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Discussion Starter · #1 ·
So the other day my car started struggling on start up, but it went away after 15 seconds. So i checked all fluids and wires and everything was ok. Then yesterday it was stuggling and it didn't go away. It was ok when i gave it throttle, but if i let it idle i would struggle. I then noticed that i had an exhaust leak from turbo to DP. However, it is not that bad that my car should be struggling that hard. So i got it home and now today i went to start it and even with throttle i stuggles very bad. Now it just stalls out. I am getting some white smoke in the exhaust as well. I temp fixed the gasket in the DP cause it was burned through. Seems like the car is getting plenty of fuel, i can smell it. Any ideas?

Mods are

T78
Greddy FMIC
VPC
Profec B
S AFC

I think thats enough of a list
 

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Put a sock on the exhaust tip and try to start the car (to get the white smoke). Then, pull the sock off and put it inside out and see if you have oil residue on the sock.

If you do, pull the spark plugs out of each cylinder. Use a flashlight and see if there is oil in the cylinder (you'll see a reflection). take a long Qtip or a papertowel or something to try to absorb that fluid in the cylinder to verify that it's not fuel - if it's oil in nature, you might have a problem with a piston seal or in my case, I had a nice quarter sized hole in the piston #1.

You also should get an FJO or something to tell you your mixture just in case its not just getting too much fuel and stalling - I don't really think this is the case, but it's good to have nevertheless - helps me isolate problems with fuel (I have Fuel pressure, FJO Wide band, Oil pressure, oil temp, water temp, exhaust temp, air temp, etc. - really helps understand whats changing in the car as you experience problems).

--ron
 

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Discussion Starter · #3 ·
I'll try that....But i can tell you this, I have changed the plugs, checked the NEW coil packs, and looked for loose wires from the EM tools and nothing. Didn't see a vacum line off either.

However i did find a loose wire off the VPC....



Here is what it is set at...and running for a while



Also these plugs by the alternator




Also these plugs by the coil packs







Any one know if those connections should be connected
 

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Boost4fun
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I know at least sth about the last pic:
These are the connectors of the OEM soleoids for the twin setup. Since you are single these are just not needed anymore. So this is ok.
Sorry that I can´t rell you sth about the other connectors at the alternator and VPC..
Mybe these gurus can chime in for this.. :)

Gerd
 

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Discussion Starter · #7 ·
Ok, so checked the sensors (O2) and they are fine. Compression was fine. The thing that they found was the voltage on the VPC was higher than normal, which they told me that it was making the car think it was at 2 PSI at idle and so it compensated with fuel. They think it is a bad sensor. Also at idle my Fuel pressure regulator was at 51PSI so they turned it down a bit and now the car can idle.

Any more ideas?
 

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The wire on the VPC is for tying into a GCC or additional HKS electronics, so that's normal. The settings seem ok , although I haven't run a VPC for about 10 yrs now, so I'm not too sure (I'm on my 3rd Supra MKIV, and that was on my first 1993.5 with Single turbo back in '94/95).

The connectors by the fan belt are for VSVs and the like that are for your stock turbo as said earlier in the thread.

The sensor issue makes sense - I think you should get a wideband O2 like an FJO or something to see what your AFR is, and that's how you tune with the VPC (or you attach a GCC back in the old days - that allowed you to map the AFR). You should be running about 14 at idle (13.5-14.5) and ~11 on boost typically. If you creep up AFR on high boost, then you are leaning out, which can be very harmful to your motor. Also, I invested in an EGR gauge to see the temp at the exhaust side of the turbo. If you are getting upwards of 1600-1800 degrees there, then you can have issues with lean out as well - the AFR really will help you make sure you don't have a lean condition, and then you will be able to properly set up your VPC.

What is the behavior of the car now that the sensor is replaced and the car is idling - is it still stalling out?

Also, the sock - what was the outcome? Was it full of carbon, or oil residue? Carbon would tell me you are running way too rich and thus possibly flooding/stalling due to too muchf uel. oil would indicate that you have a oil problem in a cylinder or bad head gasket.

--ron
 

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Discussion Starter · #9 ·
**Update**

So i went to the shop and i told them that i had check a whole bunch of things including the plugs, the wiring, the coils, the piping, the vacum lines, and do to the fact that it was running real rich (thanks to sock test ;) ), i told them to maybe check the sensors, so then they took 3 hours to come to the conclusion that it was the pressure sensor on my VPC. They then swaped out the sensor with another used one and lowered the fuel pressure from 50 to 42. Everything was running fine then. My dad then picked up the car. drove it back. I then drove the car back to the shop and on my way home from the shop, i am sitting at a light and bam, car stalls again. Go to start it up, it struggles and then it dies again. So i start it up again giving it gas, watching the smoke pour out the back, barely making it into the parking lot. Next thing i know i am being flatbeded to my house. I am headed back to the shop on mon with the same symtoms after only driving it 2 times. They said they checked everything too. Any ideas guys? My guess is that its a short that is messing up the sensor, or the unit is bad.

P.S. anyone else have this many problems with the VPC?
 

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Discussion Starter · #10 ·
The sensor with the vacum hose coming out the top is the one they said they replaced (the MAP sensor.....is this and aftermarket one or what?). According to a bunch of people, the vacum line should be pointed down. Also it is T'd in fa away from the actual manifold and many things are T'd in between it and the manifold.



Two of the Three T fittings that all run to the same manifold source (6 in all). One of the hoses leads to this attached to the pulley, under the IC pipe. Does anyone know what it is?

 
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