[Rwinter]

I was wondering if anyone had any ideas on this one, or if I'm just misunderstanding where the rev limiter kicks in. As I understand it, it cuts of at 6700-6800. My 94 968 had a brand new head put on it before I bought it, so when I test drove it and after I bought it, I treated it like new and did the break-in and kept it under 4500-5000. Today I was having some fun and took it up to 6k and it cut out (rev limiter; not flat spot) right at 6000-6200. As far as I can figure, its been like that since the new head was put on it. Any help on this would be greatly appreciated....Id like to have some idea whats going on before I take it to the dealer that did the head job.



Thanks!



-Rob

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[flash]

is it a tiptronic?



are you running at least 90 octane fuel (RON+MON/2)?

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[banditsc]

Does it have a aftermarket ignition system in it?

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[flash]

did they shave the head?

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[Rwinter]

Running 93 in it (non ethanol as far as I can tell), its not a Tiptronic, its stock everything, no exhaust, chip, or air box mods.

As far as I know they didnt shave the head...It was a new head so I would imagine they would have no need to shave it.



thanks for the ideas though, Ill ask about the shaving.



-Rob

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[flash]

wow - hmmm - i'm going to have to think on this one



i assume you are in the states, and it 93 RON+MON/2 and not RON

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[Rwinter]

Yep, in the states.



Unless, and maybe I'm being paranoid since a Porsche dealer would have no reason to do this but:



maybe they shaved the head that jumped time and got paid for a new one...



thanks for the help!

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[flash]

hmmm - it jumped time - i wonder if that is what is going on - if you are advanced, this would explain it

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[Rwinter]

It jumped time before I bought it, had a new head and new front (pulleys, tensioner, etc.) installed on the engine, timed and installed by certified Porsche dealership.



Do you mean that the timing might be slightly off...as in the timing is advanced? Wouldnt that hurt the engine/hammer the vales right away? Or would it mean that the vario-cam cant advance the timing at 5700 since its already advanced? and thats why it cuts out?



If thats the case it should be under warranty for the work.



Or did you mean something else?



Thanks though....that might be it.

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[flash]

it happens - if it's advanced too far, it will cut out - i would ring pete up at rs barn - he's going to be able to diagnose this a lot easier

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[S_Cal968]

By chance did you check for any stored trouble codes. I'm wondering if perhaps one of the hall-sensors [crank or cam positioning] is malfunctioning. I've heard if there's an error the DME will pull back on the timing and perhaps the cut-out too. It's common for fragile parts to be damaged during a major service.

Does the engine seem to rev freely?

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[Rwinter]

Flash: Ill give Pete a call tomorrow or Monday, thanks for the advise, timing does make sense.



S Cal968: I dont have a diagnostic thing to check for any stored trouble codes...but that also sounds likely...but wouldnt the dealer have tracked those down when they did the service? I remember when I test drove it, the cover was off the diagnostic plug so they did run one....still Ill check on it. Maybe they damaged something during the install and didnt run the diagnostics after....Thanks for the help!



-Rob

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[S_Cal968]

In case you didn't know, you can get the codes w/o plugging into the diag port. I think the procedure is in reference section of this site, [perhaps Flash can provide it's location].

Basically with the engine off, you depress the accelerator pedal to the floor and turn the key to on [not start] position and then release the pedal. The cluster should display a flashing indication in a specific sequence that defines any stored codes.. There's a list of trouble codes either on this site and/or in the service manual.

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[968gene]

Can you feather the throttle and work through the 6,000 RPM range? is the approach at full throttle? if so, try backing off the gas as you approach 6,000 and see if you can get the RPMs past this point. Your problem might be different then suspected.

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[flash]

the procedure and list of codes is pinned at the top of this section

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[Rwinter]

Ill try to grab the fault codes and see what that tells me.



As far as full-partial throttle...I never put it to the floor probably 8/10ths, but Ill check it out...it doesnt seem like a stumble though....its a full cut off.



Thanks for the ideas though...Ill go check them out.



-Rob

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[Rwinter]

I did the blink test but I'm having a little trouble understanding how to translate the blinks to the code sequences. Mine flashes 5 times at about a 1 second interval and then pauses for about 2 seconds, then the light stays on for 3-4 seconds, off for about 2 seconds and then blinks for 1 second. I thought those would translate to 1-1-1-1-1 (but codes are only 4 digits) and 4-0-0-1 (but I do not see any codes starting with 4).



(I posted this under the blink test post as well)



-Rob

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[xrad]

Rob:
thinking of your post as I hit the rev limiter today at 66-6700......

did you figure it out?

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[S_Cal968]

After the last sequence [ending with 1000] did you depress the pedal again? The only code with all 1's is a power supply issue - is your battery at full charge?

@Xrad: I'm guessing you have a stock chip installed? I have an aftermarket chip that cuts-out at 7100 and have tested it several times.... [img]style_emoticons/<#EMO_DIR#>/cool.gif[/img]

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[968gene]

I finally resolved my 944S' similar issue by replacing the lazy throttle position sensor, coil, spark plugs (also discovering that the old plugs didn't have the connection nuts installed) and having the injectors cleaned by a company in NY.

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