primary turbo issue
07-01-13, 10:35 PM
#1
primary turbo issue
Hi All,
This seasoned twin sequential troubleshooter needs a hand. I'm having trouble isolating a primary boost issue.
I've been slowly turning up the boost and tuning the BNRs that I picked up from the recent group buy. The car has a strange hesitation when it's at WOT on the first turbo. This started when I was initially running waste-gate pressure and is significantly worse now that I'm up to 14psi.
I've been been making WOT runs from about 2000RPM in second gear all the way to red line. From about 3500 RPM to the start of transition at 4400 RPM the car drops boost by about 1.5 psi and looses power. When the turbos transition it takes off smoothly and pulls all the way to red line. I would call it ignition break up except there is no backfire and it's not breaking up in higher RPMs ... when my water injection comes on.
I initially though that my CCV was bad as I can sometimes hear a clanking while this is going on. I've gone over everything related to the turbo transition with a fine tooth comb though. It's also odd that this does not happen unless I'm at WOT. 75% throttle on the first turbo, for example, works just fine and pulls much stronger then WOT.
Mods are in my sig. Throw some suggestions / questions at me. I'm tired of scratching my head!
thanks all!
James
This seasoned twin sequential troubleshooter needs a hand. I'm having trouble isolating a primary boost issue.
I've been slowly turning up the boost and tuning the BNRs that I picked up from the recent group buy. The car has a strange hesitation when it's at WOT on the first turbo. This started when I was initially running waste-gate pressure and is significantly worse now that I'm up to 14psi.
I've been been making WOT runs from about 2000RPM in second gear all the way to red line. From about 3500 RPM to the start of transition at 4400 RPM the car drops boost by about 1.5 psi and looses power. When the turbos transition it takes off smoothly and pulls all the way to red line. I would call it ignition break up except there is no backfire and it's not breaking up in higher RPMs ... when my water injection comes on.
I initially though that my CCV was bad as I can sometimes hear a clanking while this is going on. I've gone over everything related to the turbo transition with a fine tooth comb though. It's also odd that this does not happen unless I'm at WOT. 75% throttle on the first turbo, for example, works just fine and pulls much stronger then WOT.
Mods are in my sig. Throw some suggestions / questions at me. I'm tired of scratching my head!
thanks all!
James
07-02-13, 11:15 AM
#2
I've got an idea. I replaced my stripped out exhaust manifold with a newly ceramic coated one. Maybe the Turbo Control Actuator is attached incorrectly? ... the rod needs to be adjusted, maybe it's not working properly, etc. I'm thinking that it is allowing exhaust to leak by and at the same time making the clanking noise that has become louder as I've turned up my boost. I don't think that it's the solenoids under the UIM. I just tested them a few days back.
Has anyone else experienced a loose TCA or perhaps a defective one? What were your symptoms?
James
Has anyone else experienced a loose TCA or perhaps a defective one? What were your symptoms?
James
07-02-13, 01:02 PM
#4
Hi All,
This seasoned twin sequential troubleshooter needs a hand. I'm having trouble isolating a primary boost issue.
I've been slowly turning up the boost and tuning the BNRs that I picked up from the recent group buy. The car has a strange hesitation when it's at WOT on the first turbo. This started when I was initially running waste-gate pressure and is significantly worse now that I'm up to 14psi.
I've been been making WOT runs from about 2000RPM in second gear all the way to red line. From about 3500 RPM to the start of transition at 4400 RPM the car drops boost by about 1.5 psi and looses power. When the turbos transition it takes off smoothly and pulls all the way to red line. I would call it ignition break up except there is no backfire and it's not breaking up in higher RPMs ... when my water injection comes on.
I initially though that my CCV was bad as I can sometimes hear a clanking while this is going on. I've gone over everything related to the turbo transition with a fine tooth comb though. It's also odd that this does not happen unless I'm at WOT. 75% throttle on the first turbo, for example, works just fine and pulls much stronger then WOT.
Mods are in my sig. Throw some suggestions / questions at me. I'm tired of scratching my head!
thanks all!
James
This seasoned twin sequential troubleshooter needs a hand. I'm having trouble isolating a primary boost issue.
I've been slowly turning up the boost and tuning the BNRs that I picked up from the recent group buy. The car has a strange hesitation when it's at WOT on the first turbo. This started when I was initially running waste-gate pressure and is significantly worse now that I'm up to 14psi.
I've been been making WOT runs from about 2000RPM in second gear all the way to red line. From about 3500 RPM to the start of transition at 4400 RPM the car drops boost by about 1.5 psi and looses power. When the turbos transition it takes off smoothly and pulls all the way to red line. I would call it ignition break up except there is no backfire and it's not breaking up in higher RPMs ... when my water injection comes on.
I initially though that my CCV was bad as I can sometimes hear a clanking while this is going on. I've gone over everything related to the turbo transition with a fine tooth comb though. It's also odd that this does not happen unless I'm at WOT. 75% throttle on the first turbo, for example, works just fine and pulls much stronger then WOT.
Mods are in my sig. Throw some suggestions / questions at me. I'm tired of scratching my head!
thanks all!
James
Also the fact that it pulls fine at part throttle but not WOT may help reinforce my theory , i dont know how the adaptronic ECU deals with the twins , but in the power FC , there is part trhottle / wot settings , at part throttle the duty cycle is set to a certain % and at WOT its set to another % in order to achieve target boost . if at WOT that duty cycle is set to low , and its letting tomuch exhaust out of the primary , and directing it into the secondary . while at part throttle maybe its opening up the precontrol later which is why you get a stronger pull .
Last edited by Tem120; 07-02-13 at 01:10 PM.
07-02-13, 01:05 PM
#5
wastegate only opens up when the 2 turbos are spinning , when only the primary is going the precontrol works to bleed off excess air into the secondary to start spooling it for the transition in order to make the transition smoother , but if its letting off air to soon . it could cause this issue ...
07-03-13, 11:20 AM
#6
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wastegate only opens up when the 2 turbos are spinning , when only the primary is going the precontrol works to bleed off excess air into the secondary to start spooling it for the transition in order to make the transition smoother , but if its letting off air to soon . it could cause this issue ...
07-03-13, 11:36 AM
#7
There are three "actuators":
Wastegate - controls primary and secondary boost on my ECU, secondary (post transition combined first and second turbo boost) on the factory ECU
Pre-control - controls secondary spoolup (and has an impact on primary while doing so) on my ECU, funcitons as a wastegate on the factory ECU for the primary turbo
Turbo Control - blocks the exhauset from the secondary so that the pre-control can control its spool up prior to transition. Post transition opens up to supply exhaust to the secondary turbo
Given this thread:
https://www.rx7club.com/3rd-generati...e-what-169138/
I'm going to investigate the turbo control actuator as I have significant noise to go with this issue. The wastegate is functioning well ... I've been slowly increasing the boost and it has been doing a good job all along. The pre-control is a posibility though. I haven't found any threads indicating that it makes the noise that I'm hearing though ...
stay tuned and keep it coming ...
PS, attached is a log with a yellow highlight where the boost / RPM drop is evident. This log shows one big second gear WOT run, up an inclined on ramp. I would think that the boost wouldn't drop off prior to 4400 RPM which is where the ECU opens the pre-control actuator. I'm targeting 14psi with this tune and the primary boost is night and day from the secondary ... it's like a freight train hits when the secondary comes on line.
James
Wastegate - controls primary and secondary boost on my ECU, secondary (post transition combined first and second turbo boost) on the factory ECU
Pre-control - controls secondary spoolup (and has an impact on primary while doing so) on my ECU, funcitons as a wastegate on the factory ECU for the primary turbo
Turbo Control - blocks the exhauset from the secondary so that the pre-control can control its spool up prior to transition. Post transition opens up to supply exhaust to the secondary turbo
Given this thread:
https://www.rx7club.com/3rd-generati...e-what-169138/
I'm going to investigate the turbo control actuator as I have significant noise to go with this issue. The wastegate is functioning well ... I've been slowly increasing the boost and it has been doing a good job all along. The pre-control is a posibility though. I haven't found any threads indicating that it makes the noise that I'm hearing though ...
stay tuned and keep it coming ...
PS, attached is a log with a yellow highlight where the boost / RPM drop is evident. This log shows one big second gear WOT run, up an inclined on ramp. I would think that the boost wouldn't drop off prior to 4400 RPM which is where the ECU opens the pre-control actuator. I'm targeting 14psi with this tune and the primary boost is night and day from the secondary ... it's like a freight train hits when the secondary comes on line.
James
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07-06-13, 07:29 PM
#8
Well, I checked out my turbo actuator. It's in great mechanical shape and perfectly adjusted. It definitely makes a sound that is exactly like what I'm hearing when the problem occurs. I could see how the pre-control could do the same thing.
While I was at it I retested the associated solenoids. The rat's nest - pressure solenoid looses pressure when taped. Since I'm exposing it to 19+psi (if my fuel system will take me that far) I'm going to replace it with a MAC valve.
If this isn't the issue, I'll move on to the pre-control next.
thoughts welcome!
While I was at it I retested the associated solenoids. The rat's nest - pressure solenoid looses pressure when taped. Since I'm exposing it to 19+psi (if my fuel system will take me that far) I'm going to replace it with a MAC valve.
If this isn't the issue, I'll move on to the pre-control next.
thoughts welcome!
07-15-13, 04:29 PM
#9
Hi Everyone,
So, there were two problems, perhaps three:
1) My Turbo control boost actuator solenoid was leaking some boost during hard acceleration. Bumps, shaking, etc. cause it to trigger momentarily and briefly. This resulted in very slight movement of the turbo control actuator and the actuator making the clanking noise that I described above. This was only true past about 13psi. I think that at best these handle 15psi new. I replaced it with a MAC valve and the problem is gone. Interestingly enough this didn't effect boost after being repaired.
2) My leading NGK's electrode had been reduced to a nub. I dropped a pair of used ones in. This eliminated what was definitely breakup. The car pulls very strong now as soon as the first turbo generates boost. It's amazing that these plugs were new only 2500 miles ago. I've ordered four Denso Iridium 2719s as a permanent fix. I've also begun adding fuel to my map. Now that the misfire is gone the fuel is burning and hte AFR is too lean.
3) There is still a metal on metal sound. I think that something is loose on the engine. I've always had high knock at WOT regardless of mixture or timing. I've been searching for this for two years now. It's starting to look as though I won't find it until the engine is rebuilt.
Thank you all for your help!
So, there were two problems, perhaps three:
1) My Turbo control boost actuator solenoid was leaking some boost during hard acceleration. Bumps, shaking, etc. cause it to trigger momentarily and briefly. This resulted in very slight movement of the turbo control actuator and the actuator making the clanking noise that I described above. This was only true past about 13psi. I think that at best these handle 15psi new. I replaced it with a MAC valve and the problem is gone. Interestingly enough this didn't effect boost after being repaired.
2) My leading NGK's electrode had been reduced to a nub. I dropped a pair of used ones in. This eliminated what was definitely breakup. The car pulls very strong now as soon as the first turbo generates boost. It's amazing that these plugs were new only 2500 miles ago. I've ordered four Denso Iridium 2719s as a permanent fix. I've also begun adding fuel to my map. Now that the misfire is gone the fuel is burning and hte AFR is too lean.
3) There is still a metal on metal sound. I think that something is loose on the engine. I've always had high knock at WOT regardless of mixture or timing. I've been searching for this for two years now. It's starting to look as though I won't find it until the engine is rebuilt.
Thank you all for your help!
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