Thread: GTP down on boost.... can't figure it out...

Ok, what is left?

The actuator isn't being controlled by the soleniod you removed. Vac lines are good. The only thing left that can control it would be the actuator.

Well, installed the new bypass actuator today. That means new vacuum lines (check all of them), electronic boost solenoid removed, and brand new Eaton actuator. Just got done logging some pulls with HP Tuners.. Still seeing 4 lbs of boost max

What else should I check?? No check engine lights, no issues of any kind.. Just really low boost. Everything else is normal. Thanks in advance!

does it sound like its getting full boost? and feel like it? if so try a new map sensor, its what the pcm reads boost from.

I'd say it sounds like it is getting into boost okay but doesn't quite feel like it. any recommendations where to pick up a map sensor? I am going to search around.

Again, no leaks or noticeable issues of any kind, plus plenty of new parts. Maybe it is just in the MAP.

i swap a jy one on if you got a yard near by.

Originally Posted by Scottydoggs

i swap a jy one on if you got a yard near by.

Yes indeed! going to grab one here early this week. Out or curiosity, The car mainly reads air and adds fuel based on the MAF readings right? Wondering if this "potential" MAP issue can do damage to the car during normal driving and while under boost.

I hadn't noticed any issues in AFRs yet so...

Also, do the stock L67's come with a 2 or 3 bar sensor??

not sure if it has anything to do with fuel, but it reads the boost. its got a vac line to it from under the supercharger snout.

dont think any harm will come from driving it.

Sounds good. I actually removed it from the engine mount about a month ago and mounted it to the firewall with a new vacuum line running to it and the sensor running to it as well.

double check its wires too. you never know.

Do you have and acutal boost gauge or are you just going by what you see for MAP Kpa?

Figure 140-160 kpa is 7-9 psi I think.

Yepp. I do not have a boost gauge but I am maxing out around 120ish kPa and then I convert to psi and subtract off atmospheric. After thinking about it more, I think my MAP sensor is fine. Duty cycle on the injectors is down, low MAP readings, no knock, and what feels like a lack in power.. At this point, I am stumped again. Guess I can pull the plugs, but no check lights and it runs/idles perfectly smooth...

Originally Posted by Fivefingerdeathpunch

Do you have and acutal boost gauge or are you just going by what you see for MAP Kpa?

Figure 140-160 kpa is 7-9 psi I think.

I can also throw the data log I took today up on HP Tuners if you'd like. Not sure it will tell you more than I did in my previous post though. Let me know. Def. up for recommendations and advice at this point.

here is another thought.. I removed the electronic boost solenoid completely. I then hooked the vacuum line running from the fuel pressure regulator straight up to the bottom of the BBV.. Was that a bad idea? I thought it was a direct connection when the solenoid wasn't limiting boost.

I did some reading, and I think that is the problem.. about to go outside and put the solenoid back in. stay tuned.

Fixed it.... I feel so dumb. Thanks for the help guys. I ran the vacuum lines wrong when I removed the boost solenoid. It's back in and everything is working fine now.

Now, back to this KR issue!!!

FYI, peaked at 173 kPa = ~25.1 psi

25.1 psi - 14.7 (atm) = 10+ psi of boost on the 3.5 pulley. That was after seeing up to 9.6* of KR. Poly mounts are going in this week. We'll see if that helps with the KR at all.

Lmao