• We are no longer supporting TapaTalk as a mobile app for our sites. The TapaTalk App has many issues with speed on our server as well as security holes that leave us vulnerable to attacks and spammers.

Overboosting

Fuel pressure goes up with boost so it's getting more fuel unless the injectors are maxed out which they may be close to at 18 psi.
 

Stock fuel pump and stock injectors are "all in" at 18 psi boost at temps like -10 degF.
 
It appears that there is no control of the wastegate. The wastegate closes when the wastegate solenoid bleeds off pressure in the line. If you were to remove the tube that goes from the solenoid to the wastegate and plug it, you would get very low boost because the wastegate would just blow open. He has tested the actuation of the wastegate arm on turbo that is installed and the turbo that he removed from it last spring. Both start to open at about 8psi and are fully open at about 20psi (using a MityVac pump). The tubes were all checked as well and there are not leaks.

The wastegate solenoid is normally closed. That means that if the solenoid wasn't getting a signal from the ECU (from something like a rubbed through wire or something), the wastegate would be free too open and it wouldn't build much boost. That is not the case here. He has also pressurized the wastegate solenoid directly and it didn't leak (sled off).

Has anyone ever experienced a bad tune that just wasn't controlling the wastegate properly? It's almost as if the wastegate solenoid is getting a signal to stay wide open. Sebastian at PEFI is saying that with no wastegate control, the boost will be around the 18.5 range (+ or - a little). He is also still saying that it is not possible that it is the tune. We're at a loss here for more ideas of what is causing the overboosting and/or lack of wastegate control.
 
I too had my Speedwerx PEFI stage 3 go down. all symptoms point to head gasket but dealer did leak down and it checked normal. It is injecting coolant into the oil. He will be tearing head off in next day or so and asked me to ask Speedwerx if they would examine the ECU for a corrupt file. I called them and was told they are almost 100% sure the center piston went lean from lack of fuel. They told me they have done 800 of these and only three have gone down and that was due to a customer holding it Wide open and then letting off and getting back in it, while they had a half tank of gas, and fuel pump could not keep up. I told them I had a full tank of gas and mine went down in the first three miles after installing the tune. I was told that I must get the hi flow fuel pump. Nowhere on Speedwerx or PEFI site does it say that a sage 3 needs that. If that is true why didn't they tell me that when they sold me the tune? They tried to sell me clutching as well as an cold air intake and intercooler tunes. Needless to say I am pissed as hell. Can you recall max boost on the gauge flash? Is there an independent place that could verify the flash is not corrupt as they aren't very "helpful". Can dealer scan ECU to read max boost without erasing flash?
 
Mike Bennett said:
I too had my Speedwerx PEFI stage 3 go down. all symptoms point to head gasket but dealer did leak down and it checked normal. It is injecting coolant into the oil. He will be tearing head off in next day or so and asked me to ask Speedwerx if they would examine the ECU for a corrupt file. I called them and was told they are almost 100% sure the center piston went lean from lack of fuel. They told me they have done 800 of these and only three have gone down and that was due to a customer holding it Wide open and then letting off and getting back in it, while they had a half tank of gas, and fuel pump could not keep up. I told them I had a full tank of gas and mine went down in the first three miles after installing the tune. I was told that I must get the hi flow fuel pump. Nowhere on Speedwerx or PEFI site does it say that a sage 3 needs that. If that is true why didn't they tell me that when they sold me the tune? They tried to sell me clutching as well as an cold air intake and intercooler tunes. Needless to say I am pissed as hell. Can you recall max boost on the gauge flash? Is there an independent place that could verify the flash is not corrupt as they aren't very "helpful". Can dealer scan ECU to read max boost without erasing flash?
Click to expand...

I don't have an answer to your questions but I am curious as well.
 
Mike Bennett said:
I too had my Speedwerx PEFI stage 3 go down. all symptoms point to head gasket but dealer did leak down and it checked normal. It is injecting coolant into the oil. He will be tearing head off in next day or so and asked me to ask Speedwerx if they would examine the ECU for a corrupt file. I called them and was told they are almost 100% sure the center piston went lean from lack of fuel. They told me they have done 800 of these and only three have gone down and that was due to a customer holding it Wide open and then letting off and getting back in it, while they had a half tank of gas, and fuel pump could not keep up. I told them I had a full tank of gas and mine went down in the first three miles after installing the tune. I was told that I must get the hi flow fuel pump. Nowhere on Speedwerx or PEFI site does it say that a sage 3 needs that. If that is true why didn't they tell me that when they sold me the tune? They tried to sell me clutching as well as an cold air intake and intercooler tunes. Needless to say I am pissed as hell. Can you recall max boost on the gauge flash? Is there an independent place that could verify the flash is not corrupt as they aren't very "helpful". Can dealer scan ECU to read max boost without erasing flash?
Click to expand...
Shouldnt need the big pump for stage 3. the stage 3r on the other hand has a big pump and 3 bar sensor as indicated on precisions site. If running hard off and on the throttle with low fuel was an issue then youd hear about alot of other 280,290 and 300 hp sleds going down from the other tuners as well. My sled has never indicated a lean condition on hrs of datalogging on different days and different conditions and many times with slim levels of fuel in the tank. Hope you guys get some more solid answers soon.
 
Update...
He has now tried all of the following parts that he has swapped from other sleds that are running correctly but his is still overboosting. He has also checked his boost gauge again and is DOES read correctly.

Wastegate solenoid
BOV solenoid
MAP sensor
2.5" TD trail muffler (not sure if the real name)
ECU w/ TD Max Spool 17 tune
Stock BOV
New turbo (previously)

When he had the stock BOV installed, he also installed a stock ECU & stock muffler and saw around 11.5-11.8 psi so he is even overboosting with a completely stock setup. Very frustrating because there isn't really anything left to try.
 
twyztid said:
Update...
He has now tried all of the following parts that he has swapped from other sleds that are running correctly but his is still overboosting. He has also checked his boost gauge again and is DOES read correctly.

Wastegate solenoid
BOV solenoid
MAP sensor
2.5" TD trail muffler (not sure if the real name)
ECU w/ TD Max Spool 17 tune
Stock BOV
New turbo (previously)

When he had the stock BOV installed, he also installed a stock ECU & stock muffler and saw around 11.5-11.8 psi so he is even overboosting with a completely stock setup. Very frustrating because there isn't really anything left to try.
Click to expand...


11.5-11.8 is normal for a stock sled.
 
I’d second knapps findings, a little elevation changes mine higher, but all ok
 
twyztid said:
Sebastian at PEFI told him that it shouldn't be above 10psi... so who is correct?
Click to expand...

Depends on altitude and barometric pressure. Up in altitude, up in pressure. The ECU compensates to the barometric pressure.
 
Maybe it’s a problem with the barometric pressure sensor? If it was reading low it may up the boost to compensate
 
KnappAttack said:
Depends on altitude and barometric pressure. Up in altitude, up in pressure. The ECU compensates to the barometric pressure.
Click to expand...
We're at about 800' above sea level here.
 
You must log in or register to reply here.

Similar threads

towman
17 SW boost reading issues
2
Replies
20
Views
2K
towman
towman
sideshowBob
Boost not returning to zero
Replies
7
Views
1K
sideshowBob
sideshowBob
Srxspec
F/S Precision EFI Stage 3R kit for Sidewinder
Replies
2
Views
1K
Srxspec
Srxspec
Yamarace998
Overboost
Replies
6
Views
942
DMCTurbo
DMCTurbo
N
Smell of gas when accelarating
Replies
9
Views
1K
SCNytro
S


Back
Top