[T3] I've got another question , same one I asked a while back.

[jude]

 Jim :

  From what I recall when I had the temp sensor plugged it and the idle set at 1000 RPM in park auto trans the what I call erratic miss and struggle exists or returns. It’s difficult to describe. If I have the sensor connected and the car is in park sitting in the drivers seat idle @1000 RPM and slowly push down the gas pedal I watch the tach I have on the dash ,what I see is once the RPM reaches about 1200 RPM the rpm reading on the tach begins to climb up then I see the needle begin to rise and fall 200 to 300 RPM it then gets worse @ 2000 RPM meaning the RPM swing is still 200 to 300 RPM yet swings at a faster rate. Then when it hits 2200 RPM this swing stops. It stands out when I try to see what the charging system puts out at idle and then 2000 RPM. I also hear the engine RPM going up and down to rule out the tach. I cannot hold it at a steady RPM in that RPM range. If I drive it like this since now there is a load I don’t notice this at all. It does not surge or buck. Yet while driving this way or in park and give it gas and let off it pops out the exhaust which may be due to the exhaust leak I mentioned in the other post. With the sensor connected I also hear as well as feel this miss at the exhaust pipe, I call it erratic because it’s not a steady one cylinder miss like a wire or plug and I don’t feel it while driving . 

  A while back dealing with this I checked all the FI grounds and found a few issues and once I fixed them it was 75% better then it came back the next drive , thought I had it pinned down. 

 From what I’ve read the IAD temp sensor unplugged ad’s 10% enrichment across the board , what is confusing if this is true and with an exhaust leak allowing air the popping should get worse yet it just stops it’s allowing more unburnt fuel into the muffler. I don’t get a load back fire just a slight popping sound on a rapid decel.  

 I am not sure if an exhaust leak in my case cyl 1 & 2 and considering firing order 1,4,3 2 if this leak can affect cyl 4 or 3 or both. Since if cyl 1 fires and it’s exhaust valve is open cyl #4 is on intake open if this exhaust leak can lean out # 4 since the leak is far from the head yet before any back pressure the muffler might add. I’ve tried to find info on this yet end up with modern cars exhaust systems .  Seems the only way to know is repair the exhaust leaks . I can say this leak has been there for a good long time and yes the engine had less miles yet it didn’t do this. It all started in 2009 when I removed the  EMPI J pipes and installed the heat exchangers , if the J pipes still had a leak at the same spot at least I think it did been so long I don’t recall . I say it may not have had the leak since the J pipes were not rusted where the header fits. I still have them and they measure the same OD as do the header measure the same ID . With that said perhaps the exhaust leak presents an issue . I will know when I have the header off and check their fit . You said to use a muffler sealer instead of the Permatex ultra copper which is real high temp silicone . Is the reason temp related or is a muffler sealer metal based so the heat is transferred from the HE to the header ?


 Yes if you have the advance unit let me know the cost. This may help at least to improve MPG. 

 William

Sent from Mail for Windows 10

From: Jim Adney
Sent: Friday, July 20, 2018 4:10 AM
To: type3 at vwtype3.org
Subject: Re: [T3] I've got another question , same one I asked a while back.

On 15 Jul 2018 at 14:03, William Jahn wrote:

>  I noticed when I was fixing the cold start valve hose in the parking lot
> that I have the temp sensor in the IAD un plugged . I did this because if
> it was plugged in the engine struggled between 1000 RPM and 2200 RPM if it
> was in park. By struggle I mean the rpm was not a smooth climb it would
> sort of hang and drop between the rpm range above. It also had a miss fire
> at idle , not a back fire but an erratic miss .

This sounds sort of like the loping idle you get if the idle speed is set too 
high. Try plugging the temp sensor back in and then turning the idle screw 
down to see if this cures it.

> I do know all for runner short hoses are oily, I have new ones yet not
> the intake gaskets . I have read one can replace the paper on the
> intake spacer . I thought of pushing back the old oily short hoses and
> removing the IAD without removing the runners . It's possible yet does
> not look easy . 

I see no reason to remove the IAD. Why not leave the IAD and pull the 
runners, so you can inspect the intake gaskets. If the gaskets are the correct 
brown plastic ones but need paper faces, fix that. If they are the metal Beetle 
ones, I have the correct FI ones. When you put everything back together, 
loosen everything and make sure the runners line up with the IAD ports 
perfectly.

Unless the short hoses have been badly distorted by poor alignment of the 
runners to the IAD ports, they are not likely to be a problem. Oily is normal.

BTW, I came across an old email from you that said you wanted a 
replacement 505 vac advance can. I have one now. Do you still want one?

-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************

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