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Old 10-04-2018, 09:31 AM   #1
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Mike, Since your car is cranking slowly but can run, I would think you have a power delivery issue either due to too small cables or weak ground. Does the car always crank slowly? This can be an issue since the starter is consuming all the electrical power the resulting voltage drop is insufficient to supply the DME to fire users like the fuel injectors, fuel pump and plug coils.

My suggestion would be to temporarily run direct cables from ground post to the engine block and one to the body near the DME. If still no go then a positive jumper directly to the starter then test.

Last edited by 911monty; 10-04-2018 at 09:43 AM.
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Old 10-04-2018, 11:31 AM   #2
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Quote:
Originally Posted by 911monty View Post
Mike, Since your car is cranking slowly but can run, I would think you have a power delivery issue either due to too small cables or weak ground. Does the car always crank slowly? This can be an issue since the starter is consuming all the electrical power the resulting voltage drop is insufficient to supply the DME to fire users like the fuel injectors, fuel pump and plug coils.

My suggestion would be to temporarily run direct cables from ground post to the engine block and one to the body near the DME. If still no go then a positive jumper directly to the starter then test.


It is a 1999, all spec boxster run the 5.2.2 (97-99) DME (I think thats the number)
I have used a M535 (which is stock to my SPB) and a M531 immobilizer (with the appropriate key/dme that pairs with it)


Clarification:

Via battery or jumped -- she cranks fine -- to the point of 40psi of oil pressure -- cranking is not the issue.

It's only when Amps are limited by the jumper cables does the cranking become very slow -- but it seems as if the higher voltage is sufficient to make the difference because it fires -- at least thats the only way I can make sense of things.

I have checked both positive and negative cables. Even while cranking, I only see a 400mv drop from battery to starter (in battery mode) and a total drop of about 1.5V total (due to load on battery). This seems to be fairly typical.

Note when it does start -- it drops through the jumper cables to about 8.5v! But somehow it seems as if the initial voltage is the key -- but I don't know.

thanks for the suggestions tho -- I might have missed something... (ok clearly I have or I would have figured it out by now)


Mike
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mike@lonestarrpm.com

Last edited by seningen; 10-04-2018 at 11:58 AM.
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