jeffrored92

Boost Problems!

Ha

OK I've done a quick bit of searching, don't flame me *** for asking a question that I might find the answer for tomorrow please

I've read that if the Primary doesn't make 7-8psi then the Secondary will not kick in. My boost patten appears to be roughly 7-5-less meaning I make 7psi, dropping to around 5ish at 4500rpm which then seems to drop to around 3-4psi by redline. At first I thought maybe the vac tube to my gauge might be leaking a bit, but if I'm only making 7psi on the Primary and the Secondary doesn't kick in, that might explain what I'm seeing. Cruising down the freeway in 3rd gear around 3000rpm and I floor it, boost jumps straight to 7psi, then to 5 around 4500rpm, then drops a bit by redline. Anyone care to share info? I've only noticed this in 2nd and 3rd gears..........can't really take it to redline in 4th or 5th, might be a wee bit too fast.

Obviously I got lots more reading and investigating to do but thought I'd just see if you boys could head me in the right direction.

Looking on the flipside, if my boost isn't right that means my car could probably go faster........................

Cheers All

jsplit

Was the boost pattern like this before you installed the gauge? I realize that w/o a gauge you can't get specific psi but you should be able to feel that kind of pressure drop off.

jeffrored92

I haven't felt any change in the way the car drives. Still feels bloody quick to me. I have to admit, I didn't take a boost gauge when I took the car for a test drive so I've never known the boost patten till now. (I know I know I should have!!!)

I think the first place I'll look is for those pills in the vac lines.......it would appear that if those are missing 7psi boost is a common symptom. What I'd like is for someone who had those missing and was running 7psi boost max to tell me what their boost pattern was like..........did the secondary come online?

The drop from 7 to 5 psi is quite sharp, happens very quickly, around 4500rpm. At first I thought maybe my gauge was out a bit but then I would have expected it to rise up again with the secondary coming online.

Educate me people I am ready to learn

WaLieN

If you are missing the wastegate pills, you will only boost at 7psi on both turbos. Your best bet is to look in the newbie post -- and find the turbo troubleshooting site. With the symptoms that you describe, it can be an array of things:
-Leaky y-pipe coupler
-Clogged cat(s)
-failed turbo control solenoid/actuator
-vacccum/boost hose leak

Rated R1

What year is your car?

jeffrored92

It's a 92 build date (93 model)

Don't want to get into an argument like I read last night about build dates and model years etc!!!!!!!

Yeah I'm just gonna have to bite the bullet and start trouble shootin Hopefully it's just those pills and nothing harder to find.....

Mahjik

iTrader: (1)

https://www.rx7club.com/showthread.p...ht=boost+pills

jeffrored92

Cheers guys for the info so far

Won't be able to take off the air box and get down there to check the pills untill Sunday so I'll get back to you all around then. In the meantime, if ANYone has had the pills missing and could explain their symptoms to me just to help make sure I'm on the right path (I'd rather not unnecesarily get in there and replace all the hoses and check the actuators one by one). Boosted a bit more this morning to see what's going on. When I step on it I build up 7psi very quickly. There is a sharp drop to 5psi around 4500rpm, and it pretty much holds 5psi all the way through to redline, with a slight drop just before shifting. I posted before that it dropped to 3-4psi but I must not have been watching the gauge close enough.

Got all the links I need now, I can't believe how much info is available online for these cars, it's fantastic!

So to recap - if ANYone has had those pills missing, tell us what your boost pattern was like and if your secondary turbo came online or not (pretty please)

GoodfellaFD3S

iTrader: (213)

Yes, it will. *If* your turbo system is functioning properly with the exception of the two missing pills, you will have ~7 psi from ~3k to 8k rpms, with a slight dip at transition.

WaLieN

Try redlining in one gear, then shift, and boost again. After you shift, can you make any boost?

alberto_mg

list your mods.

having run w/o pills b4 getting a boost controller, i can tell you that you will make 7psi on both the primary and secondary turbos, so i doubt its the pills.

i would suspect a clogged cat or the 4 vac lines that are located under the crossover pipe.

you can checked for a clogged cat, but unbolting the front of it from the downpipe and shining a flash light in there to look around. if you see a mesh like rusty looking structure, then the cat is probably ok. if it looks like more solid (kinda like a shower drain after your girl's been in the shower) then its clogged.

jeffrored92

The car is stock, all I've done to it is whip out the pre-cat and put in a downpipe. I imagine the dudes would have checked the cat condition when they had it all apart but I can't be certain. Will ring them later in the week and ask if it's something they were likely to do while putting in the downpipe.

Now I've just taken out the air filter assembly, and there was a pipe coming off the top right (above the air filter) that wasn't attached to anything at the other end, and I can't see what it was supposed to be attached to. Anyone know where it is supposed to go to? I'm not talking about the hose to the air pump, I mean the other hose in the photo, coming off the right side of the air filter assembly (as looking from the front of the car)



Cheers!

WaLieN

That is the infamous "moo" hose that muffles the air pump. It is supposed to connect to nothing.

alberto_mg

Its very unlikely they checked it. Nobody ever does unless there is a problem.

jeffrored92

Yeah your probably right.

I just discovered the 1 inch hose from the y pipe to the air bypass valve was loose at the y pipe. Even with the clamp on I could rotate it VERY easily and there was a bit of oily residue around the area, so I think I might have found at least part of the problem.

Now somebody tell me, there is a bit of oily residue around where the y pipe bolts onto the primary turbo. Should I regard that as normal for a stock car with 117000 kilometers, or could I be leaking air through that join?

alberto_mg

that is pretty common depending on how much oil you find in there. its blow-by from the turbos.

good find on the hosess. those little hoses often get hard, brittle and crack.

jeffrored92

Changed over the hose to the air bypass valve (from the middle of the y pipe) but boost is still the same. I tell ya, the hose looked newish at one end and baked ROCK hard at the turbo end! I've noticed that the hose between the charge relief valve and the y pipe is in the same state (I can rotate it on the nipple very easily) but that one is a little tougher to get at so will address it sometime soon. In the meantime, I am still in the hunt for my boost leak/clogged cat/missing pills. I didn't end up checking for the pills, I got excited that I might have found the problem with that hose.....hehe won't make that mistake again.

Oh and I thought they were 1 inch hoses, but they turned out to be 3/4 inch. Internal diameter that is.