New to 928!
08-11-2012, 07:42 PM
#257
Instructor
Thread Starter
My 99p vw relays came in handy today! we replaced the air blower (been stupid for a bit and packed in completely yesterday) with one, and we have an air blower again!
I'm astonished by how much i've learnt about 928's over the last few months, i'm explaining how stuff on the car works and why to my o/h and he's been a porsche nut since he was a kid!
And i've only scratched the surface.. Have come to the conclusion that unless the wiring was redone from scratch, it will make no sense, but it works in it's own weird way so never mind.
Doc, did you hear, car pulled it's no hot start yesterday, we had the hood up when trying to start and were able to hear a click-click at the starter solenoid.
Previous investigation had only looked at the ignition, relays and CE board, I'm thinking starter motor just starting to fail now. Will get it tested when it goes in for cam belt, horn, abs, crank shaft and fuel lines.. should be this week, garage couldn't do it as they had a one of a kind something (i've forgotten what but it looked amazing) which was being a real pain in the **** as everything had to be made from scratch for it. Anyway, that's finished now so they can do our car
I'm astonished by how much i've learnt about 928's over the last few months, i'm explaining how stuff on the car works and why to my o/h and he's been a porsche nut since he was a kid!
And i've only scratched the surface.. Have come to the conclusion that unless the wiring was redone from scratch, it will make no sense, but it works in it's own weird way so never mind.
Doc, did you hear, car pulled it's no hot start yesterday, we had the hood up when trying to start and were able to hear a click-click at the starter solenoid.
Previous investigation had only looked at the ignition, relays and CE board, I'm thinking starter motor just starting to fail now. Will get it tested when it goes in for cam belt, horn, abs, crank shaft and fuel lines.. should be this week, garage couldn't do it as they had a one of a kind something (i've forgotten what but it looked amazing) which was being a real pain in the **** as everything had to be made from scratch for it. Anyway, that's finished now so they can do our car
08-11-2012, 10:27 PM
#258
Shameful Thread Killer
Rennlist Member
Rennlist Member
Hard starting can be many, many things. I wouldn't just to conclusions about the starter just yet. 928s are very hard on batteries, especially one that isn't driven much. It could be about 8 things only one of which involves the actual starter.
Start with a good strong battery, that you know is up to near full charge. Next, remove the ground strap from the back of the car near the hatch, and clean both the metal strap with sandpaper and the ground plate on the chassis. While you are in there, check the positive cable for corrosion and clean it very well. After that, you can investigate the engine to chassis ground, which I think is near the right side motor mount. It is a heavy gauge strap that goes between the engine case, and the body. Take both sides off, clean the strap and the engine, and body with sandpaper, then reinstall the ground strap. Now, take the large gauge and smaller red wire off the starter lug, careful not to ground it anywhere. Clean the starter lug with a wire brush, and the red wires with a brush or sandpaper, then reattach. Locate the yellow wire to the solenoid, and clean that as well.
This will likely eliminate hard starting issues, but if not we can proceed with other things. Let me know what you find.
Start with a good strong battery, that you know is up to near full charge. Next, remove the ground strap from the back of the car near the hatch, and clean both the metal strap with sandpaper and the ground plate on the chassis. While you are in there, check the positive cable for corrosion and clean it very well. After that, you can investigate the engine to chassis ground, which I think is near the right side motor mount. It is a heavy gauge strap that goes between the engine case, and the body. Take both sides off, clean the strap and the engine, and body with sandpaper, then reinstall the ground strap. Now, take the large gauge and smaller red wire off the starter lug, careful not to ground it anywhere. Clean the starter lug with a wire brush, and the red wires with a brush or sandpaper, then reattach. Locate the yellow wire to the solenoid, and clean that as well.
This will likely eliminate hard starting issues, but if not we can proceed with other things. Let me know what you find.
08-12-2012, 08:07 AM
#259
Instructor
Thread Starter
Its used every day, and starts fine on all but 4 occasions when engine had been warm, can't recreate it which is frustrating.
We've cleaned ask the grounds and straps we can get to, its not that its a hard start when it does this, its does nothing. Dash lights up, thats it.
We've cleaned ask the grounds and straps we can get to, its not that its a hard start when it does this, its does nothing. Dash lights up, thats it.
08-12-2012, 08:32 AM
#261
Rennlist Member
Try replacing bat neg ground strap with a generic one.
They aren't really inspectable and in moisture, with time, will corrode under the plastic cover.
The effect is intermittent and varies with temp / moisture / load. Can cut in and out while driving. Can work perfect, you park, go to restart and get nothing.
Just can't pass enough electrons to carry the power load.
Car will go dead, or nearly so. Might show 12.5 v across the battery, but 3 or 4 V, if any, from positive terminal to shock tower bolt.
They aren't really inspectable and in moisture, with time, will corrode under the plastic cover.
The effect is intermittent and varies with temp / moisture / load. Can cut in and out while driving. Can work perfect, you park, go to restart and get nothing.
Just can't pass enough electrons to carry the power load.
Car will go dead, or nearly so. Might show 12.5 v across the battery, but 3 or 4 V, if any, from positive terminal to shock tower bolt.
08-12-2012, 08:45 AM
#262
Rennlist Member
Here's a picture of one that gave us trouble.
Can corrode on either end.
I think it happens when moisture is allowed to collect in the trunk area or on the battery itself.
Happens, especially to the derelicts I'm dragging home.
Second picture is the engine to frame passenger side ground of which Doc speaks, also can be a culprit.
Can corrode on either end.
I think it happens when moisture is allowed to collect in the trunk area or on the battery itself.
Happens, especially to the derelicts I'm dragging home.
Second picture is the engine to frame passenger side ground of which Doc speaks, also can be a culprit.
08-12-2012, 09:09 AM
#263
Instructor
Thread Starter
Thanks Landseer. to me, the battery strap is clean and shiny, will give it another thorough investigation. Its ask dry in the battery compartment.
Can't seen to find the engine ground, spent ages trying to find it yesterday, it must be in there.. Wondering if maybe its been covered? Any chance of a picture of it further back so I can place it accurately in my car? Thanks!
Can't seen to find the engine ground, spent ages trying to find it yesterday, it must be in there.. Wondering if maybe its been covered? Any chance of a picture of it further back so I can place it accurately in my car? Thanks!
08-12-2012, 09:16 AM
#264
Instructor
Thread Starter
The car starts and runs perfectly nearly all the time, its used daily, its just 4 times in about 3 months its not started when warm. And we can't bloody recreate it!! Starter solenoid was clicking when we turned the key, dash lit up, nothing else.
I'm sure something is having higher resistance when its hot, so not getting current through to starter. As this is the only 928 we've had, I don't know if the time it takes to start is normal or is starting to lag, it never has any trouble (apart from these 4 occasions)
I'm sure something is having higher resistance when its hot, so not getting current through to starter. As this is the only 928 we've had, I don't know if the time it takes to start is normal or is starting to lag, it never has any trouble (apart from these 4 occasions)
08-12-2012, 11:45 AM
#270
Shameful Thread Killer
Rennlist Member
Rennlist Member
OK, new info is always good. Very intermittent and only happens when hot. Still need to clean that engine ground underneath. I would invest in some service ramps as they are easy to use, and safe. Heat affects everything, including the starter. You'll need ramps or jackstands to do both. Once you get under there, clean the ground and the positive terminal on the starter as mentioned. If it still gives you trouble, then the starter can be replaced.