wont turn over
 

Ok, I got some great advice from my previous posts. Here is what is going on. My 1984 928 would turn over when I got it had week spark but I got it to "pop" once. After looking for info on this forum I did the following. Cleaned 14 pin connector, cleaned as many grounds as I could find. ( (the ground charts don't seem to be accurate for my car or I just don't know what I am looking for.) Cleaned 1/2 of the fuses and connections so far and pulled cleaned and reset all of the relays. I replaced the "green Wire" and installed a brand new ground strap for the battery. I also dropped the alternator and cleaned all the connections and stripped back some of the corroded wires and made new connections.

Here is what happened: when I put the battery back in the horn would sound! I looked around to find something obvious but I could not. I then pulled the fuse for the horn. when I try to start the car It wont even turn over like it used to it does nothing! Now I am frustrated I feel like I took two steps back. Is it something I did or is this just a new problem?:confused:

So the starter does not even try to crank the engine? Measure your battery voltage - if it is less than 10.5 in won't. Charge the battery fully out of the car and try again. Horn sounding could be you put a relay back in the wrong place, or wrong type.

if you have an alarm sys. the car (taking bat out-disconnect of cable-or battery died) could of told the alarm sys to arm itself - someones trying to break in. so when you put the bat back in (connect) it reassuming from where it left off (armed) so youd have to let it keep sounding off and do the process it takes to shut the alarm off, the engine wont turn over either cause its locked down - theft.

ex key in ignition cycling it on and off.... but pulling fuse isn't disarming.

Alarm Disable -
 

Hey Mayoman, There is a factory alarm on your 84 that disables the fuel pump circuit and (I believe on some cars) blows the horn through the "Z" connector of your fuse panel - but your starter should still be able to spin over the motor. I had a couple of wiring issues on my 84 that spooked me a bit so I disabled the alarm using the instructions recommended in the maintenance manual.

If you would like to eliminate the alarm while troubleshooting and rechecking your previous troubleshooting steps - You need to:

1 Locate the "Z" connector on the fuse panel. They are alphabetically labeled.

2 Pull the "Z" connector (outer half) of the plug toward you - until the two halves separate.

3 Locate pin #6 and #4 within the fuse panel side of the "Z" plug and install a jumper across them. I used a short pre-cut piece of wire and crimped a couple of terminal lugs to the ends for the jumper.

4 Leave the outer half of the "Z" connector plug loose - you might zip tie it securely to one of the other wire harnesses so it doesn't move around.

Like I said - this procedure prevents the factory alarm from signalling the computer to shut down the fuel pump relay and the ignition CD box. You might verify that your battery terminals are clean, then connect a mechanic's external starter switch directly to the back of the starter terminals to make sure the starter is good. If the problem continues, the best guess is that you should probably back track the preventative measures you listed previously.

Hey Neil - Plugging in a relay back into the wrong socket may very well be powering the horn, Good Call -

Good Luck, Michael :)

its true the car doesn't even try to turn over. I will check the voltage on the battery. that would have been my first thought if it wasn't for the horn. Ok here is a little more History. When I first got the car I charged up the battery and when I connected it the horn would sound on off on off. I did some research and figured it was the factory alarm. I located the alarm module unplugged it and the horn stopped. I then Jumped the 87a and 15 pins. Horn sound was gone and the car turned over. This time when I connected the battery after the above work, the horn just sounds with no breaks. it just continues to sound til I pulled the fuse.

Also while looking around I think I may have a second after market alarm up under the dash zip tied on the drivers side and a small toggle switch mounted to the bottom of the shelf. I will post a pic of this maybe one of you knows what the heck it is and how or if I should get rid of it

http://forums.pelicanparts.com/uploa...1386524460.jpg

http://forums.pelicanparts.com/uploa...1386524480.jpg

these are what I believe may be part of an aftermarket system

I've spend a lot of time with the 84 wiring.
Best advice, disconnect the battery and let us walk you thru the grounds and the fusebox refresh.
The toggle / aftermarket stuff should be excorcised now too.

A lot of the ground charts posted on the net are for later cars.

Man, I guess I got lucky in that my PO(s) did not jack anything up with aftermarket electronics.
The stock electrical issues are enough, without having to deal with stuff like this, hang in there man.

I haven't even look at mine that much but I haven't found any obvious additions. Hoping that I don't!

MTX - Brand Alarm
 

Hey Mayoman - Just guessing but you may have located the second alarm. The MTX audio amp supplier also produced car alarms at one point. Perhaps if you can locate a part number they can provide a functional schematic layout. In the worse case scenario you will have to trace your wires back to see where they cut into the wiring harness and try to reconnect any spliced connections.

I had a similar after market alarm problem on an Audi Quattro one time that chased me around for about two weeks before I had everything sorted out. The company that initially designed the circuitry was no longer in business or had been bought out by another outfit. It had been a multi-logic unit that alternately flashed the lights, blew the horns and disabled everything but the cigarette lighter when it went off....:)

Good Luck, Michael

Hi Guys, I would love you to walk me through the grounds for my 84. I'm guessing I should work at getting rid of the after market alarm first. I will look for any Manufacturer markings and try to locate a diagram. if I cant locate I will chase the wires back. I will keep you all posted. you can start to walk me through the grounds at any time

Everything you pictured above is aftermarket crap. I hate car alarms. Think of it as a game - trace back all the wires from those & remove/splice back to original condition

Then, be sure your battery is good and fully charged. If in doubt, replace - it's the cheapest part you will ever buy for your 928. Invest in a terminal cleaner & a container of CLR, clean all battery connections, dip & clean the ground strap & the connection point to the body.

Jack up the car & block it good. Crawl under & jump the starter (alligator from large connection on solenoid to small connection on solenoid)

If you motor spins, work backwards from there. If it doesn't spin, you have a bad starter or locked engine. If you get up front & can move engine with breaker bar, the starter is bad. Do this so you don't spend a month chasing down electrical issues only to find it was your starter all along. Yes, this is from experience, as I had the quadruple crown of bad grounds, bad relays, bad starter and locked engine

(Although it sure sounds like one of those POS alarms is causing you a hassle - remove them all)

The grounds suck in these cars - My battery was 3 months old, 2 months ago I did all the cleaning of the ground strap location - And it went bad again last week, and I had to clean it again (battery acted dead no matter how much I charged - cleaned the strap location & she fired right up

On 84 there are a couple key ones.

Two on the passenger side cam cover, one just over the "O" in PORSCHE, one just above the space between C & H --- one above the O is hidden behind/under the valve that is part of the air pump emissions, you must remove it and some of the hoses (easier than it looks) to clean it. These are the most crit grounds on the car as all the engine electronics ground there.

Another crit ground is under car, linking engine with frame, pass side.

I'd replace the neg bat ground strap with a similar flat wire weave strap. We've seen at least a dozen of these straps fail for corrosion reasons, failures hidden by plastic cover. Trust me, it needs to be replaced.

( Of course the pos bat post and the little red positive on battery need to be thoroughly cleaned and carefully tightened.)

Inside cockpit you must clean the two sets of grounds located above fusebox. Fusebos needs to be removed, cleaned and re-fused with the german fuses (do NOT use BUS brand, they don't fit). Inspect back for issues.

Remaining grounds are in cockpit under steering column, in eng compartment at each side of radiator, and inside car -- behind passenger rear quarter interior panel --- PITA to reach but it does ground the fuel pump. The electrodes are brass, not plated.

I'll post a link for 84 Euro that has most of these grounds identified for you. (Euro has an engine ground near the PS cam cover that yours wont have--- its the first one I deal with on post # 7 of the link; also antilock grounds yours won't have)

Here is link, I also cleaned 14 pin connector in this diatribe, and replaced some fuel lines and other wear parts.....http://forums.pelicanparts.com/porsche-928-technical-forum/586148-ground-cleaning-16v-euro.html

That one on the pass cam cover is a hard one. It got me on my 83. It ran but ran poorly as only one side was firing.

I don't have pics of doing all my ground points but here is one under the drivers side dash. Just an example of how it looked and how you want it to look after polishing. I used a Dremel with a steel brush attachment.

http://forums.pelicanparts.com/uploa...1316835702.jpg

http://forums.pelicanparts.com/uploa...1316835708.jpg

http://forums.pelicanparts.com/uploa...1316835737.jpg

http://forums.pelicanparts.com/uploa...1316835741.jpg

This is great stuff! Landseer, thanks for the link! Cant thank all you guys enough! The pics are a huge helpGoing to start to trace the aftermarket alarm this afternoon. Then systematically go through the grounds and fuse box. I have already bought and installed a brand new ground strap from roger. I will let you know how the search for grounds goes. Making a list and checking it twice!

Just curious, but what does your username mean? Also, here is a link to my $900 1983 S that has a lot of info that might help you. Also, is this a project 928 that you got with the no start issue?

http://forums.pelicanparts.com/porsche-928-technical-forum/583848-900-1983-us-928s-latest-leo928s.html

MPDano, mayoman is a nick name because my last name is Helman... like the Mayonnaise! Yes this is a project I got with a no start Issue. BTW I made a lot of head way removing the alarm today. Many of the main wires were spliced in just behind the plug for the ignition key. Seemed pretty straight forward. I also located the two valve cover grounds. with any luck tomorrow I finish chasing alarm wires and I can get back to cleaning grounds.

Just checked out your $900 83 MPDano, Very Nice. You are a lot further ahead than my $800 84!!!!!

Quick update... Turns out the horn had nothing to do with the Alarm. When double checking to see if the Relays were in the right place I found that when I wiggled it the horn would stop. I replaced it and the horn works as it should. I located and cleaned the two valve cover grounds (they really needed it.) Charged up the battery and still does not turn over. next on my list of things to do is put in all new fuses (and clean the connections) I will also replace the starter relay.

Clean the ground under the engine.
While there, inspect/clean the starter electrical connections.
Look first for voltage there, then disconnect battery and clean them.
The 14 pin connector --- did you clean that, it channels power to the solenoid on the starter.

Could be the starter motor, perhaps light hammer taps and try it.
Could ignition switch electrical portion, also a common failure area.

Maybe Sean or others will provide more definitive ideas or tests?

Key thing is grounds, electrics and the right replacement relays (gotta be precise on early cars) as a firm basis from which to begin.