engine running rough

[StephanieGA]

To refresh your memory. 87 Cabby. Top end engine work. Had initial trouble with timing. Seem to have taken care of the timing issue. She starts fine and runs great for a few minutes then all of a sudden, sounds like she's missing. Is there a sensor or something we need to check?

Any suggestions?

Stephanie in GA

[Calimus]

Steph, it could still be a timing issue. And by that I mean ignition time (distributor). Which should be set when the engine is warm. Loosen the bold on the dizzy so that it can be moved with a tad of effort, you don't want it so loose that it moves just with the engine movement. Once the car is warmed up, turn the dizzy either way and see if that improves the running once warm. Mark where it was originally so that you have a reference point. If that doesn't do the trick, then it's going to be a vacc leak or fuel related. It could be a sensor, but you will have to check all your connections to make sure they are all hooked up. Even then, there is the thermal sensor in the front coolant flange that can act up and cause some running issues.

Try the distributor and see what happens. Keep in mind, that moving the dizzy needs to be done in very smooth fine amounts. It's very easy to move it to far and end up with the car dying. Then you will have to move the dizzy back a bit and restart & try again. It's all a bit of a fine process and just for the record, no engine runs perfect with all timing parks set to perfect TDC. They all require fine tuning.

[StephanieGA]

Husband says not distributor. He's tried adjusting it when engine warm. Also, adjusted timing belt yesterday. Went one tooth either way and that didn't change it. Did find the cold start injector unplugged but that didn't fix it either. Must have bumped it when checking earlier. He says it actually sounds like it is missing. Starts up and runs fine at first but then acts like it is running on 3 cylinders. Girl has been without her car for about 2 months now. Can't find trusty VW mechanic nearby.

Guess will start looking for vaccum leaks.

Stephanie in Ga

[Briano1234]

Well verify that you are sparking to each cylinder, as I did get 2 bad sets of plugs from Bosch...Plus had a bad spark wire....

I had replaced the spark wires and bought a new set of Bosch plat 2's... put them on all at the same time and it was worse.... It wasn't until I could swap caps and wires between my cars that I knew the wires were good.

Ohming out the Spark plugs showed 3 bad new ones... take them back get another set, but ohming them before putting them in and had another bad one.

Switch to ngk, and presto rabbit running.....

Now all told in my life I have had 4 sets of bad plugs, 2 Champion, 2 Bosch. Champion paid for a engine rebuild... Bosch's didn't get ingested into the engine.

[StephanieGA]

Definitely something to look into, but would it run smoothly at first if it was plugs or wires? Hubby says it runs like a dream right after starting it and then it is like someone flips a switch and it is running on 3 cylinders.

Stephanie in GA

[Briano1234]

Well cold you are running Rich...by nature, then as it warms then I would suspect that you are looking at the 02, duty cycle....
But I don't no BO-Diddley about CIS as it is from the DEVIL.

[kamzcab86]

Things to check:
Auxiliary air regulator: If it doesn't close by engine operating temperature, you'll have a massive air leak.

OXS thermo switch: If the switch doesn't close by engine operating temperature, the car will remain in cold-running enrichment mode, when it should be in closed loop mode. Test the oxygen sensor system as outlined here: http://www.cabby-info.com/cis.htm .

Warm control pressure: If the warm control (fuel) pressure is too high or too low when the engine is at operating temperature, the car won't run well. (Control pressure is dictated by the control pressure regulator.)

[StephanieGA]

We're doing much better and the girl finally got to drive her car to school this morning for the first time in about 2 months. Seems the residual rough idle was vacuum leaks. And a loose fuel injector. Got new seals on the way which will hopefully take care of the fuel injector issue.

Now we have a noisy water pump, we think, either that or the power steering pump. Wasn't doing it before but it is now. Yay, always something.

List just keeps getting longer

Gotta get the heat going
Fix the exhaust leak due to the missing clamp
replace all the worn out shifter parts
NEW TOP
AC for next year
windshield washer working
new seat covers on front and rear

It's a good thing we love this little car.

Stephanie in GA

[Briano1234]

I wished Dyson made the dub, we would never have a vacuum leak

[Calimus]

Steph, glad to hear you got things sorted out. An though it seems like you have quite a list, it's really not bad. As for the pump noise, make sure it's not the timing belt tensioner. If you tighten the timing belt too much it will make a hell of a whine almost like a supercharger. There should be a little bit of belt deflection on the timing belt. If that's not it, then it certainly could be one of the pumps.

Brian, you have a point, but if Dyson did indeed make the dubs, we would have a problem with the cars sucking up small animals & children. Would make for some interesting hood ornaments though.

[gull]

I wished Dyson made the dub, we would never have a vacuum leak

But then it'd really suck.