another Eberspacher thread... must be winter somewhere !

[MGVWfan]

Back from Norfolk yet Shawn?

[rickycox]

back from Xmas hols....Eber was fine on a run so I think it must be overheat switch... for now i'll run the Eber just once up to speed etc...

But !!!

on the way home after about 150 miles the car wouldn't idle ( stalled if I didn't keep blipping it ) . And today when I went out to start it it wouldn't fire !! I'm thinking I need to check valve clearance... as everything else looks fine....

[raygreenwood]

Valve clearance will not cause a stalling issue. It can cause rough idle when injection/ignition timing is borderline. Check your fuel pressure and check your CHT. Also what is the ambient air temp when this happens? Depending on what your fuel mixture baseline is...in many winter situations the ambient air temp sensor should be disconnected for the winter duration ...unless you want to make tweeks to the MPS. Ray

[rickycox]

ok...what does that sensor look like / location Ray ?

[raygreenwood]

It is a two wire sensor that screws into the drivers side of the intake air plenum just forward of the #3 intake runner.
This sensor has several problems (a) because of its aluminum body and very small mass, it actually tends to bank heat pulled from the hot metal of the plenum in hot weather. So in some very hot climates its reading may not really be that accurate with reference to the ambient air temps running through the intake. (b) They can get a little off with age (c) the sensor gives an overall 5-10% or maybe 5-15%....across the board enrichment boost. So....if the outside winter air is cooler...you already have some enrichment boost from your CHT sensor which may not end up down at the usual 70-100 ohms. Add 5-10% extra enrichment in from the sensor sensing very cold air....and add that to any adjustments to MPS setttings and fuel pressure that maybe run quite well generally but are not perfect....and you can get just enough enrichment to cause this problem in the winter with that sensor. If when it starts doing this again....if you simply unplug that sensor and it idles up by about 200-300 rpm....just idle it backdown, see how it drives and see if it starts up normally when its cold later. If so, leave it unplugged until the weather warms up. Ray

[rickycox]

cheers Ray..... update is i cant get the car to fire at all at the moment !! not since the stalling on idle problem whilst driving home ( long drive in very cold weather )

i'll investigate more...very annoying with a foot of snow forecast !!

[raygreenwood]

Check several things first:
First check the resistance of each side of the injector trigger points (this is D-jet right?), then if turning theengine over by hand while checking each side (key off) insures that both sets of points are working, then check teh reistance. Nothing higher than 1.2 ohms per set and hopefully no more than .2-.3 ohms difference between the two. If both sets operate, high resistance should not stop you, it just may make a rough idle.
Check the main ground bundle on the case centerline under the plenum.
If all of this is fine, it means that technically when you try to start it you should be getting injection.
That being said....if you were running rich to start with, and it very cold and you have too much fuel in the ports...you may technically be flooded. Pull either #3 or #1 plug and check to see if they are wet or gassy smelling.

Put a pressure gauge on the fuel line and bump the key over 2-3 times...do not try to start it yet, just rev the fuel pump to build pressure. Go inside for 15 minutes and have a beer. When you come back out.....if the residual fuel pressure has dropped too much lower than about 18 psi, thats a bit too fast and you might have either a leaking check valve on the fuel pump or fuel pressure regulator.....both of which will allow you to start if you rev the key up a few times to build pressure.........but if your plugs were wet, then this means that either the cold start valve or one or more of your injectors are leaking down.

A warning on this condition:

Warning Warning!

If your outside weather conditions are much below say....25F......and you have a D-jet injected vehicle and have not recently treated it for fuel line water.....you can crack injectors. The design of tank, pump and filter system on D-jet is very suceptable to recirculating water and not getting it out of the system quickly. In very cold weather it can first maniferst itself by forming ice pellets that clog the pump and filter. If the water droplets are already past the pump and filter before the temp drops...and they are in the injector itself...it can crack teh injector (actually it just pushes teh palstic cap out the back....or cause the pintle to push open venting residual pressure and flodding the engine....as well as making that injector inoperative until thawed. I'm notsaying this is your problem....just that its happed to me before. It happened to be about 15 degrees outside in Oklahoma City with my first 411. It had an excessiv amount of water in teh system....I had just gotten it and it sat for quite some time with very little driving at its previous owners. We got a cold snap the third week I owned it. It cracked all 4 injectors and about 8 feet of fuel line. Ray

[MGVWfan]

Never heard that one before, though it sounds plausible Ray...wow!

Good luck with the troubleshooting, Ricky, hopefully it's something simple like a coil (happened to me last year)...they can go bad partially, leaving you with misfiring, then open up completely and fail to start at all.

[raygreenwood]

Oh....it is more than plausible..
It was my first car and my first mechanical experience with no knowledge whatsoever. I had just been given a 1972 411 four door....with 55k miles on it ! My dad bought it from someone going TDY in his army unit...for $500!

So I just got my license and we get a cold snap. I can well remember the three days on my back in coveralls with teh outside temperature finally getting down to about 5F...and the floor temp somewhere around freezing or less, trying not to blow up the garage from all the fuel dripping from my cracked injectors or lines. I had to borrow from dad to buy four rebuilt injectors at $45 each.

I thought I learned from that experience but the next cold snap a year later got me ice pellets in the fuel line that blocked the Ebers suction from the little plastic accumulator in the return line. Keeping water out of teh fuel is a full time job in places that having wide rangeing weather (wet/dry and hot/cold).
CIS injection can also be quite sensitive to water in the system depending upon how the in-tank pick-up is designed. Ray