secondary air-injection leak/malfunction
12-04-05, 11:47 PM
#1
secondary air-injection leak/malfunction
There is definitely a leak somewhere that involves exhaust, because I now smell exhaust, and it seems like it is coming from UIM area.
Under GP, I checked out the DP and the turbo manifolds and bolts, and they are TIGHT, and the gaskets are also tight, so I'm ruling this out.
I vaccuum tested the check-valve closest to the catalytic converter (aka, split-air check valve), and it is good.
That leaves the Port Air check valve, Port Air Bypass and the Air Control Valve (F-115 of Workshop Manual).
Am I on the right track ?
TIA,
:-) neil
Under GP, I checked out the DP and the turbo manifolds and bolts, and they are TIGHT, and the gaskets are also tight, so I'm ruling this out.
I vaccuum tested the check-valve closest to the catalytic converter (aka, split-air check valve), and it is good.
That leaves the Port Air check valve, Port Air Bypass and the Air Control Valve (F-115 of Workshop Manual).
Am I on the right track ?
TIA,
:-) neil
12-05-05, 05:37 AM
#2
Remember, leaks at the cat can be smelled as they funnel up the tranny tunnel and into the engine bay near the UIM. Also check the secondary air injection tube where it enters the cat.
As well, downpipe leaks are possible when the bolts are tight if the flange becomes warped (often from overtightening).
I suggest you take out that downpipe and inspect both flanges for signs of leakage - look for a trail of soot showing a leak path.
Dave
As well, downpipe leaks are possible when the bolts are tight if the flange becomes warped (often from overtightening).
I suggest you take out that downpipe and inspect both flanges for signs of leakage - look for a trail of soot showing a leak path.
Dave
12-05-05, 09:17 AM
#3
Originally Posted by dgeesaman
Remember, leaks at the cat can be smelled as they funnel up the tranny tunnel and into the engine bay near the UIM. Also check the secondary air injection tube where it enters the cat.
As well, downpipe leaks are possible when the bolts are tight if the flange becomes warped (often from overtightening).
I suggest you take out that downpipe and inspect both flanges for signs of leakage - look for a trail of soot showing a leak path.
Dave
As well, downpipe leaks are possible when the bolts are tight if the flange becomes warped (often from overtightening).
I suggest you take out that downpipe and inspect both flanges for signs of leakage - look for a trail of soot showing a leak path.
Dave
I checked the entire split-air tube from block to cat, and it is good with no leaks, restrictions, or a bad check valve.
I did the stethescope tubing in the ear to localize the sound, and it is definitely coming from the UIM area, not the DP.
Also, I used a torque wrench and a NEW DP gasket during the engine build, plus there is no trail of soot around the flange/gasket area, so again I am trusting that this is OK.
I definitely can hear the exhaust port, so I'm 99% sure it is the port-air valve or the ACV that controls it.
I'll dig into the UIM later tonight.
Thanks again,
:-) neil
12-05-05, 11:05 AM
#4
Good luck. There are tests in the FSM, but most people who have trouble there just remove the system. It might solve it if you simply clean it out with carb cleaner like you can with the IACV.
Oh! Buy a new gasket for the ACV. The stock gasket on my 94 was the old paper type, and is definitely a candidate for leaks. The new type is the rubber/metal like the UIM/LIM gasket.
Dave
Oh! Buy a new gasket for the ACV. The stock gasket on my 94 was the old paper type, and is definitely a candidate for leaks. The new type is the rubber/metal like the UIM/LIM gasket.
Dave
12-05-05, 01:36 PM
#5
Originally Posted by dgeesaman
Good luck. There are tests in the FSM, but most people who have trouble there just remove the system. It might solve it if you simply clean it out with carb cleaner like you can with the IACV.
<SNIP>
Dave
<SNIP>
Dave
Won't the engine die when the engine is cold and you have the A/C on ?
TIA,
:-) neil
12-05-05, 01:45 PM
#6
RX-7 Bad Ass
iTrader: (55)
The ACV is definitely a culprit. It has a passage leading to the exhaust manifold for port air injection. With the ACV off, you will see a "wagon wheel" in the intake manifold - that's the check valve. Pressurized air from the air pump is forced through there, and heads down to the exhaust manifold. If the ACV gasket is blown out or the "wagon wheel" is missing or damaged, you could have a leak there.
I'm with Dave - the newer metal gasket is FAR superior to all the old paper gaskets. It's hit or miss what gasket you have - I think the fuel recall kit comes with the metal ACV gasket, since the ACV has to be removed to do the fuel recall.
Another possibility could be the EGR passage. It goes through the center iron housing to the lower intake manifold then to the EGR valve. If you have an original paper lower intake manifold to engine gasket and not the newer metal one, that could in theory be a leak, but if that gasket was blown out enough to have an exhaust leak you'd likely have a vacuum leak as well.
Dale
I'm with Dave - the newer metal gasket is FAR superior to all the old paper gaskets. It's hit or miss what gasket you have - I think the fuel recall kit comes with the metal ACV gasket, since the ACV has to be removed to do the fuel recall.
Another possibility could be the EGR passage. It goes through the center iron housing to the lower intake manifold then to the EGR valve. If you have an original paper lower intake manifold to engine gasket and not the newer metal one, that could in theory be a leak, but if that gasket was blown out enough to have an exhaust leak you'd likely have a vacuum leak as well.
Dale
12-05-05, 01:55 PM
#7
Originally Posted by DaleClark
The ACV is definitely a culprit. It has a passage leading to the exhaust manifold for port air injection. With the ACV off, you will see a "wagon wheel" in the intake manifold - that's the check valve. Pressurized air from the air pump is forced through there, and heads down to the exhaust manifold. If the ACV gasket is blown out or the "wagon wheel" is missing or damaged, you could have a leak there.
I'm with Dave - the newer metal gasket is FAR superior to all the old paper gaskets. It's hit or miss what gasket you have - I think the fuel recall kit comes with the metal ACV gasket, since the ACV has to be removed to do the fuel recall.
Another possibility could be the EGR passage. It goes through the center iron housing to the lower intake manifold then to the EGR valve. If you have an original paper lower intake manifold to engine gasket and not the newer metal one, that could in theory be a leak, but if that gasket was blown out enough to have an exhaust leak you'd likely have a vacuum leak as well.
Dale
I'm with Dave - the newer metal gasket is FAR superior to all the old paper gaskets. It's hit or miss what gasket you have - I think the fuel recall kit comes with the metal ACV gasket, since the ACV has to be removed to do the fuel recall.
Another possibility could be the EGR passage. It goes through the center iron housing to the lower intake manifold then to the EGR valve. If you have an original paper lower intake manifold to engine gasket and not the newer metal one, that could in theory be a leak, but if that gasket was blown out enough to have an exhaust leak you'd likely have a vacuum leak as well.
Dale
When we installed the new motor, we used a new ACV along with a new metal gasket and valve, which, IMHO, looks flimsey.
To my knowledge there are no more paper gaskets where they could have been metal. I distinctly remember installing the multi-layer metal gasket for the lower intake manifod.
Vaccuum is a strong 18, and she boosts without any problem 10-8-10, and a very fast transition, esp. now that I replaced the faulty TCA solenoid and pinched TCA lines.
:-) neil
Last edited by M104-AMG; 12-05-05 at 01:58 PM.
Trending Topics
12-05-05, 01:59 PM
#9
Originally Posted by dgeesaman
I'm not advocating removal of the ACV and the rest of the secondary air injection system. But it can be done - I think all the guys running properly without an airpump run this way.
Dave
Dave
BTW: a properly functioning sequential system on a tight motor is a joy to behold.
NONE of this would be possible without the members of this forum, and the TENACITY of us FD owners.
While the master Mazda tech I purchased the vehicle from provided impeccable routine maintenence, he never, IMHO, had a properly working sequential system!
To all of you, I am very thankful for.
:-) neil
Last edited by M104-AMG; 12-05-05 at 02:02 PM.
12-22-05, 12:13 AM
#10
My mechanic friend found some black soot by the secondary turbo oil-coolant line.
He told me to take off the heat-shield, once the car is cooled down.
Low and behold, one M8 bolt is missing and another M8 is half-way out. These bolts along with two M12's hold down the cover over the secondary turbo valve.
Part of my gasket was BLOWN out. Thank goodness I had a spare from my popped motor.
As I put things back together, I placed lock washers on the bolts to hopefully never have this happen again.
Life is good . . .
:-) neil
He told me to take off the heat-shield, once the car is cooled down.
Low and behold, one M8 bolt is missing and another M8 is half-way out. These bolts along with two M12's hold down the cover over the secondary turbo valve.
Part of my gasket was BLOWN out. Thank goodness I had a spare from my popped motor.
As I put things back together, I placed lock washers on the bolts to hopefully never have this happen again.
Life is good . . .
:-) neil
Thread
Thread Starter
Forum
Replies
Last Post
eplusz
General Rotary Tech Support
15
10-07-15 04:04 PM
