Got it running, call the fire department Options

[Mcraneiowa]

Good evening all
Picked up a 194 Porsche 914 1.8 about three months ago as a Covid project since I have to work from home for possibly the remainder of the year. Have done lots of work n the car from fixing rust to replacing worn parts,etc. and am now down to the point of trying to figure out the fuel injection system. Couldn’t figure it out. One of the people on this site has been more than helpful in helping me diagnose and help me learn about my car, tremendous thanks to, Clay. His knowledge, insight and directions have been so helpful in guiding me.
So here’s where the fire department comes in, figuratively speaking. I got a new relay double relay hooked it up still couldn’t get the car to run but it has been mentioned if those two plugs were in the wrong slots the car wont run. So I ground down the plugs to fit the new double relay and reversed them. Fuel pump startedrunning even with the key in the off position, but when I turned the key over to start car, instantly fired right up and within a few minutes it was running pretty smoothly. After about five minutes idling in the driveway I heard a pop and about 40 seconds later smoke! The lead (large) wire from the alternator to the starter basically melted the cover of the wire. Looks like it was isolated to only that wire that will need to be replaced.
Now, I’m no electrician in fact I apparently understand just enough about wiring too get into trouble, as just mentioned.

Anybody have ideas of what’s going on at this point? I’m likely in over my head and will probably have to send it off to somebody that works on automotive wiring. I recently replaced the coil, alternator, double relay, fuel pump, etc.. I’d love to hear what everybody thinks, your thoughts and suggestions and solutions, It’s OK if you think the guy working on the car was an idiot, (that would be me)and I would probably have to agree. But, on a positive note, I will say I am learning things along the way. So I’d like to hear what you guys thinking maybe i can get this straightened out.

On a side note, my wife thinks I’m nuts at this point wanting to do anything more to this car with the level of skill I have. But nothing ventured, nothing learned! Thanks, Mike

[SteveL]

Is it a new or rebuilt alternator? There is a bolt that can make contact inside and cause all kinds of problems.

[Mcraneiowa]

Is it a new or rebuilt alternator? There is a bolt that can make contact inside and cause all kinds of problems.

It’s a new alternator from Napa. Looked very similar to the old Bosch I pulled out except the bolts on the back of the alternator were quite long and I had to cut them short so they wouldn’t touch the metal plate on the back that is designed for airflow. Not to say maybe I still didn’t get them short enough but I’m pretty sure I did because i ground them down to just above the end of the nut. I wired it up same as the old one, so I don’t know where I went wrong.
I figure I’ll put the car back up on jackstands tomorrow pull the alternator and the harness out and see where I’m at I’m just at a loss.

[jmalone]

BTW,The photo is of your starter

[preach]

BTW,The photo is of your starter

Look at the smoked + wire...

[mjrrti]

Is it a new or rebuilt alternator? There is a bolt that can make contact inside and cause all kinds of problems.

It’s a new alternator from Napa. Looked very similar to the old Bosch I pulled out except the bolts on the back of the alternator were quite long and I had to cut them short so they wouldn’t touch the metal plate on the back that is designed for airflow. Not to say maybe I still didn’t get them short enough but I’m pretty sure I did because i ground them down to just above the end of the nut. I wired it up same as the old one, so I don’t know where I went wrong.
I figure I’ll put the car back up on jackstands tomorrow pull the alternator and the harness out and see where I’m at I’m just at a loss

Did it smoke the wire all the way to the alternator? It almost looks like it grounded itself on the tin that it passes through. The vibration from idling may have rubbed a bare spot where it goes through the tin. Was the grommet in decent shape? I have seen that happen, maybe the insulation was already paper thin and idling a little rough for a few minutes finished it off. Seems wierd that it didn't happen right away if it was an actual wiring mixup. Good luck.

[jaredmcginness]

Really nice looking 914. I agree it does look like the wire grounded itself on the tin.

If you are new to these cars I recommend getting a Haynes manual (at least) and checking out plenty of youtube videos on these car (Check out Ian Karr's videos)

It sounds like you have a decent grasp, dont let the old lady hold you back from learning. Best way to learn is dive right in.

[ClayPerrine]

I already pointed him to Bowlsby's site to get a new alternator harness.

There are videos and directions on here on how to pull the alternator. It's not hard, just take your time and follow the directions.



Clay

[Bleyseng]

Well, on the new rebuilt alternators they use a bolt (stud) that is too long and it contacts the rear cover shorting out the positive wire to the starter. You have to trim that stud down for proper clearance.

[dr914@autoatlanta.com]

I agree, the stud is too long and grounds on the back cover

Is it a new or rebuilt alternator? There is a bolt that can make contact inside and cause all kinds of problems.

[StarBear]

Also, to muck things up a bit, be aware that on the early 74 1.8Ls (like mine), some of the wiring is still 73 - the Haynes manual diagrams are good, but I've found a few circuits on mine that match the 73 diagrams.
I like where this thread advice is going.

[Root_Werks]

Yikes, certainly a dead short.

[914Sixer]

You HAVE to cut bolt off and make SURE you have the RUBBER CAP that goes over the lug.

[Mcraneiowa]

I’m thinking you may be correct. Didn’t happen right away and really burned the back half towards the starter to where the wires split

Is it a new or rebuilt alternator? There is a bolt that can make contact inside and cause all kinds of problems.

It’s a new alternator from Napa. Looked very similar to the old Bosch I pulled out except the bolts on the back of the alternator were quite long and I had to cut them short so they wouldn’t touch the metal plate on the back that is designed for airflow. Not to say maybe I still didn’t get them short enough but I’m pretty sure I did because i ground them down to just above the end of the nut. I wired it up same as the old one, so I don’t know where I went wrong.
I figure I’ll put the car back up on jackstands tomorrow pull the alternator and the harness out and see where I’m at I’m just at a loss

Did it smoke the wire all the way to the alternator? It almost looks like it grounded itself on the tin that it passes through. The vibration from idling may have rubbed a bare spot where it goes through the tin. Was the grommet in decent shape? I have seen that happen, maybe the insulation was already paper thin and idling a little rough for a few minutes finished it off. Seems wierd that it didn't happen right away if it was an actual wiring mixup. Good luck.

[Mcraneiowa]

I did cut the bolt but didn’t cap it. Great idea. I’m thinking at this point of looking into rebuilding the old Bosch unit and using its stead of the new after market one. Will likely put in the old one as is, I believe it’s still decent and pull it to get rebuilt next time I have to pull the engine or when it fails.

You HAVE to cut bolt off and make SURE you have the RUBBER CAP that goes over the lug.

[porschetub]

I did cut the bolt but didn’t cap it. Great idea. I’m thinking at this point of looking into rebuilding the old Bosch unit and using its stead of the new after market one. Will likely put in the old one as is, I believe it’s still decent and pull it to get rebuilt next time I have to pull the engine or when it fails.

You HAVE to cut bolt off and make SURE you have the RUBBER CAP that goes over the lug.

(IMG:style_emoticons/default/agree.gif) however the boot tends to fall apart when you remove it to undo the nut,I used a thin piece of insertion rubber clued to the back side of the cover as a just in case because the boot was history.
IMO I find it strange these rebuilt units constantly have this issue and it never gets sorted......
The alternator in this case will most likely be damaged due to going to earth on the positive side and will need to be checked @ a repair shop.

[brcacti]

Great that you are doing work on it yourself even if you're not a mechanic. We can learn this way. There will be times for us non mechanics that we will need to take it into the shop and have the pros look it over and fix things.

[ClayPerrine]

I did cut the bolt but didn’t cap it. Great idea. I’m thinking at this point of looking into rebuilding the old Bosch unit and using its stead of the new after market one. Will likely put in the old one as is, I believe it’s still decent and pull it to get rebuilt next time I have to pull the engine or when it fails.

You HAVE to cut bolt off and make SURE you have the RUBBER CAP that goes over the lug.

(IMG:style_emoticons/default/agree.gif) however the boot tends to fall apart when you remove it to undo the nut,I used a thin piece of insertion rubber clued to the back side of the cover as a just in case because the boot was history.
IMO I find it strange these rebuilt units constantly have this issue and it never gets sorted......
The alternator in this case will most likely be damaged due to going to earth on the positive side and will need to be checked @ a repair shop.

If you buy a new harness from Bowlsby, you get a new rubber boot. And I always recommend using a very thin nut and cutting the stud off flush with the nut.

[Mcraneiowa]

I did cut the bolt but didn’t cap it. Great idea. I’m thinking at this point of looking into rebuilding the old Bosch unit and using its stead of the new after market one. Will likely put in the old one as is, I believe it’s still decent and pull it to get rebuilt next time I have to pull the engine or when it fails.

You HAVE to cut bolt off and make SURE you have the RUBBER CAP that goes over the lug.

(IMG:style_emoticons/default/agree.gif) however the boot tends to fall apart when you remove it to undo the nut,I used a thin piece of insertion rubber clued to the back side of the cover as a just in case because the boot was history.
IMO I find it strange these rebuilt units constantly have this issue and it never gets sorted......
The alternator in this case will most likely be damaged due to going to earth on the positive side and will need to be checked @ a repair shop.

If you buy a new harness from Bowlsby, you get a new rubber boot. And I always recommend using a very thin nut and cutting the stud off flush with the nut.

Clay, I will order a new wiring harness for the car. I decided to pick up a single heavy gauge wire and if the other wires in the harness are fine I’ll put it back in, make sure it’s insulated from other metal contact. My thought is to do this as a test and not burn up a brand new harness.. If it isn’t something else causing this wire to overheat,then I’ll remove and install the new harness.

[Mcraneiowa]

OK so put the car up on jacks, removed the alternator (somewhat of a pain to do) and here’s where I’m at. It’s smoked the wiring in fact the large red lead wire inside the alternator air cover close to the nut was broke I half. Not sure if it was broken before I hooked it back up or that it burned it in half About an inch from the nut it screws on to
I’m taking the original Bosch alternator and the new one and the wiring to a local alternator rebuild repair shop. I’ll get their opinion to see what happened so I don’t repeat the process.I’ll keep you posted what they tell me and if there’s a better solution