Any help is appreciated. Lately (last 100-200 miles)I am getting no boost from either turbo. My car is a 93 touring, with 75K on original engine/turbos. Mods are DP, Hi-Flow Cat, Efini Y pipe, Greddy elbow and polished hard pipe kit. This problem only occurs when I stand on it, regardless of what gear I'm in. The boost guage (Autometer) barely gets above 0 before it drops down to the Vacuum side, and then I can hear a "whooossh" sound as I let off the gas. If I accelerate smoothly, the boost guage shows normal boost patterns. I have ordered a Silicone Vacuum Hose kit from Hose Technologies, as I am hoping it is a hose issue. Anyone have any ideas? Thanks

 

I'd start by looking at your BOV's. The hoses can come lose or pop off. I am not saying this b/c I've heard other people suggest this as a resolution. I have blown off the rear BOV hose a couple of times and it caused the same problem that you are talking about. Good luck

 

Definitely wait and see what things are like after the hose job. After mine was finally done, I noticed that power during boost was nice and constant unlike before where it seemed to leak and not exist at all under quick shifting. Those darn vacuum hoses!

 

Damn, i have the EXACT same problem. I checked out my MAP sensor,BOV hoses, IC hoses and Pressure holding tank. All the hoses were in tact. However i cant get boost on my 2nd turbo no matter how slow i accelerate. =( ERRRRRRRRR!!!!

 

Cetchup
Damn, i have the EXACT same problem. I checked out my MAP sensor,BOV hoses, IC hoses and Pressure holding tank. All the hoses were in tact. However i cant get boost on my 2nd turbo no matter how slow i accelerate. =( ERRRRRRRRR!!!!

are you still using a catalitic? if so it may be clogged...jc

 

Thanks for the suggestions. I'll look at the BOV as soon as I get home. Any idea how much hair I'm gonna pull out trying to complete the vacuum hose job? I'm a little nervous about it from some of the posts I've read!

 

Cetchup,
I had that same problem as you, spend mad $$$ replacing the cat with a midpipe then ECU. Ended up nothing happend. If that doesnt seem to be your problem start checking/replacing solenoids under the upper intake manifold. I was going to do that next but insted I just decided non-sequential would be easier for now.

 

Well you could have a really bad boost leak. Have you checked? Do you know what to check? It is the cheapest problem to have, the simplest to fix, and best place to start.

 

There is a hose on the back of the y-pipe that points up. If you unplug it, your charge control will open up spilling primary into secondary. Those with a working system can test this. I have, and it produces 0 boost accross the board. This hose goes from the y-pipe, to the lower intake manifold, to the solenoid rack, to charge control solenoid, and back through the lower manifold and ends at the charge control actuator. So, you can see there are plenty of areas to have this thing pop off.
For secondary turbo issues, turbo control solenoid, vacuum side (on the ACV) burn out.

 

I checked the BOV, and all looks to be correct. Where do I start investigating a boost leak? Any help is appreciated. Thanks!

 

I drove the car today, and did the 3rd gear, 35mph WOT boost test, and boost increases as normal until 4500 rpm's, and then quickly drops. Does that mean that the 2nd turbo is not coming on-line at all? And if so, where should I start looking for a problem? Any help is greatly appreciated. thanks

 

Sounds like the 2nd turbo isnt comming online like you are thinking. Check your lines going to the TCA (turbo control actuator) check the TCA itself and any solenoids which control it. I had this problem and what was happening was the 2nd turbo wouldn't move and when the charge control actuator opened up all my boost went backwards through the 2nd turbo. Therefor dropping it to zero.

 

Cetchup, racer rx, and Vintage Red Touring,

Damn, I HAD the exact same problem. I checked out my MAP sensor, BOV hoses, IC hoses, and pressure holding tank. All the hoses were intact. However, I couldn't get boost on my 2nd turbo no matter how slow i accelerate

(^_^)

Many of us have been there. Your problem is one of the control solenoids in the turbo system--either the turbo control or charge relief solenoid. Have those replaced and you should be flying again to redline in no time.

 

If your boost is reading normal before 4500rpm, your probably don't have any boost leaks. Vintage Red, your comment about no boost after 4500 is indicative of a boost control problem. As the secondary turbo spools up, its boost is vented via the CRV until the transition occurs AT 4500. When there is a problem with a vacuum tune or solenoids, the CRV never closes and all your boost is vented. That is why you hear the whooshing sound when you attempt to boost.

I'm quite sure it's a solenoid problem. Good luck!

 

Had the same problem and it was my IC piping

 

You can start here. You have a boost gauge so you need to do a 40-70 run in 3rd gear. Cruise steady at 35 mph. Floor it and have someone watch the boost and note the boost pattern. Be as thorough as possible.

You should get:
rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)

Let me know what your numbers are.

Have you checked the usual boost leak culprits?
Y-pipe
Y-pipe coupling
1" diameter hoses
Primary Turbo Inlet
Couplers To/From Intercooler

You may have multiple issues.

1. Give a FULL report on your boost behavior based on the "chart" above. How it builds, drops... everything.

2. Do you have a vacuum/pressure test gauge? If not see if you can find one to borrow. They cost less than $20, but hey thats still $20. We will use this later.

3. We need to get the primary working. The Secondary Turbocharger requires the Primary Turbocharger to generate more than 8 psi to operate actuators that control the Secondary Turbocharger. So we will need to get the primary boost where it needs to be.

These are the easy ones to check:
Y-Pipe connector hose, (coupling)

* This is a very common failure part. This short hose, (coupling) will split and vent boosted air in copious amounts. The trick with this one is that when just looking at the part on the car it will look just fine. You need to remove the 90 degree plastic duct on top and completely remove the rubber coupling, then examine the rubber coupling by gently stretching it to see if there are any splits. Typically costs about $47 at dealer.

Check ~1" diameter hoses for leakage

* If you can rotate these hoses while attached, then the clamps are too loose. Get properly sized screw-clamps if the stock ones are not up to the job. New hoses will also help, but usually tightening the hose clamps is enough. A sign that there is air leakage is the presence of oily dirt on the aluminum casting around the hoses. New hose-clamps will set you back about $10 maximum for good ones. Note, clean up the oily dirt around the aluminum so that you will be able to see if these hoses start to leak again, (carburetor-cleaner works great).

Primary Turbo Inlet

* Typically collapses under high volume air through air cleaner into Primary Turbocharger. When the engine bay is hot the rubber is more prone to collapsing. Typical symptoms are having good boost at lower RPMs and then a loss of boost at higher RPMs, this is aggravated when engine warms-up softening the rubber allowing for easier and more complete collapse of the hose. Typically costs about $90 at dealer.

To/From Intercooler

* Same symptoms as the Y-Pipe coupler. When under boost, the hose-clamps prevent the hose from expanding due to the air pressure inside the hose. Do not under-estimate the force of 10 psi or more on 3" diameter hoses, what looks OK with engine not running may not work under boost conditions.

Giving me the full results requested above should help narrow the problems down. If it is a loud whoosh coming from the passenger side it cloud be a cracked Y-pipe.

 

I took my car to a local rotary shop because i wasnt confident in taking off the UIM ( at least not yet ). I will report back to you guys on what the problem was. Thank you very much for input though, it was much appreciated.

 

You might not have had to remove the UIM. Did you check the checkvalves too? There is plenty to check before the UIM comes off.

 

I had my checkvalve that goes to the pressure tank installed backwards. This kept the system from pressurizing and cause all kinds of problems, not just boost issues. So like technovoice and others have said...check the checkvalves.

 

Thanks for all the suggestions, I'll look at each of them this weekend. I don't think it is a Y pipe or intercooler piping issue, as I have the Efini Y pipe, and polished hard pipes in and out of the stock intercooler, but I'll check all the connections. I'll report back what I find out. Thanks again

 

Sorry, I overlooked your Efini pipe. I guess its still good info for everone else to read.

Still do the test.

Cruise steady at 35 mph. Floor it and have someone watch the boost and note the boost pattern. Be as thorough as possible.

You should get:
rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)

Let me know what your numbers are.

 

Question:
Can the Y-pipe coupling and other air hoses be purchased from a non-Mazda dealership auto parts shop? If so where.

Thanks,

Ant

 

I dropped my car off at Rotary Performance this morning, and I just got the call from Chris. VACUUM HOSES!! They are replacing 5 or 6 of the hoses, using the new ones from my Hose Technologies kit. Should be back to normal boosting this afternoon!! WOOHOO!

By the way, I asked Rotary Performance about doing the entire silicone hose replacement, and Chris told me it was a 2 day job, 10 hours of labor at $65.00 an hour. Looks like I'll be attempting it on my own. Wish me luck!

 

if its a bad selenoid can i get boost on my secondary sometimes?
my boost patern is 13-5-8(when working) and 13-5-4 (when not working).
the only thing i noticed that sometimes if i only get 2-4 psi on my secondary, i can just lift my foot from the gas and floor it again and the boost will go up to normal.

 

help? please