car pop'n under boost.

[unobetr]

the car was fine. i had head gaskets changed, and then it just started.. it has run good before and after change.. i recently sent my turbo to precision and put a 63 exhaust back on, it had an 85. i also upgraded the headers, downpipe and wastegate. gn1 headers, downpipe and 46mm tial wastegate.. i think it started after that..

 

[unobetr]

I'd be more concerned that it's set correctly than it being good or bad. If your engine will start, it's working. It really sounds to me like a timing issue.

I'll wait to see your response to my last question, then I'll tell ya how to check the cam sensor to make sure it's set right. :biggrin:

engine starts fine..

 

[Black Power]

How far down did you tear the motor when you did the head gaskets? Did the cam come out, or did the timing cover come off? The headers, downpipe, and wastegate shouldn't affect the motor like that, unless you had a bad exhaust leak before the turbo.

 

[Black Power]

engine starts fine..

Gotcha. If your cam sensor is unplugged or dead, it will not start.

 

[unobetr]

hmmmm.. no to the tear down.. but! my cross pipe is not welded! it just has the clamp on it that came from GN1

 

[Black Power]

hmmmm.. no to the tear down.. but! my cross pipe is not welded! it just has the clamp on it that came from GN1

Timeline goes like this:

It's running fine
You pop the head gaskets
You don't tear down the engine far enough to remove the front cover, timing chain, cam, cam sensor, etc. Just pull the intake and heads off, replace head gaskets, and back on
It still runs good
Change out the exhaust, now it starts doing the popping

Correct?

If that's the case, I would look at what I did right before the problem started happening. If the GN1 clamp is sealing off and not causing a pre-turbo leak, that's not it.

 

[unobetr]

Timeline goes like this:

It's running fine
You pop the head gaskets
You don't tear down the engine far enough to remove the front cover, timing chain, cam, cam sensor, etc. Just pull the intake and heads off, replace head gaskets, and back on
It still runs good
Change out the exhaust, now it starts doing the popping

Correct?

If that's the case, I would look at what I did right before the problem started happening. If the GN1 clamp is sealing off and not causing a pre-turbo leak, that's not it.

looks correct.. how can i check the clamp under boost?? i know of no way.. i do need to get it welded though...... hmm.. wonder if i have a header gasket leak.. im not hearing any ticking or anything though.

 

[unobetr]

i had the head gaskets done.. i believe they only pulled just enough off to pull the heads..

 

[Black Power]

If you think it could be your cam sensor, here is how you check/adjust it.

The key things to remember are that when the balancer is on the mark, it could be either TDC #1 and #4 at the same time. Make sure you check for air coming out of the spark plug hole (#1) or pull the driver's side valve cover, look for the intake stroke, then after the intake valve closes, keep rolling it around until it hits the mark. Stop there, get your tape measured out, tape it to the left hand (when facing the engine) of the mark on the balancer, and roll the engine to the edge of the tape. That's where your motor needs to be when setting the cam sensor. The rest of it's just poking around with a volt meter or a Casper's cap.

Cam Sensor Information

 

[unobetr]

i dont think its the cam sensor.. do you think it could be?

 

[Black Power]

i had the head gaskets done.. i believe they only pulled just enough off to pull the heads..

Oh, so you didn't actually do it.

I would get ahold of whoever put the head gaskets on and (if they aren't Buick people) ask them about pulling the front cover or messing with the cam sensor. If they did there are a few things that could have gone wrong. They possibly could have timed your cam back in wrong, they could have set your cam sensor 180 degrees out, in which case it would still run, but run like crap.

If you get curious enough and you have another car to drive and enough tools/ability, you might pull the front cover off and take a peek.

 

[unobetr]

i had my uncle do it.. hes been a GM mechanic for 30 years. ill ask him if they took the sensor out or the cover off.. i wouldnt think so..

 

[unobetr]

just saw this on the page..

Several people have found that when running a bigger cam with advanced valve timing, it sometimes will help cure a popping or sputtering symptom by advancing the cam sensor a few degrees. The above values give you an idea of what to shoot for.



i have a 218/218 cam

 

[Black Power]

i had my uncle do it.. hes been a GM mechanic for 30 years. ill ask him if they took the sensor out or the cover off.. i wouldnt think so..

Yeah, ask him. If you can eliminate it being valvetrain timing and a 180 out cam sensor, that will help. I dunno why, from the video it just sounds like something is not in time.

 

[Black Power]

just saw this on the page..

Several people have found that when running a bigger cam with advanced valve timing, it sometimes will help cure a popping or sputtering symptom by advancing the cam sensor a few degrees. The above values give you an idea of what to shoot for.



i have a 218/218 cam

Yeah that's a fairly big cam. Nothing that hasn't been in quite a few cars on here. You might also track down some others on here that have used the 218 in their cars and ask them if they advanced it a little bit. I have a 212 and set it exactly where it told me to.

While you are at it, when you take a look at that cam sensor, either tell me which direction the wires on the cap are pointing, or take a picture of which way they are pointing, just for the sake of curiosity.

They can be pointed any direction and the cam sensor be set correctly, but if they are pointing a goofy direction, that might be a clue that it's been tinkered with.

 

[unobetr]

http://i.imgur.com/ihsE5.jpg

voltage is .8 on wire B


EDIT:: .84 actually

 

[Black Power]

http://i.imgur.com/ihsE5.jpg

voltage is .8 on wire B


EDIT:: .84 actually

That cam sensor looks like it's been set by someone who knew which direction to set the wires towards. Like I said, you can't tell from looking at that whether it's set right or not, but it's a good indicator that the person that set it has done it before.

Good sign.

How are you testing the voltage? I guess key on, ignition off, one to ground, the other to the back of the B terminal?

Whatever you do, do not loosen the bolt that holds the cam sensor down and start rolling it around. If you want to check the sensor, make SURE the engine is 25 degrees after TDC on #1 before you loosen that bolt and start playing with the sensor. Otherwise you are gonna have a car that won't start :tongue:

 

[TurboBuRick]

Sounding like a worn cam lobe. Is it a flat tappet?

When you blew the head gasket did any anti freeze get in the oil?

To test the cam sensor, unplug it with the motor running. Take the car for a ride and see if it still pops.

 

[Black Power]

Sounding like a worn cam lobe. Is it a flat tappet?

When you blew the head gasket did any anti freeze get in the oil?

To test the cam sensor, unplug it with the motor running. Take the car for a ride and see if it still pops.

Good idea right there. When you are done and you shut it off, just make sure you plug it back in before you want to drive it again :biggrin:

 

[unobetr]

it almost sounds like the rev limiter......