Starting issues - replacing alternator "Y" cable

I've been experiencing starting issues for a while, but they all seem to stem from "something else" - starter motor, alternator and battery have all been replaced in the past few months with new genuine Bosch items I got stranded in a supermarket car park at the end of December after a short journey in the freezing cold. The AA guy tested the battery and charge from the alternator... stated it was lower than ideal, but not so much as to fail either - I noticed a slight grumble developing from the alternator, hence didn't have a big issue replacing the battery and alternator at this point just to keep me moving (everything needs to be replaced eventually in any case..) I also bought a solar trickle charger and compact jump starter(!) I've since used the trickle charger routinely when parking up during the day and have had to jump the car a couple of times in as many weeks...! Amps/volts?! on the dash can be seen to fall while driving and at the point of parking up on short journeys or those with slow moving traffic - I can see the dash reading fall below 12 in that kind of driving i.e. I'm not really suspecting a battery drain while the car is parked up... Is this all symptomatic of corroded power cables or bad connections? i.e. increased resistance of poor connections not allowing the alternator to re-feed the battery properly? I'm on the verge of replacing at least the "Y" power cable (I've previously replaced the main o/s/r earth strap with a genuine OEM replacement) - is this a sensible next step and how involved is it ie. engine out or engine in?!! My indie is still backed up with various winter projects so can't really get me booked in until early May, but I'm going to need a proper resolution on this before that.... :dont know:

Or should I back up a step and just get under the car to disconnect and wire brush the junction/connection between the "Y" cable and the long cable from the front of the car...? - some posts suggest that just that alone solves things(?!) - its on the n/s/r of the gearbox so I can imagine it sees a fair bit of contamination over 20+ years... :dont know:

I had simular issues as yourself and i replaced the Y-piece cable after reading this post below. https://rennlist.com/forums/996-forum/764630-updated-alternator-starter-cable.html You wont be able to clean the corrosion because its the copper wire under rubber shielding which corrrodes. I hope this helps.

I replaced mine due to similar issues, transformed the car. I did do the alternator regulator whilst in there. Y cable very easy to replace if you warm up the plastic box and remove it.

I replaced y cable which cured my slow start issues 3 years ago. However, had mot last week and after running idle on the ramp for 20 mins it would not crank on hot engine. I am about to replace earth straps at battery and engine. Both battery and alternator check as fine.

If you can get the Y cable out you will be able to see if it is corroded, to be honest though, its not an expensive part and if you have gone to the faff of getting it out you may as well replace. Best tip I found on replacing the cable easily was to heat (in hot water) the plastic end on the right hand side as you look in the engine bay, remove it and that enables you to thread it through the air con pump without having to move/remove the pump.

Do you happen to have the PN for the cable? Is it main dealer only?

There are ultimately 4 powercables and 2 main grounds to the main power loom the Y shaped piece connecting the jump post, starter and alternator is either 996 607 019 01 (-01 cars) 996 607 019 03 (01- cars) There's also short section from the jump start post to the n/s of the gearbox where it then bolts to the main long section running down the belly of the car - that's the connection I'm also going to clean and scrub with a wire brush There was a TSB re. early 997 versions of the Y cable i.e. early failure... but I'm thinking its just the prime section for the body of the cable to degrade over time given it connects over the engine... that underbody connection is then my other candidate based on how exposed it is.... I ordered a new Y cable amongst some other parts today - not sure the individual cost of the cable, but suspect its in the £60-80 range

Fair to say the "Y" cable was the culprit Dash reading is now pinned to 14 and car starts instantly...

Good thread, great result, well done.. :thumb:

Hi all, just read through this thread. Is there a decent how-to anywhere for cable replacement process?

I've been considering this for some time actually. A popular mod on motorcycles, particularly v-twins, is to improve starting cables with thicker, better insulated and components. Manufacturers tend to air on minimum thicknesses, obviously they have a volume to consider not just one, and so they tend to be weaker as they get older. I would assume the cars are the same.

There are a couple of renntech articles that are worth reading e.g. https://rennlist.com/forums/996-forum/870715-alternator-starter-cable-replacement-simplified-5.html Unfortunately the most comprehensive guides I found also included a lot of unnecessary steps and drama! Essentially you need to find a good how to guide re. removing the throttle body and front t-piece of the intake - I would refer to Pelican Parts "starter motor replacement" thread for this - first steps are the same Once you have the t-piece out you will be able to unbolt the lead from the starter... you can also reach behind the alternator to remove the cable with the alternator still in place - a good purchase if you don't have one is an angled inspection mirror (a lot have little led lights) The cable then threads through under the off-side intake before being mounted into the back the plastic connector block that forms the jump start point - the new table comes with the plastic block - destroy the old one - follow the advice of soaking the new one in hot water to allow it to be pried off... with it off there is no need to move or unbold a single thing on the off-side i.e. a few guides talk about rotating the air con compressor and similar - this is all totally unnecessary..(!) If you use the starter motor guide to remove that t-piece of the intake, everything else is as simple as routing a new cable exactly in the place of the existing one, which acts as your guide. If you've done a lot of these steps before, its a 30 min job at worst. If you unsure, I still dont think it would take more than an hour taking your time...