To revive this old thread, I am in the middle of replacing the injector boots. Engine is out, so fairly easy job. I noticed that the contacts themselves are greased, and I read that I should use silicon grease when replacing the boots. The replacing itself is not that hard, I made a simple tool with to needle like pins on the end, which frees the two tabs on the connector. Just a little push and out come the connectors. But when I installed the first few boots, I used normal grease that you use for example for the CV joints, not silicon grease. Is that a mistake? Has the silicon grease an insulating, non-conducting function? Which other grease does not have? Or maybe a conductive function? Or is it just to be sure that the grease does not harm the new rubber boot, as normal grease maybe does? The contacts themselves were very greasy, but I cannot see which grease that was originally... So, what I would really like to know is if I have to buy special grease (and clean the first connectors I have already done), or is normal grease good as well. Thanks!
Bosch Fuel Injector Plug Kit Includes 4 Connectors and 8 Contacts with Boots | eBay These are the correct corrugated type. You will need to remove the pins form the connector housings to replace the boots. Any of the extraction tool for removing JPT pins will work fine. If you contact the seller you may be able to buy the boots separately.
thanks (nice to see the original respondents back in this thread!), but I only want to replace the boots themselves as a precaution, and have done that already on one bank of cilinders. It is easy enough with the simple tool I made. But as I read some more on this forum about which boots to replace while having the engine out, I stumbled upon this thread, where silicon grease was mentioned. I used normal grease, would that harm connections in any way?
I don't recall ever having worked on a 355, so take this with a grain of salt-- I'm sure the 355 guys can tell you for sure... but I do not believe that the injector connections were greased from the factory. As a WAG, perhaps at some time in the past a mechanic decided to add grease for corrosion protection? Two types of electrical grease are sold. The most common is actually an electrical insulator. Its purpose is to increase corrosion resistance and to make it easier to remove the rubber insulator boots. You see it used most often in spark plug boots. It should not be applied to the terminals themselves, only to the protective boots. There is also a conductive grease available, but you don't see it nearly as often. It used to be sold most often as something to apply to the horn slip rings for your steering wheel. It's intended to be applied to the contacts themselves, but you don't want it all over the connectors because it could increase the chances of a short. If you're just greasing the boots I don't see how using regular old grease would hurt. Dielectric grease offers better insulation properties, but that's more important for spark plug leads than for low voltage injector leads. I've put regular old "waterproof" grease on rubber boots for trailer connections for as long as I can remember. I can't see where it would cause a problem unless it hurts the rubber boots over time. You don't really want it on the contacts themselves though, since there's no way to know what it will do to conductivity. So the non-Ferrari-specific answer is that you can use conductive grease on the contacts themselves but you don't really want it all over the inside of the connector, and certainly not in-between the contacts themselves. And you can use dielectric grease to help keep water out and make the boots easier to remove without tearing, but you don't really want that on the conductors themselves since it has pretty decent insulation properties. Or you could use both if you wanted. And you can probably use regular old waterproof grease in place of dielectric insulator grease as long as you don't expect it to either help or hinder the connections themselves (in other words, don't use it on or between contacts). If it were my car and it had a bunch of grease in the injector boots when I took it apart I'd first check to make sure whether or not that was a factory thing. I kinda figure it's not though, in which case I'd get rid of all the old grease and then decide if the situation called for using *any* grease, and if so, which kind. If the car lives right on the coast with high levels of salty humidity, I'd be tempted to use both conductive grease to protect the contacts and dielectric grease to keep moisture out. If the car lives in a desert climate I might wipe a bit of dielectric grease inside the rubber boots to make them easier to remove but it wouldn't be a huge deal either way. I tend to try to reassemble the things the same way the factory put them together unless there's a compelling reason to do otherwise. I'm just a guy workin' on cars, so I try not to second guess the factory except when there's an obvious deficiency in the original design. Hope that helps in some way.
That sure helps! The car lives in a normal climate, not near the sea and not in a desert. But is stored inside when not used, and is only used when it is not raining. Which means it is not used much if you know the Dutch climate So I better clean the contacts on the connector and on the injector then! And finish the other 4 injector connectors boots the same way.
Unless a 355 guy says otherwise, I think I'd clean the insides of the boots and injector connections by hand and with brake cleaner or some other spray solvent. I'm an overly cautious type, so I'd put a thin coat of dielectric grease on the inside of the boot or the outside of the injector before I made the final connection, but that's it. I think you'd be better served by applying an electrical contact cleaner such as Deoxit than some random grease (not that the two serve the same purpose, but I'd rather clean the connectors than to apply something with unknown electric properties). BTW, I'm pretty sure Deoxit does make a conductive grease if you ever need one. Good luck on your engine-out service! I love how hands-on the 348/355 owners here are. Show us some pics of what you're doing in another thread. We love pics here. And make sure you post some pics of your car out in your lovely countryside once you get it running again. I've never been to The Netherlands but it looks beautiful in pictures.
