03 s10 4x4 4.3 CC ~122k on it

I replaced the cap and rotor a few months ago, only to find out that I did not full screw in the screws for the rotor. Long story short get it home and I find out that was the problem. Being it still was running rough and had a fair amount of play on the rotor I replaced the entire distributor. Now it starts and idles just fine till I try to drive it. It will go through the rpm range but very slowly like it is being held back. I checked my Ultra gauge and I am geting 14/15 deg of timing advance at idle and around 40 deg at 2k rpm. Is that correct I can not seem to find anything if that is correct or not.

I am 100% positive I replaced the distributor in the say way it came out, the old one was marked as is someone already removed it, could it be off a tooth? With the amount of play it could have made it run better? I think it could be turned 1 one way or the other, would it be safe to take it could and try it?
How do I check the timing with a light?
I see 1 line on the pulley and 1 on the motor so I am confused being there is no meter just 1 line on each.
Maybe crank position sensor?

Thanks for the help in advance.

 

Timing lights are obsolete on this engine. Timing is viewed with a scan tool. The timing reading you're seeing is what the PCM is applying, and it is NOT adjustable.
There are two index marks on the crankshaft vibration dampener. They are used for positioning #1 piston at TDC, (Top Dead Center).
If the distributor is not installed properly, (off one tooth or more) DTC P1345 will set in memory and the Service Engine Soon light will come on when the engine is running. Also, whenever the distributor is removed, camshaft retard MUST be checked and adjusted with a capable scan tool.
As for the crankshaft position sensor... If there are no DTC's in memory pertaining to the crankshaft sensor, or its circuits, the sensor is fine, leave it alone . If the sensor, (or timing cover) is moved, removed, replaced or disturbed in any way, the crankshaft position sensor relearn MUST be performed with a capable scan tool.

With all of that in mind.... if camshaft retard is out of spec, it can cause misfire, hesitation on acceleration, stalling, reduced power, poor fuel mileage, and premature deterioration of the distributor cap & rotor. Have you checked fuel pressure and leakdown? Have you checked the fuel filter for restriction? Is the SES light on while driving?

 

Thank you, that the explanation I needed.
The SES light was on but now I have forgotten the code. As of now the light is off but I have not driven it more than 3 miles.
I already replaced the fuel filter has the fuel pump was the first place I looked when it stalled. I rented a fuel pressure gauge and it broke and I took it back, I will get another rental and will try to test the fuel presure tomorrow.

I would like to get a good scanning tool that can do the case relearn and adjust the camshaft retard any recommendations. I have been looking at snap-on MT2500.

 

On your 2003, apply battery voltage to the pump prime terminal in the underhood fuse panel:


Fuel pump running, (engine off) pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes after the pump shuts off.

Snap on MT2500, Solus, and Solus Pro are all good choices, (check Ebay). Make sure the software is updated to your model year, (annual updates are $1K available ONLY through Snap on). Also make sure it has the interface cable. Personality keys are not necessary for your Blazer.

 

Just check the fuel pressure and it sat at 55psi for 10min so that is good.

Would this scanner do the job?
http://www.ebay.com/itm/140981557689...84.m1438.l2649

 

Pressure held 55psi for 10 minutes after the pump shut off? Or while the pump was running?

Fuel pressure and leakdown are two different tests. While the pump is running, pressure must be 60psi to 66psi.

Second part of the test is leakdown. It must remain above 55psi for at least 10 minutes.

Post the results of both tests. The results will tell if there's a problem, it will NOT tell what the problem is.

EDIT: That MT2500 is only good through 2004 model year vehicles. Updates for ALL model years are included when you purchase each update, ($1K). If any updates became available since 2004, the scan tool software will not have them.

 

Sorry I was not more clear. It was at 65psi with the pump running, then when off it went down to 55psi after 10 minutes.

 

Fuel pressure and leakdown are fine.
Make sure the cap is wired correctly. Pay close attention to cyls 1 & 3:



If that's OK, check for an exhaust restriction. Remove both upstream oxygen sensors and drive it just far enough to tell if there is any difference in power.

 

Wires are good. I tested the back pressure and it was between 0-1 at high idle and 1-2.5 at 2k rpm.

I took it for a drive and it started out ok but it almost did not make it up a small hill. I also noticed the timing advance was around 0 when i just started it when it was cold, but after the drive its up to 16-18. I also noticed white some in the exhaust.

I just got to looking at the ground and it appears to be spraying out small ??aluminum?? flakes out of the exhaust.
Another edit: the truck does appears to have stock pre-cats and cat. but it does has a aftermarket muffler. Note I changed the up steam O2s a month ago.
Got a pic of the flakes I you are on the right track with the muffler and or cats are going out literally.

 

2.5psi backpressure is high, should remain below 1psi. Not sure what those particles are, but it could be pieces of catalyst indicating it is deteriorating causing the backpressure to increase. With the engine off, if you rap on the converters with a rubber mallet, do they rattle?

Coolant at operating temperature, at idle, in park or neutral, closed loop operation, the ignition advance should be 17 or 18 degrees, so that's fine.