happens to your fuel trims when you accelerate or decelerate? Finding the pattern of your fuel trims will help you diagnose the problem.

 

[Kong76]

What happens to your fuel trims when you accelerate or decelerate? Finding the pattern of your fuel trims will help you diagnose the problem.

When I accelerate the ltft goes up slowly. When i let off the throttle they come down slowly. If im at 10 on ltft on freeway and i let off they start to drop. I think the stft go from a 2 to -1.5 or so on let off.

 

[mustangpegasus51]

If it was a vacuum leak your LTFTs would go down when you accelerate and up when you let off again.

This might be something like a fuel pump issue as described here:

 

[Kong76]

If it was a vacuum leak your LTFTs would go down when you accelerate and up when you let off again.

This might be something like a fuel pump issue as described here:

Yea I was leaning that way. I dont know how to check pressure. There is no shrader valve. Like to know what the pressure is when engine is under load. I think I have plenty of fuel at idle. Numbers look normal.