SOLVED: 1998 S70 base - rough idle, odor, undrivable (culprit was distributor cap) Topic is solved

[sleddriver]

Glad you figured it out! Frustrating, no doubt. While on the subject of ignition, check both the date & brand of the ignition wires. If they're more than 10yrs old and NOT Bougicord, replace them. Be carefull when installing new ones to keep them well away from the crank & camshaft position sensor wiring. You may also want to verify that wiring still has insulation on it.

[MagicBus]

I just picked up a new distributor cap from the store, just in case the old one is cracked and that's how moisture got in there.

With the engine running, lift the hood in the dark, see if you have a personal thunderstorm under the hood.

I did that the other day when I first suspected the ignition coil (it looks like I have a spare now). No such activity seen.

[MagicBus]

Glad you figured it out! Frustrating, no doubt. While on the subject of ignition, check both the date & brand of the ignition wires. If they're more than 10yrs old and NOT Bougicord, replace them. Be carefull when installing new ones to keep them well away from the crank & camshaft position sensor wiring. You may also want to verify that wiring still has insulation on it.

I installed them myself in September 2016. They are Bougicord and were brand new at the time. Whenever I buy a used car, I tend to do ALL maintenance items to get the car to a "0 mile" state in terms of maintenence as my starting point. This car was a slight exception. The timing belt was only halfway through its lifespan, and everything looked OK upon a visual inspection with the covers off, so I decided to wait on that.

[MagicBus]

Good deal.

You could also smear generous amounts of dielectric grease around the seal of the distributor cap.

I used to have that intake problem when working on the older "new beetles." Their intake boot is/was some sort of what felt like rubber and over time it deteriorates to the point where you have a fight to the death to get it on - just to find out it isn't sealing...

I'll check the cap for cracks today and seal it with something. I like the idea of dielectric as opposed to silicone. But. I'll need to stop and get some.

As for the intake boot, I really just didn't seat it properly nor clamp it down. Complete rookie mistake. Not a problem with the parts. Just my dumbassery.

[FLXC90]

Glad to hear you got it back to drivability. When I got my S70 a couple years ago, compression numbers were all over the place, and one was drastically low, like yours. I did two top-end seafoam treatments (sucked into the intake through the vacuum tree) about three days apart. Got all 5 around 175=180 with less than 10% variance.