JPP

I knew that ... I'm just pokin' fun at the "naysayers" ...

Cactus

I used to do this as well until Steve Weiner said it was unnecessary.

cpdjfd107

Not to start a debate but this is the 1st season I have started my car after a long storage and I was wondering about pulling the DME. So even though it is not necessary, (nothing really is), is it still better to do or just a waste of time?

ginch

Thats good advice thank you. I have never removed the DME so I have a question. Do I need to remove the battery leads prior to removing the DME or just open up the case and remove it? Also, approximately how long do I crank the car for with the DME removed to allow for sufficient oil pressure build up?

Thanks in advance!

Derek

Mike J

This is from a guy who earns his living repairing 911's?

I doubt if a proper study has been done here to I am not sure why he would say that, but it seems to me that cranking over the engine without any fuel/ignition to make sure oil is well spread/splashed within the engine is prudent. I do this when:

1 - I do an oil change and the oil filters and sump are empty.
2- The car has been sitting for more than one or two weeks. This is based on reading articles stating that the majority of engine wear occurs on startup as the oiling system are being established, so I figure give it a head start.

Everyone is welcome to an opinion of course, and mine is the above. Worse case, it will not do any harm other than perhaps a bit more starter wear, so what's to lose?

Cheers,

Mike

Mike J

No key in the ignition but the battery connected. Pull the DME. Jump in and and crank the engine over until you see the oil pressure rise to at least one bar. Pull the key out, go back into the trunk and plug the dme back, and start the car (assuming you take the fuse cover off and on again...).

If the car has been sitting, it only takes a few seconds. On an oil change, it could take up to 10 seconds.

Cheers,

ike

Slow Guy

Not trying to start anything but can you point out that post?

Full disclosure, yes I remove the relay when doing an oil change and starting after longer period of non-use.

Slow Guy

We're too warm too early, 81 today and 83 (?) tomorrow. I think it's going to be a long hot summer.

Only thing good about hot weather is the women wear less....

Gunter

Like Mike says.

As you crank the engine with the DME relay removed, you'll notice an audible change of sounds coming from the engine as the lifters get oil plus the oil pressure warning light in the dash goes out plus the pressure gauge will flicker around 1 bar; 5-10 seconds should do it.

I'd recommend this after long storage or when changing oil were the old oil is allowed to run out over night or after a rebuild, of course.

Re winter storage: I don't believe in starting periodically during storage but instead, crank the engine occasionally with DME relay removed for a few seconds.

Plus, without the DME relay, nobody can steal your baby.

nskd3

Ugh...snowing here today after a nice sunny weekend. So it doesn't look like a long summer in New England.

Cranking the engine with or without the DME in place, don't you still create friction from the moving parts? If this is true, why would it matter one way or the other?

Gunter

Big difference between a slow crank and immediate fast fire-up with no or low oil pressure.

One example: The main bearings for the crank are a special metal and are lubed similar to Babbit bearings, Google it to see how it works. The crank literarily floats on a film created by oil pressure.

Oil pressure is extremely important and a "spun" bearing is usually starved of oil.
There is good reason why low RPM is recommended by every car manufacturer including Porsche during the break-in period.

Cactus

If I search i might be able to find it. Would be easier to ask him and let him explain.

Slow Guy

I suspect turning the engine over at <100 RPM causes less wear than turning it at close to 1200+ RPM.

Mine usually takes (2 -3) 5 sec. cranks to get up to about 2.5 bar, then I put the relay back.

I used to think having a summer home and a winter home would be nuts (I'm from Fla. and we had lots of "snow birds") but as I've gotten older it's sounding better and better.

Ocean Blue C2S

Where do you unlpug the DME relay on my OBDII setup ( 1998 Porsche 993)???

I am totally unfamiliar with these electronics, never had that issue on the 6 Porsche 356 models that I owned... Picture would help?

Cheers,

Bert

ginch

Hey Bert,

It located in the fuse panel on the passneger side in the trunk. Just un button the carpet at the top which reveals the fuse panel. Its very accessable!