polyfc

okay, i made my own mbc's and installed and set them up yesterday and i had no boost problems whatsoever. Today I steam cleaned/pressure washed my engine bay and after that I was getting no boost. So I took the intakes and ic pipes off and checked all the lines and nothing came undone anywhere in the engine bay. Although the small vac hose the goes from the uim to a piece on the secondary turba intake setup came off while i was pressure washing, but i put it back on. I have the hks system to clarify. Well when i slapped everything back on i had boost again. I went to leave my place later in the evening and I had no boost again. stopped in a parking lot checked around and I had boost for about 3 minutes then it stopped again. then i spent the last hour or so on my way back without boost and it arbitrarily came back again. Now when i went wot on second gear it worked but when i shifted into 3rd I had nothing again and that's what the car is currently at.
I've been running over what the problem could be for hours. It's not a vac leak and there's no audible boost leak; and ever if there was it wouldn't be as sporadic as it is. And if i somehow got a solenoid or something of that nature wet it should've dried out by now and also wouldn't have the random boost issue. I checked the clips on my actuators and those are on. The only thing i can really think of is the waste gate is sticking open and it'll close but stick right back open. But then how would pressure washing the upper half of the engine cause that? I coud see it being something electrical, but the inconsistency is very confusing

Larz

Maybe the hoses leading to the controller are getting pinched off or in a position where there is restriction. I don't have a controller, but it does replace the turbo control solenoid, right? I had a similar problem and the hoses going to the controller had kinked.

polyfc

The mbc just replaces the pills in the boost and precontrol lines. I thought it might've been those at first also but they aren't kinked anywhere.

Mybaby

if u r running the stock twins maybe the c clip fell off the actuator rod that opens door the rear turbo. its right underneath the exhaust mani extension.

dgeesaman

iTrader: (7)

You may have a loose vacuum line (maybe water has allowed a loose line to slip off) or a bad check valve.

Dave

polyfc

I just went and checked around under the hood about 20 mins ago and all the lines are still there. But if it was a vacuum line wouldn't it be a consistent problem? I thought i might've blown something off when i went wot last night but i didn't which is why i thought it might be the wastegate. could water have gotten into anything from the small hose that popped off when i was pressure washing to cause this much trouble

polyfc

here's the piece the hose came off of in case there's any confusion

TT_Rotary

iTrader: (3)

if u ask me, the fastest way to check for a air leak, is to take some carb spray and spray away, and well, u know the results.. =) just a quick way to check for a vacuum leak, sounds like it is, if it keeps turning on/off.. b/c if u messed something up, ur boost wouldnt keep kicking back on, i was gonna go w/ larz on this one.. something w/ a vacuum line.. good luck w/ it though.

polyfc

well i messed around with the car today, i switched out the bov in case the stock one had failed. That didn't work; so i replaced the hose that connects that to the uim with a stock one to see if maybe the silicone had failed or the line was too small and it still did it. I'm heavily leaning towards it being the wastegate. One very peculiar thing did happen. As i was running it up and down the street at wot it did boost more than previous days but it would sometimes not boost then later in the gear the boost would step up to say 5 then 7 then 10; there was also an instance when i had no boost at all and at 6k the boost came on at 10 psi. I figure if it was a hose or a vac line it would be a consistent problem and even if it was electrical it wouldn't fluctuate as much. I have no idea how to check the wastegate so i'm going to try and mess with that tomorrow but in the meantime if anyone has any ideas or thoughts on what in the hell this is please post as there' a great many people on here who are far more educated on the rx7 than i am.

polyfc

had anybody ever experienced something like this or has an idea cause i am at a complete loss

AWD-RWD racer

iTrader: (5)

im having kind of a similar problem. i sometimes get boost. then none. then it tries to build boost then it falls, then rises, then falls. usually no higher then 7-8 psi then falls to 3-4. if you figure out whats going on wit yours, please let me know. if i figure mine out, ill let you know/.

adam c

iTrader: (2)

I would replace the check valves. Your symptoms sound like that may be the problem.

polyfc

i'm starting to think so as well. i am getting boost most of the time today but i began noticing that when it wasn't allowing boost at wot once i let off the gas i hear a strange noise coming from the driver side of the engine bay. it's kind of a difficult noise to describe it occurs the same time as the bov would go off when boosting though.

AWD-RWD racer

iTrader: (5)

any update?

polyfc

nothing, i am starting to think it might be a check valve though cause that noise i'm getting on the other side of the engine bay. and it's boosting a lot more. you having any luck?

AWD-RWD racer

iTrader: (5)

no luck here. i bet we are having the same problem. under wot , its harder to build full boost sometimes it works sometimes it doesnt. .

silverflash2

iTrader: (2)

If your running more than stock boost, I've have the same problem in a way. I go WOT, boost is good, i slow down, accelerate, no boost, drive alittle bit, with no boost, then all sudden everything is back to normal. Then the cycle starts again. I think i know why, from doing some research on here. I'm running 12-14 lbs of boost. They say that you should put a air regulator somewhere in the system, that way the turbo acutators are getting 10lbs of boost, but your turbos are still giving the engine 14lbs of boost. The turbo acutators stick with higher boost pressure running thru the system. I haven't done this yet to verify it works, but alot of people running more than 10lbs of boost, said this fixed the problem. I plan doing it, when i'm done rebuilding my motor. Try searching for the thread if you are running more than 10lbs of boost.

silverflash2

iTrader: (2)

Here's the link.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/weird-problem-boosting-480079/

fitzrx7

iTrader: (1)

You drive that car anymore before we fix it and I will pimp smack you boy.

For real though, I'm pretty sure that it is a leaking vacuum line, sticking check valve or cracked wire that is shorting out. One of those three I would almost be on. The car is running on the primary and never transitioning to the secondary. It spools the secondary but never switches over to it. You just hear it spool through the relief valve. Control system is fooked.

Fitz out

AWD-RWD racer

iTrader: (5)

I STILL HAVE NOT FIGURED OUT WHAT THE PROBLEM IS. IM TAKING THE CAR TO THE SHOP ON TUESDAY. ILL UPDATE WHEN I FIND OUT.

srry caps