No Start aftering replacing Dist Cap and Rotor

[ausgezeichnet]

Just replaced the distributor cap and rotor on my 84 Carrera. Now when I turn the engine over it does not fire. All I get is a few coughs but not near enough to start. So, I screwed some thing up.

Here is what I've checked:

I checked and double-checked the correct spark plug wires were on the correct spot on the cap. Both by they way they originally were on the car and by matching the cylinder number on the top of the cap to the actual cylinder.

I also double-checked to make sure all the spark plug wires were fully seated on both the distributor end and spark plug end.

I made sure the new rotor was installed in the same position as the old one.

I made sure the cap was installed in the same position as the old one.

Here are a few things that don't seem right:

The first time I installed the cap I had to push the retaining screws very hard so the cap was VERY snug. When I removed the cap it looked like the rotor was rubbing on the inside top of the dist cap. I think the rotation of the distributor cap was off slightly when I put it on the first time and not seated properly. I was more careful to re-install the cap and check it so I think it is on correctly now. Not sure if I damaged the rotor or the cap so that it will not start.

I had to pull on the spark plug wires extremely hard to get the wires off the top of the cap. I may have screwed up the wires by pulling on them too hard.

When I checked the spark plug wires on the spark plug side, I could wiggle them back and forth when holding them at the point of the wire were you grab it to push it onto the spark plug. Is this normal?

What is the best way to keep diagnosing this problem? I think it might be to check to see if I am getting spark. What is the easiest way to check to see if I am getting spark in each plug? Or getting juice from the coil? Thanks.

[slater]

To check for spark, pull a plug out, stick it in the end of the wire, and hold the side against a conductive surface and watch for spark as a buddy cranks the engine. You should be able to see a spark. Did you double check to make sure it is the right rotor? Is it making contact with the cap correctly? You said it was rubbing on the inside top of the cap- where was it rubbing at, it is supposed to touch the small spring-loaded piece in the top center. Is there any chance you knocked your points out of wack when you were doing the install?
It is pretty normal to have to give a good tug on the wires to get the off the cap, and the plug ends do wiggle a bit even when they are on (at least they do on mine).


EDIT- You may want to wear some gloves while checking for spark! (ask me how I know!)

[Tigerrat]

Assuming the car ran with the old parts you are at the point I'd back up and put the old ones on to see what happens. Especially since you've raised some questions about fit. Ken

[Gunter]

It sounds like something got screwed up with the cap sitting in the wrong position. There is a cut-out on the edge of the distributor body which mates with the cap. Look closely at the inside center of the cap and check the spring-loaded black contact which is supposed to ride on top of the rotor when the cap is in the right position. Re-check the wires for the correct firing order with the cap in the right position!
You can use dielectric grease, or Vaseline, to make it easier to fit the ignition wires. Make sure that the Beru connectors sit on the spark plug correctly; they kind of "snap" on.

[ausgezeichnet]

I just checked and I am getting spark from each wire using the technique Slater suggessted. It is a nice blue spark. I assume this means the coil, distribtor cap, rotor and wires seem to be connected OK.

Slater: The rubbing on the inside of the cap was in the center. The red plastic part surrounding the lead from the coil was rubbing on top of the center of the rotor. The top of the outer edge of the rotor was also rubbing on the top of the inside of the dist cap.

Gunter: I found the cut out and made sure it was positioned properly.

Tigerrat: That is a good idea I'll try unless some one else has another suggestion since I verified I am getting spark.

I am still not too comfortable with the plug wires. They do not seem to seat well. They are red Nology wires which the PO installed. I have no idea how old they are. Are those wires any good? They don't seem to have a god reputation on this board. I May just replace them with Clewetts.

Thanks.

[ausgezeichnet]

Well at least I have it running now. But is is running very rough. I think one of the cylinders is not firing. I think I may have installed the rotor 180 degrees off which is why it was probally rubbing.

[stlrj]

You're still not getting the firing order right. Check it again.

All it takes is having one wire swapped and you end up with two plugs missfiring!

I've done that too many times to know how easy it is to do.

-Joe

[no substitute]

1-6-2-4-3-5.
Cap fits correctly one way only. Same with rotor.

[stlrj]

You may have the wires right on the cap but may have lost track of one as they go over to the right side of the engine behind the fan.

That's where I have been known to get it wrong.

[Steve87-911]

If it turns out to be that the wires are on wrong, there are tiny numbers on the bosch cap that tell you which wire goes where.

Next time you might label the wires as they come off. Or you can sort of leave the wires on the old cap (remove the heater blower intake duct first) move the old cap out of the way a tad, shove on the new cap and then one by one replace the wires from the old cap to the new. And to get the wires off you should twist them a bit and then pull straight out (which ain't so easy) and don't wiggle them around.

Some people even take a picture first so they don't screw up. I don't know what kinda dork needs to do that though.

[Gunter]

Ausgezeichnet: From what you describe, the rotor may have been put on wrong; it has to sit deep in the cut-out of the distributor shaft. There is a "nose" inside the rotor which fits into the cut-out. Follow each wire from cap to plug, going with the distr.-rotation and firing order. I found that sometimes, when the plug connector does not sit correctly on the plug, the spark will go to ground instead of going through the plug. Maybe your new cap/rotor got damaged when it was put on wrong?

[ausgezeichnet]

Thanks guys. It turns out I did not have the plug wires making a good connection on the spark plugs.

I really had to play with them to get them seated properly. Is it typical to need to make several attempts to get the spark plug wire seated properly? I was able to feel the tip of the plug to make sure it was not loose and all the spark plugs seemed snug.

I also reconnected the green wire to the part below that had been knocked off. Any one know what it is?

[jacko241]

Oil pressure sending unit

[Gunter]

Originally posted by Gunter
I found that sometimes, when the plug connector does not sit correctly on the plug, the spark will go to ground instead of going through the plug. Maybe your new cap/rotor got damaged when it was put on wrong? [/B]

Well, good, you found it!

That wire is for the oil pressure sender. There are two units for oil pressure: One is in the back on top of the engine to activate the oil warning light in the dash, the one in your picture is the sender showing the actual pressure.
Underneath the oil pressure sender in your picture is the oil temperature sender.

[ausgezeichnet]

It's running pretty good now except for acellerating in the 1400 - 2000 RPM range. The whole back of the car shakes like it is only firing on 5 cylnders. Above 2000 it runs fine. Below 1400 including Idle it runs fine. Runs this way hot or cold no difference. Any thoughts on what might be causing this?

[stlrj]

You might still have a plug connector that was not fully seated on the spark plug and has slipped off. Or one of your plugs may have gone bad when it wasn't firing when you found a loose plug connector.

-Joe

[ruf-porsche]

You need to find out which cylinder is miss firing.

Could be a bad wire, bad plugs, bad injector or the valves for that cylinder may be too tight.

[Gunter]

It sounds like one cyl is still not firing. If you have courage, and be REAL careful, you can pull off each ignition wire with the engine idling and the one that is not firing will show up. But, the Voltage on these things is real high! You would have to wear insulated rubber gloves and don't stand in a puddle! Stand on dry plywood. Also, if you have AC, don't get caught in the AC belt when you get zapped! Also, sometime after dark, open the lid and you might see where the spark is jumping from the wire to ground. Cheers.

[ausgezeichnet]

Thanks for the feedback. Would any of your suggestion explain why the problem only occurs in a limited RPM range?

I noticed another symptom today. I took it out for spin and all of a sudden the engine died while I was stopped at a street light. All the warning lights came on just like when you turn the key before cranking it over. When I tried to start it again I got the same results as when I had the rotor in backwards, the engine just cranked with out firing. I finally got it started after about 10 minutes. It died the same way a few more times (while idling).

This is a puzzling one. Since I may have damaged the rotor, I am going to replace it. Next I will replace the spark plugs (don't know how old the current ones are), then I will replace the spark plug wires. Hopefully one of those actions will take care of it. We will see.....

[Gunter]

You may also have a bad connector; these connectors have a small resistance (1 Ohm?) and it shows up more at low RPMS. Before you take out the plugs, blow out the holes with compressed air to prevent any dirt from falling into the cylinders. Most people go with copper plugs, not platinum. If the ignition wires are old, replace them. New rotor is good but the cap may also be damaged; look closely at the sprig-loaded center which rides on the rotor.