Car Bucking, Turbo Spiking... **HELP***

[Blitzeclips]

We have done this already. Thats the thing, either the wastegate isn't below 8psi, or it is. Would this explain the bucking? It still ocured even after the BC was disconnected..

 

[DSMcrazy3]

We have done this already. Thats the thing, either the wastegate isn't below 8psi, or it is. Would this explain the bucking? It still ocured even after the BC was disconnected..

Something doesn't make sense to me, but it could be my pain killers..

If you have a pressure source attatched to the wastegate actuator, then it should open once this certain amount of pressure is reached. Unhook the actuator arm from the flapper arm and make sure you can open the flapper door. Also make sure you can pull the arm out of the actuator a bit, so you will know the diaphram is good and not sticking. As long as there is a pressure source on the actuator, like I said, it should open. If it isn't it's either stuck or still set for more than 8 psi.

 

[Blitzeclips]

Well guys, I think this is it. The vacuum lines aren't as efficient as the should be, and the FMU vac from my MBC is tee'd as well. I think it's the problem I'm having, the FMU is reading from my intake manifold where it should be reading my turbo. We've decided to tap into the 90 degree elbow (welded on steel) for a better source to the wastegate, eliminated about 1 foot of hose in the process. Along with that, we will hook up the FMU solo, and see what happens... wish me luck... I've about had it with this stupid DSM.

 

[XMasta19]

No need to get upset with your car...I'm sure some of us have had it a tad bit worse than you Just make sure you're doing it all right and double checking. Get those lines hooked up correctly and you should be a little happier.

 

[GSGoinFast]

Well guys, I think this is it. The vacuum lines aren't as efficient as the should be, and the FMU vac from my MBC is tee'd as well. I think it's the problem I'm having, the FMU is reading from my intake manifold where it should be reading my turbo. We've decided to tap into the 90 degree elbow (welded on steel) for a better source to the wastegate, eliminated about 1 foot of hose in the process. Along with that, we will hook up the FMU solo, and see what happens... wish me luck... I've about had it with this stupid DSM.

No, that is a bad idea. You want the vacuum lines exactly where they are. If you hook them up closer to the turbo, you will be in front of the throttle body, which means upon closing the throttle plate, the engine will be getting vacuum but the fmu will read boost still until the BOV gets rid of it all. So in short, you need your vac lines hooked up to a Vacuum source, not a boost source. Also, DO NOT runt he fmu without the stock fpr.

Next, I told you that you needed to test the wastegate to see what it was set at. I didn't test it, I just modded it and gave you a way to adjust it. Take off the MBC and just use the wastegate. If you rush up to 8 psi and look as though it will keep going, let off and adjust the wastegate. Tighten the bolt on there and try again. If you max out the bolt, you have to take it off, and throw another washer or 2 on there and try again. keep repeating this process until you get the boost where you want it. Of course, like Josh said, check to make sure the flapper isn't stuck.

I think your bucking problem may just be your going past what your fuel system can handle and therefore aren't getting enough fuel. But first and formost you must get the boost where you want it.

 

[dr1665]

I think your bucking problem may just be your going past what your fuel system can handle and therefore aren't getting enough fuel. But first and formost you must get the boost where you want it.

Dude. So it IS fuel cut! . I knew I wasn't retarded after all.

Seriously, dude. What have you got to lose? Yank that MBC out of there and give it a shot! If you can get that thing dialed-in 8psi on WG, you'll be out there spooling around town like a champ while you wait for your uprgaded fuel system components come in, allowing you to properly fuel that pig and turn up the boost with the MBC.

You're almost there.

 

[VelocitàPaola]

Hey, where's Paul at? I'm surprised he hasn't chimed in by now..

I was away on business...

I don't have much to add to this thread other than you may want to clean up those vac/boost lines so they conform to a more functional configuration. Here's how mine are set up; you should probably follow suit.

 

[Talon ESI-T]

3 possabilities.

1. Fuel Cut. 95 or no 95, i dont care.

It is also a rule of thumb that all 96's will need a FCD; However, I own one that does not require one. My point is not all ECU's are created equal.

When you make an assumption based on a generalization, you are setting yourself up for a real kick in the head.

2. Spark is being blown out due to weak ignition ststem.

3. Insufficient fuel system.


Recomendation....Get a wideband.

Terry

 

[Blitzeclips]

Ok, so to clear some things up. We have pulled the MBC so we can see exactly what the wastegate is set to and adjust as necessary. By hooking the FMU up solo I meant we will be moving it to a dedicated vauum port on the manifold, instead of having it T'd, and moving the wastegate signal closer to the compressor. It will be set up almost exactly as the diagram above shows except the FMU will be coming from the unused center port on the manifold instead of being T'd.

 

[4UH8ERS]

Like me and everyone else has said since the first post. You are getting fuel cut most likely. you need to make sure your not creeping past 8psi, assumptions are your worst mistake. You need to figure out exactly what your wastegate is dialed in at. Get a Wideband.

 

[Blitzeclips]

We re-did the vacuum lines and tapped into the compressor outlet. Everything is running pretty good, and I can hold 5psi at WOT up to redline.

Tonight or today we should be setting the MBC for 8psi. Then I can see what kind of power I can actually get into with the car. Should be good fun..

Only thing I have noticed here and there would be an occasional sputter getting into power or 4-5k.

 

[Blitzeclips]

Well, my car is finally up and running, full 8spi and all. Feels great. Although, I am looking forward to turning the boost up and use my motor to it's fullest. I havent had many problems thus far, so I'm in the clear for now.

I want to thank all of you who have helped me reach this point. You honestly wouldn't believe how helpful you've all been. From day 1 with searching to find parts, to the last post you all replied to. It's truly appreciated guys. More than you would think.