vaccume leak... where?

[denn454]

i went to the track last night and to my suprise i could only pull 13.5# thats it. i opend up the boost controll all the way, and eventually ended up pulling the hose off the wastegate, but no luck.

I'm thinking its likely a vaccume leak somewhere. are there any common places where i should start looking? for this leak?

Also i got a code 32, thats some egr valve code, i haven't checked to see exactly what it means, but could that be leaking my other 6 1/2# of boost?

I know i made one mistake, when i was hooking up my tcc switch i put it in the lower row 2nd hole from the left. (first with a contact thing) and turned it on. when i did that it almost killed the engine and i figured somethign happend and it was trying to lock in first, which i thought was impossible. so i turned the switch on (grounded that plug) shifting into 2nd. I have no idea what that did, or if it would have hurt anything. stupid operator error...

 

[progress1vebmx]

I was boosting pretty high once and the vaccuum hose came off from the EGR solenoid going into that vacuum block. Well, I put it back on and the EGR solenoid starts to smoke, I check my vacuum gauge and it's at 10#'s running ****ty, I take it off, and it's at 20#'s. I need to buy a new EGR solenoid thingy

 

[Royal-T-Ltd]

You might have a big exhaust leak. Listen for the ticking. Maybe try to look around the crossover.

 

[scottyb]

IC and up-pipe hoses are good?

Check again.

and again.

 

[denn454]

I THINK i've narrowed it down to the vaccume block hoses, the little 1" rubber ones before the metal lines. there is definatly a leak from that area.

I know there is a leak in the headder, but its been there since i've gotten the car and hasn't gotten any worst. this is something that just happend the other day. I'll also look at the egr colenoid.

 

[77tech9]

Buy one of those vac pumps it helps out a lot.

But with that low of boost with hose off, you have a problem somewhere else i think, headers might play a key.

 

[cathan]

speaking of vaccuum.......how much vaccuum should a healthy GN pull at idle, car warmed up?

 

[denn454]

hum... you know i've never really payed much attention. i think mine is in the range of 10-15"

 

[denn454]

i got all my leakes taken care of. but now try to explain this to me...

I take off and end up getting 20# pretty darn fast. then i run a little past the 1/8th and somehow the boost jumps up to 25# and just stays there.

i launch at about 5# and no wheel spin, heres my time slip: and yes i am kindof imbarased to be showing this...

60' 2.886
330' 6.988
1/8 10.055
mph 81.29
1000 12.644
1/4 14.832
mph 103.06

launch sucked, i think its a combionation of my new orange stripe converter and a cracked header. thats not a big concern right now, i understand what its doing and thats 1/2 the battle. i'm really concerned with the boost jumping like that. the weired thing is it did it consistantly. it shouldn't be jumping like that 1/2 way down the track should it?

 

[77tech9]

With cracked headers.... fix the problems and then see if it does the same thing.

 

[Paul Clark]

Are you sure there's no wheel spin?
60' time seems pretty poor for a 5# launch with no loss of traction.
The e.t. doesn't seem to match the mph unless you're spinning the tires someplace.
Wonder if your boost gauge is accurate?
Try putting a white strip on your rear tire with shoe polish and have someone video tape the start of a run. Play it back in slow-motion.

 

[denn454]

i fixed the header, droped 1/2 a second, and lowerd the usual 60' time a tenth. i think it has a 2.1 or so in it witha little light tuning.

i still have a weired boost problem i don't understand. I run about an 1/8th mile at 20# then out of nowhere it spikes right around half track at 25#. i got the spike down to 23#. its not like surge, its constant. to simplyfi it, the first 1/2 of the race is at 20#, the second half it rises to 25#. itsnever done that before, but has done it the last 2 times at the track.

could that be a bad wastegate acuator? I have a bigger puck and sometime i'll make the wastegate hole a little bigger, but i dont' see that helping much.

any ideas?

 

[Paul Clark]

You improved your E.T. but what about the mph?
You guys who really know this stuff, correct me if I'm wrong - but I think if your E.T. improved it was the result of better traction.
Fixing your leaks (I think) should have resulted in an improved mph also. ???

 

[denn454]

mph stayed the same, actually droped 1 mph, but it was a windy day.

there was no traction loss. it pulled so slow it wouldn't have been possible to loose any traction. I might have another exhaust leak just before the turbo i'll look at.

the launch isn't so much of a concern as the boost thing is.

 

[cathan]

Geez I wish I could get 25 psi out of my stock turbo, but I'm at 5800 feet altitude. I'm maxed at 20.

It's probably wastegate related, boost creep is common with exhaust modifications. But without knowing if there is knock, you can't tell if it's really an issue.

I wouldn't be embarrased about your times, these cars are finicky and 15 years old. It takes time, patience and money. It took me a long time to get mine even to where it is now, and it needs valve springs badly.

Are you racing on street tires? That would explain the 60 foot times. Mine went from mid 2-sec to 1.9 when I switched to drag radials. Sticky tires are crucial!

Chris

 

[MistaScott]

Code 32

The code 32 means you may have a bad vac line around the EGR valve or solenoid. Basically, the solenoid is not able to do its job. Usually it means you need a new EGR, new solenoid, or carbon cleaning in the EGR port.

First, visually go over the vac lines, then suck on the EGR vac line and make sure the EGR holds vacuum. If it doesn't, it's a bad EGR valve.

Let engine idle with EGR solenoid vac line off and see if the solenoid is pulling vacuum. If it is, the solenoid is to blame as it should only pull vacuum at 2000 RPM and higher.

 

[XLR8]

Dennis, are you locking the converter? When the engine gets a high load - at around 85 mph for me - you can get a boost spike. Is your WG cranked down so hard that it is not able to bleed exhaust gasses when needed? Can you set the WG lighter and use your boost valve to raise boost?
To get better times get - or borrow - some tires and launch at 10# - 14# psi and hold on. You have the mph for a much better et.

 

[denn454]

i am locking the converter, i could try a pass unlocked and see how that helps.

i have the wastegate rod at an about stock legnth, and controll boost with a bleeder vlave boost controller. i could understand it if it happend at the top of each gear or something like that, but this happens durring all of 3rd gear, maybe a little of 2nd i never really payed attention to where its shifting.

I couldnt' build anymore than about 8# before, but now that the header is fixed i have no idea what i can launch at, i didnt' want to try it last time at the track because i was going for consistancy not speed, but i'll definatly try next wed. i go up.

someday it might run good...