1G doesn't boost to full PSI until 5-6k RPM? help in troubleshooting/solving please!

[jayboogie]

hey guys, thought i'd post this here - i read the other threads and all of those cars had heavy mods done to them.

so here's the thing: i don't know if it's just me, or if it's my car acting up... it's a 90 talon tsi fwd with an intake (w/recirc pipe) and a magnaflow system including high flow cat/muffler w/2.5" piping.

for some reason when i put full throttle in any of my gears.. my car's boost level goes from 0-4/5 psi and then as the RPM's rise to about 5-6k it hits about 9/10 PSI (and yes i have an aftermarket boost gauge).

i bought this DSM from the original owner who is an elderly lady.. it has 150k on it but solely from commuting.

the car has been sitting for the past 9 months, prior to that i drove it for about 2-3 months. i got it back 3 days ago... since then i have changed/replaced

-spark plugs
-spark plug wires
-pcv valve
-changed oil/filter/etc.
(plus more, these are the only ones that apply to the situation)

basically all the standard stuff... also, my dipstick has been popping up less than an inch but i'm pretty sure it's the dipstick itself as it's still the original that came with the car. other than this it drives well, doesn't sputter or die and doesn't make any strange noises.

the gas in the tank is 91 octane - half 9 months old, half brand new.

is this because of the gas or some other problem? do i just remember it being faster than it really is? i'll do another leak test on wednesday as this is my weekend car/project

thanks in advance!!

-jb

 

[WillyC]

Could definitely be the gas, could be a boost leak or it could be the timing. You need to check for a boost leak by building a compression tester. You also need to check the timing. Severly retarded timing could potentially cause this, but I don't think thats it. Also make sure the wastegate isn't staying stuck open, that could be another potential cause.

 

[1GawdJunkie]

This link will provide instuction on how to build a boost leak tester.

http://www.vfaq.com/mods/ICtester.html



You will find this and much more at

http://www.vfaq.com/index-main.html

"Dipstick popping out - happens due to crankcase pressure pushing the dipstick up:
A good running motor will blow out a dip stick with a shriveled hard rubber seal
A dead motor (lots of blow by, busted pistons) will blow out a good dipstick
A 1/2 dead motor will blow out a 1/2 dead dip stick
Depending on the actual cause and the severity, the fixes can be:
A spring/wire to hold the dipstick down
Pinch the tube at the top a bit
Get a new dipstick
A full engine rebuild or new pistons
If it blows out under boost with a glowing red turbo and manifold, it makes a nice engine fire. If it happens even once, figure out the cause and fix it."

 

[rocknsnoboarder]

but a gm MAF and MAF translator. this will allow you to adjust the amount of airflow at WOT. I have one and found out that whenever I adjust the settings to add more air at WOT my turbo spools up quicker, which makes sense, more air, faster spool.
also check into boost leak, but to me it doesn't sound like that's your problem, because you're able to reach full boost. I think your problem is in the airflow. Just my 2 cents

 

[fanatic26]

coule it possibly a clogged cat? That gave me some boosting issues a few months back

 

[L2RTSiAWD]

also check into boost leak, but to me it doesn't sound like that's your problem, because you're able to reach full boost. I think your problem is in the airflow. Just my 2 cents

You can reach full boost and have a boost leak, it just takes longer.

 

[steve]

but a gm MAF and MAF translator. this will allow you to adjust the amount of airflow at WOT. I have one and found out that whenever I adjust the settings to add more air at WOT my turbo spools up quicker, which makes sense, more air, faster spool.

You need to read up on what your MAFT does. Once you do you'll understand how amusing this post is.

Hint: It doesn't directly change how much airflow you have, just how much the ECU sees. Since the ECU bases how much fuel to inject off how much airflow it sees the settings on the MAFT change the air to fuel ratio, richening or leaning the car while in open loop.

jayboogie,

Since most aftermarket PCV valves leak under boost you need to test yours. This can cause both your low boost and the dipstick to pop out. As the others has stated you need to check for other boost leaks. I would be very surprised if you didn't have any on a 16 yo 150k car.
Depending on what kind of gas the car has been running the ECU may be using the octane reductions to the timing maps or currently seeing knock. If you had a datalogger you could check but simply resetting your ECU by pulling the fuse marked room in the drivers footwell fusebox for 30 seconds will clear all the stored parameters.

Steve

 

[rocknsnoboarder]

You need to read up on what your MAFT does. Once you do you'll understand how amusing this post is.

Hint: It doesn't directly change how much airflow you have, just how much the ECU sees. Since the ECU bases how much fuel to inject off how much airflow it sees the settings on the MAFT change the air to fuel ratio, richening or leaning the car while in open loop.

My fault steve. I knew the MAFT didn't actually adjust how much air goes into the intake. I was thinking one thing and typing another.

Thanks for the clarification.

 

[steve]

I was thinking one thing and typing another.

I do that all the time. Sometimes I catch it before I hit Submit.

Steve

 

[jayboogie]

thanks for everyone's replies! yeh like i said im def. doing a boost leak test again on wednesday. 9 mo's ago i found out my injector seals were leaking so i replaced those... hopefully they don't need to be replaced again. as far as my dipstick goes i just have to see if the new dipstick will fix the problem.

thanks again i'll keep everyone informed!

 

[spoold]

I had the exact same problem on my e3 16g. If you are still on the internal wastegate, take the cotter pin off the wastegate flapper that holds the arm on. Take the arm off the flapper, and move the flapper to the passenger side. If you can move the flapper towards the passenger side of the car MORE than when the wastegate arm is holding it in place, you have a wastegate problem.

The wastegate sounds like the culprit perhaps, if it is, you can either buy a new one or add some (no more than 2-3) crush washers to pull the wastegate arm farther over and secure the flapper closed.

 

[jayboogie]

I had the exact same problem on my e3 16g. If you are still on the internal wastegate, take the cotter pin off the wastegate flapper that holds the arm on. Take the arm off the flapper, and move the flapper to the passenger side. If you can move the flapper towards the passenger side of the car MORE than when the wastegate arm is holding it in place, you have a wastegate problem.

The wastegate sounds like the culprit perhaps, if it is, you can either buy a new one or add some (no more than 2-3) crush washers to pull the wastegate arm farther over and secure the flapper closed.

that could be it... when the car was in the accident the front was crushed in... from the looks of it it was pressing against the radiator fans.

we will all know by tomorrow! today the boost was actually working pretty well...

ill keep posting! thanks for the help.