What could cause this issue on start up?
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,187
Likes: 266
From: Virginia
What could cause this issue on start up?
On an initial cold start the car starts normally with no issues but after I shut it off for a bit and restart it revs really high for a sec then drops down to normal idle. It does this whether the car is on for a few mins or is fully warmed up. Starts fine when dead cold but on a restart it will rev pretty hard, hard hard enough for the lifters to chatter for a sec. The car is cammed and tuned. Could it be something in the tune or more likely a mechanical problem? I thought maybe something like a sticking throttle body blade or something. I’ll try to get a video soon.
Safety Car
Joined: May 2016
Posts: 4,669
Likes: 1,849
From: Erlanger, Kentucky
I would check for vacuum and exhaust leaks. Check air filter coupler clamps, throttle body bolts, intake manifold bolts, inspect all hoses and connections. Also check exhaust manifold bolts, re-torque them.
It sounds like something is expanding when warmed up and causing a vacuum leak somewhere.
It sounds like something is expanding when warmed up and causing a vacuum leak somewhere.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,187
Likes: 266
From: Virginia
I would check for vacuum and exhaust leaks. Check air filter coupler clamps, throttle body bolts, intake manifold bolts, inspect all hoses and connections. Also check exhaust manifold bolts, re-torque them.
It sounds like something is expanding when warmed up and causing a vacuum leak somewhere.
It sounds like something is expanding when warmed up and causing a vacuum leak somewhere.
Le Mans Master
Joined: Dec 2005
Posts: 6,999
Likes: 1,685
From: Southeast TX
Unhook the vac line where it goes into the NPP box. Plug the line. Golf tee works great. If the issue disappears, your trouble is between the box and your vacuum source. If the trouble remains, reconnect to the box and plug the lines where they connect to the mufflers to see if that resolves the issue. It's most likely something to do with the NPP system if that issue wasn't there before the installation.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,187
Likes: 266
From: Virginia
Unhook the vac line where it goes into the NPP box. Plug the line. Golf tee works great. If the issue disappears, your trouble is between the box and your vacuum source. If the trouble remains, reconnect to the box and plug the lines where they connect to the mufflers to see if that resolves the issue. It's most likely something to do with the NPP system if that issue wasn't there before the installation.
will do
