Idle Problems with 83.5-85 Water Boxer 1.9l

We talked last time about idle problems and the Vanagon. However I was focusing on problems that the later model vans have. In this newsletter I want to take a look at the idle problems that the earlier 1.9l digijet vans can have.

We spoke about the idle switch being properly adjusted. The 83.5-84 vans have two switches one for idle and the other for full throttle. These can be tested at the switch with an ohm meter. Basically you want to see zero resistance at the switch when it is in the closed position.

The upper switch is for idle and the lower is for full throttle. If the idle switch isn't closing at idle position you can adjust a screw until the switch closes.

I have had the idle stabilizer unit that is on the firewall be the cause of a fluctating idle as well. This is a small plastic box that has two round plugs going into it and is mounted near the coil. Unplug the two plugs and plug them to each other (you need to do this to time the van properly). If the idle is steady then your idle stabilizer unit is probably bad. If the idle is still lumpy then you are probably looking at a vacuum leak.

If the switch is working properly and you are still having a bad idle then you are going to check your timing with a timing light. I like to set the timing to 7 degrees BTDC. I know the book says 5 degrees ATDC but I have found that the 1.9l Engine runs crappy at this setting. I have found you can safely advance the timing to the same setting as the 2.1l Vanagons with no ill effects. In fact usually it increases your horsepower and smooths out the idle. Then adjust your rpms down by turning the idle air screw (large slotted screw on the top of the throttle body) in a little. Count your turns so that you can put the screw back to where you had it originally if need to.

Next I would check your manifold pressure (vacuum) at idle. It should be around 15"Hg at idle and the needle should be steady (no vibrating or fluctuating). If your vacuum is low or the needle is vibrating then you probably have a valve issue that is causing your idle problem. Double check your valve adjustment. The Bentley manual is acutally wrong on the proper adjustment of valves. I normally set mine to zero lash (the adjustment screw is just touching the valve stem at TDC on each cylinder).

You want to be sure that you have no vacuum leaks in the intake system as this can cause unsteady idle in the 1.9l. You can get some starting fluid and while the van is running you can spray around the engine compartment at the intake hoses. If the idle goes up then you may have a leak in that area where you are spraying.

If the Air Flow Meter is worn out this can cause a poor idle. Usually this is more of a rough running at idle than a wildly swinging idle. The only way to really troubleshoot this is to swap in a known good AFM from another 1.9l Vanagon. If your is really old and has a lot of time on it and you have tried all of the other troubleshooting you might want to buy a rebuilt unit. I have these in stock if you find you need one.

Finally the Temp II sensor for the fuel injection can throw things off. This sensor is located in the thermostat housing and has a blue plug on it. You can test this sensor with a chart from the Bentley manual and an ohm meter. If the sensor tests OK, I would test the ground for the sensor and the wiring to the ECU with an ohm meter as well. I have found that the wiring on the older vans is getting fatigued with age and can have bad spots in it. If you find a bad spot you should be able to cut it out and splice in a new piece of wire pretty easily.

Email me and let me know if this write up helps you with this issue.

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Clearance

Fall is also a great time to get some great deals on parts here at Van-Again We are looking at some parts that we have had sitting around for a while that would probably have a better home installed on your van and we are slashing prices to get them there. Here is a list of things that are close-outs and specials that is only being advertised through this email list:

Brown sliding door interior panels for all Vanagons 84-87 with brown/tan interior.- $199 (SOLD)



Performance Digijet ECU- $250 (1 left) This ECU is a brand new VW unit that was made for 2.2l water boxers that were sold in Europe. It has a more aggressive fuel map which should give you some more power out of either a 1.9l engine or a larger water boxer that is using the Digijet fuel injection system. This system was used in 83.5-85 1.9l Water boxers only here in the US.

Vanagon front heater core- $199

Diesel VW Rabbit/Jetta/Vanagon Fuel Pump (brand new)- $695

We will be updating and changing our list of clearance parts as we sell things and stumble across other items. Since these are clearance items they are NOT available through the webstore. Email us or call if you are interested.

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