Acceleration H-E-S-I-T-A-T-I-O-N-!

[cinciguy89turbo]

I've got an 89 turbo with a hesitation issue. It idles fine, cruises fine and with light acceleration does ok too. But when I want to get on it the turbo spools, but it falls on its face...hesitates hardcore! I sort of checked for a boost leak (noticeable holes and making sure they are connected!) I have an aftermarket boost gauge, and blow off valve. The yellow sensor that says Sensor ASSY Turbo Pressure has a hose connected to it, but it goes into a "T" and the other hose goes nowhere, (I plugged it up and my vacuum went from 10 to about 16 at idle) but it looks like the main hose is going to the blow off valve. The orange, brown and white connector is not connected, nor can I find it! Will this affect how my car runs? If it does where can I find where this plug goes?

If not can anyone help me with anything to check. I feel like I'm searching for a needle in a haystack:icon_surp

 

[dumbo]

Don't worry about that sensor, it is STRICTLY for the stock boost pressure gague. Cap it all off. Your vacum seems kinda low, check for vacum leaks. And check for codes.

 

[cinciguy89turbo]

What's the best way to check for a boost leak? Is this what the hesitation sounds like?

 

[lsaint07]

could be too much fuel when under boost.

 

[s383mmber1]

codes......?

 

[cinciguy89turbo]

I don't have a check engine light because my dash is messed up. If I'm not mistake this is how you check for codes right? Also took the car out today and I noticed that I'm only getting like 5 psi of boost shouldn't I be more like 12-13 (stock)? Does that definitely mean boost leak?

 

[isnms]

Don't worry about that sensor, it is STRICTLY for the stock boost pressure gague. Cap it all off. Your vacum seems kinda low, check for vacum leaks. And check for codes.

+1 Your vacuum does seem low. Look here for what vacuum should be
http://www.users.bigpond.com/ergoff/vac1.htm

Then check over all your vacuum hoses here
http://www.cygnusx1.net/Supra/TechTips/vacuum_hose.aspx

 

[Angry7M]

I don't have a check engine light because my dash is messed up. If I'm not mistake this is how you check for codes right? Also took the car out today and I noticed that I'm only getting like 5 psi of boost shouldn't I be more like 12-13 (stock)? Does that definitely mean boost leak?

LOL stock boost is around 6psi.

 

[cinciguy89turbo]

I do think it is a boost leak! I'm only getting 5psi of boost max, and when it idles its like 15-16 of vacuum...Idk if this is normal. I have a couple of pictures here I don't know where some of these hoses/valves go. Any help would be awesome nobody wants to work on this car because it's been "chopped up" as they say. But I know everything was perfect before the swap. And I'm pretty sure these things were off before the swap. I bought a Chilton's manual, and its not a lot of help with the turbo setup. Honestly I'm sort of a newbie when it comes to the mechanical. I could tell you specs (hp, torque, 0-60) of any car all day...Thanks so much guys the schematic helps...i'm still a little lost though lol

There are little read boxes around the specified objects


What is this little guy and where do the hoses go. (I have aftermaket blowoff valve) The openings are not sealed. But I was told that if they were it would blow my headgasket! Scary thought been there done that!


This is open as well it looks important where does it go?


I just want to make sure this setup looks normal...


This "T" off of the MAP sensor and one line goes to the boost gauge (aftermarket) and the other goes nowhere. It is open.

 

[cinciguy89turbo]

anyone? lol :1zhelp:

 

[bsupra]

anyone? lol :1zhelp:

I had the same problem but mine was stock. I had the exhaust manifold leak(the common problem we have on MKIII). Made it tight, then disconnected the battery for 15 min. Then problem solved. Again, that was my stock turbo supra.

 

[dumbo]

Can anyone read these days?

 

[cinciguy89turbo]

Can anyone read these days?

I plugged that line off. Is there a good way to check for a vacuum leak? And my instrument cluster isn't working so I don't have a way to check for codes. That's killing me too...I'll be reposting that thread. I appreciate your help man.

 

[Angry7M]

I plugged that line off. Is there a good way to check for a vacuum leak? And my instrument cluster isn't working so I don't have a way to check for codes. That's killing me too...I'll be reposting that thread. I appreciate your help man.

Yep, you can do a vacuum leak test with a smoke machine. You can go get that done at a PepBoys near you.

Theyll hook up the smoke machine to your vaccum lines and start injecting ii into your lines and if you have vacumm leaks youll see smoke start coming out.

 

[jetjock]

What he said. I also suggest you buy a TSRM. And there are at least two ways to check for codes with a dysfunctional MIL. One will show if codes are set and the other will let you read them. However if it was me I'd fix the dash...

 

[cinciguy89turbo]

Yeah I'm having the dash fixed soon before I run out of gas haha!

Found the big problem!!!!! there were only 3 bolts holding the turbo to the exhaust. I'm sure a ton of air was leaking! found a 4th bolt and put it on runs 95% better!!!!! I'll be doing a smoke test to find out if there are anymore leaks.....Still has a slight hesitation when shifting to the next gear. I sealed up the "T" off hose and my vacuum is about 20....boosting about 8psi too!

Thanks guys for your help! New to forums...on a forum for all 3 of my cars now!
90 Supra/03Altima 3.5SE/97Maxima GLE

 

[nsngarage]

Boost at 5psi sounds "semi" close to right, like Isaint said it almost sounds like you're flooding yourself somehow.. maybe the FPR vacuum is off?

 

[cinciguy89turbo]

hmm....fpr ok. yeah now its like the hesitation is gone but now the car feels very labored and heavy like I have 2 tons of brick in the car.

 

[cinciguy89turbo]

:icon_surp ITS FIXED! My factory BOV was still attached and that was a huge boost leak so it was sealed up. Also my CPS was pretty much destroyed. Luckily I had another one and I put it in and had it timed. It idles a little low, and has a hard time starting when cold. But other than that the things hauls balls! When I first got on it I'm pretty sure my heart skipped a beat! Scared the shit outta me! :aigo:

Thanks for all of your help guys! I'm new at this and I've learned so much from you guys so far! I'm just glad my car is running properly!