Rennlist - Porsche Discussion Forums - 964 Turbo Forum

In need Advice on porsche

Mikejr — Thu, 04 Jun 2026 15:15:10 GMT

I�ve always loved the classic air-cooled Porsches, especially the 964 and 993. In your opinion, which one offers the best ownership experience and why? I�d love to hear from owners and see some photos of your cars.

It's Here. NEW EZ 69 units 3.3 and 3.6 Turbo

heliolps2 — Sat, 30 May 2026 19:31:54 GMT

Hello everyone,

I have some great news to share regarding the new solid-state replacement for the Porsche EZ 69 ignition control unit.

Last year, both Anthony and I sent our original EZ 69 units to Steve to assist with the development and testing of his new replacement module. A few weeks ago, we received the first test units back from Steve, packaged in some incredibly nice hard cases. The new units even look very similar to the factory Bosch units, which is a nice touch for those of us who appreciate originality.

Our initial testing was a mixed success. Both cars started immediately, but neither ran particularly well. We experienced rough idle, popping, and general drivability issues. The good news is that Steve was extremely responsive. We sent the units back, he made some adjustments to the calibration, and the turnaround time was impressively quick.

I reinstalled my updated unit a few days ago and have already logged over 200 miles. So far, there's really nothing exciting to report�which is exactly what you want from an ignition module! The car starts, idles, and drives exactly as it did with my original EZ 69. In other words, it works as well as the stock unit.

For those not familiar, the EZ 69 is the ignition control computer used on the 964 Turbo. It receives engine speed and load information, processes ignition timing maps, controls ignition advance and retard, knock control, boost-related timing adjustments, and ultimately commands the ignition output stage. These units are now over 30 years old, and age-related failures of internal components, solder joints, and capacitors have become an increasing concern. Having a modern solid-state replacement eliminates many of those reliability concerns while retaining factory functionality.

An added bonus is that I can now safely store my original Porsche EZ 69-01 unit as a backup and preserve it for the future.

Anthony should be receiving his updated unit on Monday and will report back on his experience as well.

It's great to see a modern, solid-state solution becoming available for one of the more critical electronic components on our 964 Turbos. If long-term reliability proves to be as good as expected, this could be an excellent option for owners looking to future-proof their cars while maintaining stock operation.

I'll continue putting miles on mine and will provide updates if anything noteworthy comes up.

Best regards,
Helio

Overboost

Carrerafourturbo — Sat, 30 May 2026 17:26:27 GMT

Hi all! Another question. What can happen to twin turbos during/after an overboost? Anything consequential? Thanks, no boost. carrerafourturbo

Twin distributors, which distributors fire upper/lower plugs?

Carrerafourturbo — Sat, 30 May 2026 16:51:07 GMT

Hi all! I just entered a disertation on the 911 forum, probably should have been here. In short I have a converted '91 911/964 to a 3.8L, TT. Electronic boost control allowed me to overboost ( only time in years). While tuning it up and replacing many hoses, I noticed that the master distributor fed the LOWER plugs, the slave then feeds the UPPER plugs. I read SOMEWHERE years ago that this is backwards. It's been this way a long time. Adrian says BOTH upper and lower (Companion) plugs simultaneously fire. Anyone know if "backwards " makes a difference? I replaced all "air" hoses but still have NO boost. Leaky hose(s), turbo(s) unhappy, distributors switch (doubtful). 700+HP acting like stock 964 w. 250 (whole) HP! Any ideas, HELP! Many thanks, carrerafourturbo

turbo gets rich when hot

peterpullin — Sun, 24 May 2026 08:16:10 GMT

hi guys, i do the repais and maintenance myself for years. fuel head, full engine rebuild, etc. now i ran in an issue i can not solve for a wile.

all fuel pressures are fine warm and cold.
system pressure in spec.
car starts warm and cold
afr cold 12.5 apx.
both pumps new or old - no difference
fuel accumulator new or old - no difference
check valve new - or old no difference
fuel head rebuild and checked flow and amount of fuel. fine so far

if i start the engine and let the car sit it starts at 12.4 afr and gauge quickliy raises to 10,0 and freaks out: too rich.
fuel pressure starts in spec and rises as it should. complete in spec.

i have no ides what to do next. car runs fine with pedal to floor (ways too rich) - but no crusing or power in mid range.

checked everything 10 times. running out of ideas.

WTB: 964 Turbo CARGRAPHIC GT-Sport Exhaust System

salastro — Sun, 17 May 2026 09:10:43 GMT

Hi - I am looking to purchase in good condition 964 Turbo CARGRAPHIC GT-Sport Exhaust System. Let me know if you are willing to sell or trade.