Readiness moniters

[Bugsinrugs]

My battery died recently and of course I Lost my readiness moniters. Driving the BMW cycle just did not work this time. So I took my car to a dealer and they got them to set but when the car is turned off they disappear. No check engine light or stored codes are present. Anyone with any ideas? Oh yeah. I have a 1996, 993

[matt demaria]

It sounds as if the dealer did the 'short test' which forces the computer to check the monitors. This is used to check the hardware only but does not take the place of the normally computer commanded tests.
IIRC the monitors will try to run 3 out of 10 drive cycles (for the early cars) where a drive cycle is defined as starting with the oil temp (or coolant) and the air temp is between 30 and 85 degrees and the two are no more than 3 degrees apart. The gas tank has to be between 1/4 and 3/4 full.
1996 Porsche was one of two cars that had a federal exemption for the monitors because of problems with the software.

[Bugsinrugs]

Thanks. I am going to talk to the technician that worked on my car today. I am still confused because they say it wil pass the smog test. Just don't shut off the engine

[lateforlunch]

Ive seen this before on 1996 model year cars, Ive also seen where the DME just flat out refuses to click off the readiness tests. Unfortunately in both situations a new DME was needed to correct the problem. If you wind up replacing yours replace it with a '97 -'98 version as the '96 is problematic.

[Nine9six]

Originally Posted by lateforlunch

Ive seen this before on 1996 model year cars, Ive also seen where the DME just flat out refuses to click off the readiness tests. Unfortunately in both situations a new DME was needed to correct the problem. If you wind up replacing yours replace it with a '97 -'98 version as the '96 is problematic.

This is inaccurate and incorrect statement.^

Yea, a 97 or 98 DME is preferable, but this is due to the EDIT (flashable chip), as opposed to the non-flashable chip in.the 96 DME.

[lateforlunch]

Originally Posted by Nine9six

This is inaccurate and incorrect statement.^

Yea, a 97 or 98 DME is preferable, but this is due to the chip socket, as opposed to a soldered in chip in.the 96 DME.

While I admit calling 1996 model year DME's "problematic" might be a little overboard I dont see where its necessary to say my entire statement is inaccurate and incorrect.

Im not a liar, I've replaced 2 1996 DME's. The first was due to readiness issues not storing completed trip information. The second wouldnt click off the tank vent test no way no how, swap the DME and presto it clicked off all readiness tests.

Just offering my experience

[Bugsinrugs]

Sorry, but being a novice. Is the DME the same as the ECU? Thanks

[lateforlunch]

correct DME = ECU

DME is digital motor electric

[Bugsinrugs]

So, I found a company in Florida that will go over my DME and upgrade it to make the monitors easier to set. Sounds good to me. Any opinions? Cost would be 695

[mysocal911]

Originally Posted by Bugsinrugs

So, I found a company in Florida that will go over my DME and upgrade it to make the monitors easier to set. Sounds good to me. Any opinions? Cost would be 695

Right, their "upgrade" is a modification to always have the monitors set.
If the ECU is really a '96, the modification is complicated compared to
the later ECU ('97/'98) and less reliable. By the way, neither ECU has
a chip socket, i.e. the main difference is that the later ECU is flash-able.
Also, the '96 does not have an inherent problem retaining the monitors
with the key 'off'.

[Bugsinrugs]

Originally Posted by mysocal911

Right, their "upgrade" is a modification to always have the monitors set.
If the ECU is really a '96, the modification is complicated compared to
the later ECU ('97/'98) and less reliable. By the way, neither ECU has
a chip socket, i.e. the main difference is that the later ECU is flash-able.
Also, the '96 does not have an inherent problem retaining the monitors
with the key 'off'.

Can you clarify? Above says there
is an inherent problem but your saying there isn't.
Am I misunderstanding?

[Nine9six]

Originally Posted by mysocal911

Right, their "upgrade" is a modification to always have the monitors set.
If the ECU is really a '96, the modification is complicated compared to
the later ECU ('97/'98) and less reliable. By the way, neither ECU has
a chip socket, i.e. the main difference is that the later ECU is flash-able.
Also, the '96 does not have an inherent problem retaining the monitors
with the key 'off'.

Dave is correct, and I was wrong about the soldered vs socketed chips.

The 95 993 has the socketed chip. 96 thru 98 have soldered chips, but the 97 & 98 DME are flashable, whereas the 96 is not.

So, I found a company in Florida that will go over my DME and upgrade it to make the monitors easier to set. Sounds good to me. Any opinions? Cost would be 695

The cost is unnecessary...
I reset my drive cycle monitors the first time out, per the sequenced resetting procedure.

Drive Cycles

I used the cycle out of Adrian Streather’s “Porsche 993: The Essential Companion” (p. 192). It specified:
Cold start, idle for 10 to 15 minutes
Drive at 2200 rpm for 8 miles
Drive at 2500 rpm for 5 miles
Drive at 1800 rpm for 8 miles
Allow to idle for 3 minutes.

Since it specifies rpm rather than speed, it is easier to do.


Porsche 993 cycle"

1) Start cold engine and idle for approximately 2 minutes, 10 seconds. This checks secondary air injection and evaporative leak detection systems.
2) Accelerate to 20-30 MPH and maintain steady speed for 3 minutes, 15 seconds. This establishes closed loop oxy-sensor operations, response times & switching times.
3) Accelerate to 40-60 MPH and maintain steady speed for 15-20 minutes. This evaluates catalytic converters while oxy-sensor response and switching times are checked.
4) De-accelerate and come to a stop. Idle for 5-6 minutes. This checks evaporative leak detection system.

Remember:
The diagnostic checks above will be discontinued if:
1) Engine speeds exceed 3000 RPM
2) Large fluctuations in throttle position
3) Road speeds exceed 60 MPH

I hope this helps...
p.s. Go to rennlist.com, to the 993 forum and search on, "drive monitors"

[Bugsinrugs]

Thanks, I have done the BMW drive cycle six times. That's the second cycle listed. The monitors still would not set. The dealer got them set but shutting off the engine erase the monitors.
That seems to me a problem with the DME.
When I have the time I will try the cycle again.
Thanks again for the replies.