It does not seem as though rotating the cam sync can even be done without puling it up out of the bore. It does not seem as though base timing can be changed by loosening the hold down bolt and rotating, agreed?

What can cause late timing with one of the engines? I changed the plugs and wires, had anti-seize snuff out the spark. I removed all it and went from no start or even close, to starts fine and idles fine. It is down on power and sluggish stumbles a bit on tip in throttle response. Exhaust logs glow read under moderate load. The cats have about 1000 miles on them, don't see how they could be clogged. It drives 70 down the road, does not sputter but drives like timing is 5-10 degrees late. I have driven a car with clogged cat and this does not remind me of it.

Never had a P0401 before the spark plug ground issue even with minimal anti-seize. Now I have one. So fix one problem and another seems to show right behind it. Intake manifold was professionally cleaned. Could this have irritated something in the EGR system giving me the insufficient flow code?

Any techs out there know what can cause late timing? How much out does timing need to be to throw a code or is it not set up to throw a code on timing alone?

 

 

Away for a while and getting back to it.

It's late timing or random misfires so random the engine is completely smooth running, which I find very unlikely if you think about it logically. Rich mixtures don't cause this and neither do lean, because they would be lean enough to cause obvious misfires which would not allow as smooth running as I have. For now I am going with my most likely culprit....timing.

My strengths are theory...weakness is this particular vehicle.

Where does this engine receive its timing reference(s)? Can harmonic balancer slip or alteration of some sort throw off a reference from down there, toothed wheel or something? Or is timing reference just from the 'cam synchronizer'?

What can the ECM get input from that can command it to retard timing? I have not determined if it's only pulling timing with the P0401 code in play. ie CEL light on for which that is the only code I am getting.

Will insufficient flow code cause ECM to pull timing out at heavier loads where the EGR may not be working as it should to dilute the mixture? Where would this signal come from? EGR reference box or the regulator? I am referring to the two devices other than the EGR valve itself, that are wired into the system. I would think there would be a code for those two devices malfunctioning, but nothing would surprise me to this point.

Any codes for this thing for bad knock sensor? I know if everything is working correctly knock sensor sensing knock can pull timing.

Its at the point where I am close to having to start replacing the most likely parts. I will probably pull the EGR tube at the EGR just to see what happens but I cant see it being related to insufficient flow unless it somehow got clogged itself which seems pretty unlikely.

Heat gun is showing even warmed up exhaust temps of about 410*F 1-2 inches after the collector. Temps are cooler on individual 'headers' at points forward and vary a bit but I have seem plenty of that on other engines. I run it up to higher idles a bit and get same even temps after both collector points but higher low 500* F readings.
Again engine is smooth running. I get a bit of hesitation on larger throttle inputs from low idle and have heard one or two back/after fires, but rare. No hesitation an accel under load. Again, smooth starting and running, no pinging now, just down on power and glowing exhaust logs. I am trying to drive it under conditions that cause this as little as possible, because it's asking for more trouble. Guessing those things are 1200* or more to glow like that.

 

 

I am giving out symptoms on a silver platter, along with some tech data. More data: When I first saw it random misfiring on a local shop's professional scan tool, it was misfiring all cylinders and running but not smoothly. It is running smoothly now. I have seen engines with too much or too little timing run smoothly.

I have asked a specific question, how is timing referenced by the computer on this thing. Any answers?

Any specific questions for me? My level of knowledge is fine for stating the symptoms. Insufficient EGR flow code doesn't say much about glowing exhaust logs and low power, but my observations do. Based on my observations I have asked some specific questions. Does anyone know the answer?

If not, I'll either get my own high end scan tool and or start inspecting/replacing egr related parts even though that code doesn't give much to go on and I don't have any answers about EGR retarding timing (when it doesn't need to).

Do you disagree with my statements about what causes glowing exhaust headers/manifolds? If so, in what way? I have diagnosed the symptoms accurately.....now what is causing it? That is what we are doing here. For that, folks with knowledge about a particular engine step forward. Otherwise, I continue to add to my own knowledge of a particular vehicle's engine management system. I am providing quite a few specifics with none flowing back in my direction.

 

 

Broke a weak inch long segment of vac line above the right rear cylinder. I replaced that and it may have solved the P0401 EGR insufficient flow code. The code never came on soon after starting.

But I found the issue. Hard to tell from what's in this thread, but the evidence of it is in the first thread I started on the subject. The answer relates to the professional fuel injection service I got when the problem started. That service was done and the fuel filter was changed just as a precaution and because it may have been original to 1999 or 98 probably.

Without giving it away, I test drove it with an infrared thermometer. I found the exhaust manifolds will start to glow around 800*F, which is cooler than I expected,l but Ive read that is normal for cast iron manifolds. I thought it took more like 1000-1200 degrees which is hotter than these things should be under the conditions I put them under while they were glowing. My 'correction' for the issue however brought down my egt as measured on the outside of the manifold back near the O2 sensor and the first couple inches of the collector....100-150*F. May not seem like much but it was one of the symptoms of the issue I was experiencing. After correcting the issue the temps dropped that much, the glow was much less pronounced and drivability got better.

So, what was it? Remember, I went in with probably 2 gallons usable fuel in the tank which I am guessing is probably 4-5 gallons total. Has anyone checked? It's the 35 gallon tank. I went in low expecting to drop the tank and change the filler neck/hose assembly. I haven't done that yet because it didn't make sense to unless and until I got this other problem fixed.

 

Too high concentration of fuel sys detergent in my almost empty tank. Not sure how much they put in but I believe its a 35 gal tank. Maybe they put in enough for that or 15 gal average. I don't know, it wasn't mentioned or seen in paperwork. I was just told it was FUSION. As soon as I added 6 and then a short time later, 9 more gallons of fuel, things improved. Starting cold or hot and running, as well as the egt drop. I guess it slowed down the burn rate, causing egt to rise.

Van is running better now than before all this mess started.