Hello. OK, heres the deal..... I installed a new motor a few months ago and have now put 1000 miles on it never boosting over 2psi. I decided I would install an AVCR and slowly increase the boost over the next few weeks. I did the AVCR install and set it for approx 7 psi. I took the car out for a test drive and it cuts out (feels like a lack of fuel) at 4 pounds of boost. I mean it completely loses power. It idles perfectly, has good vac, revs smoothly to 7k (that's as high as I've taken it so far) when it's not under boost. The a/f meter looks good. Also, I noticed a week ago that the new lines from the oil inj pump still looked new... no oil in them. I swapped out the pump with one that I knew was good, but 100 miles later I still have no oil in the lines. I'm not too concerned about this at this point, as I've been running pre mix for the break-in. Could these be related problems? I've pressurized the intake system and all is fine -no leaks. It has a new fuel filter. Last weekend I converted it to non-sequential to see if it was a turbo control problem. No improvement, still cuts out at 4 psi. What do you think? Is it a boost problem? Is it an ignition problem? How about a fuel problem? I will absolutely send $100 to anyone who can help me figure this out! Thanks!!!

 

it might be the avcr...try setting it to higher psi

 

Well for $100 bucks it worth a shot! This dont seem logical due to only 1k on them, but it sounds to me like it could be the plugs.

I let my car sit for a little over month. I went out one day and as soon as I would get to about 3-4 lbs of boost it would cut out. I could rev it to 6k just as long as I wasn't boosting. I changed the plugs and everything was fine.

 

Did you do the full non-sequential or just the "poor mans" way. I know to control boost with my Power FC I had to switch the lines from the wastegate solenoid to the turbo pre-control solenoid. Not sure if that will make any difference with the AVC-R, just thought it was good info.

Oh have you also tried to reset the ECU, maybe it's in limp mode.

 

Thanks everyone for the suggestions.
Lost Rotary: I've done as you say and set the AVCR to higher settings, there was no difference. I suspect it's not really an AVCR problem, sensor check has all values where they should be and I suspect that when the AVCR is working it stops boost at a pre-set level but still allows the revs to go higher. Not so in this case, the engine cuts out and absolutely falls on it's face until you let off the gas.
Dial 911: good suggestion, I have a feeling it may be something weird like the plugs. I'll swap them out and see what happens.
7-sins: I did do the poor mans version, but I also disconected the AVCR and installed the home depot boost control, no difference. I have reset the ECU a couple of times since this all started, but I'll try it again. I disconnect the batt and step on the brake for 30 seconds, right?
At first I thought this was definitely a boost problem. Now I don't think so. I'm leaning toward ignition or fuel.
Anyone have any procedures I can follow to rule out certain components??????

 

My friend had a problem just like this because he forgot to put the boost pills in.

 

You have reset the ECU a few times? I had a similar problem that the engine would just cut out when boost was coming on. It would also rev to 7K at idle. I heard it was 20 seconds on the brake pedal. You could also disconnect it probably.
Thanks

 

are you sure it happens at 4lbs of boost? or does it happen at any boost level but at a certain rpm range...


i had a similar problem after one of my motor swaps. first...does your car do this at any given time?
my problem was just as you described, and i replaced EVERYTHING to figure it out. even what turned out to be the problem was replaced and it still didnt fix it.
the problem was with the temp sensor. not the sensor itself, but the signal it was sending. testing the sensor, it was fine. in reality, the signal was bad ????
when you would start the car right up and floor it right away ( i know you shouldnt do this, but frustration over a few months of troubleshooting can cause you to do bad things ) there was no problem. boosted fine, didnt fall on its face or anything. but stop the run, turn around and head home and try to do the same....it would happen.
my solution....put an adjustable POT in the line right before ECU to trick it to think the car was running cooler than it was. prior to doing this, the ecu read the temp as being extremely HOT even though it wasnt.

pm me for my paypal address if i am right

 

Thanks for the reply
silver 94: I've tried just about everything with the turbo control system, including messing with the pills. I've even tried it with the non-sequential set-up ( no turbo control actuator, gate wired open. turbo pre-control actuator left in place but lines disconnected and plugged. Wastegate control operated with boost controller.) and no lines attached to the wastegate actuator, wich should build unlimited boost. That is why I'm thinking it's not a boost problem but ignition or fuel.
Vipereater: I reset the ECU after each "fix" that I try. I just completely removed the ECU to remove the AVCR that I had installed...... back to the needle valves. I'm thinking simpler is better!
Rxrotary2 7: That's an interesting suggestion, I'm going to go out and check the values on the sensor. How did you ever figure that one out???? If I can't figure this out over the next few days I'll try your suggestion. Right now I'm hoping for a simpler solution.
Thanks everyone! Keep the suggestions coming!!!!!

 

Too many boost controlers. I would simplify it and see what will control it best. If you have the PFC, set the boost very high as well as the duty cycle or it will cause fuel cut when trying to control boost with other boost controllers in addition to the PFC.

 

Make sure the double throttle valve isn't staying closed.

 

Make sure your throttle position sensor isn't out of range.

 

The only two reasons you shouldn't be getting boost with the non-sequential... a boost leak somewhere, but it looks like you have taken care of that, or how the home depot valve is adjusted. Try messing with that valve. Also with the Power FC there is a boost cut setting so the boost wont spike above a given point, maybe in the AVCR there is something similar.

 

I had the same symptoms....turned out to be a bad ignition coil for the leading plugs. It's a pain in the *** to check...you might be able to get the contacts for the ohm meter in there without taking anything off---I already had my upper intake manifold off, so it wasn't a problem. Check the Service Manual (page G-20) for the procedure. Good luck!!

 

Hello,
ZoomZoom: I probably wasn't very clear about what I've tried. Right now I have the non-sequential set up with absolutely NO lines to the wastegate control, which if I'm not mistaken should produce unlimited boost. I've removed all the turbo control solonoids, plugged or removed all lines to and from these solonoids, and soldered in 300 ohm resistors to avoid error codes. There is literally NO turbo control system at this point to go wrong. There has been no effect on the stall out. That's why I'm convinced it's not a turbo or turbo control problem. Am I wrong in this assumption? I don't know for sure.
Spooled up7: I've already removed the dbl. throttle valve and solonoid. The TPS is within range according to the readings from the AVCR, but I will check it. Today I've changed the plugs, removed the AVCR for good, Removed and reinstalled the ECU, cleared codes (by the way, I'm getting no error codes), checked values on boost sensor and temp sensor. Just took it for a drive..... no go

 

Hello,
7-sins: The AVCR is now gone so it can't be the settings or the install. I too thought there might be a fuel cut built in.
rotarywhat?: Good thought on the ignition coil. I just pulled off the intake and checked all coils - everything is good there. I also swapped out the crank angle sensors with a pair that came off a good running engine. Just checked voltage on the boost sensor again, all seems to be OK. Going to go check the TPS again.

 

Hello, I forgot to ask, there are two plugs in the engine bay that are not plugged into anything. One is a blue plug behind the air pump and the other is a black plug in the drivers side corner of the firewall. Are these supposed to just hang there?

 

I had the same problem. it was a bad fuel pressure regulator....check your fuel pump, lines etc.

I was not experiencing cut off unless I boosted past four lbs....if I stayed under that I could go all the way to redline with no probs....as soon as I got on it the car would cut out.

I also had a fuel smell coming from under the plenum which is where the fp regulator is located.


j

 

Artguy: Thanks for the suggestion, I did replace the fuel pump recently with a high performance one.... maybe it's not working the way it should. I'll install a fuel pressure gauge in the next couple of days and see what I've got. Good idea!

 

I know the problem!

It happened to me, check the throttle body electrical connector, mine had the same problem when mine was loose! make sure it is in tight!

 

indo audio: which connector are you talking about? The one to the TPS?

 

Maybe I could help with the payment if I try the water thermo sensor and that is the problem, Becuase I have the samilar problem.

Which connector are you talking about TPS sensor?

 

Hi Mostin, what's going on with yours? What have you tried?

 

Have you already checked the vacuum hose to the MAP sensor for splits?

 

What boost gauge are you using? It could be way off and your may be hitting fuel cut.