1995 Eurovan Camper T4 Engine Problems
Straight 5 SOHC 10V 2.461 cm3
2.5L(ACU) 5cyl 5spd manual ~170k miles
I have been fighting trying to diagnose this engine problem for a while and have got no solution. So here is what it does, when driving if you lug the engine down, maybe to about 2000 rpm the engine shutters and sputters. If you press the accelerator more when it is doing this it will stop shuttering and sputtering but it will loose all power and coast down to about 1000 where the shuttering and sputtering will return. If you wind the engine up higher using shift points of about 4000 rpm you can get the van up to 60 mph. If you do the same using shift points of 2500 rpm it will shutter and sputter in third gear and you cannot go any faster. This is all for a flat road, if the grade is steeper it will happen in a lower gear or at a lower speed and rpm, and vice versa for a down hill grade. The road to my house is very steep and I must have it at 3000 rpm to get it to make it up my hill, if I try at a lower rpm it will shutter and sputter and not make it. It never did this before, you could lug it down and it would power through. It is also difficult to start usually taking about three tries to get started. Prior it would always start on the first try.
So here is what I looked at and replaced in sequence to determine the problem but to no avail.
VW
When this happened I was about 150 miles from my house I thought I might have got bad gas so I put some fuel drier and fuel injector cleaner in the tank. This did not help. I drove it the 150 miles or so back to my house and put more fuel into it with no improvement.
When I got home I put a new fuel filter on it. No improvement.
I put a new cap and rotor on it. No improvement.
I replaced the throttle position sensor. No improvement.
I tested all the spark plug wires and all the spark plugs and they all looked fine. All the spark plugs looked fine with no fouling, all had a nice white clean apperance. They were all properly torqued and seemed fine. I pulled the distributor and it looked fine. I shot it with a timing light and it was about 6 degrees advanced at 2000 rpm. I tested the Idle air control vavle and it cycles under 12v power. I removed the throller and cleaned and inspected and no problems. I checked the temperature sensors and they all seemed fine. The engine will shutter and sputter when the engine is cold and when it started happening the engine was hot so I do not think temperature has anything to do with it.
I vaged it with a chinese vag-com each time I did any testing and got a few codes but they were all bogus. Once it said intake air temp (code #00523), I pulled it tested it and cleared it and it has not came back. Once it said intake manifold air pressure (code #00519), checked all vacuum hoses and cleared the code and it has not came back. I had replaced all the vaccum hoses about 1 year ago when I did the clutch, so they are all in very good condition.
The only problem I know of is the kombi valve leaks a little and it melted the air check valve prior to it, so I have a gaskest blocking off the combi valve and the SAIP is not connected.
I am running out of things to test.
Any good ideas?
Franks