97 4.3 vortec po300 of death please help
#1
97 4.3 vortec po300 of death please help
Hello new here to the forum. I am haveing po300 problems. started off as a cyl 1 and 2 misfire, replaced coil, plugs, wires, cap and rotor (acdelco), maf, tps, distributor, checked for vaccum leak by spraying every inch of the motor, cyl 1 was misfireing at 96 misfires per cycle and cyl 2 was 79 misfires per cycle, now i have a cyl 3 misfire at 185 per cycle, checked fuel have 64 psi with key on and 55-60 with it running, also did a injector test and all the injector pressure to 65 and go to 30psi t the same time, replaced with new cam sensor, new egr reading on my scanner at 1500rpms my cam would go to -17 degrees so i resat the timing at 0 degrees and it seems to running a little worse. Starts with no trouble but has a small rumble seems like it has a radical cam , If you go to pull out i stumbles a bit but runs fine with higher rpm. misfire counter goes down between 20 and 65 at higher rpms
check engine light flashes unless i am on the gas at around 12 1300 rpms and higher
here the specs from my scanner,.
rpm 700
tps 0.57
b1s1 495-600 MV fluctuates constantly
B2B1 200-550 MV fluctuates constantly
B1S3 200-740 MV fluctuates constantly
A/F RATIO IS 14.7
MAF 7.5
BARO (KPA) 95
MAP 2.05 V 49(KPA)
COOLANT 94DEG CELSIUS
INTAKE AIR 16 DEG CELSIUS 2.66V
IAC 84
DESIRED IAC 84
DESIRED IDLE 650
IGNITION 13.5 VOLTS
MISFIRE CYL 3 184 PER CYCLE
KNOCK 4.65
SPARK ADVANCED 22
KNOCK RETARD IS 0
CAM RETARD 0
CAM RETARD CHANGES TO -17 AROUND 1300 RPMS AND SLIGHT TO NO MISFIRES AFTER 1200 RPMS
B2S1 SWITCHING FROM LEAN TO RICH CONSTANTLY
egr 0.76
check engine light flashes unless i am on the gas at around 12 1300 rpms and higher
here the specs from my scanner,.
rpm 700
tps 0.57
b1s1 495-600 MV fluctuates constantly
B2B1 200-550 MV fluctuates constantly
B1S3 200-740 MV fluctuates constantly
A/F RATIO IS 14.7
MAF 7.5
BARO (KPA) 95
MAP 2.05 V 49(KPA)
COOLANT 94DEG CELSIUS
INTAKE AIR 16 DEG CELSIUS 2.66V
IAC 84
DESIRED IAC 84
DESIRED IDLE 650
IGNITION 13.5 VOLTS
MISFIRE CYL 3 184 PER CYCLE
KNOCK 4.65
SPARK ADVANCED 22
KNOCK RETARD IS 0
CAM RETARD 0
CAM RETARD CHANGES TO -17 AROUND 1300 RPMS AND SLIGHT TO NO MISFIRES AFTER 1200 RPMS
B2S1 SWITCHING FROM LEAN TO RICH CONSTANTLY
egr 0.76
#6
ok so after ripping everything apart i come to find someone changed the spyder already........... took it to a local shop they cleaned it n tested it it was fine put it in and still same thing cyl 3 misfire?????????? what next
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#8
Look at the posts inside your distributor cap. If you see signs of excessive arcing you have a problem with the gears at the bottom of your distributor. It’s a common problem in high mileage Vortec engines. It always leads to random misfires. Go to www.vortecrighttime.com and get their rotor. They guarantee it will fix random misfires permanently. I had the same problems with my last two Vortec equipped vehicles. The new rotor completely fixed it. I got a new distributor. It worked for about 6 months and the misfires came back even worse.
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syuchimiuk
Express, Savana & G-Series Vans
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March 20th, 2011 10:54 AM