[insite94]

Hi All -



I just installed my RacerX Speed-6 chip this morning. Long story short, this hopeful skeptic is now a believer. What a difference this chip makes in performance!



But...detonation/pinging/pre-ignition occurs at exactly 6000 rpm and stays on until 6500+/- rpm. <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" /> Feels like instant headwind accompanied by clattering of detonation, then it regains composure on up through redline (wherever that is since I haven't revved it there, and probably won't, at least not on purpose).



Car is an early '92 - NS820089 (#29 off the assembly line). 91 octane gas (don't have 93 at the pump in CA) is fresh (1 week old).



Anybody have an ideas on how to eliminate this? Mis-match/bad chip, add race gas to the mix, let the engine get hot first, add fuel system treatment to get the gunk/carbon off the valves/head/plug?



Stumped - All wisdom appreciated.



Thanks!



Buzz

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[Dave]

5+ years into 944/968 ownership, I am finally a believer in replacing the DME relays on these cars with a fresh one (993 part number). Don't know if this will help, but my DME relay gave me similar issues at the track yesterday. It was original (Nov'91) and I limped home on the relay out of an '86 951.



I have two relays on order from Paragon as a result.

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[flash]

nuts - i was afraid somebody would do this



i cautioned every step of the way that you probably cannot run the racer x in an early 92, and that it was only for the later DME, but somehow i just knew that information would end up getting skipped somewhere - bummer



for the record - only autothority and weltmeister make chips for that DME - the weltmeister for the early model was on sale at performance products for 179 the last time i looked (it was 279 for the later one)



call me when you get back from the tire store

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[Silver BLT]

Buzz,

Did you try adding a few gallons of 100 octane like Joe suggested?

Silver BLT

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[promax]

Hi Buzz,



Firstly, your chip is likely to be fine. The chip is a pure binary device and is unlikely to be the cause of any problems. Your really need high octane gas (93) but you should still be OK with 91.



Is this only happening under WOT (Wide Open Throttle)?



I would investigate the following

* MAF calibration (causing too lean a mixture at WOT)

* Vacuum leaks (causing too lean a mixture at WOT)

* Poor Injector Spray Pattern



I can also send you a ProMAX Chip to try. This will help you identify whether the chip is a little too radical for your particular engine (i.e. state of wear, calibration of MAF etc.). If both the Racer and ProMAX chip cause the same symptoms - you will then know you have some issues to investigate.



If you need any help - please get in touch. andrew@promaxmotorsport.com



Regards,

Andrew





[quote name='insite94' date='Jul 23 2005, 12:32 PM']

Hi All -



I just installed my RacerX Speed-6 chip this morning....detonation/pinging/pre-ignition occurs at exactly 6000 rpm and stays on until 6500+/- rpm.



Anybody have an ideas on how to eliminate this? Mis-match/bad chip, add race gas to the mix, let the engine get hot first, add fuel system treatment to get the gunk/carbon off the valves/head/plug?

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[promax]

Hi All,



I would like to add that both ProMAX 7100A and 7700AT versions are suitable for use in all USA model 968's. We have had no issues with any year (early 92 thru to late 95!)



Regards,

Andrew



[quote name='flash' date='Jul 23 2005, 01:30 PM']nuts - i was afraid somebody would do this



i cautioned every step of the way that you probably cannot run the racer x in an early 92, and that it was only for the later DME, but somehow i just knew that information would end up getting skipped somewhere - bummer



for the record - only autothority and weltmeister make chips for that DME - the weltmeister for the early model was on sale at performance products for 179 the last time i looked (it was 279 for the later one)



call me when you get back from the tire store

[right][post="7805"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

that's very cool to offer



i agree the chip is probably fine - i also agree that you are likely seeing a lean condition - the engine condition can certainly be a contributing factor - the pinging and knocking tells me that you may have defective anti-knock sensors or a defective O2 sensor - i would look at those too, especially if the high octane fuel fixes or changes the problem



the early 92 (and i do mean EARLY) uses a different ECU than the rest - the part number you would be looking for is 0261-200-474 - as far as i know, based on previous threads and phone conversations, the promax, like the racer x, is developed for unit number 0261-203-070 - buzz has car #29 and he has the late ECU, so this is a non issue for him



all other chip manufacturers say that the units are DIFFERENT and that the one for the later unit should not be used in the early unit - could be a marketing thing - who knows?



that being said, so far, i have not even seen an early unit, so i have not been able to verify any of that - i think we are only talking about a handful of cars though



as far as i know, only autothority and wetmeister claim to make chips specifically tuned for the early ECU - other chips may work, but i would have to see the air/fuel charts to see - as i said though, i haven't even seen an early ECU yet, let alone tested one, so that isn't likely to happen



if you are one of the rare people to have one of the early ECUs, i would still play it safe and go with the weltmeister until somebody does some testing and has data to show

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[insite94]

[quote name='Silver BLT' date='Jul 24 2005, 10:11 PM']Buzz,

Did you try adding a few gallons of 100 octane like Joe suggested?

Silver BLT

[right][post="7852"]<{POST_SNAPBACK}>[/post][/right][/quote]



Ron -



I tried the 100 octane, which did the trick. Pinging went away, which was good. Turns out my ECU is the later model so no problem with an early unit. All is well...almost.



Now I can't get the MotherShip Light (MSL) accompanied by 'airbag' to shut off. Not sure this is chip-related since the light came on for the first time in 6 months PRIOR TO my installation of the chip. Shop said they couldn't find a code, so they reset. Driving down the road the light came on again. Then I installed the chip. No dash light issues for the first 2 starts (even during the pinging sessions) Now it's on from the moment I release the emergency brake.



Bob suggested it might be something bordering the edge of failure like an oxygen sensor or knock sensor, but then a different light should be on, I think.



I drove it 350 miles with the chip with no other issues and the pinging is gone (for now) even on 91 gas.



Now...to chase down and fix that MSL!

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[insite94]

[quote name='promax' date='Jul 25 2005, 01:29 PM']

Hi Buzz,



Firstly, your chip is likely to be fine. The chip is a pure binary device and is unlikely to be the cause of any problems. Your really need high octane gas (93) but you should still be OK with 91.



Is this only happening under WOT (Wide Open Throttle)?



I would investigate the following

* MAF calibration (causing too lean a mixture at WOT)

* Vacuum leaks (causing too lean a mixture at WOT)

* Poor Injector Spray Pattern



I can also send you a ProMAX Chip to try. This will help you identify whether the chip is a little too radical for your particular engine (i.e. state of wear, calibration of MAF etc.). If both the Racer and ProMAX chip cause the same symptoms - you will then know you have some issues to investigate.



If you need any help - please get in touch. andrew@promaxmotorsport.com



Regards,

Andrew

[quote name='insite94' date='Jul 23 2005, 12:32 PM']







Hi Andrew and thank you. Yours is a kind and generous offer...very much appreciated. And yes, the car only had issues at WOT. Non-WOT acceleration didn't cause the pinging. But 3 gallons of 100 octane seems to have solved the problem for now, though it would not hurt at all to run some injector cleaner through the fuel system in hope of improving the spray pattern. I will do that this week.



No need to send a chip at this point, but that may change. Now if I could just eliminate the airbag MSL <img src="/forum/images/smilies/968/dry.gif" class="smilie" alt="" />



Again, Andrew, many thanks for your offer.



Best,



Buzz

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[Silver BLT]

Buzz,

Very happy to hear the pinging went away, Joe knows his stuff. About the MSL, have you replaced the DME relay yet? I know they have caused a myriad of issues one would think is non related.

Silver BLT

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[odb812]

andrew, i definitely have the early dme unit, my vin is 076. are you sure that your chips would work in my car? i have an autothority chip now, but i would like to replace it with a better chip.



[quote name='promax' date='Jul 25 2005, 03:31 PM']Hi All,



I would like to add that both ProMAX 7100A and 7700AT versions are suitable for use in all USA model 968's. We have had no issues with any year (early 92 thru to late 95!)



Regards,

Andrew

[right][post="7873"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

odb812 - have you actually checked that? - car number 29 (VIN number 89) has the later unit - i haven't been able to nail down where the cutoff was - i specified the DME part numbers above - they should be clearly visible on the outside of the box



as for changing chips, i've told everybody the same thing, if it's working fine, and unless you are racing, or really pushing it from 6500 up, and need every last pony, i wouldn't bother - the difference, while easily seen on paper, is not really noticable in the car

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