1998 V70 Melted distributor rotor

bronco · Post by **bronco** » 24 Oct 2019, 10:21

So as I was merging onto the freeway yesterday my V70 died in a really ugly area at the top of an on ramp.

I'm right in the way of people trying to merge on and there was a sharp radius to the ramp so as they exit the turn I'm basically dead in the way

.

I managed to roll backwards onto the ramp a bit and get the passenger side practically touching the guardrail and thankfully during the 40 minute wait for a tow no one slammed into the car. It was dangerous enough that I couldn't really try to figure out what was wrong.

I get home and there are no codes on the scanner , I can't get my pressure tester on the fuel rail so I pull the core and crank it and plenty of fuel sprays out.

Then my spark plug tester that I keep in my bronco won't work so I put a timing light on the coil wire and it flashes so I think its got spark but for whatever reason I decide to put the pickup for the light on #1 wire and no flash , no spark on any plug wire but spark on the coil wire !

So I decide to pull the cap off and when I do a cloud of white dust puffs out and I find the rotor is completely melted??

in pic 2 its hard to see but there is a round burnhole in the underside

in pic 3 you see the inside of the cap covered with the white dust from the burned rotor

has anyone ever seen this ? Is it indicative of a bad part or something else ? Not sure what brand the cap and rotor are they were new but not in a box I found them in a baggie left by the previous owner in the pouch on the back of the drivers seat. They were put on about 2000 miles ago if that

Post by **misha** » 24 Oct 2019, 14:57

If there is not stamped Bosch on both...cap & rotor....that's why they burnt.

bronco · Post by **bronco** » 25 Oct 2019, 07:00

Googling outside of this forum is bringing up various discussions of too high plug wire resistance causing melted rotors .

Also that some rotors have resistors built in and those can disapate too much heat and melt the plastic

I don't see a name on the melted rotor , its black and is marked 3/47 on the upper side of the base and F 168 on the lower side. The bolts have an allen head unlike the torx head on the rotor I pulled from my parts car

Post by **erikv11** » 25 Oct 2019, 09:33

Glad you didn't get slammed on the side of the road!

A Bosch rotor has allen heads.

What is the date code on the wires? I'd also check if they are all fully seated.

Post by **abscate** » 25 Oct 2019, 10:22

bronco wrote: ↑25 Oct 2019, 07:00 Googling outside of this forum is bringing up various discussions of too high plug wire resistance causing melted rotors .

Also that some rotors have resistors built in and those can disapate too much heat and melt the plastic

I don't see a name on the melted rotor , its black and is marked 3/47 on the upper side of the base and F 168 on the lower side. The bolts have an allen head unlike the torx head on the rotor I pulled from my parts car

There isnt enough current in a spark plug wire to generate "melt plastic" type temperatures. Thats probably just bad parts.

bronco · Post by **bronco** » 25 Oct 2019, 20:00

abscate wrote: ↑25 Oct 2019, 10:22
bronco wrote: ↑25 Oct 2019, 07:00 Googling outside of this forum is bringing up various discussions of too high plug wire resistance causing melted rotors .

Also that some rotors have resistors built in and those can disapate too much heat and melt the plastic

I don't see a name on the melted rotor , its black and is marked 3/47 on the upper side of the base and F 168 on the lower side. The bolts have an allen head unlike the torx head on the rotor I pulled from my parts car

There isnt enough current in a spark plug wire to generate "melt plastic" type temperatures. Thats probably just bad parts.

I only say that because I'd seen it in my fords that had CD type ignition boxes . There was a box made by crane that could burn holes in the cap

I do have a used Bosch rotor in there at the moment , I'' get a new one and keep the one I have in there as a spare .

I do want to check the wires and plugs though to see what the plug gaps are at

bronco · Post by **bronco** » 27 Oct 2019, 07:31

the car stunk like rotten eggs for about an hour after I got it running , I think cranking it with no spark probably dumped a lot of raw fuel into the cat

bronco · Post by **bronco** » 12 Dec 2019, 07:09

The car quits again !

I didn't drive it for 5 days , I go to the store to get drygas for my beloved bronco, which has a carb full of ice and won't start stupid ETHANOL

, it collects water in the bottom of the fuel bowl that froze and plugs the jets.

I go in the store get a 6 pack of Heet come out and my volvo won't run and its the same symptoms , but this time A: I have a bosch rotor in it and B: I have a spare under the seat and C: I wisely parked under a streetlight.

I pull the cap and the rotor looks ok but the inside of the cap is completely soaked with a layer of condensation. I dry it with a rag put it on and drive home.

Questions , how was I able to leave the house in the first place and why is it wet ? Maybe it has a wetness problem that led to the melted previous rotor? I didn't drive through any puddles and it wasn't raining at the time.

My working theory is that when I left the house the water in the cap was in solid form that melted from engine heat while I was in the store..

Post by **scot850** » 12 Dec 2019, 09:46

Have you pressure washed the engine bay recently? This will cause water to leak into the distributer cap and cause shorts.

Otherwise can't think of a reason why water is in there. Did you drive through deep water or puddles?

Is it a Bosch distributor cap? Aftermarket ones can let moisture in causing condensation in the cap.

Neil

bronco · Post by **bronco** » 12 Dec 2019, 10:21

no pressure washing but its been weird weather , we got a foot of snow then it warmed up and rained and melted all the snow and it then got cold , the car never moved during that time. I never even cleaned the snow off the rain did so when I went to drive it that day 3 of the doors were frozen shut , it started and drove though then sat while I was in the store and then refused to start.

It may have been one of those weird situations where everything was either wet directly or covered in condensation which then flash froze.

Thats what happened with my bronco , when it wouldn't start I swept the snow off the hood and opened it the entire engine was soaked in condensation . It has an edelbrock 4 barrel carb , I thought maybe the needle and seat was plugged so I pulled the top off the carb and there was a half inch of ice at the bottom of both bowls with liquid gas sitting on top of it. The ice was blocking the jets and accelerator pump from the fuel and I had to bring the carb inside to thaw overnight. I've never seen anything like that in my life. Then I thought well this won't happen with the volvo at least

The rotor is bosch the cap might not be I'll have to check , the plastic dome inside the cap that goes over the rotor was also soaked .

I think there is supposed to be an outer cover over the cap which is not there also