please help Danglerb or Alan

86porsche · 02-17-2008, 10:53 AM

hi lads, im still having an issue with not being able to switch off car by the ignition switch. To make things worse i cannot start the car any more so im hoping ye might be able to help me out in some way or il pull my hair out. I havnt had much time to work on the problem but had a few hours to spare today so went to solve it. since we last talked i bought a new battery but still my volt meter on the dash bottoms out when i go to crank the car.so my first question is why would this happen? this issue im having is weird to say the least.went to check the connections on the fuel pump today as the cover was off when i bought her, i cleaned the ground and checked if she would start.no start but my issue of the car not switching off had stopped.though great solved something but tryed cranking her for a few more times and problem was back again.very strange! i have also found that if i disconnect the small cable on the positive from the battery i am able to use ignition switch as normal but if i connect this small cable again i cant turn the dash lights off with the key and must proceed to pulling relay xvi again. I put a volt meter on the fuse board today and checked the voltage at the relays.

results

Ignition off

EZF 12V AT pin 30
fuel pump 12v at pin 30
Lh 12v at pin 30 and 86

ignition on (key turned twice)

Ezf 12v at pin 30,86 and 87
fuel pump 12v at 30 and 86
Lh 12V AT PIN 30 and 86

can ye tell me if these readings are correct? if not why could i have 12v at pin 87 on EZF for example, that doesnt seem right to me.just to add a little more, i can hear the fuel pump run when i bridged 30 and 86 and ignition is off, but dont think it runs when the relay is in, but not sure cause its quiet hard to hear when im cranking the car.(could this be the cause of the no start) I was on my own today so im unsure if i have spark also and could not check pump properly, but will find this out when i get another pair of hands. for the mean time i want the concentrate on the ignition switch issue and im sure it will help to getting her back to starting up.hope this is not too long winded.thanks for the help again lads.

Danglerb · 02-17-2008, 03:54 PM

Off hand I can think of two ways to approach this problem, check stuff and find the problem, fix things until it starts working.

I'd start with number two and work though all the ground connections.

Charley B · 02-17-2008, 06:48 PM

Quote:

Originally Posted by 86porsche

........ if not why could i have 12v at pin 87 on EZF for example, that doesnt seem right to me.just to add a little more, i can hear the fuel pump run when i bridged 30 and 86 and ignition is off, but dont think it runs when the relay is in........

It sounds like you have a bad ignition switch. Jumping the fuel pump relay is bridging the live lead into the relay to the hot lead to the pump, so it bypasses the ignition. With the relay in, the ignition has to be on to activate the pump.

Alan in AZ · 09:03 AM

You need to do a better job of describing exactly whats going on, since it sounds like you have at least 2 separate issues. Don't assume they are related and just be methodical. Its good that you can measure voltages - however they are all normal and at this point describing the behaviour in really good detail is rather more important. You are getting ahead of yourself...

Start with the issue where it won't start.. What exactly happens...?

When you turn the key to start - do all the dash lights go out? voltmeter drops to what level? does the starter do anything? does the starter relay click (this is the kind of info thats most helpful).

This sounds like a classic bad battery or bad battery connection

I'd test the battery post voltage direct while you try to start does it also bottom out - if yes your new battery is toast (most likely because other things on the car weren't turning off and its totally discharged - fully charge it ASAP and disconnect it until you fix the issue).

If it stays good -

Clean all the major connections both battery posts, ground point at other end of battery strap. try again. If still no good monitor voltage from the rear ground point direct to battery positive post while starting. If this bottoms out while starting - replace the battery ground strap.

If this looks good check connections at the starter motor big terminal. You should have found the issue by this point...

Most likely culprits - battery & battery ground strap

To you other on-running issue - replace the ignition switch.

From what you mentioned - what is this small lead from the battery - is it stock or aftermarket - do you know where it goes?

Alan

86porsche · 02-18-2008, 12:06 PM

ok thanks for the replies. this is an issue i posted a few weeks back for info on relay xvi so i skipped some details maybe.since then iv been trying to fix it with no luck.this problem happend suddenly not long after buying the car, when i got home and went to switch her off it kept running with the key out and had to pull the negative of the battery to kill her.so il try and be more clear to whats going on.I turnto start all lights on the dash dont go out and the volt meter drops the bottom, last line on the instrument 0 volts,after crancking it will go back to 12volts.starter motor will engage and car will cranck but wont start,then when i go to turn key to off all lights will remain on the dash but radio will turn off. I then proceed to pulling relay xvi and the lights and votmeter will go off at this point hence why i was thinking it was an issue with that relay. I have ruled this out cause iv tried another relay with no success also the switch works as it should with relay out,so can it stil be the switch? this seems to be the most likely problem but would like to know for sure be i buy one. the battery is new and i always disconnect the negative lead so it wont drain but will check if it bottoms out there which i havent done. to answer your question about the lead on the possitive, yes thats how mine looks one large positive and one smaller cable (not after market) but mine has only two smaller cables not four when i cut back the outer sleave to check for corrosion. im not sure where it goes and was hoping ye could tell me. it goes out of the battery tray with the larger one and the goes back inside under the car and i cant trace it from there, if i disconnect this cable i dont have the issue of not being able to turn lights off by the ignition swich,just to add, when this lead is disconnected from the main positive lead i have 12 volts when the ignition is on at this lead, so its getting energized from somewhere other then the battery.could this be normal? this is all i know at this point and am grateful for all suggestions i have tryed to rule out as many of the obvious ones as i can but am still learning about this car as iv not had it long and its a real pain to just look at it in the drive and not take it for a burn!

86porsche · 02-19-2008, 10:13 AM

I just want to add, did a quick check on the battery and negative ground strap. the battery was reading 12v and when i went to crank her it dropped to 9.5 volts so i assume this is correct? the negative is also getting a good ground and looks to be in good condition.would this leave only the starter motor to cause the volt drop on the dash or do i have a faulty instrument? the last thing I want to add is when i went to do this quick check of the battery I put back on the ground strap and touched noting else. I wanted to see if i could use my ignition key and was able to turn on and off the dash lights as they should twice, but it wouldnt work after that. I had not tried to start the car when i did this just turned key to on/off.definately switch? the reason i want to be sure it is because im from Ireland and must ship part in from USA or England. but why would it work all the time when iv relay xvi out? this problem seems to fix itself if i leave the car with the negative off for a few hours.weird! If i can get these answers im sure il have her back running soon. cheers 86porsche

Danglerb · 02-19-2008, 11:25 AM

(Please put in spaces like this)

I just want to add, did a quick check on the battery and negative ground strap. the battery was reading 12v and when i went to crank her it dropped to 9.5 volts so i assume this is correct?

the negative is also getting a good ground and looks to be in good condition.would this leave only the starter motor to cause the volt drop on the dash or do i have a faulty instrument?

the last thing I want to add is when i went to do this quick check of the battery I put back on the ground strap and touched noting else. I wanted to see if i could use my ignition key and was able to turn on and off the dash lights as they should twice, but it wouldnt work after that. I had not tried to start the car when i did this just turned key to on/off.definately switch?

the reason i want to be sure it is because im from Ireland and must ship part in from USA or England. but why would it work all the time when iv relay xvi out?

this problem seems to fix itself if i leave the car with the negative off for a few hours.weird! If i can get these answers im sure il have her back running soon. cheers 86porsche

*************************************

When cranking its normal for the battery voltage to drop some amount. I don't know how much is OK, but it makes a BIG difference how and where it was measured, as each connection, battery post, battery cable, etc could have abnormal voltage drops indicating they need attention or replacement.

Looks good can be deceptive, all the mating surfaces should be shiny clean, with the proof of a good connection being very little voltage drop under a high current load. The voltage measured in many locations should be essentially the same as at the battery post.

Taking the ground on and off and having it work a bit makes me suspect the ground or cable.

*** Hopefully Alan will correct anything I guessed wrong.