Ok, my BAFX ELM327 showed up yesterday and it does link with the Blazer. So I now have a scanner that will connect. I have it setup to read a few things but I still need to buy the Torque Pro App. Right now it's only running the free version. I'm hoping I can watch the manifold vacuum, coolant temp, and TPS to see why it's running rich since the regulator repair. It starts great when cold, has a stumble/hesitation just off idle until it gets warmed up. Then once it's just slightly warm it will turn over and fire but boggs and RPMs drop/ vehicle shakes for the first couple seconds and then recovers. So it all points to a rich condition in my opinion and I'm suspect of coolant temp sensor or intake temp sensor. I have been driving it daily and pulled the battery cable a week ago so it would unlearn any bad information it had picked up with the EVAP hose disconnected.
I'm not going to let this thing get the best of me but it's sure putting up a fight.

Edit:
Air and coolant sensors are working and after sitting for 7 hours there was almost a 10* difference between them with the CT reading higher. It wasn't until I got home that I found the OK voltage displays so I'll have them for the next drive. The air temp was within 2 degrees of air temp which should be good enough.

Edit Edit:
From this mornings drive I have determined that I installed a 185* thermostat which probably wasn't a good idea on this thing. The intake air sensor is reading about 3* warm but nothing to worry about. I think vacuum was around 45kpa which converts to 13" mercury. That seems a bit low for idle but I will confirm later today. What had me thrown was timing. Idle was running almost -30* at idle and then would go up as I would drive. I did notice that TPS% was 0.0 but I should probably adjust it to get it up to 0.1%. That might have something to do with the hesitation off idle but timing could also play a role in that as well.
Does anyone know what I should be seeing as far as timing and vacuum at idle?

 

Bump... don't leave me hanging CaptainHook!

So I've been thinking and I've decided that I'm a tooth advanced on the distributor. Yes the housing is in the right place but I never used a timing light when I installed it because it is pinned to the manifold and cannot be adjusted.

The distributor gear looked like it was in good shape from what I remember. Going by the pictures I have seen online, I would have known if it was not.

However, the gear looks like it has 13 teeth which makes each tooth worth almost 28* of timing. Since timing is retarded by -30 to -25 degrees at idle could I assume that is the problem? Unless I hear otherwise to tell me I'm wrong I will plan on setting it to TDC on #1(I can pull the valve cover and plug to make sure it's 100% TDC on compression stroke if I have to) and see where the rotor is pointing. I remember reading something about some marks on the housing that should be lined up during install but maybe that's where I went wrong.

 

Sorry for the delay, had to replace the operating system on my PC and have no clue how to post the images from my smart phone, probably has something to do with the not so smart operator

#1. "So I've been thinking and I've decided that I'm a tooth advanced on the distributor."

If the distributor is not timed correctly with the camshaft, P1345 will set in memory and the check engine light will come on. In other words, no DTC means you have it timed correctly.


#2. "...the gear looks like it has 13 teeth which makes each tooth worth almost 28* of timing."

That is correct, (27.6923076923 degrees to be exact ) When camshaft retard is off by ~25 degrees or more, in either direction, it triggers the P1345.


#3. "Since timing is retarded by -30 to -25 degrees at idle could I assume that is the problem?"

Where are you getting this reading? With a timing light on the dampener, or on the scan tool?


#4. I remember reading something about some marks on the housing that should be lined up during install but maybe that's where I went wrong.


Here's the procedure using the marks: Remove the distributor cap so you can see the rotor clearly. Using a socket and ratchet on the crankshaft bolt, manually rotate the crankshaft clockwise** until the lines on the dampener are aligned like this:




AND the rotor is pointing at, or within a couple of degrees of the "6" on the distributor housing like this:





#1 piston is now at TDC on the compression stroke. If the distributor is not aligned with the "6", or within a couple of degrees, remove and install the distributor so it lines up, or is within a couple degrees the "6". The key here is if P1345 is NOT present, you have it timed correctly, and all this BS is unnecessary.


**During this procedure, any and all slack in the timing chain MUST be on the right, (passenger side) of the engine. DO NOT rotate the crankshaft counter clockwise.

 

So because of the position sensor in the distributor, it's highly unlikely that it's a tooth off. I will check it next time it's warm. Both with a timing light and by setting 1 at TDC.
I was watching the timing on the scanner and cannot understand why it would be pulling so much timing.

I was thinking that the window that triggers the cam sensor could be wide enough to not set the code.
I was hoping you had some insight on what timing I could expect to see. A mechanic said the vacuum reading I am seeing is low but I need to verify with a gauge and eventually a compression test.
There is a lot of information I need but I'm not sure which is the instigator. It would be nice to have a little power and performance out of this thing.

Maybe we'll come back to this in a few months when I can fill in a few of the blanks.

 

A timing light is an obsolete tool on this engine. #1 there are no timing index marks to read, and #2 you can read precise ignition timing right from the scan tool.

With the engine idling at normal operating temp, (~198F), transmission in park or neutral, all accessories off, PCM in closed loop, throttle closed, ignition timing advance will vary slightly, but it should be 18-21 degrees, and idle RPM should be 650.

 

This weather is not easy. It was 65 4 days ago and now -10 overnight tonight.
Here's to hoping I get to work tomorrow. I can verify the crank vs distributor this weekend. It should warm up a bit.

Thanks for the help. That sounds about right for a vortec style cylinder head timing.
I have the distributor timing at 0, curve advance of 11 - 22, and then another 6 degrees on my other car but that's as high as I can get before it gets knock counts.

 

In the first post #31 you checked IAT & ECT sensors: Just for grins, check those again after the vehicle sits for 10-12 hours. Check them with key on, engine off, don't start the engine before testing. Both should be within 2, maybe 3 degrees of ambient.


In the second edit: At idle, TPS should be 0%.


Vacuum at idle should be ~18" (13" is definitely low).


Thermostat needs to be 195F. It should regulate ~198 depending on ambient temp.


In regards to timing... are you reprogramming it? If so, what happens if you put it back to original?

 

So I'm good besides figuring out why I'm 40 degrees off on timing and running low on vacuum. The timing could be causing the vacuum problem so I'm going to start by trying to find out what is going on there.

The comment about timing with vortec heads was about my car that is a 327 with '96 vortec heads and TBI. I had to start out with a stock 80s 350 tune and modify it for a smaller engine making twice the power.

 

Sounds like a plan I think you're on the right track.

 

I got some pics I can't seem to upload at the moment but can later if they will help. I lined up what I thought was the timing mark(s). The rotor points pretty much dead on the 6. There goes that theory.
So it has to be detonation causing it to pull timing. Then again the scanner could be wrong. I'll follow up with vacuum gauge, compression tests and check plugs I suppose now that the regulator problem is behind me. After looking at the wires today I guess I never changed them and #6 was pretty loose on the cap. So I'll add a wire change to the list tomorrow and post the results.
If it has a bad cylinder I won't be surprised on this thing.