3VZE 3.0 runs horribly after head gasket job and EGR/PAIR delete...

[thewanderlustking]

Just did the Headgaskets, that's a hell job I wouldn't wish on my worse enemies.  I would be happy though, if the truck was running good...  On the first couple test drives, it had zero power and fell flat on its face.  A couple rounds with the timing light setting the timing to 10, then 12, it feels almost peppy now.  But after maybe half a mile it will loose some power and pop/det when trying to accelerate after a turn.  Once it does this, it gets a little worse and takes less provocation to pop and will do it going straight too.  Weird det noise, sounds like I am running over an acorn...  

 

It also stinks.  The first drive smelled like burning clutch or melting plastic.  It's an automatic.  Now it is a more exhaust kinda smell.  No exhaust leaks heard/visible.  When the EGR was removed, I also removed the PAIR valve.  Apparently that's for pulsed air injection into the passenger side manifold.  So I have some issues to sort out and questions.  

 

1)  I suspect putting the PAIR back on will help with the smells?  It helps the 3way catalytic function better according to the FSM.  I couldn't find anything actually getting hot either plastic wise, or brakes etc.  Now the original burning plasticy/clutch smell could well have been a bit of the old Toyota wiring loom that got removed and perhaps fell somewhere onto the crossover pipe or something.  But the next couple drives that smell was less, and the exhaust stinks was then more noticeable.  

 

Next:  The power loss-knock/pop/det whatever it is, concerns me MUCH more.  The EGR thermistor had been disabled and bypassed for a long time with a resistor.  So I assumed nothing else in the EGR system was working correctly...

 

2)  Would an EGR delete cause detonation/pre ignition?  It seems to be occurring when the EGR "should" be closed anyways under load, but I need to really study up on how the EGR system works.  I have not ever had to tune or repair EGR systems beyond replacing parts on more modern setups...  THIS SEEMS TO BE THE MOST LIKELY CULPRIT.  

 

3)  More of a statement than a question, I am having issues sorting out exactly what valves are what in the vacuum line octopus mess.  You need to know what the valves are first, to even look them up in the FSM...  I need to replace all the obvious lines first, and then try and sort out what valves go to what.  My fuel pressure regulator is likely not hooked up correctly for starters.  For some reason that goes to a valve, and not straight to the intake.  

 

Timing belt and all that should be perfect.  I rolled the engine over 20x or so before putting the covers back on.  Everything stayed lined up (except the belt markings as they shift due to uneven teeth count etc).  

 

4)  I did notice one strange bit of behavior, the timing seemed to go the wrong direction, say from 10 to 12 instead of 10 to 8 when the jumper was removed.  Nothing was said about the TPS sensor in the FSM, but does this need to be fiddled at the same time like on the 22RE?  I probably need to go hunt down better timing directions than the FSM...  

[WME]

2 hours ago, thewanderlustking said:

 Would an EGR delete cause detonation/pre ignition?  It seems to be occurring when the EGR "should" be closed anyways under load, but I need to really study up on how the EGR system works.  I have not ever had to tune or repair EGR systems beyond replacing parts on more modern setups...

Maybe EGR will lower combustion temps

[thewanderlustking]

2 hours ago, WME said:

Maybe EGR will lower combustion temps

 

This is actually listed as one of the primary purposes as I deep dive into it.  I haven't found "proper delete kit instructions" yet, just posts on various forums.  I was hoping to see "you many need to retard timing afterwards" in the instructions to collaborate my theory.  I did find a random mention elsewhere that using EGR allows for more advanced timing.  So essentially the same thing.

 

Ironically all the posts I am reading by people that have specifically done this on the 3VZE, claim it runs perfectly and no mention of the timing needing to be retarded.  Fortunately this post here has some good delete instructions  that will actually help with reversing and hooking the valves back up correctly.  Including the FPR.  I just replaced a bunch of the vacuum lines.  I am going to apply this and fix those too and see what happens.  

 

Leaving the EGR off/alone for the moment.  Gonna tackle one piece at a time and see what helps and what doesn't.  But from what I am reading, the EGR does way more good, than harm.  I also saw mention that EGR cools the exhaust valves.   There really doesn't seem to be any reason to remove it, other than cleaning up the engine bay.  Or if it has failed...  Its starting to look like maybe my failure was just the EGR temp sensor.       

Edited March 16 by thewanderlustking

[thewanderlustking]

I did end up putting the EGR and PAIR systems back together.  I had to replace all the vacuum lines on both systems, and every other line one was either replaced, or repaired.  The idle up line (for AC/PS/etc) I didn't have the correct size for, so I silicone tape wrapped it.  

 

According to Toyota, EGR's purpose is to cool combustion and allow for more timing advance.  Specifically for better power and economy.  It also helps cool the exhaust valves.  PAIR is to help light off the 3way cat for better emissions (I think it mentioned NOX specifically).  I see no reason to disable either of these systems.  When I start to tune on MegaSquirt, I think I will need to disable PAIR temporarily, but I believe I can leave EGR enabled.

 

I am not sure the poor running issue was EGR/PAIR related though...  Timing was off.  Fixing the EGR and PAIR systems got it running better, but the last/biggest improvement was more time spent with the timing light.  I am set to 12 right now.  It wants more, but I think 12 is safe until I can get a good baseline.  

 

The Check Engine Light did come back on tonight.  I haven't pulled the codes yet with my expensive Toyota OBD1 scan tool (a paperclip).  I removed the resistor from the EGT sensor plug though and plugged it back in.  So I suspect that's why the light came back on.

 

Ironically, there actually are OBD1 "scan tools" for Toyota...  Most just are a fancy plug with a handle you pop in and then it shorts the jumper.  About 60-100 on eBay.  Kinda silly when a paperclip is free.  But, I did actually get one of my high end modern professional scan tools to connect and read actual PID data!  The jumper thing is a pain in the keister to get to work sometimes.  I am tempted to make up a diagnostic box that plugs in, lets you select the jumpers, reads battery/02 voltages, and accesses some of the other functions available on that plug.  There are a handful of pretty cool features on it!  For this to work, I need a converter plug that actually has all the pins populated...   

 

 

[extech]

i think the thermister in the egt is how this system knows egr is flowing. also excess egr can burn up the passages

[thewanderlustking]

Yes it is.

 

It's been a while and I forget the exact details, but I had owned the truck for maybe a year when the check Engine light came on.  Now I also remember seeing it come on when the gas level got low a couple times, then go back out.  This time was different, the tank wasn't low and the light stayed on.  I figured out the code and it pulled up something like EGR flow or thermister.  Details are fuzzy here but the diag flowchart had me check the thermistor and I think I found it unplugged.  Plugged it in, but the light came back on at some point.  I remembered the EGR delete kits came with resistors, so I stuffed one in there and the light stayed off until now.  

 

Again, I don't remember exactly what I found that day, but something I saw led me to believe the EGR system had been disabled.  Maybe the plug had been unplugged with a resistor in it, and the resistor had finally fallen out?  

 

Whatever the case, I want to get it sorted out and correctly working.  As you said too much flow can cause some ugly damage too.  I qm hoping the EGR temp is available in the data stream.  We shall know soon enough!!!