Trouble shooting help needed

0-60N4

0-60N4

Member
I have a problem that has stumped me and I need some help.

Truck was running fine but under high boost, I was gettng some oil mist from the driver side valve cover vent filter. So I installed a Moroso breather/oil separator on the valve cover and vented in into a Greddy catch can/separator. I located the catch can where the cruise control was. When I removed the cruise control, I unplugged the electrical connector and two vacuum lines and plugged the vacuum lines.

When I went for a test drive, I found that when started to slightly get into the boost, the truck would cut out really bad and backfire. I also noticed oil smoke behind me and smelled it. I determined the hoses to and from the catch can were crimped when the hood was closed so the engine could not vent. The extra pressure was causing some oil to leak out of the oil pan gasket and get on the down pipe. That was the source of the oil smell and smoke.

I relocated the catch can and tighted the bolts on the oil pan. That seems to have taken care of the oil leak but the bad stumble when getting into the boost is still there.

At light boost and about 4,000 rpm, it will abruptly shut power and backfire if I don't let off the gas (but engine does not die). I have good fuel pressure and the fuel pressure regulator appears to be working fine. As long as I don't get into the boost very much, it runs fine.

Any ideas what has happened or what to look for?
 
B

BillC

New member
Check your PCV valves on the passenger side. Sounds like the front one (that connects to the plastic intake crossover pipe on the stock setup) has clogged.

The rear PCV valve vents the crankcase when driving in vacuum, and the front one vents the case when driving in boost.
 
ed hess

ed hess

race or get outta the way
jim

Since it ran fine beofre you touched the vac lines...i would go back and double check those same lines.

is the vac line still connected between the fp reg and the map sensor.

eliminate the pluged lines entirely.

hth

ed
 
0-60N4

0-60N4

Member
I no longer have a PCV valve to the intake.

The driver side can vent to atmosphere.

I did reconnect the cruise control with vacuum lines.

checked fuel pressure regulator - opened/cleaned and check for proper pressure.

Lines connected to fpr and map sensor.

I'm thinking the map sensor maybe just went bad at the same time. MES again?

I'll connect the diacom and get MAP readings to verify.
 
0-60N4

0-60N4

Member
according to Diacom, the MAP sensor is working fine. Shows good vacuum and pressure responses.

Still searching for the problem.
 
0-60N4

0-60N4

Member
Thanks for the help. It was ignition. I changed cap, rotor button, ign. module, wires and it was better but still had a miss. Changed plugs and coil and it fine again. Strange that the ignition went bad just when I worked on the catch can and oil separator but SyTy's always seem to do strange things.
 
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