http://www.914world.com/bbs2/index.php?sho...298758&st=0mepstein wrote:We have 20 bad ecu's (3.2 engine computers) in the shop. I sent a couple to Steve Wong / 911 Chips for repair. He asked if they were from a 914-6 conversion car since they had a particular defective part. They weren't but most of our cars are 3.2's into early 911's so sort of the same idea. Steve said the reason we were blowing ecu's is because we were mixing the ecu's with a non 3.2 tach. It's very common for a 914 conversion to either modify their 4 tach with an electronic unit or modify an early tach to work with the 3.2. Steve said it may work for a short time, sometimes longer but failure often happens at high rpm. Go to the track, ralley or just some spirited driving and the higher rpm's kill the ecu's. I have to believe him since we have a pile of them to prove it. We had one burn out after 1.5 miles. Even hooking up the shift light wire on the 3.2 tach incorrectly will burn up the ecu's. Not right away but over time. A rebuilt ecu runs $900 and the burnt core is worthless. It's a known problem so it isn't accepted by most, if not all of the ecu rebuilders. You also must use a coil for a 3.2. No substitutes.
https://www.pca.org/tech/32-dme-vs-tach-compatibility12.01.2016 Asked by Larry Moeller [GG]
"a post recently appeared on 914World suggesting that a 3.2 DME can (and probably will) be irreparably damaged (fried) if hooked up to an older 911 tach (i.e., anything other than '84-89) or any converted 914-4 tach
I have a 914/6-GT with a 3.2 & Wong chipped 082 DME, and have been running a 911 tach (OEM to my car, 901.741.302.04) for past 3 yrs (albeit not more than a few thousand miles & no racing nor prolonged high-rpm)
when i did the 3.2 conversion, Palo Alto Speedometer checked/refurbished my old Tach & said it was compatible with the 3.2
nevertheless, the 914World story scared me enuf to buy a 3.2 tach as "insurance", (which i am installing tomorrow)
but, i am wondering: (1) if there is really any validity to this, and (2) secondly if SC tachs are exempt from the worry, since there seems to be controversy on that point??
the post link is:
http://www.914world.com/bbs2/index.php?showtopic=298758 ALSO SEE
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http://forums.pelicanparts.com/porsche-911...ty-chart-3.htmlhttp://forums.pelicanparts.com/porsche-911...tml#post3972081http://forums.pelicanparts.com/porsche-911...an-replace.html