the dreaded relapse

Longbeach412 · Post by **Longbeach412** » Fri Mar 18, 2005 5:52 pm

Ray!, where the heck you been

?! Glad you're back

Well, I guess the old sensor is trash now!! Funny, the new one has a thinner wire!. Hey Bill, its that small detail that gets you man......been trying to get to that sucker for a week now and it just didn't feel right. Well. back on it when the rain stops in "sunny" cali!

raygreenwood · Post by **raygreenwood** » Fri Mar 18, 2005 6:36 pm

I have not been able to get onto the forum since last week....something about " fatal error creating session...PHBB....What up with that? Ray

DeathBus · Post by **DeathBus** » Fri Mar 18, 2005 6:43 pm

you should come to the samba when that stuff happens

http://thesamba.com/vw/forum/viewforum.php?f=33

raygreenwood · Post by **raygreenwood** » Fri Mar 18, 2005 6:49 pm

Something screwy with their membership records. I went to register...they say the name is already in use and do is the password. It happened the very first and only time I tried to sign up too. I din't have time to mess with it. Missed you guys though. Ray

DeathBus · Post by **DeathBus** » Fri Mar 18, 2005 6:54 pm

WE REALLY missed you!

(doesnt it make you feel all warm and fuzzy?)

Guest · Post by **Guest** » Mon Mar 21, 2005 11:54 am

This is not getting any easier

.......Last night I removed the runners and placed the socket on the temp sensor with plenty of care........same crap!!.....the thing turns with ya about half a turn and binds! This afternoon I'll be taking the cooling tin off as well, to get a look at what the hell is going on in there

........But to be realistic, I don't expect this to slove the problem. Its beginning to look like it was installed wrong to start with. I have to start thinking about other alternatives, like can a helicoil be appropriate for this application? and, can the temp sensor be bypassed by grounding or wiring it to a dummy resistor?

Longbeach412 · Post by **Longbeach412** » Mon Mar 21, 2005 11:56 am

Crap! that was me

..........AND an update, I got the bugger out. at lunch time I gave it another try after soaking the bejesus out of it with WD40. that did the trick. It was aluminum binding against aluminum.! When the new one goes in, it will have anti sieze on it for sure.

Longbeach412 · Post by **Longbeach412** » Mon Mar 21, 2005 3:44 pm

Now that I got the old sensor out and testing it against the new, they both give out the same resistance!!

, So am wondering if the old one was just not seating right, and if so, might that have been caused by old anti sieze working as insulator??......hmmm.......waduall think, should I use anti sieze on the new sensor or go in dry?

raygreenwood · Post by **raygreenwood** » Tue Mar 22, 2005 3:01 pm

Check the art # on it....are there any letter codes? Ray

MGVWfan · Post by **MGVWfan** » Tue Mar 22, 2005 5:17 pm

Usa antisieze, and measure the resistance between the sensor's nut and the head, to be sure there's no problem. You should get zero (0) Ohms from the nut to the head. If there's a few Ohms or more, maybe the antisieze is insulating the sender from the head. I've never had trouble with antisieze causing something like that before, though...

raygreenwood · Post by **raygreenwood** » Tue Mar 22, 2005 5:26 pm

I'm really going off memory now...but I had thought at one time that there was more than one part # for the CHT...like an early and late....one with a letter code. But, I may be thinking of the ambient air temp sensor. But make sure of the part #. There were numerous D-jet cars ....some non VW...that used a basically identical sensor.
Also...when in doubt...since you cannot return electrical parts...re-crimp the connector on it...and check again. Or you have have a nice crimper, drop by the dealer and get a new factory style female terminal with the wire strain reliefs, and clip just theend off and check the wire and sensor...then crimp on a new terminal.
Just make sure you are not testing it from the ECU through the harness..to the sensor. And on taht note...the wire in the loom had better not be adding that much

. Also...tecnically this is a "modified" ground. Make very sure of your grounds everywhere.
Now.....just for giggles and grins...to see if this is the problem, attach a variable ceramet resistor to the wire in place of the sensor.....send the spare leg to ground. You can get a little blue one with 3 legs and a screw at radio shack for $7. Attache that in...cleanly, set it first with your VOM so....say 2100 Ohms.....see if it starts. Then 5 minutes in...turn it down to say 1000 ohms.....5 minutes....500 ohms.....stop around 270. Ray

Longbeach412 · Post by **Longbeach412** » Tue Mar 22, 2005 5:55 pm

Hey, just got here. I need time to digest these 3 last posts but, here are some updates: The new CHT is in, and the motor has been started. Remember, with the old CHT, it would start, idle great for a minute then slow, stunble and die. With the new CHT it starts, idles great for a minute then slows, stumbles and keeps on idling rough. So there is an improvement. My mechanic says check the Aux Air Device and I will next chance. But first I need to catch up on your posts guys. Some fleeting remarks; I know for a fact the codes on the old and new CHTs did not match, and the new one has a thinner wire, so I never needed to modify the socket. I just wound up the wire into a coil, iserted it into the socket and in it went

DeathBus · Post by **DeathBus** » Tue Mar 22, 2005 6:05 pm

Wouldnt a thinner wire denote the sensors inability to give a higher resistance rating?

MGVWfan · Post by **MGVWfan** » Tue Mar 22, 2005 8:11 pm

The difference in resistance of two short lengths of wire of different gauge is insignificant for this application...the current passed through the CHT sensor is only 10-15 mA, so the difference in voltage drop would be unmeasurable.

It's also likely the new sensor has a different insulation jacket, probably thinner.

Hmmm!

raygreenwood · Post by **raygreenwood** » Tue Mar 22, 2005 9:59 pm

Hmmmmm. I don't recall the conversation regarding having to modify the plug. It shouls have been a simple female connector , plugging straight into a T-1 male connector. It sounds like you had the wrong part.

Where it sounds like you are now....is running just slightly rich in baseline fuel mixture. Don't worry too much right now about the AAR. In 5-8 minutes from start-up, it should be totally closed and have no bearing on this. So start it, let it run for 5 minutes and then plug the hose so you get it out of the picture.

Now...still rumbleing? Like.....ever so slightly rising maybe 100-200 rpm over say 2 minutes...then back down so it sounds like it may die....but never does?

That can signify several things, mostly the fact that just a little too much fuel is being delivered at idle...and inconsistantly.

Electronically...this can stem from several things. (1) poor connections at the injectors themselves. While idleing, one at a time...put pressure on the indivicual injector plugs with your fingers. Inward, then side to side. Any changes or rumbles? (2) Fuel pressure stability. Get a really accurate gauge. They can be had from grainger for about $35 or less....ut it must not be more than 10-15 psi higher in range.....should be like 50 psi...and have 1/2 psi graduations. I posted a bunch of part #'s somwhere in t he type fourum back in like September. Part of this is a cycle. Fuel pressure is fluttering...idle changes slightly...so does vacuum....idle pressure changes more.

(3)This can also be small vacuum leaks...like advance chamber, injector seals or boots, or TB shaft seals. The car may be sensitive because you may be right on the edge of being to rich.
(4) This can be slop in the advance and distributor. Check it with a timing light. If it is hopping more than 2 degrees at idle...you need to tighten up the springs in the mechanical section, take some slack from the breaker plate.

(5) This could be caused by poor voltage to the FI system. Check the voltage at idle at the main relay.

(6) If your ambient air temp sensor is connected.....its that two wire sensor in the intake manifold....disconnect it. It should idle up about 200-300 rpm without it. It enriches about 5-10% across the board, but has poor heat transmission and heat banking properties. Most D and L cars run better without it. It would be much better if it had a vacuum switch to keep it out of the loop under say ....1500 rpm and out of the loop at all until ambient is above 85F. Ray