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Forge RV holding open at WOT (could be result of boost leak)

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DSMunknown

15+ Year Contributor
4,108
42
Sep 16, 2004
Worcester, Massachusetts
I believe I have a boost leak and am not sure where it is coming from. Also, my Forge 1G re-circulation valve (RV) is not performing properly.



A few things you need to know:

  • My vehicle profile is fully updated.

  • My car is a daily driver, during the summer, I run 15-16psi. However, now that it is the winter season, I have turned down my MBC to about 12-13psi.

  • Regarding vacuum, I generally see between 15 and 16 on a consistant basis, although I will hit 17 every now and again. I was told by Andy M. that I should be consistantly in the 17-18 in.mg. range, but this is the least of my problems right now.

  • I have done boost leak tests in the past and am very familiar with how to properly perform them.

  • I performed this test about 10-12 times in the span of an hour, so it was not just one single pressure test that was performed.

  • The reading on the gauge never stayed constant for any length of time. It simply was a gradual decline from whatever psi I chose to peak at.

  • I replaced all of my fuel injector insulators (aka o-rings) this past Monday because I had a leak at #4. I used this article as a guide, and I also used RedTurboEclipse’s cheap fix to replace all four old OEM insulators, even though only one of them was leaking. I followed the first article to the letter, and I did not unhook/unbolt/disassemble anything that was not in that write-up except for the battery. I had to take the battery out because one of the metal connections keeps coming off of an ignition wire. Here is a photo of what I am talking about (the metal connector is inidicated by the red circle). By the way, the wires that are pictured are not the ones I am using, I simply took this off of Extreme PSI's site for a quick reference:

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  • I used lots of soapy water (all over the injectors, the top of the intake manifold gasket, the BOV vacuum hose, the BOV, the top of the gasket between the TB and intake manifold, the top of the gasket between the TB and the TB elbow, the PCV valve, the end of the PCV connection, the FPR, and other places). Here are some photos to help out those who reply to this thread (the red circles indicate where I put the bubbles):

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  • When I cleaned out the TB area with Deep Creep, I reinstalled the OEM gaskets with regular black RTV silicone, so as to limit the possibility of leaks. I am confident that there are no leaks coming from that area.

  • I tested the system consecutively up to 20psi, and one time at 25psi.

  • I used this device to give me immediate readings on the level and reaction to the air that was injected into the system:

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  • Obviously, there is air coming out of the valve cover (where the oil filter is naturally connected to). Thus, I am struggling to hear over the escaping air. However, I put my ear so that it was practically in contact with the middle of the fuel rail. The air leak seems to be coming from around the intake manifold area.

  • The CEL light came on today, but on Monday when I took the car out (naturally) it did not come on.

  • I always quadruple-check all of my lines/hoses/connections - I am very persistent on myself regarding this, so I am more than 95 percent sure there are no loose/forgotten connections that I simply have overlooked.


There are a few points regarding the Forge RV and performance when I have done some WOT pulls:


  • For anyone who is familiar with this RV, it is supposed to hold boost extremely well.

  • I am currently running the green spring, supposedly good for 5-15psi, but is known to hold even more.

  • I recently received my RV back from Patrick Robles over at Forge Motorsport for the revised lock ring after sending it to him to fix it (the old one was leaking like crazy).

  • Forge also proves two “plates” to aide the springs with keeping the RV closed and hold boost. As you can see, they are not currently installed (I just don’t see them as necessary for the amount of boost I consistently run).


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  • Over the past two days (that is, Monday and Tuesday) I have done about ten WOT pulls, with generally the same results.

  • The RV does not seem to close like it should. When I am traveling with between 10 and 0 amount of vacuum, the RV is partially open and re-circulating back into the intake pipe. This is normal and this is what it should be doing. I can hear when the RV is doing this, because there is a constant “hiss.” However, the problem is that in second and third gear the RV does not want to stay closed when I put the engine under heavy load. Over the past two days, on some WOT pulls, I have seen the gauge read as high as 7psi (!!!) and the RV still be partially open.

  • Additionally, the RV seems to perform normally and hold boost in the higher gears (that is, fourth and fifth), regardless of RPM or throttle position.

  • Last night I made two consecutive passes in second and third gear. The first time the gauge read 7psi with the RV still partially open (I know this because I can hear the distinct hissing, similar to the hissing when I am traveling between 10 and 0 amount of vacuum) when under WOT. I kept my eyes on the boost gauge, and the RV did not close until very high in the RPM range. I decided to do a second pull and try and remember to look at the tachometer right before I let off the throttle. This time, right as the boost held and shot up to 10+psi, the engine hit 5500 rpms and was climbing. The throttle was roughly about 90-95 percent open.


Update:

Now, I would be inclined to assume that the CEL came on because one of my sensors has failed and needs replacing (particularly, my PCV probe sensor). I am assuming this because I followed the guide and the guide tells us that the PCV sensor needs to be disconnected, so perhaps I damaged it somehow (although, I see this as doubtful because I was very careful not to scrap it against anything).

I am also assuming that my problem is directly related to my replacement of the insulators, because the CEL was not on before I performed the install, and the performance of the engine wasn't nearly as bad as it currently is today. Therefore, something must of went wrong as an indirect/direct result of the install process. The only other thing I can think of is that my valve cover gasket is leaking from the intake manifold side. I will go out and put soapy water all over that area to make sure it is not that.

I did more boost leak tests today (Thursday). The leak almost sounds like it is coming from inside the intake manifold (because it is a little bit muffled). However, I am just guessing; I could be way off.
 

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I would try to isolate the problem. Instead of testing the whole system I would take the intercooler piping off the intercooler and test the intercooler. Then test the LICP and intercooler. Then intercooler and UICP then UICP to the TB. Sounds like your TB shaft seals may be leaking or the EGR valve or something that is connected to the intake manifold. Also I would definately replace the TB gasket and coppercoat it to make sure it seals well. I would start with boost leak tests from various locations. Also try switching BOV's if you can. I have heard of Forge BOV's but one DSM's I haven't heard very good things about them.
 
That's a really good explanation of what's going on, and what you've done.

Although I can't say why the BOV is staying open under boost (I'm not familiar with that BOV), this might help track down that pesty leak.............
http://dsmtuners.com/forums/showthread.php?t=215694 start at around post #6, it talks about the EGR leaking, which could be the issue there, especially since you hear it in the intake.
 
So what you are saying is that your Forge valve stays open when your boosting, but when you pressurize the intake with an air compressor it stays closed?

Do you have a different spring you could put in your valve, or possibly shim it up so that its a bit stronger?
 
Wow...

Well if this were my car the first couple things I would try would be:

1) Shimming the BOV spring/checking that the vacuum line is correct. BOVs operate on the principle of using a vaccuum line that comes from the intake manifold (after the throttle body) to hold the valve down under boost, and pull the valve up under vacuum In theory, it should be equal pressure on both sides of the valve until you're off the throttle. I think you know all of this, but I figured I might as well clarify. the spring shouldn't actually be doing anything.
2) start at the throttle body elbow with your boost leak testing, and then move backwords. I'd agree that your description sounds like you could be getting some leaking from the EGR, or any and all vaccuum lines as you have circled in your pictures. You also want to try and make sure that all of the valves are closed when you do a boost leak test. This would mean bringing cylinder 1 up to TDC.
3) A quick way to seal small boost leaks is to use Orange RTV. It's not pretty, but small leaks can be dabbed with the orange RTV, and then use a torch or a heat gun to solidify it. Seems to work pretty well.
4) I would replace that spark plug wire. That's just bad news waiting to happen.

Other than that, I don't have very much advice for you.
 
You also want to try and make sure that all of the valves are closed when you do a boost leak test. This would mean bringing cylinder 1 up to TDC.


Actually to insure that each "cylinder" is closed (not leaking straight through from intake out to exhaust)............it should be roughly 30* ATDC. Remember to only turn the crank CLOCKWISE.
 
Anthony,

I have nothing really new to add here. I'm in total agreement with Jim, Greg and Adam in their recommendations. I'd start with the simple stuff like installing the shim plates in the BOV to see if that makes a difference and then boost leak testing separate parts of the intake setup to isolate where the issues is instead of testing the system as a whole.

I'd also have that CEL read.

Keep us posted,

Andy
 
Anthony Im in the same boat as Andy here...I have nothing to add except that I am looking at a well working 1G BOV as Im typing, and if you would like to put it on to see if thats your problem I would be more then willing to let you use it. Im going to be down in Fall River today working on my buddy Josh's( chowda on BayStateDSM.com) GSX. If you want to stop by you can, and I will have it on me, or I could mail it, or I will be heading down past Worcester next weekend, and I could bring it by then... Its all up to how ever you want to go at it buddy. Gimme a shout on my cell...18602133069, I have pretty good service around here so I should get your call.
 
First and foremost, I want to thank all of you for responding and giving helpful information. It is much appreciated.





The short response ---> I just needed to install the shims. That seemed to alleviate the major problem that was occurring.




95blackGsTurbo said:
I would try to isolate the problem. Instead of testing the whole system I would take the intercooler piping off the intercooler and test the intercooler. Then test the LICP and intercooler. Then intercooler and UICP then UICP to the TB. Sounds like your TB shaft seals may be leaking or the EGR valve or something that is connected to the intake manifold. Also I would definately replace the TB gasket and coppercoat it to make sure it seals well. I would start with boost leak tests from various locations. Also try switching BOV's if you can. I have heard of Forge BOV's but one DSM's I haven't heard very good things about them.



I will try to isolate the system, I just haven't found the right-sized PCV cap as of yet. But what are these issues you speak of, Adam? Perhaps you are refering to Tyler's thread about the Forge RV leaking? As I have already mentioned, I was experiencing the same issue and sent the RV back to Forge Motorsport for repairs. Are there some other issues of which you are aware of?





FORMONTOYA said:
That's a really good explanation of what's going on, and what you've done.

Although I can't say why the BOV is staying open under boost (I'm not familiar with that BOV), this might help track down that pesty leak.............
http://dsmtuners.com/forums/showthread.php?t=215694 start at around post #6, it talks about the EGR leaking, which could be the issue there, especially since you hear it in the intake.



Thanks Jim. I will keep this in mind and consider this possibility. I will read through the EGR link on VFAQ (even though it's for the pre-94 cars).

I take seriously Doug's explanation that when one gives a vague description of the problem, one can only expect vague diagnoses in return. And after seeing Andy's thread where he gave a solid original post, I thought I should follow suit.




blackGSX2g said:
So what you are saying is that your Forge valve stays open when your boosting, but when you pressurize the intake with an air compressor it stays closed?

Do you have a different spring you could put in your valve, or possibly shim it up so that its a bit stronger?




Yes Matt, that is exactly what I am saying. Yes, I have two other stronger springs, but I very much doubt I need them with the amount of boost I am running. What is perplexing me is how drastically the effectiveness of the RV was altered after I replaced my injector insulators. The Forge RV had responded quite nicely up to this point, so I don't see why the spring (without the shims) was not able to perform in the same manner as before.
 
drivemusicnow said:
Wow...

Well if this were my car the first couple things I would try would be:

1) Shimming the BOV spring/checking that the vacuum line is correct. BOVs operate on the principle of using a vaccuum line that comes from the intake manifold (after the throttle body) to hold the valve down under boost, and pull the valve up under vacuum In theory, it should be equal pressure on both sides of the valve until you're off the throttle. I think you know all of this, but I figured I might as well clarify. the spring shouldn't actually be doing anything.
2) start at the throttle body elbow with your boost leak testing, and then move backwords. I'd agree that your description sounds like you could be getting some leaking from the EGR, or any and all vaccuum lines as you have circled in your pictures. You also want to try and make sure that all of the valves are closed when you do a boost leak test. This would mean bringing cylinder 1 up to TDC.
3) A quick way to seal small boost leaks is to use Orange RTV. It's not pretty, but small leaks can be dabbed with the orange RTV, and then use a torch or a heat gun to solidify it. Seems to work pretty well.
4) I would replace that spark plug wire. That's just bad news waiting to happen.

Other than that, I don't have very much advice for you.




I will keep all four of your considerations in mind, Greg.

A comment about #3 - Why would you suggest Orange RTV over anything else (such as Permatex's black RTV or Ultra Black RTV or Black Rubber Sealant)? I thought it was hideous when I used the Orange RTV to stop my BISS leak, never mind the idea of having orange dots all over the engine bay. :rolleyes:

Regarding #4, I will indeed replace the plug wires ASAP. I thought I saw some product on "Two Guys Garage" that was essentially an anti-stick lubricant that one could apply to the spark plug-to-coil connection to prevent problems. Is anyone familiar with such a product, and is it necessary?




andymoraitis said:
Anthony,

I have nothing really new to add here. I'm in total agreement with Jim, Greg and Adam in their recommendations. I'd start with the simple stuff like installing the shim plates in the BOV to see if that makes a difference and then boost leak testing separate parts of the intake setup to isolate where the issues is instead of testing the system as a whole.

I'd also have that CEL read.

Keep us posted,

Andy



Thank you, Andy. The CEL was a very simple fix. As I mentioned before, I had to remove the battery. As we all know, when disconnecting the OEM positive terminal clamp there are two nuts that need to be taken off or loosened. When I took off the first nut, it fell down into the engine bay and I could not find it (and no, it did not fall onto the ground). After about 30 minutes of looking, I gave up and decided to just use the single nut.

Whether I needed both nuts on the positive terminal clamp or the car just needed to be reset I could not say. But When I went down to a local hardware shop, found an appropriate nut, and preceeded with the install, the CEL turned off. Yet again, a simple fix was all that was needed.




fourreGsixty3 said:
Anthony Im in the same boat as Andy here...I have nothing to add except that I am looking at a well working 1G BOV as Im typing, and if you would like to put it on to see if thats your problem I would be more then willing to let you use it. Im going to be down in Fall River today working on my buddy Josh's( chowda on BayStateDSM.com) GSX. If you want to stop by you can, and I will have it on me, or I could mail it, or I will be heading down past Worcester next weekend, and I could bring it by then... Its all up to how ever you want to go at it buddy. Gimme a shout on my cell...18602133069, I have pretty good service around here so I should get your call.



Thank you Dustin for the offer. Actually, I already have an uncrushed 1G BOV lying around. Why? Because it is a reliable BOV and it is always a good thing to have a spare BOV within reach. I got it off Ebay and keep it around for emergencies. :)

BTW I'm surprised you haven't departed for CT yet. I would have thought you would have gone by now. If you could stop by and confirm the possibility of the EGR valve failing, that would be great. I'll cook (OMG) you some home-made peanut butter cups for your long trip home. What will you be taking, the Mass Pike-to-395? I will call you and PM you the directions.
 
I get out of UTI on friday for break...Im heading down then, I couple stop by, but it would be around 10pm cause I get out of school at 8.15, and it takes 30 min to get to 495, and about 20min on 495 to 90, and yes I will be taking 395. I got your PM on BaystateDSM.com, and will use your map quest directions if its not too late. Give me a call on my cell, and we can talk. Yeah I love having spares of everything...2 1G IMs, and 2 2G IMs, LOL, along with a couple VCs soon. Honestly I would spend the $10, and have a machine shop make you an EGR block-off or get one from SBR, or w/e to see if it fixes it. But then again Mass, is one Nazi state on mods LOL.
 
Well, I wanted to update this very old thread I started to keep everyone informed (as if anyone cared or was actually paying attention :rolleyes: ).

After having boost leaks up the wazoo (and not fixing them due to laziness and cold weather), suspected clutch slippage, and in a money crunch, I suffered with the symptoms that I have already posted up for a long time.

So I tried a number of things with the Forge 1G RV. Back last summer I noticed I was having the same problem that Tyler (CanadianTSi) was having (in this thread), so I sent back the RV to Forge and had them replace the lock ring. There was a lot of air leaking out of the same spot. When the RV returned to me, the air stopped leaking out. Let me just say (as I have said in the past) that the Forge Motorsport customer support is superb.

Anyways, over the past 9 months I've been fighting with a CEL and finally revamped my 7-year old OEM exhaust system, among other things. I'm still fighting the 0403, but am taking it to a trusted local shop next week to get it finally fixed. I did my EGR block-off plate install guide to see if the suspected EGR valve was to blame. The issues persisted.

Recently, I finally fixed all of my boost leaks (that stupid PCV valve was alluding me like a pedophile online; that "leaking EGR" suggestion seems very awkward in hindsight). Anyways, I did the ol' BLT from two locations - the compessor-side housing and the throttle body elblow. I tested from the elbow first, taking Adam's advice. The pressure held strong after I re-routed the PCV feed line and capped off the intake manifold nipple.

(Yes Bruce, I know; BLT FTW ;) )

After I was completely sure there were no more leaks up to that point, I turned to the compressor-side housing. I know, I know, some people won't agree with people when pressure testing is done there, due to the possibility of messing up the turbo seals. I decided to do it anyways, regardless. I found absolutely no leaks in the rest of the system, and the needle held strong like it's supposed to (but obviously leaking gradually down after a short time).

So I bolted and clamped everything down. I did this process (the BLT testing and putting everything back together) multiple times. After each time, I would take the car for a spin, with the Forge 1G RV installed.

The boost would still not hold properly.

I would still here the relief valve stay partially open at WOT (or even at 50 percent), and it would not fully close until 4500-5000 RPMs. I would still build boost while the RV was partially opened at WOT, as I explained in the first post. I would have to either play around with the pedal while driving and hope to catch the valve so it would close, or I would have to hit boost in a higher gear (fourth and fifth gear never really seemed to have a problem, just the first three gears). More than half the time, when on the on-ramp to the highway, in 3rd gear, going about 40 MPH, I would craddle the pedal to get the valve to close. If I tried to just go all out, it would not always close (although, sometimes it did its job correctly).

So I have three springs and two shims I have to work with that I can put into the Forge RV. I tried the green spring (the weakest) by itself. I tried one, two, and three shims in combination with the green spring. And I tried the yellow spring (one level above the green spring). With the yellow spring, the RV would certainly close, but it would close way to early (around 10 In.Hg.). Similar results I found were with the green spring and the three shims. With the green spring and two shims, I was still closing early, but it seemed to be the best compromise out of all five options I tried (it would close around 5 In.Hg.).

In case anyone is wondering:

  • Green - 5-15 PSI
  • Yellow - 15-23 PSI
  • Blue - 23-30 PSI
When I purchased the Forge RV from Extreme PSI, I recieved three springs (green, yellow, and blue) and two shims. Since I did not want to purchase some expensive kit such as this one for one or two more shims, I visited my local hardware stores. I decided that purchasing cheap metal washers that had the same outside diameter of the shims I already had would act as a nice, cheap, easy alternative. Now I had plenty of extra shims. This is how I was able to try three shims with the green spring.

I highly doubt using washers in place of the shims made these issues for me. I find virtually no evidence to believe otherwise.

So I finally decided to try one of my uncrushed 1G BOVs out instead. Fixed the problem immediately.

Don't get me wrong, Forge Motorsports puts out solid products. But I still can't imagine what I missed and what I am overlooking. Maybe the green spring is faulty (although, I doubt that). I just can't think of what could be causing these symptoms.

So initially, there were boost leaks that needed to be fixed. Now all of my evidence points directly to the Forge RV.
 
Usually when this happens it is a result of the piston needing some more grease. I can send you a packet if you don't have any fully synthetic grease handy.

Also try pushing the valve up a few times with your finger, the piston might be coming to rest against its sealing surface at a slight angle. Obviously if this happens the valve will leak. While doing this also try capping off the vac port once the piston is lifted, if everything is kopacetic the piston will drop just a bit, if the seal isn't up to snuff the psiton will drop all the way down to its seat.

As to why it started after fixing your leaking injector grommets, if they leaked enough they could have changed the relationship of the manifold pressure and the pressure in the charge pipe enough to drastically alter how the valve actuates.
 
patty AT forge said:
Usually when this happens it is a result of the piston needing some more grease. I can send you a packet if you don't have any fully synthetic grease handy.







Now that you mention it, I do recall the grease looking increasingly dark and dirty each time I removed or inserted a shim, or whenever I changed a spring. Just as a note, do the Forge CBVs need regular maintenance (such as, greasing the rings every so often)?







As to why it started after fixing your leaking injector grommets, if they leaked enough they could have changed the relationship of the manifold pressure and the pressure in the charge pipe enough to drastically alter how the valve actuates.







No. I was having the same problem both before I fixed all of my boost leaks as well as after. I figured the RV was not closing properly due to multiple boost leaks. I also figured that when the T-25 was boosting, it had to overboost to overcome the leaks (so to speak).
 
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