LQ4 swap - need diagnostic help
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Teching In
Joined: Sep 2012
Posts: 29
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LQ4 swap - need diagnostic help My 2004 LQ4 (van DBC motor) swap runs OK, but has a few issues. The PCM was wiped and tuned by a reputable shop. It was tuned for my setup running premium fuel.
-Pings under heavy load @ high rpms
-Throws P0174 sometimes after spirited driving
-As the engine warms up, it idles smooth and clean until it is about to go into closed loop. For about 1-2 mins the idle gets rough, and it starts running real rich (black smoke from tailpipe). Once it hits closed loop, the idle stabilizes and the exhaust cleans out.
I don’t have a wideband, but I’d say it idles rich (smell).
What do you guys think? Here’s a few things I’ve read that I need to check.
-vacuum leaks
-fuel pressure
I really appreciate the input!
-Pings under heavy load @ high rpms
-Throws P0174 sometimes after spirited driving
-As the engine warms up, it idles smooth and clean until it is about to go into closed loop. For about 1-2 mins the idle gets rough, and it starts running real rich (black smoke from tailpipe). Once it hits closed loop, the idle stabilizes and the exhaust cleans out.
I don’t have a wideband, but I’d say it idles rich (smell).
What do you guys think? Here’s a few things I’ve read that I need to check.
-vacuum leaks
-fuel pressure
I really appreciate the input!
