A2 experts, need help, 91 Golf, running issues.

Sounds like you need an O2 sensor or try replacing the blue coolant temperature sensor. It can cause all sorts of Digifant gremlins...

It is mounted on the cooling flange on the front of the engine. If you are looking at the engine compartment from the front of the car, it is in a black plastic flange between cylinders 3 and 4. Here is an easy trick to quickly test the sensor. The engine sensor is blue and the dashboard gauge sensor is black. Swap the connectors and see if the car runs better with the engine plugged into the dashboard sensor...

I have a similar problem. I've had it for a while; its been discussed here before. I tried swapping connectors and no dice. I currently drive my '91 Jetta with the temp sensor diconnected (ie open loop)

Sounds like the ignition system is wet and needs to try out. Might want to replace the dist. cap, rotor, and ignition wires.

There's more tha one belt. There are two (I think...I'd have to go out and look) belts under the hood that drive the alternator, A/C, and power steering. I think one is shared by two components and the other is standalone.

alternator belt.

All good ideas.

Never done it myself, but I believe it includes removing the water pump.

I think you have just a few issues that are probably fixable w/o too much trouble. The 1.8L 8V engine in these cars is tough and ages gracefully and doesn't seem to lose a lot of power either as it ages.

30000 | kms on them tho. Car has about 70000kms on it total, almost all stop and | start city driving, the last 25000kms have much more highway travel tho. | | When this car runs, it runs with so much strength and flexibility it makes | us not want to invest money in a newer car.... but when it runs like | this.... a newer car looks quite tempting. | |

The belt slip when wet might be able to be fixed with a splash shield available from the dealer for ~30USD. I had that problem and the shield took care of it. Gun a little wd40 on the dist cap before replacing to see if that helps displace any water. Stalling could be a temp sensor (~15USD).

One more thing you might check which plagued my 90 Jetta--the hose to the pcv valve had a hidden hole on the underside. Replacing it made a world of difference. It's a VW part with one big end and one small end to fit between the valve and a pipe. Also, make sure you don't need a new idle bypass. If the idle is searching, this is usually the problem.

The timing belt is not real difficult to change, but very difficult to adjust correctly. It takes a special wrench, and the instructions in the Bentley manual are really vague. If you get it wrong, it makes a terrible noise and you have to take everything apart and try it again. I'd suggest finding a friend who has done one successfully before you start.

Finally, after you get all the tuneup parts changed and the oil changed (pay careful attention to the weight specification--VWs want heavier oil than American cars), take it out on the highway and get it up to 100kph in third gear and drive about five miles. VWs do not like carbon buildup, and "mostly stop and go driving" will eventually make them run crappy.

Keep on the digifant tuning--once you get it all right, nothing runs smoother or better.

BTW, if it vibrates a lot at idle, change out the front motor mount. They're usually shot by 50-80,000 miles, but that oil-filled construction really damps the engine vibration when they're in good shape.

Pat Moore

85 Jetta (wrecked the 90...sob)

The hoses are fine, we inspect them routinely.

We don't even have a shop manual on this car, we might just get a mechanic to look at it.... I worry tho, can a snapped belt cause valve damage on an

8V VW?

The oil has just been changed 15kms ago :-).

Trust me, this car does NOT have carbon, I drive the the engine hard, using all the power from 2nd and 3rd gears routinely, not afraid to drop to 3rd gear on the highway to do some veyr loud passing maneuvers. And we use injector cleaner once a year.... The short hop driving is mainly my dad, I take the car out on the weekends and give it a thourough thrashing for him..... tho sometimes he will do it himself.

Nope...the 1.8 8V engine is a non-interference engine.

Because when this car runs without water in its engine bay it runs perfectly fine, and the VW dealer tested our O2 sensor a year ago when the car failed emissions, it had a lot of carbon on it. Cleaned it up, and it worked perfect..... I know how the engine reacts to a screwed up O2 sensor, it runs fine up to like 3000 rpm, then doesn't want to go anymore. With the sensor disconnected the car will run with a bit more punch, but it blows slight amounts of smoke and burns a LOT of gas.

Of course over the past year it COULD have died, but there is no indication of a failure.

I have no idea what a throttle switch is... the car's accelerator and throttle seems to work fine tho, as tested by my own personal feel for the car. The intake on the PS?? PS - power steering?? don't have that... what intake are you talking about here.

The throttle switches are located on the throttle body (on the intake manifold). There's a black rectangular box with a lever on it.

After re-reading my message, I admit I could have been more clear! The air intake has the inlet positioned close to the grill on the passenger side (ps) (in the Jetta at least).

How are things with the tune-up (have you performed one yet)? How's the negative battery terminal? Is the cable in good shape and is the ground clean? (preferably grounded on the block but it may ground to the upper tranny support).

Good luck! Darryl.

Yup.. there are two of them...an idle switch and a wide-open-throttle switch. They're on Digifant II cars. The 8V 1991-1992 G/J/GTI cars are Digifant I if built for California and they won't have them. Instead those use a throttle valve potentiometer.

Ahh the air intake... Seems fine, I don't really know where it is sucking air in, we clean out the airbox every 6-12 months, and get a new filter at least every year, so I think we are good in this department.

Rob,

You car is Digifant II....Canada never ever ever had Digifant I

- Peter

Right, for the G/J/GTIs although I think the Corrado G60s were Digi-I though.