Slow hot start problem fixed

My 1998 996 Carrera 2 has been sluggish to start when hot for as long as I can remember, I finally got around to swapping out the y-cable for it and it has fixed the problem. Here is what I did. MC

Thank you MC. Mine has had the same issue for the 9.5 years that I’ve have it, I even bought the Y-cable a year ago but never fitted it due to a badly broken wrist. Haven’t watched the video yet due to airport lounge flaky WiFi but hopefully it’s not too dexterous a task.

Great video, enjoyed it.

To revisit this problem again..... is the problem because of internal failure/resistance of the cable itself or corrosion/contamination of the external contact points? I guess the procedure would be the same for either option but the external issues may not need a replacement cable? Any insight would be welcome. Thanks

cdmci, I once bought a new battery as the result of intermittent and worsening issues when trying to use the starter motor..... Had a quick look for any signs of hot (temperature) at the usual connections in the various attachment points in the circuit, i.e. battery, solenoid, and the starter motor it`s self, no discolouration on the terminals, or the immediate area of the insulation at the point of connection from cable to terminal, so guessed it was time for a new battery..... WRONG... ! On the car in question, the heavy cable to battery terminal connectors were of the lead cup type, with a self tapping screw that passed through the top of the cap and into the battery terminal below. When I removed the cap from the battery the cause became obvious due to the degree of build up of verdigris/corrosion that had built up under the cap, hidden from view, and as such had increased the resistance in the starter circuit which had the effect of dropping the voltage available at the starter motor (and all other circuits) when the ign key was held in the start position.... a failure to start, that include lights dimming (or spurious fault codes) when trying to engage the starter can indeed be the sign of a possible battery failure due to age, and as in my case the battery was a few years old, I arrived at entirely the wrong conclusion.... DUH! Once the crud was cleaned up in the cup and on the terminal, everything worked as it should..! Moral of the story, check the simple stuff first..? Visual checks are good, but voltage checks are better and best carried out while the engine is being cranked over on the starter starting... you guessed it...at the battery terminals...and working your way checking each connection on the route to the starter, bearing in mind that to maximise the effect of voltage drop/resistance it is best to have the circuit under load and measure in search of a voltage DROP. I have read where there may be a "T" joint on the starter cable route which in time can cause issues at the points where the "T" is created.

Hi, digging up an old thread, I have the problem of slow or no cranking when the engine is hot. wait for the engine too cool and there is no issues with starting. Voltage on the dash showing just over 14 when cold but drops to just over 13 once warmed up. Was thinking the 'y cable' may be the culprit but when hot it turns over no problem when I connect a jump pack to the battery? Any help or pointers would be very much appreciated.

This was the problem with mine, I lived with it for years but finally changed the Y-cable. My car now starts immediately whatever the weather and no matter how hot or cold the engine is.

I'd love to know what it is about the Y cable that deteriorates and causes this. I've had a very thorough inspection of mine and it's bright copper on shiny terminals now but I was getting this issue as well just before I pulled the engine out. Mister corn did a YT vid on it and I hold his point of view in high esteem but I'm going to see if by dodgy earth and now shiny terminals will help. Just noticed MCs vid is at the top

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Hard to say, however, other than the test I suggested U.M. I would likely cut open the crimps to inspect for resistance build up due to corrosion, and re crimp them, or use solder and insulation of whatever type you use... On the other hand, might be simpler to replace...? And as you have the engine out why not pull the starter apart and check out the brushes, and clean between the commutator segments, and while there perhaps just replace the solenoid, while although robust units they are switching very high current and the contact points within can burn.... I have stripped down a solenoid on a friends 928 which ever had issues relating to the starter, and reversed the burned copper disc within to present it`s clean side across the contact points, which I also cleaned up.... Worked a treat.... Simpler to just replace the unit, as I suspect they can be bought direct from Bosch or any auto electric business...?

Yeah you're probably right but I'm on a tight budget. The starter is only 3yrs old, it's a Hella which I thought was German but it's from China. I could strip it down , I just did one on my boat engine, solenoid was duff but a new one was £22 and it now works perfectly. I just don't think it's the cables, they look like new still. Testing it on another vehicle is hard as the starters on all my stuff is really hard to get at and it needs a big engine to test it.

I purchased a new battery, the y cable, a Bosch starter and an Earth cable. Turns out I improved it 90% by cleaning the + distribution block near the gearbox and also installing a new Earth lead, again cleaning all mating surfaces and using dielectric grease Annoying as the engine was removed for work in 24 and really should have been done then by the garage, I’d have thought? Took me 10 minutes on my drive for each. Still have the cable and starter that I might fit at some point, just cos I can’t return them!

That's exactly what I'm thinking , clean up all the connections especially that one above the gearbox but also the I've made a new earth strap as mine was toast. I'm glad you've mentioned this.

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Tight budget has been a way of life for the majority of the years I have enjoyed Porsche involvement, having been brought up by parents of the WWII make do and mend philosophy..(-: I think my solenoid repair above, is an example of that..(-: As 911lufter seems to suggest even with all the components in perfect condition, all it can take is one cruddy connection be that an either the earthing or live side of things....or a combination of both, and as you know, there are quite a few connections in the starter circuit from beginning to end. It seems a relatively simple matter to clean all the points of contact that are simple to access. If you come across one showing signs of heat or crud build up, you could be on to a winner... Keeping my fingers crossed for you.. (-:

It's all done Luddite, I just need to get the engine back in to test it but the heatshields needs some TLC before I can do that. The terminals are like bright zinc plate over copper

I read this thread earlier and thought this picture might point the way as to the condition of the positive cable where it joins to the rear cable which terminates at the starter motor and alternator. The Joint terminal is attached to the side of the gearbox inside a little plastic box. I have attached a picture of what mine looks like (2007 997.1 3.6 Cabriolet). Although there were no starting issues it is clear that this joint is not in a servicable position and shows dirt and corrosion. Tomorrow I shall be cleaning everything and reassembling with dielectric grease. I hope this helps, just lucky I was seperating the box from the engine today.