vacuum leak on bank 2 4.0l sohc

jmg8550 · Feb 3, 2009

anyone ever have problems with a vacuum leak on the drivers side bank, maybe a warped manifold. Long term fuel trims on that side are way up (23% enrichment). injector pulse width at 3.6ms. fuel trims on bank 1 are normal. no codes yet but idles terrible. drives just fine. compression at 140psi, plugs look lean on all 3 cylinders of bank 2. no misfire on the ignition or injection systems. checked cam timing and everything is in spec. tested for leaks, none apparent. o2 sensors functioning normal.

jasonl · Feb 4, 2009

sounds like one of the rubber O-ring intake gaskets is partially sucked in causing an intake leak. Did ya spray some carb cleaner around the intake manifold? It seems it def has an intake leak to cause the rough idle and the fact your fuel trim is trying to over compinsate to correct itself.

jmg8550 · Feb 4, 2009

Yeah I tried carb cleaner and it never changed all that much. The idle was so crappy that it was hard to judge what was changing. A little history on this truck... the driver was cruising down the highway and was trying to pass a vehicle when a cam follower decided to come out of it's spot and locked up the passenger side camshaft, thus breaking the bolt on the jackshaft bolt on that side. Trashed the cam, the timing cassette, and the follower obviously. When that happened, the engine went past redline(since it was at wot) and bent all exhaust valves on the driver side head. All that was fixed, and the engine never ran as good. It has all new gaskets and o-rings up top. Maybe the intake o-rings slipped. But it seemed to get progressively worse. No codes have ever turned up. but it is on the brink of sending them. I guess when I check the gaskets I'll look for manifold warping at the same time. Thanks for the advice jasonl!

vacuum leak on bank 2 4.0l sohc

jmg8550

15+ Year Member

jasonl

15+ Year Member

jmg8550

15+ Year Member

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