No acceleration when turbo starts spooling

[240life]

I just put the first 50 miles on my fresh rebuild. The car idles perfectly, has 65psi oil pressure while driving and operates at 180 degrees. I compression tested all 4 cylinders before start up and got 150 on all of them. When the car is under no load I can rev freely with no issues...., but when I drive the car all it wants to do is bog when the turbo starts spooling. I can hit 7psi but it wil go nowhere. The car runs perfect untill the turbo starts working. I am confused to why this would be happening. Everything in the car has less then 500 miles on it before I rebuilt the bottom end. I am running cp 8:5:1 pistons, new crank, main and rod bearings by KING, eagle rods, arp hardware, tomei headgasket, nismo fpr, walbro 255lph pump, using a summit gauge to regulate fuel pressure, Greedy rs bov (atmospheric) and greegy fmic and intake. My maf is from a sohc and the wiring harness is new. Every thing was done by me both times the engine was installed and worked perfectly the first time. If anyone has any ideas as to why this could happen other then fmic clamps please chime in I am open to suggestions

[otterman]

You do a boost leak test?

Maybe where the manifold meets the head? Seen it happen on a friends SR, big gaping hole there, exact same problem.

[240life]

Not yet, The weather here sucks and I don't have a garage. I was considering this. I will spray some ether in the area and see if it picks up idle. Thanks for the advice. Anybody else have any more possibilities?.....I have a new fuel pump comming too just in case my walbro is crapping out

[shift_SRDETuser]

check vac lines and also look for any blockage or build up around the turbo itself--

[240life]

check vac lines and also look for any blockage or build up around the turbo itself--

Turbo is very clean and nothing is obstructing it's intake...as far as the vac lines go they are all new including the t's. I am going to look at the diagram on the old heavy throttle website to compare it to the way I set mine up.

You do a boost leak test?

Maybe where the manifold meets the head? Seen it happen on a friends SR, big gaping hole there, exact same problem.

wouldn't a bad intake gasket cause a erratic idle? Or cause stalling...or are you talking about a hole in the actual intake itself?

[240life]

Well H.T. explains the vac. diagram a little different then the way I got mine hooked up. I will fix this before I drive home...... Any more suggestions would be welcome this car runs really strong at idle and while under no load so I KNOW it will run great when it gets to boost finally.

EDIT: It wasn't the vac. lines. I did it exactly as H.T explains it and everything is the same as before. A friend of mine called me at midnight and said my turbo could be blowing out the spark on my plugs. I might try and regap them

Modified by 240life at 8:50 AM 11/14/2008
Modified by 240life at 8:57 AM 11/14/2008

[blinker_fluid]

sounds like the ecu is pulling timing under boost. Make sure your base timing is correct and all sensors are working.

[Project240]

Check your ECU codes, too.

FYI, my car was just doing this exact same thing, and it threw a code 34, knock sensor. Knock sensor tested fine with a multimeter. Turned out my MAF was bad; swapped it out with a working one, and the car runs like a dream now.

Check your MAF wiring, make sure it's shielded the way it should be. Test the MAF itself as well, per the FSM instructions.

[240life]

Yeah I'm going to be having my buddy help me with the electrical. I will test my maf as soon as it freaking stops raining....Unfortunately my ecu doesn't have the light and can only be tested using the consult ports, it is a 1995-96 black top.

[240life]

sounds like the ecu is pulling timing under boost. Make sure your base timing is correct and all sensors are working.

I thought it sounded like the ecu was sending it into limp mode, I am positive my timing is correct, I just tore the engine apart to inspect the insides a day or to ago, everything is done by the fsm...... I think I might possibly have some electrical issues in my chassis harness that could be causing issues throughout the rest of my systems and causing faults....my fuel pump just stopped working and the fuse is good, I then replaced it with a brand new one. A couple months ago I messed with the fuse boxes moving them.....so I will be pulling a harness from another 240 suspecting this to be causing multiple problems.

[240life]

I have BOOOOOOOOOOOOOOSSSSSSSSSSSSTTTTTTTTTTTT!!!!!!!!!!!!My fuel pressure gauge was faulty. And I was running to much fuel pressure. My fuel sending unit isn't letting any voltage to the pump so I wired it temporarily to a switch to get it to a buddies garage where we figured out the issue

[Kalypso]

another happy customer

[240life]

I couldn't be happier...it was well worth the time and money spent. I had to fix a couple connections and move my fuse box to a better location to correct the sending unit issue now I can spend some time buttoning up the rest of the interior. Thanks to all who gave me some ideas and got my gears spinning.

[wzntha]

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[240life]

The maf wires are wrapped in a grey casing that if I remember correctly has a layer of thin wire before you get to the three ground and signal wires. You just want to be sure to not let any of the outter wire touch the three inner wires when you splice the connection to your MAF or you won't recieve the proper voltage or signal as far as elec. tape goes you should use heat shrink tubing and solder the connections

[wzntha]

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