Any Chevy Automechanics?

1995blaster

1995blaster

New Member
Jul 30, 2009
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Well got a FEW questions for you guys who are mechanically inclined.

I have a 1997 Chevy Pickup 5.7 V8. When i bought it there was a rock knocking. I had the motor rebuilt, i removed it and installed. When i got it together, no knocks or ticks but i took it up to get the codes ran (the light wasnt lite up on the dash) It had showed the cam crankshaft alignment, mass airflow sensor's im gonna assume the guy took the dash light out or it is burnt up. It has a slight mis, a pretty bad flutter with a hesitation up until 2,000rpm's and horrible gas mileage like 5mpg.
So I replaced the plug wires, distributor cap, rotor, Mass air flow sensor, and and a sensor under the distributor. Still has the misfire but not as bad. Hesitation is almost gone but the flutter is still there. I just put 20$ in gas in and drove it around about 30 miles didnt go down but a tick mark so i think thats cleared up to. But still has the mis so i took it up to get the codes ran it says mass airflow circuit low input and camshaft position circuit low input. Did some research and it just shows either faulty part or the circuit isn't complete OBD-II Trouble Code: P0340 Camshaft Position Sensor Circuit Malfunction OBD-II Trouble Code: P0102 Mass Air Flow (MAF) Circuit Low Input
They distributor shaft gear was also wore decently bad, i read that if it was bad would give the timing play and would make the computer advance and retard causing a miss etc and flutter so i wouldnt show any codes. Any other opinions?
Also considering the map sensor, it doesn't show any codes but it controls fuel so maybe its making it run rich and causing bad fuel mileage. and dumping to much in causing a flutter when you gun it.
 
i dont have much experience with the 350's but if the distributor gear is worn i can see that maybe bringing up the crankshaft sensor code. thats all i got for ya, sorry.
 
to set the timing on that properly, you have to use a scan tool and get it to where the computer is only trying to correct within +/- 2*

take care of that distributor gear too...
 
Ya i knew that, i forgot to mention that i had i took it to a shop that had that tool, they said it came up that the timing was fine. So that makes me think it is a sensor or something else no controlling the fuel input or something.
 
Honestly sounds like an electrical issue, Like either a sensor is bad or the comp is not sending out enough voltage or recieving enough voltage
 
I would of looked if it wasn't dark, if i remember there is only 3 one on the block and one on the firewall and another on the frame. Mileage added up to be like 5 6mpg. But i replaced the mass air flow sensor today and drove it a few miles and it only went down a tick so i think i got that figured out.
 
I spent like 20 on a cap and 10 on a rotor and 40 on the sensor then its another 30 for a gear. Oreily's said 120 for a whole new distributor heres a new complete one for 53$ BRAND NEW COMPLETE DISTRIBUTOR FOR VORTEC ENGINE V8 | eBay

In the first post i said i cleared them and the low input circuit codes came back. Did it twice, shut it on and off unhooked battery and drove it around in between.
 
Last edited by a moderator:
What is your fuel pressure?? Is it the original pump?? Those engines need 60+psi. If you have anything below it they start giving you problems. Get a gauge on there and see what your at. Should be above 55 at idle. Join up at fullsizechevy.com and hit up a search TONS of info on this. Bunch of guys too that know their sh*t.
 
If your camshaft position sensor or crankshaft position sensor is bad they will both cause all the problems you have mentioned, both tell the computer advance or retard the timing and if they have low or high output or input they are not telling the computer the right thing to do which will cause bad fuel mileage and to idle rough or have a slight misfire
 
Busted Warrior said:
What is your fuel pressure?? Is it the original pump?? Those engines need 60+psi. If you have anything below it they start giving you problems. Get a gauge on there and see what your at. Should be above 55 at idle. Join up at fullsizechevy.com and hit up a search TONS of info on this. Bunch of guys too that know their sh*t.
Click to expand...


that website is the shizzle^^^^^^^^
 
just a get spreadbore intake manifold, holley 400cfm carb, hei distributor and a mechanical in block fuel pump and ditch that computer lol.
 
I have a little experience with those engines, a friend has a 96 5.7 vortec 1500 that I replaced the engine in a few years ago. You stated the distributor gear and shaft was worn and you are getting a mis-alignment from cam and crank sensors. From what I remember, the cam sensor is under the rotor and pretty much uses the dist. for cam position. I would start by replacing the distributor first. I saw the same on my friends and put a new dist. in with the new engine. Another thing to check is the crank sensor, its in the front timing cover behind the balancer. Pull it out and look for damage to the face of it (possible contact when the last engine wore out). From what i remember, those are easily damaged and is a common issue. And as mentioned before, fuel pressure is a big issue with those engines, make sure its within spec, if not replace with an AC Delco pump, they are pricy, but have seen many aftermarket pumps not put out enough pressure and they dont last as long. It has to do with the design of the injectors. Same issue with the 4.3 vortec, has to have the OE fuel pump. Hope I helped some.
 
did u replace sparks plug ? if u did what type of plug did u use ? (ac declo ) the trouble code u got will make it hard to start . i would check to see if ur converters are bad . bad converters will make u burn hella gas .also put some Zmax in the oil n in the gas tank dis stuff wrks
 
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