Ok I'll try not to tell my whole life story on here. I have a 2000 model yukon Denali with the 5.7 vortec. About a year ago I started having a p0303 code showing up. First thing first was to change the plugs and wires. I replaced them with oem AC delcos but didn't cure the problem then I changed the dist. Cap and button that didnt work. So since then I've been chasing forums for a fix. I found a lot of ppl were having problems with the old style FI. So I did the MPFI upgrade still no fix. Compression is fine also. The truck only has 110k miles on it. Any advise would be greatly appreciated.
Can't get rid of p0303 misfire
- Thread starter TaddyIOMC
- Start date
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SunlitComet
OBS Jedi-Do Good
some tsb's I found on the subject ground g103 pcm ground rusted over time and a binding valve when towing or going uphill for which the cure was opening .002" more clearance. the ground wire is at or near the thermostat housing.
BTW.
BTW.I couldn't find the ground wire you was talkin about but I ran a cam /crank sensor retard test. The scan tool said a normal reading is between 0-2 degrees but the results showed -13 degrees. Do you think it is the cam or crank sensor that is going out.
SunlitComet
OBS Jedi-Do Good
are you sure you are reading CAM_RETARD.? what is the exact name of perimeter you are reading?
SunlitComet
OBS Jedi-Do Good
Wow then you have an adjustment to make raise engine to 1000 rpm and adjust distributor body till it reads 0.0 you can go off either direction no more then 2 degrees from zero. That is the name you should use for the setting of dizzy. But you should have thrown a p1345 code if it is that far off. If 1999 year you need to raise to 2000 rpm and check at 4000 rpm.
Yeah one of my good friends was a MAC salesman the scan tool belongs to him and I kept askin him to come run all the test for me but he just let me borrow it I'm thinkin he doesnt know much about it either just had access to buy one at cost. I've just been playin with it to see what I can find out using it. Im just a shade tree mech. I'll look for the dizzy setting tomorrow to see if I can advance the timing. I'd much rather work on my 92' Z71 TBI than deal with all this computer/sensor junk!!
---------- Post added at 09:56 PM ---------- Previous post was at 09:52 PM ----------
Last year when I was driving it often I think I remember it using coolant but not leaking any where. I jus wonder if maybe the head gasket might be leaking water into that cylinder and not letting it fire right. Is that possible?
---------- Post added at 09:57 PM ---------- Previous post was at 09:56 PM ----------
The p0303 is the only code stored and pending
---------- Post added at 09:56 PM ---------- Previous post was at 09:52 PM ----------
Last year when I was driving it often I think I remember it using coolant but not leaking any where. I jus wonder if maybe the head gasket might be leaking water into that cylinder and not letting it fire right. Is that possible?
---------- Post added at 09:57 PM ---------- Previous post was at 09:56 PM ----------
The p0303 is the only code stored and pending
SunlitComet
OBS Jedi-Do Good
you don't actually set the timing advance the pcm takes care of that you just set the dizzy sensor to be in correlation with the crank sensor. that is what cam_retard is. and why it likes to be at zero.
are you still loosing coolant and by now you probably would have ruined a converter if it was missing because of coolant leak.
are you still loosing coolant and by now you probably would have ruined a converter if it was missing because of coolant leak.
SunlitComet
OBS Jedi-Do Good
Still losing coolant tho?
