duowing

Ok I know I'm starting another thread here, but this is just a weird thing I came across. I was trying to figure out the cause of my miss. So I start checking the plug wires, timing, etc. Finally I notice 6 is a bit different than the rest, so I pull the cap.



Well I've never really paid much attention to the dizzy cap before so everything looks fine, then I go and compare it to another cap I have:



I notice that I have pretty much no middle contact point. Is it that this thing broke, or does the rotor just slowly wear it down? Anyway I'm gonna go get a new cap and rotor, and hopefully that'll take care of my miss.

NismoPick

Holy shat.... That could definitely cause an ignition prob.

nismo619

There is somthing missing from the top rotor cap looks like the center eletrode thats supose to touch the rotor it self. Could it of broken off and got into the distributor ?

NismoPick

Could have broke or worn down. I think it's spring loaded????

duowing

Yeah they are spring loaded, still seems weird that it'd grind it down that much. Either that or the previous owner never did actually put a new cap on. Although the rotor does look a little banged up.


Mainly around the plastic center edges of the rotor.

Kind of hard to tell from the pics, but it looks worse up close.

NismoPick

As long as the rotor contacts (tip and center) are clean, it's ok.

Bruce_Aldridge

I tuned up a 79 Dodge Ramcharger some years ago, it ran so bad when I was finished that I had to send it to the shop. Thirty minutes later I got a call saying it was fixed. Turned out the new cap was missing part of the center electrode and a couple of the outside one completely. Since then I always check visually before installing! And A new part is always suspect until it proves itself!

z-hag

dayummmmm......the ones in my old 75 luv truk used to do that kind of thing at exCTLY 3001 MILES AFTER ESACH TUNE UPoops.......and stop running, not start....all kinds of fun tricks.......whew.....

Bruce_Aldridge

Did your Luv truck have to get warm for the head lights to work? They did do all sorts of fun things.

duowing

Alright cap didn't change anything, and I pulled my plugs to check. I'm not good with this ignition stuff, but to me this looks like the signs of too much fuel maybe?





I tried to get decent pictures, taking pics of spark plugs is not easy. They look like at least from what I can tell maybe too much fuel, but I don't think it would be enough to cause a spark issue.

duowing

Well, I'm waiting for my new Rotor to get here, I got my new cap, but I was messing around with the old rotor and cap. I noticed that if I placed the rotor in the middle of the cap, just as it should sit together on the shaft with the cap on. The rotor doesn't touch any of the contact points in the cap, there is some gap in between the rotor and points. The rotor's tip also does look a bit worn down, and kinda singed.

NismoPick

The rotor tip shouldn't TOUCH the cap contacts... you'd have a lot of metal shavings really quick if it did. The spark jumps the gap (just like the spark plugs).

duowing

I'm in eternal confusion with this car. The oil dipstick doesn't seal properly so it is causing a vacuum leak, because when I put my finger over the tubing for the dipstick the engine speed just slightly raises, but then when I use my timing light, my timing mark for the number 1 spark plug starts bouncing around where otherwise it stays perfectly smooth if the oil dipstick tube isn't plugged.

I went ahead and pulled a vacuum line to spray cleaner at just so I'd know how the engine would sound when there's a leak, and you can hear the engine speed lower and the idle corrects itself, but I can't find any spots that seem to follow this pattern. How much change in engine speed should the dipstick tube being sealed and unsealed cause? If I pull the oil filler cap that causes a big difference. I can't figure this out. Is it possible I have a leak at the intake manifold gasket that's small enough to affect my engine but, not enough to be caught by my spray?

thxone

I say the dip stick causes more of a problem on the N/A engines but yeah I would still seal it up better...I used tape around rubber part of the stick itself and it fixed my leak, makes it a little hard to put back in but it seals up....of course you could always look for a new dipstick.

z-hag

the truk i luv'd to hate went over grapevine @25 mph==took cat and put pipe thru.......55-75!!!
headlites worked too well-kept leaving them on after work and having ded batt.....but got me to races and back--laguna seca, riverside,sears point, and holtville......quite nicely............never again.........




sorry bout the threadjack, sugah.....

duowing

Well I put some silicone sealant on my dipstick to see if that would help. It seems to. Anyway here's one thing I noticed. When my car is in Park or Neutral, the timing mark bounces some for the 6th cylinder, but when I have the car in Drive the mark seems to sit more smoothly. It may also be contributed to the fact that I sealed up the intake leak around the dipstick. I'm also wondering if maybe the Z31 ECU will just fix some issues. Also I still don't know where that factory splice is that nismopick mentioned that's in the wiring harness for the ground wires. I'm trying to find that so I can fix it and just make sure I don't have an issue there.

NismoPick

6th cylinder??? You always use cylinder #1 to set timing.

It's the bottom ecu plug, bottom (or almost bottom) black wires. If you unravel the electrical tape you will see about 2 inches into the harness a splice for ground wires. Mine was corroded, brittle, and half of the strands were already broken. I cut out that entire section & soldered in some new wire.

duowing

Alright one last thing to go along with this. I've noticed that when I pull my plugs the threads seem kind of wet, I think oily. It looks like oil, but the electrode and upper part of the plug look fine, and look more like a normal plug with no signs of oil on it. I was searching. On HybridZ someone said that this is a sign of worn piston rings, but I've seen in a few other places that this could just be related to the valve cover gasket? Also I noticed what looks like possibly some oil around my valve cover, but it hasn't gotten any more wet or made any more marks.



I got a new valve cover gasket, so I'll replace that, I just hope that I don't actually have worn rings...I've had this issue since I got the car, and we did do a compression test at one point which showed no problem.

duowing

Is that splice inside the cabin? Because I started pulling away alot of the electrical tape and I can't seem to find a splice, they're 3 separate wires at least as far as I can tell, and they run separate for a while. Or at least out into the engine bay.

duowing

I went ahead and replaced my valve cover gasket today. I think it was 3, it might have been 4 of the bolts, but they weren't tight at all. I put the wrench on them to loosen them and they just spun with no problem. I don't know why they were left like that, but it looked like the gasket had been replaced before as it was in pretty decent condition, and it all came out in one piece with next to no gasket material left. I wonder how much of a vacuum leak this could cause? I was also amazed at how clean it still looks.

Oh and could a leaking valve cover allow for a drop in the oil pressure gauge reading? I know that these things are old and generally inaccurate and need replaced, but I'm just wondering.

JPerkins

at an idle, or really low speeds, my oil pressure guage always reads zero. i had it tested, my oil pressure is fine. its just a quirky guage. just get an aftermarket one.

NismoPick

It's not the gauge... it's the oil pressure sensor. It's a common prob that is easily remedied w/ a new one.

duowing

Alright so my car still seems to idle kinda crappy, the sealant I used on the dipstick wore off. So I'm thinking I might just go the thxone route and use some sort of tape. Would electrical tape work, I'm just afraid of it possibly falling off down into that tube.

I was squeezing the hose that goes from the throttle body into the air regulator, and I could hear what sounded like a vacuum leak, but I can't hear it when I let go of the hose. Anyway I pulled the hose off, inspected it, no cracks or anything. I can't seem to hear it when the car is warmed up either. The sound seemed to be closer to the throttle body side of the hose. So maybe it's a throttle body gasket or something? I've been thinking about doing the 60mm throttle body upgrade anyway.

Or I'm wondering since the MAF is alot more sensitive if maybe the dipstick not sealing, would cause more of an issue than when I had the AFM setup, either that or it might be causing more of an issue since it can't use the AAC valve.

thxone

I used blue painters tape...never had a problem.

duowing

Alright cool, I'll prolly just wrap some electrical tape around it then. I think i also need to do a boost leak test, to see if I can maybe pinpoint where I seem to be losing vacuum at. The car generally seems to drive really well, and it seems to boost fine, but it idles really oddly.

I was using a piece of vacuum hose and placing it against other hoses, and I can hear the sound of air from the hose that comes off the Throttle Body and runs to the Air Regulator, I also noticed that if I stick the hose around where the MAF meets the boots, I can hear the sound of air, I don't know if you should be able to hear it or not. I've tried many many times spraying brake cleaner around the intake manifold gasket where it meets the head and seen no difference. So I'm hoping that's all ok, I did scrape the intake gasket up a bit when putting the intake manifold back on, but I don't know if that would be enough to actually cause the gasket to leak.