If you put the (28-pin) chips in backwards on S4-up, it will not run. The chips can be turned around and usually will run.

On a S2/S3 put a (24-pin) chip in backwards and it will fry. Cannot be erased or repaired.


S3 chips should be installed in pairs as the extra ignition advance needs better fueling for safety.

S4 can use whatever EZ chip because of the knock sensors. Ideally installed in pairs, but most of the power increase comes from the ignition chip.
The S4.S300s EZ chip creates a custom WOT map for each installation and constantly adjusts the overall advance level for conditions.
(I sell the EZ chip separately for S4s for use with the stock 19# LH chip.)

 

I personally, was able to damage the solder on the chip carrier by changing my chip one time. That is something to remember here. It sounds like random people with random chips have been in and out of this car multiple times.
I don't know if the S4 boards are hardier then the S3's but...

I gotta go with AO, something else was likely going on. Chips are likely fine, but...betcha Ken would check them and validate that. In fact, I bet he's already offered.

 

I was thinking the same thing. Or if they tried disconnecting / reconnecting after the install on the chance that the chips took a bad reset?

 

Sounds like they bumped the Temp II sensor connector while installing the fuel injectors. What's been described here has nothing to do with the chips.

 

Yes it was certainly the case that something was affected during the swap, which was basically a failure of the whole Temp circuit. But still no one knows why, since the reassemble works very well (I just drove it to Santa Clara and back, 300 miles, ran like a top with proper mileage). They re-tipped my old injectors, so that's something good.

I wonder why they don't do LH or EZK module diagnostic checks at my shop. At least I don't think they do. I've never heard anything about that before.

And yes please don't let this story tell you anything bad about Ken's chips! There's nothing likely wrong with the chips. The story is just about how hard it can be to get everything right on these cars, even when you have know-how and test equipment.

Sorry Ken I don't mean this thread to be anything against your chips; it's all about the whole process presenting multiple challenges for different reasons.

 

Hidden in all this is one of the reasons that it's very tough to find a shop that will work on the 928, and in that fraction find a place that doesn't pile insurance money onto every repair. Kudos to Sean's shop that they work on his car for fair prices, and stood with him honestly through the whole upgrade episode. On these older cars, it's always a crapshoot on what collateral damage will be done during any regular service or repair. Most of us have learned to take care of the long list of WYAIT's during any procedure, but know that it's darn tough to convince a car owner that that some $300 job really deserves to have another $1k thrown at it for insurance/WYAIT against some possible future failure.

I had installed the replacement LH controller in Sean's car before it was his, rebuilt by Rich Andrade in Phoenix. My spare went into the car while his was redone so virtually no downtime was experienced. The car ran fine with the Autothority chipset in there. So the failure with installation of Ken's chips is a headscratcher, especially when the controller suddenly came back to life after testing, when nothing obvious was changed. Headscratcher for sure, thankfully with a happy ending.

 

Thanks dr bob for not posting another one of those "your shop is stupid" missives that a lot of folks fall back on. Things happen with these cars that are hard to track down and figure out, it's all part of life. The shop I use may not be as expert as Greg Brown but they are closest thing we have around here. They are straight shooters that I have relied on for many years, since my days with the 944.

After this whole episode, the owner told me that he will no longer agree to assist any clients with mods, chips, etc. So there goes another one.

I just wish they had trusted Ken's chips more, but their instinct was to undo what *seemed* to cause the problem, only to find out that was not the case.