sighh....no boost

[4BangerV8Killer]

so yesterday i bought a 92 6/4 for 1500 bucks....checked it out. the only thing is the turbo wont build any pressure at all, not 1 psi.....vacumes fine at -17 off throttle but no boost on throttle. Doesnt bog when i gun it or anything like that. just runs like a crappy 1979 honda would with 50sum hp. I checked the turbo. no oil leaks, shaftplay and comp wheel spins fine. any ideas on what else i could check? today im gonna go ahead and check the ic and try to find a vaccume leak. but are the 14b's prone to having the wastegate stuck open at all?

 

[diablos991]

Check for boostleaks and proper wastegate operation.

 

[fourreGsixty3]

These are older cars, I would check the acuator arm, and the WG, it sounds like your WG is stuck open, over time the flapper can move out of place a little, and be stuck open. Does it build up boost in higher rpms? Even if the WG is stuck open it should be able to build some boost in higher rpm's. I would check for boost leaks, as well.

Dustin

 

[4BangerV8Killer]

no i can gun it all day and it wont build any boost at all, thats whats confusing me so much

 

[brute]

I'd check the actuator and arm. Make sure there are no restrictions preventing the flapper from opening or closing. Try to move it by hand. That's where I'd start. Let us know.

 

[4BangerV8Killer]

nope the actuator/arm moves but im not sure 100% if its fully closing anybody have a pic of a stock 14b act arm

 

[4BangerV8Killer]

pretty nice for 1500 and its a 6/4

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[chanley talon]

Did you look very close at the wagate arm where it ataches to the turbo. It should not be easy to move. It holds the wasgate flapper shut very firmly . Also take the intake tube loose thats attached to the turbo and try to spin the turbo . ONLY DO THIS IF THE CAR IS COOL. If it dont spin its a hunk of junk!

 

[4BangerV8Killer]

ya, iv done both of those things....it wasnt easy to move (took a screw driver to bearly move it) and as i said before the turbine spins fine and has absolutely no shaftplay

 

[fourreGsixty3]

Pull the o2 housing and see if the WG flapper isnt obstructed or anything like that. Can I would say pull the turbo off and check to make sure the fans on the exducer side are still there (this highly unlikely, but it moves freely, the actuator arm moves and its not too easy to move it, so I would just check them). There has to be a reason why the kid sold it for so cheap since its like the best combo out there for DSMs.

Dustin

 

[4BangerV8Killer]

he bought the car and only had it for 3 weeks....he didnt know much about dsms and just wanted the car off his property ....but him and his brothers had a 2nd gen supra hitting 12.1 and a 2nd gen rx7 with 750whp......

Im suspecting it to have a cracked intake mani...i can hear hissing from the injector area but cant pinpoint anything....and the valve on the left top side of the valve cover doesnt have a hose and the other part (on the intake mani) is capped off so im not sure if that makes a difference

 

[fourreGsixty3]

I believe that valve you are speaking of is the PCV, that usually has a hose that goes from it to a nipple on the intake pipe. That wouldnt make you not gain any boost, people will just throw little filters on it to make sure that nothing goes inside. Even with a boost leak you should get some boost...unless it is a multitude of leaks, or two different problems like the flapper being open, and having a boost leak(decent size). I would still pull the turbo and have a close inspection if it. Also pull off the top heat shield and check the exhaust mani. for cracks, the 1Gs are prone to crack since they are so thin.

Dustin

 

[spectr019]

Im suspecting it to have a cracked intake mani...i can hear hissing from the injector area but cant pinpoint anything....and the valve on the left top side of the valve cover doesnt have a hose and the other part (on the intake mani) is capped off so im not sure if that makes a difference

Well yeah what everybody has said about the actuator is what I would suggest to check out first also. uuum oh and can you even hear the turbo spool up in the slightest way at all even though you aren't feeling any boost? If you don't see anything wrong with that, I would say take the turbo out and check everything, just be careful NOT TO TAKE IT APART too much cause the wheels and everything are precisely balanced, so don't go too crazy. But hey look at the bright side, this could be your excuse to get a new turbo!

As for the cracked mani, my buddy's 1G did that also, but he just had to tighten up the throttle body and he was good to go, so make sure all the connections are tight. Although as I'm sure you know, the 1G mani's are prone to crack.

Ben

 

[fourreGsixty3]

As for the cracked mani, my buddy's 1G did that also, but he just had to tighten up the throttle body

Can you provide some additional info into this? I just dont see how making the connection from the TB to the intake mani will fix a crack. Also when I said 1G mani's are prone to crack I was refering to the exhaust mani. not the intake, those seem to be decent thickness, and I havent heard or cracked intake mani's like you hear of crack 1G exhaust mani's. So a long story short, could you ellaborate on the statement I quoted?

Dustin

 

[4BangerV8Killer]

iv been around dsms for about 5 years and know the engine pretty well......its not the pvc valve its the valve on the top of the valve cover and the hose goes right to the intake mani...i know the exhaust manifold is cracked but not cracked enough to prevent boost. i think the intake manifold is cracked because i hear some hissing there, and its all polished so i know its been pulled so im not sure if it was dropped or not.

still no boost and when i do go full throttle i can hear a faint whistling. but not a turboes whistle it sounds more like the old school beetle engines

 

[fourreGsixty3]

Seriously I would pull the turbo and inspect the CHRA, and the fins on the exhaust side. I seriously dont see a crack in the manifold preventing from boosting, and post a pic of this valve you speak of.

Dustin

 

[chanley talon]

Your orings where your injectors fit the head are for sure leaking. Are you hearing the hissing while running or shut off? you have to vaccumm lines in the intake valley one big one sticking straight up and the other right above the coil pack . If all 3 was leaking you would have no boost and major hissing.

 

[chanley talon]

Your orings where your injectors fit the head are for sure leaking. Are you hearing the hissing while running or shut off? you have 2 vaccumm lines in the intake valley one big one sticking straight up and the other right above the coil pack . If all 3 was leaking you would have no boost and major hissing.

 

[Samzer]

Is that common in a DSM? Ive done research and never heard anything like that happening. Where did you get that for $1500 anyway?

 

[4BangerV8Killer]

heres a pic of the valve.....i know where its supposed to be....and the intake mani side is capped and i capped the valvve with my finger and it didnt do much.....i know the injectors are probably leaking but that would never be enough to prevent even a little boost....im guessing there must be a huge hole under the exhaust mani which is unlikely or the intake mani is like i said before cracked somewhere. yesterday i FT all the way to 5k rpms and my guage just stayed at 0....and my vacumme on idle is at -9ish....(autometer gauge)

When i idle surge the engine shakes hard...im gona try and get video of this and host it but the exhaust sounds bad and when im under the hood and rev the engine it sounds terrible not like a 4g63 should

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[Wildeclipse2000]

heres a pic of the valve.....i know where its supposed to be....and the intake mani side is capped and i capped the valvve with my finger and it didnt do much.....i know the injectors are probably leaking but that would never be enough to prevent even a little boost....im guessing there must be a huge hole under the exhaust mani which is unlikely or the intake mani is like i said before cracked somewhere. yesterday i FT all the way to 5k rpms and my guage just stayed at 0....and my vacumme on idle is at -9ish....(autometer gauge)

When i idle surge the engine shakes hard...im gona try and get video of this and host it but the exhaust sounds bad and when im under the hood and rev the engine it sounds terrible not like a 4g63 should

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That is your PCV valve, but will not matter.

You would be surprised what will happen if your injector O rings are bad. What you need to do is a boost leak test.

I doubt you have a cracked intake manifold, but you might have a bad gasket between the head and manifold. You really need to do a leak test first,because if you can hear a leak, that means it is big enough to make the car not boost properly!

 

[talondude4]

Did you check for cracks? clean all the grease off, make sure there is no cracks. cracks= pressure loss.

 

[4BangerV8Killer]

iv done all the visual checks...no cracks except for a few smalls on the exhaust manifold which have been epoxied already. i check all the hoses, nothing seems out of place..im gona do a boost leak test soon but ihave to make another tester cause iv seemed to misplace mine. but STILL on a boost leak id stil be able to pull at least 1psi, no?

 

[4BangerV8Killer]

some engine photos

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[Wildeclipse2000]

but STILL on a boost leak id stil be able to pull at least 1psi, no?

No not necessarily, if it is a big enough leak for you to be able to hear it, then it is more than likely big enough to creat no boost at all. You vacuum numbers are telling you that you have a huge leak if you are only drawing 9 inches of vac. at idle.