Engine having issues at low boost
Thread Starter
On The Tree
Joined: Jan 2008
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Engine having issues at low boost I was on the highway yesterday and I got on it, and at around 5700 the car stopped pulling as hard as usual. I got off it and put it in 6th to cruise. At low rpms and low boost levels the car hesitates and runs real rough, but if I get the revs a little higher and just a little boost the car smooths out and seems to run normal. Granted I didn't go WOT b/c I was afraid to do more damage. I took was looking at my exhaust manifold and there was a crack at the weld were the first exhaust port tube meets the main collector tube. So today I took the exhaust mani off (which took me an entire day, b/c of how crowded things are in there) and there were cracks on 3 of the four weld spots where the exhaust port tubes meet the main collector pipe that goes to the turbo. I understand that this is def a problem, and I plan to have this re-welded, but does this seem like the reason the car is running so crappy? Or is there a chance screwed something else up along with this. The car doesn't smoke now, nor has it ever, and it seems to idle fine. Just under light driving conditions such as in 6th gear cruising on the highway it runs poor.
Any help is greatly appreciated
Justin
Any help is greatly appreciated
Justin
yea, that's sounds like it was the problem. the exhaust gases where escaping before they can get to the turbo witch caused the turbo not to spool as well as it used to before. i do not think this could of broken anything. just weld it up and you should be fine.
is this a log style exhaust manifold ?
is this a log style exhaust manifold ?
sounds EXACTLY like when i had an exhaust leak and it burned thru the silicone layer of my spark plug wire causing it to arc. Poor performance, rough running, bucking, hesitation, etc.
I dont think that the exhaust leaks are causing your cruising problem, where any of the plug wires burnt or brittle when you removed the manifold? I would bet this is the problem.
Do you have a wideband on the car?
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Thread Starter
On The Tree
Joined: Jan 2008
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i don't have a wideband on the car, but there are mesh sleeves over the plug wires, and there doesn't appear to be any damage to the plug wires. It def was caused my my wot run and was an issue for the whole next day until I took the manifold off. Now I am gonna have it rewelded and get it back on. Which wires would be best for this application?
Justin
Justin
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Verdad Gallardo i don't have a wideband on the car, but there are mesh sleeves over the plug wires, and there doesn't appear to be any damage to the plug wires. It def was caused my my wot run and was an issue for the whole next day until I took the manifold off. Now I am gonna have it rewelded and get it back on. Which wires would be best for this application?
Justin
Justin
Your sig pic is from when the car was on my dyno.
The Wire fire boots also dont seem to help any at all and in my case made things worse. if the boots touch any part of the manifold and the wire it will curn or char the silicone.
Take the boots off and check ur wires for char marks with a pin hole in the center.
Take the boots off and check ur wires for char marks with a pin hole in the center.
Thread Starter
On The Tree
Joined: Jan 2008
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Ok, so taking the turbo and the manifold off was a HUGE pain in the butt, and took an entire day. I got the manifold rewelded, and ported, b/c there were weld buildup inside of the manifold that was restricting flow. I figured I would try and put the turbo and wastegate on the manifold before putting it back in, b/c the bolts holding the turbo and wastegate on are imposible to get to once they are back in the engine bay. Sure enough it worked and I was able to slide everything back in already assembled. All I had to do was hook the exhaust back up, and reinstall the powersteering pump and sway bar (since they were the pieces in the way of the turbo and mani from sliding back into place. I also moved the plug wires from the passenger side to the drivers side, since there is way more clearance on the passenger side, i figured there was less chance of arcing. Started the car up, and it sounds way better now that there is no exhaust leak. So, I am not sure if the wires are what fixed the problem or the rewelded manifold, but regardless IT"S FIXED!
Thread Starter
On The Tree
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One more question, got the car back together and it is making .5 less psi of boost. My boost controller remembers max boost and it used to be 12.3 now it's only getting 11.8, could the welding or porting of the manifold have anything to do with this, or should I be looking someplace else?
thanks
justin
thanks
justin
