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desufnoC
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1,842 Posts
Discussion Starter · #1 ·
Ok, so she went down for a BHG about a month ago, and now she’s back.

She's running well enough, but not perfect, and I need some help to work out the kinks.

Timing is stock, used a timing light. And base FP is about 39psi. Spark plug gap is about .31

First problem is she seems to bog off the line. Once over 1.5k she seems to regain her composure and pulls good.

I didn’t really touch the TPS, but could it have been messed up some how? My SAFCII still reads 100% @ WOT, and [email protected] no throttle.

Second problem is a slight miss. Under boost, she doesn’t seem to miss, nor @ idle much, but when in third around 2.5k which is about 50mph. (4spd auto). I only notice this miss when in vacuum and cruising.

Third problem is from time to time, after setting the fuel pressure, it seems to change. What would cause the FP to fluctuate after setting it?
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Things I'm happy with:

She seems much stronger @ idle. Never was the supra this loud, nor move so much exhaust "air flow"

All the boosting I’ve done tonight testing things, changing FP, etc etc, the overflow bottle hasn’t budged an inch. Not one slight bit of overheating. I’m very happy with my new CSF race rad.

Anyway, its good to be boosting again, I know Ill work things out, just thought Id see if anyone has any suggestions to get me going in the right direction.

Thanks.
 

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when this baby hits 88mph
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2,198 Posts
congrats on getting it going!

as far as the couple bugs, could be a lot of things really. if this gas has been in there a while to loose ground to something as simple as the ecu is trying to relearn. the more mods you have the longer that seems to take. id just put some fresh gas and some miles on it and see if it improves. no need chasing problems that dont exist :)

dave
 

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HKS T51R
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2,732 Posts
just a quick quesiton how is the titan mhg? and thats awesome you got it running again. i agree with dbsupra could be something as simple as bad gas or ground.
 

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desufnoC
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1,842 Posts
Discussion Starter · #6 ·
Gj
You won the battle against the bhg
Thanks, wasn’t really that bad @ all, just somewhat time consuming. I would have had it done much quicker than a month, but I waited almost 1.5 weeks on a HKS HG I ordered that had no ETA, so I decided to go with what they had in stock.
hows the defcon downpipe? im getting mine in 2 days
I cant complain, I’ve had it for a long while now, I’m adjusted to it, but its an amazing difference from stock. The best is now the BIC DDP. But if your getting the defcon @ a good price, then its certainly worth it.
congrats on getting it going!

as far as the couple bugs, could be a lot of things really. if this gas has been in there a while to loose ground to something as simple as the ecu is trying to relearn. the more mods you have the longer that seems to take. id just put some fresh gas and some miles on it and see if it improves. no need chasing problems that dont exist
Thanks dave. I guess the one thing I'm wondering about is what would make base FP fluctuate from time to time. What would be bad aside from the regulator itself?
just a quick quesiton how is the titan mhg? and thats awesome you got it running again. i agree with dbsupra could be something as simple as bad gas or ground.
There is one rivet you MUST remove. Its located in an area where the head and block seal. My old MHG was also a Titan, and this was not done (I got it when it was BRAND new, and nobody knew about it) and I can see where it failed to seal over it. Ill get a picture of it if I can.
 

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when this baby hits 88mph
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2,198 Posts
myMUSICveins said:
Thanks dave. I guess the one thing I'm wondering about is what would make base FP fluctuate from time to time. What would be bad aside from the regulator itself?
the fuel pressure up vsv going bad, not a clean vac source or the fuel pump.
 

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Registered
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3,249 Posts
Kick ass dude! I know how you feel, I finally got mine back on the road after 7 months of winter (and me moving 500 miles away). Happy boosting!
 

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2005 LP640
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930 Posts
myMUSICveins said:
There is one rivet you MUST remove. Its located in an area where the head and block seal. My old MHG was also a Titan, and this was not done (I got it when it was BRAND new, and nobody knew about it) and I can see where it failed to seal over it. Ill get a picture of it if I can.
*silence*

MOTHERFUCKER!

SON OF A FUCKING BITCH STUPID FUCKING CAR GOD DAMN HEADGASKET RIVETS.

Alright I'm going to go shoot myself now. Peace.
 

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JZA70 448 rwhp everyday
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2,994 Posts
Congrats, and good luck.

~scott
 

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Supra Fan
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4,114 Posts
87turbosupra said:
*silence*

MOTHERFUCKER!

SON OF A FUCKING BITCH STUPID FUCKING CAR GOD DAMN HEADGASKET RIVETS.

Alright I'm going to go shoot myself now. Peace.

Dont worry, I did the same thing. ALso sLow66 still has that rivet in and runs 25+ psi, still has not blown.

I didnt realize the rivet problem until after, but considering its brass(maluble) i hoping it crushed enough so the hg sealed. :x: :x:
 

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desufnoC
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1,842 Posts
Discussion Starter · #13 ·
Thanks for the kind words.
dbsupra said:
the fuel pressure up vsv going bad, not a clean vac source or the fuel pump.
Damn, I think I'm going to replace it then, with my discount it's still like $50, but its worth it, I need the FP to be consistent.

I routed the BOV back into the accordion hose today, with the adapter that goes onto the Greddy Type-S. It's weird, it sounds like compressor surge, but if the air is getting routed back to the intake compressor wheel, is that the sound it's supposed to make?I'm afraid it's compressor surge.
 

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desufnoC
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1,842 Posts
Discussion Starter · #14 ·
Well, I replaced the FP VSV, and my hot starts have improved, and I think my fuel pressure is staying consistent as well, so that’s good.

I’m still trying to figure out my miss/bog issue. It usually wont miss under WOT, or very light throttle. But if I stab @ the throttle, or give it partial throttle with only a little boost, it misses. Stabbing the gas from a stop usually will bog, followed by a couple misses, and then pulls hard with little to no missing.

My SAFC reads 100%@ WOT and 0% when not touching the throttle.


How would the car respond if the TPS was bad?
 

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Supra Fan
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4,114 Posts
myMUSICveins said:
How would the car respond if the TPS was bad?
what voltage is the safc reading from the tps when closed/open?
 

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mine does that too. if im cruising at like 2500 in 2nd or 3rd and i give it about half throttle it feels like its bogging but then boost kicks in and then its fine. i dont know what the problem is.
 

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2,767 Posts
if its pulling in more hz, then its highly possible that its a vacuum (boost) leak. that's what mine always did when i had one. its also good to have an idea of how many hz it normally pulls in at a given boost level. on my car its like @15psi=1800hz @18-20psi 2000hz @20-23psi around 2200hz on a stock afm.
 

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desufnoC
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1,842 Posts
Discussion Starter · #20 ·
Well I just took her out for a test spin (doing a lot of this lately) and here are some numbers:
what voltage is the safc reading from the tps when closed/open?
Around .565-.570 @ 0%
Around 3.35-3.4 @ 100%
if its pulling in more hz, then its highly possible that its a vacuum (boost) leak. that's what mine always did when i had one. its also good to have an idea of how many hz it normally pulls in at a given boost level. on my car its like @15psi=1800hz @18-20psi 2000hz @20-23psi around 2200hz on a stock afm.
Kinda hard to know for sure, but: (Lex replica AFM)
~60hz @ idle @ around 800RPM
~800hz @ ~ 8psi
~1000hz @ ~ 10-12psi

The odd thing is, the past couple days the idle has been backwards, it did not want to idle when cold, and when warmer, would want to idle around 1100-1200RPM. Today, didn’t want to idle well when cold, nor wanted to idle well when warm. @ the VERY end of the test drive, she would finally hold an idle @ an odd 800ish RPM, and that’s when I was able to see the HZ @ idle.

For some reason, now I'm thinking AFM sensor? MAN I'd sure like to figure this out. I'm going to scan for codes Tuesday @ work.
 
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