Alright.. I pulled apart the manifold and checked hoses today... these are my symptoms...

I couldn't see anything visually wrong...

I think my turbos are shot, here is the deal:

Boost cleans up to 7psi
Anything after 7psi and the car is rough...

Feels like air is going nowhere and slowing down the car.

If I floor it in low gears, turbo spikes to about 15psi and then has a loud POP and feels like the car just hit something and kicks it back real hard, but does not stop it.

In 4th gear it will go up to about 11psi but anything over 7psi is real rough and does not accelerate.

I don't know if this is a huge vac leak, a solenoid problem, or if my turbo is just shot to ****. They were new when I put them in 13k ago.

Once again, anything over 7psi and it ***** out... bogs down, and just plain runs like ****.

Any suggestions?

 

Breakup/hesitation after 7 psi sounds like a boost leak AFTER the map sensor that is not an issue until you approach 7 psi - then the boost leak lets out siginificantly more air.

This would be pretty easy to spot at idle however.

For now, move the boost gauge line to a nipple off of the turbo manifold (use a tee-fitting with a pre-existing hose/nipple coming from the y-pipe).

Then tell me what boost you're saying in 1st gear and 3rd gear pulls. If the car is set for 15 opsi and you have a stock IC you should see around 17-19 psi at the gauge.

The point here is to see the boost right from the manifold and remove the turbos from the equation.

But right now, it sounds like a UIM or LIM leak.

 

Alright, I need to find myself a t-fitting, and then I'll try that out. I can't think of a line I could use off the top of my head, but you say anything off the y-pipe?

 

I'm having similiar problem to yours only i can't go over 9psi. If i hit 10 psi, it starts to break up, shake, what not. I changed wires, sparks, fuel filter, reseted the ecu, checked for boost leaks and didn't find anything wrong.

I'm also thinking it could be turbo related, as i see oil in the turbos.

Amel

 

Yeah I've done just about the same. WHen i pulled my manifold yesterday, there was a bit of oil inside, moreso then there should have been. Perhaps it's a faulty gasket? If it's a UIM leak that's fairly easy to get to, but if it's the LIM, I think I'm going to have a bit of a problem, heh. Anyway, I need to come up with a T. I am trying to get vac lines from XS Engineering, but they've been out of 4mm for weeks.

Also, what's the easiest way to get to your turbos? My air pump is still present. I can try and remove the whole air intake assembly, I've removed the upper portion several times. I just dont have all the time to tear her apart.

I am thinking if I fix the problem, would it be worth going poor man seq?

 

I hate non-seq. I don't know about others, but it's loud and i don't get full boost untill 4000 or so.

Easiest way to take turbos off is, take intakes off, airpump, y-pipe, dp and then unbolt the turbos.

Amel

 

Easier said than done. It doesn't look that simple. I removed and replaced my engine with the help of a couple friends, and let me tell you... when I had to strip that thing down to the core, getting the turbo assembly off was one of the most pain in the *** things to do. Can you just unbolt the turbos individually? It would be a pain in the *** with all the actuator rods and whatnot. It would at least take 3 hours if you knew what you were doing I would think....

 

I don't see a way you can take each turbo out by itself. you could get to some of the screws but not all. I had to take my turbos off 3 times so far, so it is easy once you have done it.

 

If you can you are the man. There are several posts detailing step by step turbo removal. Do a search and they will pop up. It is kind of nice to have an extra set of hands when you actually go to pull them off of the car because they are kind of heavy.

I think it is all moot though, becuase I think your turbos are fine. I think you have some other type of issue. Have you messed with your maps at all? Did this problem occur all of a sudden? I had a problem similar to this once. I reloaded my maps via the Datalogit and then my car ran fine.

 

Hrmm, no I'm using base maps... I tried resetting the ECU... no luck....

 

Don't even start worrying about LIM and UIM leaks right now. Your idle will surge and the car will be idling at 1500 rpm if you have one. This is a simple boost related issue - either control or a leak.

If you want, you can remove the line that goes to the bottom-facing 90 degree nipple on the y-pipe, place a bolt in the open end of the vacuum line, then use that nipple as a test point for your boost gauge.

The line exiting the nipple with a 90 degree bend going DOWN is for the fuel injector air bleed. It will not hurt the car to temporarily disconnect this.

 

Hrmm, as soon as I get ahold of some 4mm vac line, I am going to do the robinette manual boost controller. This way I can elimate some prespool on the secondary. I have a full exhaust, dp, mp and cat... and my wastegate is ported. I will remove the hoses tomorrow and get that reading and let you know. ALso, when i rev the engine, and let it off real quick, the engine bogs really crap like and shakes really rough, then it recovers. It only lasts about one second, but it's a pretty rough idle after i rev it and let it fall... kind of like it's choking to recover. Damn XS needs to get their *** in gear so I can re-do all my vac lines with silicone. heh.

 

Well I decided to say **** it. I just went to LBC and picked up some silicon hose for a hose job this weekend. I expect it to take all saturday and sunday to get it done right if I take my time. I have some experience pulling the damn engine apart, so it will probably suck, but it will be worth it. I am also going to replace all the gaskets from teh extension manifold and up, we'll see if this fixes the problem, if it doesn't, well I'm going to be pissed, lol.

 

Alright well I have done all of the vac lines, and I am still getting the crap *** leak after 7psi. I checked my intercooler tubes, and they are not cracked either. The only other place I can think it is escaping from would be the cross-over pipe, which still has a paper gasket on it. I am going to pull it and replace it with a metal gasket.

I know it is not the vac lines any longer since I had just finished replacing all of them.

Intercooler 'accordian style' tubes are fine.

Any other suggestions on where it could be leaking?

 

I replaced the cross over pipe flange with some RTV to seal any of the leaks that could possibly be there. Yet still after 7psi the turbos feel like they are venting air, and the boost isn't as strong, although It will read 10-12psi on the gauge, it really isn't boosting very strong at all. I dont know what the deal is.

Any suggestions?

 

Check your Cat converter. Could be plugged

 

It's all straight pipe.... DP, MP, and Catback.

 

All the solenoids tested out fine?

 

*PLEASE READ CAREFULLY*

I have not tested all the solenoids....

but.. here is my understanding of how pressure flows through the engine (without all the details)...

Primary Turbo spools, building pressure. It then flows through the y-pipe, through the crossover pipe, down to the IC, then from the IC to the elbow, to the TB, to the UIM, to the LIM.

I understand the pressure tank holds pressure for the primary turbo, does it also hold pressure for the secondary turbo? What if my Check Valve was bad (the one leading to the pressure chamber?)

Now at 7psi the wastegate becomes active, slowing down the primary, and the secondary is preparing to come online (prespool).. this transition yeilds roughly 8psi stock. Once the wastegate has closed boost from the primary, the secondary will then boost the desired amount.

As far as the 'hardware' is concerned. Leaks could be caused at: Y-Pipe Coupling (I have efini, it has a flange), Intercooler Piping, Throttle Body, UIM, or LIM gaskets. All of these are good and I have finished a complete vacuum line job, so there are not any leaking lines.

If I am wrong, please let me know.

My boost is strong up TO 7PSI on the primary, and anything above 4500RPM when the SECONDARY is boosting. My 2nd turbo is strong at all levels, but my PRIMARY IS SHITTY after 7PSI. The turbo itself is fine though.

Now, what controls the PRIMARY turbo after 7PSI? Is there a solenoid that could cause rough laggy boost after 7PSI? Perhaps the Wastegate door is being gay and not doing it's job. Perhaps the WG Control Solenoid? But if it was this solenoid, the 2nd turbo wouldn't boost at all correct?

I need to know which solenoid would control primary turbo operation Above 7 PSI

Please look at my signature and note my modifications (exhaust, etc).

I have checked the gaskets, replaced all vacuum lines, checked intercooler hoses, and crossover from ypipe flange. Made sure the TB, UIM, and Elbow were all seated properly and torqued to spec. My Wastegate is ported!

I'm going to post this in the advanced tech section also... perhaps somebody knows the engine operation well enough to located a problem such as this.

 

^bump
any clue?

 

I put my cat conv back on, and I bypassed my WG control solenoid and my precontrol solenoid. I thought by putting my cat on that I would get rid of the creep. Nope... turbos are still hitting 16 psi, and it's strange...

I'll get up to 7psi on the primary SLOWLY increasing the throttle and I can't really feel the leak or whatever it is at 7PSI, but if I floor it (WOT) then it goes all the way up to 16PSI. I have my boost controller **** all the way open which should be giving me a minimal boost and yet I am still hitting 16PSI, how the hell is this happening?

I replaced my restrictor pills with bleeder valves, I replaced all my vac lines, and I removed the precontrol and wg control solenoids from the equation. I made sure the flow of pressure from the turbos to the manifold were all sealed well, and reset my ECU and put my CAT back on the exhaust.

I do not have a single clue what could cause these problems, and it seems that nobody on the forum has experienced any of this, or has any clue what is going on.

I'm real close to selling it. I do not have the money to pay somebody $60/h at the shop to try and figure out the problem, nor do I have the cash to go single, and nobody seems to know what the hell to do.

If anyone has any ideas, throw them my way.

THanks

 

Have you checked for any ecu codes? If you do not have any codes that does not necessarily mean no solenoids are bad. Some of the output devices do not set a stored code.

I have not studied this enough, but believe a faulty turbo control solenoid valve may exhibit those symtoms.

You could probably check this by swapping that solenoid valve with one of the emissions related solenoids near the rear of the motor. Be certain the solenoid is getting power and has continuity to the ecu.

 

I have a Power FC, and I'm not seeing any problems, all my voltages are in range.

I am looking to just replace all of the solenoids to see if this fixes a problem. I wish they were not such a pain in the *** to get to.

I was told you can 'test' a solenoid with a 9v battery or some crap, I have no clue how to test them, can you fill me in on this?

Thanks

 

One approach is to disconnect the harnesses from your PFC and ground each solenoid individually. For example ground the harness at 4R and you should hear the solenoid click. You need to have the battery on; I can't remember whether or not you need the ignition switch on. I used a long speaker wire with a sewing needle attached at one end. I inserted the needle in the ecu harness. I routed the other end through the passenger's side window and grounded that in the engine bay area. This way I was able to hear the solenoid click. When you ground the wire you only need to touch ground momentarily just enough to hear it click. Using this method you will no have to remove the rats nest unless you have a bad solenoid. If a solenoid does not click, be sure to check for continuity and power at the solenoid connector before pulling the solenoid out.

Here are the ecu pins for the rats nest solenoids:
Pressure Regulator 4M
Relief 1 3P
Switching 4N
EGR 4O
Turbo Control 4R
Charge Control 4T
Double Throttle 30

The ecu harness can be deciphered in the Self Diagnosis section of the service manual pages F26-65.