Fuel Cut: What is it? How do I fix it? [merged]

[Slanted J]

All fuel cut threads are combined here.

I've tried doing a search but to no avail.

I was just wondering what Fuel Cut is. I've heard it tossed around alot, but do not actually know the details behind it. And, naturally, I can gather that its when the fuel is cut off, but when and why.


Thanx,
Jon

 

[Boost95]

Keep in mind that this can be because you were boosting with a huge leak through your EGR. Good luck.

Ehh now im nervous. IM going to go down and pull the vac line and check it. Ill post in a few

 

[Boost95]

I pulled the line off the WG to the BOV tee and checked it. It has no leaks in it at all. If the line from the BOV to the IM is leaking would that have an effect?

 

[oldman]

If the line from the BOV to the IM is leaking would that have an effect?

Yes, check it anyway. We're now on page 4, fix this damn thing already.

 

[Boost95]

I just noticed its on page 4 already. I want the thing fixed mre than you can imagine. Thanks for sticking with me Bruce. Ill go pull the other line off and post.
-Mike

 

[Boost95]

Pulled them and no leaks. Is just blowing thru them enough pressure for me to find a leak or is there another way?

 

[oldman]

Pulled them and no leaks. Is just blowing thru them enough pressure for me to find a leak or is there another way?

They would have show up during the pressure test. Apply compress air directly to the actuator and see what happens.

 

[Boost95]

How do I apply the air thru the actuator? What needs to be connected to the litte nipple. When I do put air into it what should I hear?

 

[oldman]

How do I apply the air thru the actuator? What needs to be connected to the litte nipple. When I do put air into it what should I hear?

I will leave you with this and I think it's time you do some thinking on your own. There are only two ways that you can get all out boost.

1. A defective actuator. When pressure source reaches the spring rating of the spring inside the actuator (about 10psi), the arm will move towards the driverside which will then opens the flapper to stop boost from increasing. A defective actuator will not move so flapper never opens and boost continues to rise. Use the air compressor you used for pressure testing and apply air directly to the actuator nipple. If the actuator is working properly, the arm will move forward at about 10psi.

2. The pressure source or part of it never reaches the actuator.

I think you have more than enough info to figure this out, hopefully we will hear about the fix next time you post.

 

[Boost95]

I understand how the wastegate works I was just wondering how to put air thru the WG. The actuator looks like it has never opened by looking at it. WTF I am the second owner, I bought the car from the original owner who is 65 and probably never got into boost Ill try what I can think of 2morrow and then post. Thanks for the help.

 

[Boost95]

I understand how the wastegate works I was just wondering how to put air thru the WG. The actuator looks like it has never opened by looking at it. WTF I am the second owner, I bought the car from the original owner who is 65 and probably never got into boost Ill try what I can think of 2morrow and then post. Thanks for the help.

 

[Boost95]

I pressurized the WG actuator and it opens and closes just fine. I then re routed my VAC line from my actuator to the BOV tee. I think it was getting kinked on the intake pipe the way it was ran. Once I re routed it, I took it for a ride and it boosted straight to 10-11 psi and stayed there. I came to the stop sign pulled away and got on it and there was no boost at all. The car is not jerking etc it just feels like an n/a car. And my idle is still god sitting at about 18. If you have an idea to throw out let me know while im trying to figure it out.
Thanks,
MIke

 

[oldman]

1. Make sure the actuator arm didn't pop off.

2. Remove the intake pipe and make sure the turbine spins freely.

3. Repeat pressure test and make sure none of the couplers had popped off during your test runs.

 

[Boost95]

Actuator arm popped off. There is nothing holding it on. I need to find a cotter pin or something to keep the arm on.

 

[laserspeeddemon]

I was going to suggest taking off the actuator arm. If you were still hitting boost after that, then you have a creep problem, but you have found that out yourself. I am having boost problems myself. But I don't have the time to check it out. I beleive I am leaking air through my PVC. But who knows. I just need to get my daily beater on the road so I can have time to work on the DSM.

 

[Boost95]

I had to drill out the old pin that held the arm on and put another in to hold it. The car boosts straight to 20PSI. I think my cheap ass MBC is the problem. Time to get a new spring from LOWES. Hopefully that will fix it.

 

[98gst62]

I installed my new dejon powerhouse big sidemount and am running 110 octane on my setup in profile and turned the boost up to 18psi and when i reached full boost the car backfired really loud so i let off the gas and everything was fine. is this fuel cut or am i doing something else?

 

[CanadianTSi]

Fuel Cut feels like you hit a brick wall.

I would triple check all your Intercooler connections.

 

[98gst62]

wouldnt the connector pop off if it was loose at all or can air just escape through them
after that i turned it down to 15psi and it held just fine

 

[Boost95]

I removed the MBC and am just running the actuator right of teh BOV T. The car is still hitting fuel cut . It boost to 10 then creeps to 12-13 and hits fuel cut. There is a leak coming from around the turbo area now!!! Any tips?

 

[oldman]

The fact that you were able to hit 20psi, actuator arm fell off, you then started hitting fuel cut again indicates that more leaks are still present or new leaks have developed during your 20+psi test runs. Also, I suspect that you never did finish the leak test, kinda got lazy after you blocked the EGR. Go back to the leak test and make sure all leaks are taken care of.

 

[Project Draven]

r u running stock fuel pump and injectors? if so the stock fuel pump and injectors can only withstand 16 lbs of boost with no problems anything over and u hit fuel cut or worse problems

just a thought for ya

 

[CyberEye]

wouldnt the connector pop off if it was loose at all or can air just escape through them
after that i turned it down to 15psi and it held just fine

They wont neccisarily pop off, they can expand under high boost and juest leak air like a siv, which is why you need tbolt clamps and good multy ply silicone couplers. Do a boost leak test to at least 20psi.

And like was stated, if you don't have a bigger pump and injetors, get them now, as well as an safc or other form of tuning

 

[2gPressure]

just a thought but maybe your flowing more air than you used to at 18 psi, because the 18psi in the intake manifold is cooler denser air which results in more air flow past your air sensor to fill up the intake manifold with the denser air. and the more air through the sensor means more fuel and fuelcut. i like to look deep into things and make them seem more than they are, it's a hobby

 

[Boost95]

There is a leak coming from around the turbo area now!!! Any tips?

I did several tests after that. I wont get around to finishing up the work until 2morrow after work. It was leaking near the turbo. It was bubbling near my j-pipe and IC pipe. After I fix these hopefully I will be set

 

[Boost95]

Well, I fixed the leak around the turbo. Now I can hear it leaking near the EGR maybe?? The car wouldnt even build past 13psi before. The car will now take as much air as I put into it and keep building. Once I stop at about 20psi it leaks out slowley. Should it not leak any boost at all or is this normal because im STILL hitting fuel cut. Ehhhh