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Wed Nov 09, 2005 1:45 pm

hey folks, hope you can help. 87 16v scirocco wont start- cranks over fine, has spark, fuel pump comes on when key is turned. Took it to a shop and they diagnosed it as a sticky air flow meter and they said they cleaned it and it started. Ran good for a week- now same symptoms-no start. I checked the Bentley and I took apart the airbox to get to the airflow meter and cleaned and lubed it. Also removed the fuel distributor and cleaned the control plunger (this was a bit sticky) still no start. I just want to get it running so I can get it back to the shop so they can fix it properly. Any ideas?

Sat Nov 12, 2005 9:16 am

Troubleshooting the 16V CIS-E setup really requires the Bentley Manual. Since you have it, I'm sure you've seen everything that I'm about to talk about in it. I've done a few of them over the years and it can take anywhere from a few minutes to hours to diagnose problems.

Did they hook this up to a CIS fuel pressure tester and verify pressures were correct?

Has anyone verified that the in-tank fuel transfer pump is working?

I'd also try verifying that the fuel distributor is working and that the injectors are spraying properly. This requires that you pull the injectors out of the head. Then you have to bypass the fuel pump relay to get the fuel pump to run all the time, then you have to have the rubber boot above the air flow meter flap off so you can pull up on the air flap with a pair of pliers to open it up. Then the you should hear a "rrreeeeeeeee" sound as flow goes out to the injectors. The injectors need to all start spraying about the same time, and about the same pattern. When they get old or gummed up, it may be that you'll have to run air flow meter all the way open and closed a few times to get good flow to the injectors. Uneven flow will be either the fuel distributor or the injectors, or both - on very rare occasions there might be something wrong with one of the fuel lines.

Something else that happens to 16V motors is that the seals inside the ignition distributor go bad. You say you have checked for spark, but I've seen it where the spark comes and goes because of this problem. With the distributor on its side, oil leaking into it will start to mess up the hall sending unit. Pop the distributor cap, remove the rotor and dust shield and see how oily/gunky it is in there. (Sometimes you can blast it out with electrical contact cleaner, or chlorinated brake parts cleaner (both are the same thing - tetrachloroethylene. But if that works, it's just a band-aid, not a fix)

There's other things that can go wrong too - the throttle position switches that tell the engine it's at idle and full throttle, I've seen them go bad and mess up the computer.

Bad connections and grounds in the fuel injection wiring harness can happen. A bad engine temperature sensor can have an effect. More rare but possible, are things like the knock sensor, as well as the potentiometer and control pressure regulator on the air flow meter.

-Andy

Fri Nov 18, 2005 9:58 am

Another big problem with C.I.S. is vacume leaks look at all the boots aswell asthe the injector seals, Have someone crank the motor and listen for whistling sounds!

Wed Nov 23, 2005 11:30 am

If you are going to take it back to the shop, you may want to find another place to take it, I think they really did not find the real problem.

The above ideas are great starting points! Get familure with all the compnets and the problem will pop out of nowhere!