Naaa, good quality, name brand is fine. Borg Warner, Echlin, etc.

 

Ok changed the coil with a ACDelco brand.
There's definitely an improvement, but I still have the lack of power.

I also found the source of smell, it's the parking brake that fell on the muffler, it was melting. I fixed it correctly.

I also check to see if my rear wheels were locked by the parking brake or something, and no they are free.. I also observed back and forth movement (side to side when looking at the front of the wheel, like into the differential and out, I don't know if that's normal)...

The lack of power suddenly goes away after like 5 minutes of running.. It's as if the truck cuts power to the transmission until it reaches operating temperature, is that even possible? As soon as it gets hotter, I get wheel spin and all.. The power comes back suddenly! And I have absolutely no issues after that. I think I have no more misfiring due to the newer coil, however when it's lacking power it's winding the engine up and the transmission doesn't shift, however, I hear some kind of cutoff through the muffler, like a Bzzzt bzzzt bzzzt (impossible to write a sound :P ) I'm pretty sure it's not misfiring at this point, and my RPM is not reaching 4K.

I'm a bit clueless now! The truck starts right up, very very easily, on park or neutral absolutely no problem.

I did a quick test also, put it in reverse in my driveway, with the brakes on, and try to reverse. The engine reach a point where it begins to cut power, I can feel it, it's like a cylic process (a bit like a cutoff but at far less rpm). I stop that, try again 10 seconds later, and the truck is able to reverse against braking power. And that's 10 seconds later.

As if as soon as it starts to need power, it kinds of engage power the next time you ask for it.

I lack a better explanation of what I observe..

 

The business about regaining power after 5 minutes might be a clue. Do you have a scan tool that indicates loop status, (open or closed)? If so, see if it changes to closed loop just as it regains power.

 

I'm charging my laptop as I write this..

What should I look for apart from this (fuel trims / O2 sensors?) ?
I have a cheap ELM327 and freeware scantools.

 

Should be a menu that shows live streaming engine data. It will show TP sensor, MAP, MAF, EGR, fuel trims, injector pulse width, coolant temp, inlet air temp, oxygen sensor data etc etc etc. It should also show "Loop status" and after it should say "open" or "closed". What is ECT, (engine coolant temperature) on the scan tool, (not dash gauge) when the engine is fully warmed up? Is the check engine light on? If so, what codes are in memory?

 

Ok I found a software that can log and playback the recorded data, I will do that in a short while.

 

Ok, I didn't record properly when the engine was cold, so all I have is when hot, but there's still some interesting info here....


Cylinder 1 Spark Advance goes up to > 42 degrees.
The data logger send many Red things everywhere (PCMScan).
It does a map with fuel trimxRPMxMAP and there are red squares.

Honestly I'm not sure what I see here, so I'm attaching the csv file, maybe you have a better idea than I do!

Remove .xls extension to these files, otherwise I couldn't upload them.

Also, this time I listened with the windows closed and no stereo, there is a slight intermittent smooth grind noise, not something I would be scared of. I bet this is coming from the distributor area.. Is it possible that the distributor gear is worn?


Pasting a screenshot of the graph.

 

Can't get the files to open.

Yes, distributor bushings and gears both can wear. Can cause misfire, hesitation, rough idle, etc etc, and can also cause the rotor segment to contact the distributor cap.

 

The .csv file can be opened in excel.
The other file is a log that can be played back in PCMScan if you have it.

The Graph I just attached show a snapshot.

The O2 Sensor is going crazy, from 0.0 to 1.0 all the time.
Is that normal ?


Oops forgot the legend on the right.. ReAttached..


Btw, This graph is at IDLE . So 19 degrees spark Advance at Idle.. Is that strange??

 

The News!!

I removed the distributor, check the gear, seems fine, I didn't see rounding or scuffing marks.. I tried to look at the camshaft gear but couldn't see it, so I don't know the state of it!

One thing I noted, I can rotate the distributor for about 5 degrees and up and down a bit too. I guess this is normal considering it's an helical gear and the camshaft don't turn, thus it rides up and down on it when rotating.

Also, there's no play in the bushing.

However, there was no dielectric grease on the rotor and cap and the contacts were clearly just sanded away.. So the garage screwed me over and didn't really replace the cap, they simply sanded the contacts....
So I sanded them again because they were starting to oxidize (white deposit where the spark happens) and Iv'e put dielectric grease. Also sanded the rotor contact and dielectrical grease there as well.

Started up the truck and seems once again much better.

However, still there is this lack of power when cold and some hesitations on acceleration even when hot. But I can say that I don't think there is misfire anymore, I don't see why there would be everything seem to be to specs!

I wonder if it's the transmission now. I can rev it up to 2500 rpm and at that point it starts to struggle and don't want to shift to second gear, then after a little while second gear shifts kind of forcibly I would say. Definitely lacks power even when hot, lack of power is cyclic and not constant but far worse when cold.

Also, stopped at a light in Drive it struggles on idle. I put it to neutral, no more struggle...

This points to transmission issue..