Inherited a problem, that I can't ID.
2000 Chevy 3/4HD.
A used truck, that has had this problem since 2nd owner has had it.[He bought it w/ 160K on the odometer. Now at 236,000]
Truck starts easily when cold.
Starts easily, if restarted very soon, after warmed up.
Has prolonged start time, [say 10 secs of cranking], if it is allowed to sit for, say 10 minutes. When it does start, it throws black smoke, and nearly raw fuel out the tp's.
Clear flood helps to shorten the cranking time, and the resulting smoke show.
The long block was replaced in Jan 08, but the top end was off the orig engine. [@Approx 230,000 mi.]
GM tech scanned and said his findings were inconclusive. He did replace 1 inj.
New plugs, wires, fuel filter, have been put in. No cure.
I hooked up the scan program,[V2] and find:
A. A/F is constantly fluctuating from 2+, to 50.
B. Timing retard is constantly fluctuating from 2* to over 20*.
C. Idle is smooth @ approx 725.
D. IAT reads about 95*. Ambient was 75*.
E. Only fault code was for steering input theft det. Shown as "HC". I cleared the codes, and this 1 reset immediately.
MAP is steady at 36KPA.
**I found an air leak at the cleaner elbow. The mass air was dirty, so I cleaned it. No change.
**The owner changed 2 temp sensors. No change.[NAPA brand].
**The owner does not know if the O2's have ever been changed.
**Knock sensors are out of original long block. Maybe overtorqued??
I have a download of the tune file, and a datalog, but will have to have DFE1 post them, as my wireless router is on the fritz..
Now, the ?...
NE suggestions as to where I begin???
SORRY for the "editorial"!!