joispoi
06-26-2005, 06:57 PM
I just installed gauges last weekend. The first thing I noticed was low boost pressure. It was peaking at 6psi and falling off to two lbs. On straightaways, at 45-50 (15-1600rpm) boost was at zero. I replaced a vacuum line and boost improved, turbo whine came back, peaked at 9psi but still falls off to zero on the straightaways, even at 70 mph..... I'm guessing this is still not normal.
Should boost ever be at zero (other than at traffic lights and when I park it at night)?
What is a normal boost pressure for a level road, unloaded at 50-60 mph, engine at 1600 rpm?
Silvy
06-26-2005, 07:05 PM
around 50 mph, 1600 rpm on the flat at constant speed I see 2 psi. Go up to 60 mph and hold it there--3 or 4 psi. 65-70 mph I see 5 psi. When I jump on the pedal at any speed, it will spike to 9 or 10 but quickly fall back to 6 psi and jump around a bit during and between shifts. I have a stock ecm with original vac system.
joispoi
06-26-2005, 07:14 PM
I need to go buy more vacuum hose....:Get_him:
Texas Diesel Guy
06-26-2005, 08:42 PM
Weak Vacuum pump, leaking vacuum lines, bad WG actuator solenoid, leaking WG actuator vacuum pot.
Lots of possibilities, need to diagnose before you run out and buy, unless you just got money burning holes in your pockets.
CanadianRigger
06-26-2005, 09:55 PM
Ah damn, i'm on fire TDG.....(just kidding)
gmctd
06-26-2005, 10:31 PM
Make an identical run pulling a 10k trailer, and post your findings..................
Silvy
06-26-2005, 10:39 PM
sorry to be a bit off topic but since it has to do with boost.... CR, you haven't blown that truck up yet with that much boost? (analyzes avatar:cool_shad)
CanadianRigger
06-26-2005, 11:20 PM
sorry to be a bit off topic but since it has to do with boost.... CR, you haven't blown that truck up yet with that much boost? (analyzes avatar:cool_shad)
Not yet...
quantum mechanic
06-27-2005, 12:29 AM
me neither, nothing a couple days wrenching couldn't fix.
nickg
06-27-2005, 01:55 AM
I'm begining to suspect my truck may have been tampered with... I see min 4-5psi boost at any cruise speed, during mild acceleration I get 10-12psi and it will hold it as the truck accelerates, once the load comes off the engine it will cut back to 7-8psi . under hard punches I see spikes of 14-15. and there is virtually no turbo lag, I just have to lightly touch the throttle and the boost needle starts climbing!
I'm going to hook my scanner to it and compare readings.
I had a bit of a drag race between lights with a fellow I know he has a newer F$rd one ton dually (2001 possibly newer) and I held my own off the light. from 0- 90K he only got a truck length on me...this likely explains my poor fuel mileage LOL