JackoliciousLegs

I read 2.7V off D terminal at 5.5psi. It read 1.0V at idle. That sounds about right... i think.

What should I check next? I'm still only boosting 5.5psi.... :-(

JackoliciousLegs

bump... what's next?

HAILERS

It could be a clogged exaust system, OR if your throttle body is stock it could be the secondary throttle plates are not opening everytime all the way. The outboard secondary plates are the ones I talk about. There is a cam....a dashpot....and spring linkage that helps/prevents them from opening all the way. Pull the intercooler off and stare at the front part of the throttle body while you open and shut the throttle with the cable. You might have to remove the intake duct in front of the throttle body to observe the outboard secondarys open and shut.

Or.....I don't have experience with the EBC of a series five, but its a solenoid that opens and shuts??????? At a given boost pressure???? Well I might see if I could put a MittyVac on the boost sensors nipple and raise the pressure to the sensor with the Mittyvac (watch the pressure with your boost gauge) and monitor the boost solenoid. Also watch the voltage amount from the boost sensor while doing this and see just how high it will go at say 10psi.

Is the vacuum/boost line b/t the turbo and the boost solenoid intact? Holds a good vacuum?

I gotta go read up on how the turbo and solenoid work on a series five. Frankly it sounds a lot like the solenoid is not working and the turbo just boosts to the five allowed by the turbos spring.

HAILERS

2.7 sounds a little low for 5.5 psi. The one volt at idle, fully warmed up engine, sounds alright. It seems the pressure sensor is working. Are you reading boost with an aftermarket gauge? Yes. The factory one is a little suspect

The chart with this url is somewhat accurate for voltge vs boost pressure. http://www.teamfc3s.org/info/articles/fcd/diy_fcd.htm

JackoliciousLegs

I just removed my DP and presilencer because of the creep issue. The fact that it doesn't seem like it's strained makes me think it's not clogged exhaust. It just hits that 5.5psi and that's it.

I am reading boost with an aftermarket gauge.

All my vacuum lines are ok. I'm thinking I'm just going to hook up a MBC and see if my A/F ratios stay ok. I'll remove the intercooler and take a look at the movement around the dashbot and see if there's anything fishy under there. I'm pretty sure I'm getting full throttle. Wouldn't there be other symptoms if the throttle is sticking closed?

What are the control devices on an S5 to engage that EBC?

HAILERS

You'd never notice the outer secondary plates not opening. When you look at them you'll see why.

Try removing the airfilter and going for short run and boosting. Maybe a difference will be seen. Did you remove/replace the stock filter assy recently?

The EBC is what NZ described. It uses a pickoff line from the turbo to a solenoid on the left of the engine. The ECU uses the output voltage from the boost sensor to open/close the solenoid just mentioned. I really need to read up on series five before posting like this. I do believe that is how it works.

Is your stock boost gauge showing movement when you boost??? That would be an important clue.

JackoliciousLegs

stock boost gauge reads low. with key on, it reads 3mm below center. when it boosts, it barely reads any positive pressure... if at all. At idle, it sits all the way at the bottom.

The car is 100% stock except for a catback.

PS Thanks so much for looking into this for me!

HAILERS

The series five gauge might be different than my series four. You say with the key to just ON it reads 3mm below center. Do you mean it reads about 3mm below zero???? My series four reads 0 to 40.

I'm not trying to make a big deal out of the gauge readings. It seems like the output from the boost sensor is probably getting to the ECU since the signal from the boost sensor splices off the ECU and the gauge. Movement of the gauge needle was what I was looking for.

JackoliciousLegs

the needle moves.. a little. but it's supposed to read 0 at ON, right? It doesn't. Everyone told me not to worry. Should I check the voltage from the pressure sensor at the ecu?

HAILERS

I've two turboii at this moment and when the key is to ON, the needle does not get up to the zero. It lies about three/four needle widths below the zero. Much like yours and many others.

Attached is a jpg of the turbo and solenoid. Colored lines are in red and yellow.Big Deal. It's something in case you don't know where the solenoid is. Make sure the connector is on the solenoid. It should have one wire that is black/white. That wire has 12v on it all the time the key is at least to ON. The other wire puts a ground on the solenoid to make it open/shut which in turn regulates the boost pressure. I'm fairly sure it works like that.

If it were my car I'd monitor the solenod with a meter from inside the car while driving under boost to see how it acts.

A manual boost controller is just fine. I've on on my series four. About nintey bucks or so.

HAILERS

It would be interesting to monitor pin 3R while driving/boosting and see if any action is happening there. Attached is a jpg of .....

JackoliciousLegs

so Im not quite sure how to monitor the lines going into the boost controller. Test voltage? test continuity between what and what?

HAILERS

Actually you should do it from the interior of the car and pick off the Duty Solenoid signal on that pin 3R AT the ECU. What you'd do is leave the plug on the ECU alone, but with your meters positive lead you'd back probe the pin 3R of the ECU and put your meters negative lead on a good ground in the car, such as one of the studs that hold the ECU bracket in place on the car.

As the last jpg says, when the car is idling the voltage should be below 2vdc. I'm not real sure what it should read when boosting. Sorry 'bout that. It should change though.

It wouldn't hurt to somethyme take a look at the boost sensors input to the ECU. At idle and when boosting.

The attachement is a picture of your ECU's plugs. It's looking toward the ECU. Wires on this side. They count from the right to the left in a up/down fashion.

3R is the duty solenoid voltage. See my second to the last jpg for the output at idle. Driving???? Got me. Gotta go up towards 12v at some time.

JackoliciousLegs

thanks for all your help hailers... i'll test that asap. i'll let you know :-)

JackoliciousLegs

First off, thanks EVERYONE for helping me with this. I'm so grateful.

I was testing lots of things including batter and alternator (almost bad). I started pulling stuff apart and I was about to get to the ECU and I discovered that the contacts on the pressure sensor and stock EBC were all fouled up. Cleaned them and now I'm seeing 9psi. Hooray!

That's what I get for not cleaning the contacts on a 15 year old car.

Thanks so much everyone! HAILERS, you rock! NZC, you're always awesome too!