Dashpot mod: to solve engine stalling when venting BOV to atmosphere

[NashMan]

Not going to argue with you Nash...you are well known for "fixes" like this, so there is no point.

It's not ok to introduce air at idle at any other source than the ISCV path on the stock TCCS...every Toyota tech article I've seen backs me up on this. I've seen the results 1st hand too.
That's all I'm going to say on this matter.

What tekdeus did to solve the problem (delaying the dashpot closing time) illustrates he knows how the TB and associated ISCV air path works. More important, how the ECU controls it and why the engine stalls when the BOV is vented to atmosphere. The best way is to recirculate the BOV, but it's a good solution (excluding emissions) if that option is not used.

no the real proper fix is not to run a atmosphere venting bov ( brads works never said it didn't kinda neat idea but whould bug me at stop lights)

and the 80's ecu is pretty stupid and slow and it will re-just how it See's fit after some time

my idea came from sogi dsm's and bunch of other cars

i Sean carbon do more damage then this will ever do


and i rest my case on this not every thing is white lab coat world

 

[tekdeus]

I assume that the pinhole was tiny enough that you couldn't silicone it and make a smaller hole? I've never taken a look inside to see how small the hole is...

Yes, the pinhole is so tiny, that there was no obvious way to create one smaller.

 

[survyor2]

Does this issue become obsolete when running AEM EMS with a map? I had the dieing problem when i was using the AFM and it still dies sometimes now that I'm on the EMS.

Dennis

 

[jdub]

You should be able to set idle directly with the AEM...speed density is the way to go and should eliminate this problem.

 

[MA70witBoost]

i was wondering... is there really all this need to cut open the dashpot? couldn't you just seal up the air inlet between the dashpots filter and the dashpot? further more, couldn't you just put the manual boost controller at the bottom of the dashpot where the air filter would go instead of having to T it off and not seal off anything??

 

[BOOSTEDSUPRA]

i was wondering... is there really all this need to cut open the dashpot? couldn't you just seal up the air inlet between the dashpots filter and the dashpot? further more, couldn't you just put the manual boost controller at the bottom of the dashpot where the air filter would go instead of having to T it off and not seal off anything??

this does sound like it should be possible...but, maybe the dash pot has to be in place for some reason....but theredicly....ya, i think thats all you would need to do........can some one elaberate more on this? :icon_bigg

 

[tekdeus]

The diaphragm has to be able to suck air in quickly, but then let it out extremely slowly. The boost controller in line would not allow enough air to be quickly sucked in. The dashpot VTV has a very sensitive check valve designed for this, and must be cut open to block the original outflow pinhole. The boost controller is the new substitute outflow pinhole, Tee'd in.

 

[BOOSTEDSUPRA]

The diaphragm has to be able to suck air in quickly, but then let it out extremely slowly. The boost controller in line would not allow enough air to be quickly sucked in. The dashpot VTV has a very sensitive check valve designed for this, and must be cut open to block the original outflow pinhole. The boost controller is the new substitute outflow pinhole, Tee'd in.

ahhh, thats what ran through my head, but i wasnt sure, cool idea, and dude, SIIIIIICK ass paint color! LOVE it!:evil2:

 

[MA70witBoost]

The diaphragm has to be able to suck air in quickly, but then let it out extremely slowly. The boost controller in line would not allow enough air to be quickly sucked in. The dashpot VTV has a very sensitive check valve designed for this, and must be cut open to block the original outflow pinhole. The boost controller is the new substitute outflow pinhole, Tee'd in.

dammit... so i gotta cut open another dashpot. I had a spare laying around and it didn't fare all that well when i used a hacksaw to cut it open. Decided to scrap it and just keep running the motor as is for now. Hey tek, what ya use to cut yours open?

 

[Evilempire1.3JZ-GTE]

I just dont believe venting the BOV to atmosphere is wise with a MAF system.
The metered air the is supposed to be in the engine is not correct to what the ECU delivers to the engine these issues tend to burn holes in pistons or FOD if not cought right away leads to rodknock & other isssues.

If you keep it MAF then recirculate.
A BOV to atmosphere on a MAF system is also another possible reliability issue if it fails.

The proper solution is stand alone + MAP then atmospere does not matter because MAP will read from the plenum pressure directly.

As far as the mod though to keep the engine from dying, modifying the dash pot is a brilliant idea & nice walkthrough.

 

[tekdeus]

dammit... so i gotta cut open another dashpot. I had a spare laying around and it didn't fare all that well when i used a hacksaw to cut it open. Decided to scrap it and just keep running the motor as is for now. Hey tek, what ya use to cut yours open?

Just a fine toothed hacksaw and a vise. If you look at the first pic, you may get a better idea of where I cut.

 

[Randy87T]

This is an old thread but it just gave me the reason for the stalling I have been having for a long time. I knew it was something to do with the dashpot/vtv but when I tested them individually they worked fine. Didn't know that it was the bov being vented to the atmophere that was causing the ecu to flood the engine. Great info !!!

Now for the good and the bad.

The good. I just installed the the Synapse Synchronic bov yesterday and recirculated back preturbo and I bet this fixed my stalling problem. Any takers ?

The bad. but didn't get a chance to try it out because as soon as I had finshed installing the bov the car started leaking power steering fluid all over the ground. CRAP !!!!!!

As far as the ps leak goes will be going out shortly to see what the cause is. Hope it's an easy fix.

 

[blue7mgte]

Awesome post, hopefully I'll remember this when I install my blow-off and have issues...

 

[KicknAsphlt]

I remember reading this thread a few years ago and was gonna do this mod instead of installing the recirc fitting into my SSQV... Main reason being, the line would be about 6ft long now that my BOV is on the driver's side of the car...lol.

 

[Sside]

Is there any way to get the pictures back on this mod? I would really like to try this out but after reading the directions over and over I am still confused on what to exactly do. I would greatly appricate it if anyone or Op could post pictures of this or help me out with it. PLEASE HELP!!!!

 

[jetjock]

Ugh...

 

[Sside]

Ugh...

My exact response when I couldnt see the pictures......

 

[jetjock]

Doesn't need pictures. Just follow the description. It's a real hack though. Could be done a lot nicer using any off the shelf miniature flow control valve. Not that I would want anything holding my throttle at 2000 rpm for a few seconds...

 

[Sside]

Doesn't need pictures. Just follow the description. It's a real hack though. Could be done a lot nicer using any off the shelf miniature flow control valve.

Would you mind explaining this to me Jet? I promise to post pictures and step by step instructions if ya help me... Please .... I read the descriptions but I am just not inderstanding exactly about the manual boost controller part... Basically my understanding is to cut open the vtv, seal off the small metal hole... Put vtv back together, t off the vacum that goes to it with a boost controller and tighten the boost controller slightly... ...

 

[Sside]

Yeah I am a little worried about it actually holding the rpm's but its a better choice for me at the moment than maf pro (I'm short on money and not experienced enough for it)..... Well since you are here Jet, would the Lexus AFM help this? Just literally putting in a lexus afm and not turning up the boost.... I know alot of guys doe the lexus mod to make more power and raise fuel cut but I just want my car to not shut off and I would hate to go back to the stock bov even thou it would be the smarter thing to do but my bov is my guilty pleasure....