Secondary Boost Diag - Did I Miss Something?
10-14-02, 08:15 AM
#1
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Secondary Boost Diag - Did I Miss Something?
Been using all the wonderful info from you guys, especially P'cola FD and rpm_pwr, to troubleshoot my secondary boost problem. I've got things pretty well isolated as follows:
- overall pattern 11-6-6
- line integrity okay (replacing hoses as I go anyway).
- 0 reading on the TCA pressure line under all conditions
- measured from nipple behind CRV (tee'd into line)
+ the secondary produces boost below 4500 rpm under moderate accelleration in 3rd/4th but not WOT (TPA doing it's thing?).
+ the reading is 0-6-6 under WOT.
It's obvious the TCA pressure solenoid (or related area) is bad and I'm going after the rats nest now. However, now that I think about it I would have expected the TPA to have done something under WOT not just moderate accelleration so this leads me to believe I may have missed something in my zeal to go after the obvious.
Any feedback/insight would be greatly appreciated especially if it helps me avoid an oh-s**t after putting this thing back together.
- overall pattern 11-6-6
- line integrity okay (replacing hoses as I go anyway).
- 0 reading on the TCA pressure line under all conditions
- measured from nipple behind CRV (tee'd into line)
+ the secondary produces boost below 4500 rpm under moderate accelleration in 3rd/4th but not WOT (TPA doing it's thing?).
+ the reading is 0-6-6 under WOT.
It's obvious the TCA pressure solenoid (or related area) is bad and I'm going after the rats nest now. However, now that I think about it I would have expected the TPA to have done something under WOT not just moderate accelleration so this leads me to believe I may have missed something in my zeal to go after the obvious.
Any feedback/insight would be greatly appreciated especially if it helps me avoid an oh-s**t after putting this thing back together.
10-14-02, 08:26 AM
#2
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
For the record:
- '94 R2
- the turbos have 6K miles on them.
- the motor has only 2K miles on it.
I't likely the problems were caused by the dealer when the motor was replaced as I argued with them day one that the boost wasn't right. But the Mazda tech support team that makes judgement calls for things under warranty (expired last month) would not support my claim.
- '94 R2
- the turbos have 6K miles on them.
- the motor has only 2K miles on it.
I't likely the problems were caused by the dealer when the motor was replaced as I argued with them day one that the boost wasn't right. But the Mazda tech support team that makes judgement calls for things under warranty (expired last month) would not support my claim.
10-14-02, 10:15 PM
#3
Hamado things my way!
Join Date: Oct 2001
Location: Pensacola, Florida
Posts: 1,245
Likes: 0
Received 0 Likes
on
0 Posts
From what nipple were you taking readings from behind the crv? You should be looking at the nipple coming off of the y-pipe between the CCV and the secondary turbo. You should go ahead and do the hose job while you test the solenoids as well.
10-14-02, 10:58 PM
#5
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Doing Viton as I go. I changed everything I could outside of the rats nest and then went through one more round of on road tests before arriving at the documented symptoms posted earlier. Now the UIM is pulled and I'll be down for a while as I only get about an hour a day to work on this.
See diagram for the nipple where I took the secondary reading from.
Jon
See diagram for the nipple where I took the secondary reading from.
Jon
10-14-02, 11:19 PM
#7
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
r0gu3, are your symptoms exactly the same? Maybe we can help each other.
It's going to be a while (weeks) before I get operational again as I'm going to make other changes as long as the UIM is off (i.e. injectors, replace the fuel pulsation damper, etc.) and will only work on it a few hours here and there when I'm in town. I'll track your handle
It's going to be a while (weeks) before I get operational again as I'm going to make other changes as long as the UIM is off (i.e. injectors, replace the fuel pulsation damper, etc.) and will only work on it a few hours here and there when I'm in town. I'll track your handle
Trending Topics
10-14-02, 11:32 PM
#8
Senior Member
at risk of making myself look like an idiot because of dfferences between countries:
1) Simples easiest test. Pull either hose off the pressure chamber - do you hear air rushing out? If not then check the hose and check valve going to your y-pipe. Check the hose going from the pressure chamber to the nest. This one used to come off on me ALL the time.
2) If you passed test 1. Pull off strut brace, x-over pipe. Of the 'solid' hoses that come up from the turbo's there should be all 4mm and one larger one (6mm?) check the connection onto that pipe. Pull it off. You shouldn't be able to blow into either the hard pipe or the rubber hose that goes to the nest. If you can blow into the hard pipe that connection (to TCA) has a leak. If you can blow into the hose, that connection (to solenoid) is broken.
If you're seeing 0-0-0 at the TCA pressure side, but you passed 1 and 2 then you have an electrical wiring fault to the solenoid. UIM removal time
HTH,
-pete
1) Simples easiest test. Pull either hose off the pressure chamber - do you hear air rushing out? If not then check the hose and check valve going to your y-pipe. Check the hose going from the pressure chamber to the nest. This one used to come off on me ALL the time.
2) If you passed test 1. Pull off strut brace, x-over pipe. Of the 'solid' hoses that come up from the turbo's there should be all 4mm and one larger one (6mm?) check the connection onto that pipe. Pull it off. You shouldn't be able to blow into either the hard pipe or the rubber hose that goes to the nest. If you can blow into the hard pipe that connection (to TCA) has a leak. If you can blow into the hose, that connection (to solenoid) is broken.
If you're seeing 0-0-0 at the TCA pressure side, but you passed 1 and 2 then you have an electrical wiring fault to the solenoid. UIM removal time
HTH,
-pete
10-15-02, 12:00 AM
#9
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by rpm_pwr
at risk of making myself look like an idiot because of dfferences between countries:
1) Simples easiest test. Pull either hose off the pressure chamber - do you hear air rushing out? If not then check the hose and check valve going to your y-pipe. Check the hose going from the pressure chamber to the nest. This one used to come off on me ALL the time.
2) If you passed test 1. Pull off strut brace, x-over pipe. Of the 'solid' hoses that come up from the turbo's there should be all 4mm and one larger one (6mm?) check the connection onto that pipe. Pull it off. You shouldn't be able to blow into either the hard pipe or the rubber hose that goes to the nest. If you can blow into the hard pipe that connection (to TCA) has a leak. If you can blow into the hose, that connection (to solenoid) is broken.
If you're seeing 0-0-0 at the TCA pressure side, but you passed 1 and 2 then you have an electrical wiring fault to the solenoid. UIM removal time
HTH,
-pete
at risk of making myself look like an idiot because of dfferences between countries:
1) Simples easiest test. Pull either hose off the pressure chamber - do you hear air rushing out? If not then check the hose and check valve going to your y-pipe. Check the hose going from the pressure chamber to the nest. This one used to come off on me ALL the time.
2) If you passed test 1. Pull off strut brace, x-over pipe. Of the 'solid' hoses that come up from the turbo's there should be all 4mm and one larger one (6mm?) check the connection onto that pipe. Pull it off. You shouldn't be able to blow into either the hard pipe or the rubber hose that goes to the nest. If you can blow into the hard pipe that connection (to TCA) has a leak. If you can blow into the hose, that connection (to solenoid) is broken.
If you're seeing 0-0-0 at the TCA pressure side, but you passed 1 and 2 then you have an electrical wiring fault to the solenoid. UIM removal time
HTH,
-pete
have suggested in other threads and ended up as stated in the original post.
The TCA hoses (vacuum and pressure) are 'out front' and their hard pipes join up with the wastegate and pre-spool hard pipes. The only larger hose I see is on a common 3 way tee shared by the upstream (venting) side of the wastegate and pre-spool solenoids. I did not specifically test this larger line.
That said, both the vacuum and pressure lines from the hard pipe down are good (before and after replacing the hoses). However, the upstream side of the TCA pressure lines does vent (I think it's suppose to when the solenoid is 'closed' as it has a breather on it...pressurized when open, quickly depressurize when closed). I believe that this solenoid is never opening.
However, I'm worried that a lack of pre-spool under WOT says there is something else going on too.
Jon
10-15-02, 11:57 PM
#13
Senior Member
Join Date: Oct 2002
Location: Bartlesville, OK.
Posts: 394
Likes: 0
Received 0 Likes
on
0 Posts
Since the engine has been replaced, doesn't that make you wonder about the harness, too? But if it had been cut or shorted wouldn't you be getting a check engine light? Have you verified for any errors?
10-16-02, 12:38 AM
#14
There and back again
Join Date: Feb 2001
Location: Camarillo, Ca
Posts: 967
Likes: 0
Received 0 Likes
on
0 Posts
Pre-spool works only when everything else is working. If you are saying that your TCA (Vacuum and Pressure) are not showing any vacuum or pressure, then you can count on the solenoids not working.
I have actually never heard of both solenoids failing, but I have had experience with the vacuum solenoid (on top of the ACV) loosing continuity in it's coil.
You said you tested these, but how did you test them. Did you take a drive with your boost gauge teed into each one (one at time)? And you didn't see anything?
It sounds to me that at least one line should be working since you are getting measurable boost past 4500 rpm. You would get no boost if the TCA did not actuate.
IMO, your TCA is acting slow, and mistiming with your CCV and CRV. You could have good prespool, but unless the TCA is there to back it up when the curtains fly open, your secondary turbo is caught with it's pants down.
Just my opinion.
I have actually never heard of both solenoids failing, but I have had experience with the vacuum solenoid (on top of the ACV) loosing continuity in it's coil.
You said you tested these, but how did you test them. Did you take a drive with your boost gauge teed into each one (one at time)? And you didn't see anything?
It sounds to me that at least one line should be working since you are getting measurable boost past 4500 rpm. You would get no boost if the TCA did not actuate.
IMO, your TCA is acting slow, and mistiming with your CCV and CRV. You could have good prespool, but unless the TCA is there to back it up when the curtains fly open, your secondary turbo is caught with it's pants down.
Just my opinion.
10-16-02, 11:35 PM
#15
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
The vacuum side of the TCA works fine. Only the pressure side is 0-0-0. I tee'd in my spare guage and did road tests.
Except under moderate acceleration in 3rd and 4th there is no pressure on the secondary side of the the CCV before 4500 rpm and then it's 5psi the second the valve opens. I think this is all coming from the primary and, since the vacuum side of the TCA is for when you take your foot off the gas and it needs to close the valve then I believe the TCA is not opening at all, not even slowly, and I believe the secondary doesn't spool at all under WOT. If it wasn't for the occasion sign of boost under moderate acceleration (starts at 2500 and climbs to 8 psi before falling to 5 at 4500) then I would be worried the secondary was no-op/frozen..with only 6K miles on it.
Jon
Except under moderate acceleration in 3rd and 4th there is no pressure on the secondary side of the the CCV before 4500 rpm and then it's 5psi the second the valve opens. I think this is all coming from the primary and, since the vacuum side of the TCA is for when you take your foot off the gas and it needs to close the valve then I believe the TCA is not opening at all, not even slowly, and I believe the secondary doesn't spool at all under WOT. If it wasn't for the occasion sign of boost under moderate acceleration (starts at 2500 and climbs to 8 psi before falling to 5 at 4500) then I would be worried the secondary was no-op/frozen..with only 6K miles on it.
Jon
10-16-02, 11:37 PM
#16
Full Member
Thread Starter
Join Date: Sep 2002
Location: Lakeside, Montana
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Also, no check engine lights (before the PowerFC). I have not been able to acertain all the sensor codes in the FC Commander yet to see if in fact that solenoid was being activated. Probably should have figured that out before tearing into the UIM.
Anyone have a good source for the different types of soldenoids? The TCA pressue one is a 90 degree 2-way with a breather for pressure releif when it 'closes'.
Jon
Anyone have a good source for the different types of soldenoids? The TCA pressue one is a 90 degree 2-way with a breather for pressure releif when it 'closes'.
Jon
10-17-02, 12:23 AM
#17
There and back again
Join Date: Feb 2001
Location: Camarillo, Ca
Posts: 967
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by mauimoon
The vacuum side of the TCA works fine.
...I think this is all coming from the primary and, since the vacuum side of the TCA is for when you take your foot off the gas and it needs to close the valve then I believe the TCA is not opening at all,...
Jon
The vacuum side of the TCA works fine.
...I think this is all coming from the primary and, since the vacuum side of the TCA is for when you take your foot off the gas and it needs to close the valve then I believe the TCA is not opening at all,...
Jon
The TCA uses two sources, Vacuum and Pressure to actuate it at or near 4500 RPM. The vacuum works to open the door, as does the pressure. The internal spring closes the door when there is NO vacuum or Pressure. The TCA solenoids vent the air between them and the actuator when not in use. Mazda designed the TCA actuator to react faster by using to sources over one. One source is often not enough to move the door if the working source doesn't have a good charge of vacuum (sytem leak) or pressure (check valve, chamber, or hose line leak).
If you do not see pressure in from the TCA pressure solenoid, you will need to trace the lines leading to the solenoid. Y-pipe hose, check valve, hose, chamber, hoses, solenoid, hoses, TCA in that order.
10-17-02, 12:36 AM
#18
don't race, don't need to
I'm very sorry to break my newbie head in here, but where the hell can I find a resource that goes through ALL the specific vacuum/pressure circuits under ALL driving conditions that actuate and control these turbos? Or is it stricly for the 1000 post initiates?
10-17-02, 12:45 AM
#19
There and back again
Join Date: Feb 2001
Location: Camarillo, Ca
Posts: 967
Likes: 0
Received 0 Likes
on
0 Posts
The forum is a good starting place. Just click the search button and enter in secondary turbo, or low boost, and a whole mess load of post will show up. You can also look at the 3rd gen archives.
Most people that are looking to figure this monkey mess out have at one time or another visited this site.
http://home.istar.ca/~dvandit/TurboRe-n-RE.htm
Most people that are looking to figure this monkey mess out have at one time or another visited this site.
http://home.istar.ca/~dvandit/TurboRe-n-RE.htm
10-17-02, 12:47 AM
#20
There and back again
Join Date: Feb 2001
Location: Camarillo, Ca
Posts: 967
Likes: 0
Received 0 Likes
on
0 Posts
sorry for the bad link. I copied it from an old printout I had from three years ago. The link is either dead, or I entered it wrong. I have seen it recently from other links though. It's kind of a bible to many.
The shop manual is a very good source for funtion and specific details.
The shop manual is a very good source for funtion and specific details.
10-17-02, 12:57 AM
#23
There and back again
Join Date: Feb 2001
Location: Camarillo, Ca
Posts: 967
Likes: 0
Received 0 Likes
on
0 Posts
try the root page, the first one is taking the turbos out and stuff.
http://home.istar.ca/~dvandit/
http://home.istar.ca/~dvandit/