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Won't start....more woes...
https://forums.tipec.net/viewtopic.php?f=25&t=23501		 Page 1 of 1
Author:  mikseymono [ Mon Aug 06, 2018 2:14 pm ]
Post subject:  Won't start....more woes...
Hi team....

So, in trying to service alternator..... (does not increase voltage when started....but will when you rev to 3000 rpm....have a new regulator on order)......I put another negative lead on to back on alternator to see if I have an earth issue...and something went 'sparky bang' ...if thats a word.....I have tested the coil and that is fine.

It cranks over, but no tach bounce......exactly like I had when my reference sensor went bad...but this is a different thing altogether right?

Any ideas please?

Thanks,

M
Author:  Waylander [ Mon Aug 06, 2018 2:46 pm ]
Post subject:  Re: Won't start....more woes...
you just blew the DME computer up at a guess,

that's why you should always disconnect the battery first
Author:  mikseymono [ Mon Aug 06, 2018 3:02 pm ]
Post subject:  Re: Won't start....more woes...
any way to check if it is fubared..................?! without plugging in another......as i do not have access to one.............

M
Author:  j.c [ Mon Aug 06, 2018 3:21 pm ]
Post subject:  Re: Won't start....more woes...
There is a saying "a little bit of knowledge is a dangerous thing" if I was you, i would slow down and concentrate on one thing at a time and be a bit more methodical in your work,
Given your latest issue, I would first check all the fuses, second, get a wiring diagram (usually found with a bit of googling) learn how to read one, figure out which terminal you shorted to ground (big burn mark should make it obvious, look on the diagram and find out what feeds that circuit (prob be either starter circuit or main live),
Where is the battery on 924s?
Quick look at the diagram, I would say check for voltage at terminal 4 on DME while cranking,
Author:  mikseymono [ Mon Aug 06, 2018 4:43 pm ]
Post subject:  Re: Won't start....more woes...
Thanks J.C.

I was trying to be methodical today, just the alternator to service. However, I think I have shorted something in trying to get a negative lead onto the back on the alternator from the battery and touched one of the threaded bolts on the back of it..........

There is no crank bounce on the tacho when I try to start now........like the sensor problem...which I have fixed.........

Given the non bounce on crank....does this point towards sensors again or is it a number of things?

Will try, as you suggest, to see if there is power on terminal 4 of the DME when cranking. I have had enough of it today......

Battery is top right of engine bay as you look at it from the front i.e above passengers footwell.

Thanks,

M
Author:  broady_6 [ Mon Aug 06, 2018 9:16 pm ]
Post subject:  Re: Won't start....more woes...
As above, please slow down a bit. You say you were trying to be methodical. But when doing anything electrical it is always best to disconnect the battery despite how careful you think youre being. We have all made a silly mistake while rushing or frustrated, do you best to mitigate it in the first place.

I would take step back, get a note pad an itemise you cars issues. Then work out how you can safely investigate what might be causing the issue and then how to resolve it.

Sorry to teach you to suck eggs, just trying to save your car from further hassle or worse still hurting your self.
Author:  mikseymono [ Tue Aug 07, 2018 8:22 am ]
Post subject:  Re: Won't start....more woes...
OK...update alert.

Left it alone to think about itself over night......

Tested sensors again with meter at leads and back at the DME. All good.

Cranked up car.......tach bounce yes.....and fired up.

Gee........ :bounce:

Whilst I am ecstatic...to say the least...would like to know how it rectified itself from being a large paperweight to a car I can at least drive to a competent garage.............

I think it may be the speed sensor. The female plug ends are brittle, moulded type, and there were times when a certain bending/twist to the plug would render this non tach bounce/start issue. I have a couple of female leads on order...but for now I am putting it back together content in the knowledge that I haven't fried anything from yesterday and will take stock of what I have done to the car so far....reverting back to baby steps.... :oops:

Thanks for all the support though.

Michael
Author:  Baztop [ Tue Aug 07, 2018 8:57 am ]
Post subject:  Re: Won't start....more woes...


That's exactly what is so great about the Tipec Forum!!

Exasperation, concern, expertise, straight talking - but a good result in the end. It's simply brilliant!

Barry
Author:  mikseymono [ Tue Aug 07, 2018 9:00 am ]
Post subject:  Re: Won't start....more woes...
Thanks Barry....quite agree....just like to know what happened and how it rectified itself! :D

M
Author:  scam75 [ Tue Aug 07, 2018 10:52 am ]
Post subject:  Re: Won't start....more woes...
Maybe you blew up yourself, and the body's regenerative powers fixed you overnight! There is absolutely no way you have blown up a car component that has self healed unless of course you own a 1958 Plymouth Fury.............. :lol:
Author:  Matt749 [ Tue Aug 07, 2018 2:33 pm ]
Post subject:  Re: Won't start....more woes...
You might well have tripped an inrush current limiter which goes high resistance when subjected to very high current. They get hot and effectively block the current with a very high resistance. I don't know in this case but I suspect the DME will have some kind of input protection to mitigate exactly what you have done. They take time to cool down and then revert to low resistance. That's the only self fixing component I can think of.

As others have said, it is very easy to allow your "inner chimp" to take over when things are not going well and you will just make it 10 times worse by rushing. We've all been there and taking an hour away to think the problem through can save you from making an annoying issue a very expensive problem. Ask me how I know.

These cars are quite simple and very well engineered so applying logical diagnostic techniques with a good multimeter, some basic tools and this forum as support will allow you to identify the problem eventually.

Good luck with it.
Author:  mikseymono [ Tue Aug 07, 2018 3:14 pm ]
Post subject:  Re: Won't start....more woes...
Thanks for replies.
Currently its up on ramps whilst I await my new Alternator regulator and looking at BS timing marks. Will be checking all earth connections as well and not diving in with monster cables attached to battery and accidentally touching components.... :bounce: ..Will report back on that one later in the week.

Everything else, apart from my performance issues.....struggles to get past 4000 rpm (see other epic thread...still think this is the speed sensor wiring) has been very simple to diagnose and fix. I even timed myself in taking out speedo cable, for new odometer, and putting it back in...under 15 mins. First time was close to 4 hours.......

Putting inner Chimp back in his cage.......... :albino:
Author:  tr7v8 [ Tue Aug 07, 2018 6:25 pm ]
Post subject:  Re: Won't start....more woes...
Worthwhile getting a new look for the speed sensors. That area is very hot and the connections go intermittent
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