how to change setting in dme computer

[dreamer944]

Hi i have 85.5 944 non turbo, that at moment have problem passing emissions, I try everything new cat, new sparks, new oil, new air filter, the co is great 0.50 but my problemm is hc need to have 150 my is 200, so many people recommend retard the timing but like these cars are ecu manage So the computer is what I have to be set, I read Long ago in wilk page something abut 4 set of computer ecu Bosch, and he talk about some tool ! anyway I will like some help, do I need special Bosch tool to set computer! if not what is right way to set the different setting , without screw the computer and what will be a good setting (position switch)to run not to rich and pass emissions! lowing my hc

[hpservertech]

You can't change it. Unless you have an eprom reader and writer.

Fix the problem,dont mess with the dme to fix it. Most likely a vacuum leak. Check for those first.

[88BlueTSiQuest]

First check for obvious problems, vacuum leaks, etc..

http://members.rennlist.com/951_racerx/FQS-adjust.html

[nynor]

you can change the timing and the mixture in very small increments. however, this is likely not the issue. PM if you want more specific instructions.

[mistahsinclair]

High HC suggests running a little rich. You're not wildly over the limit so it could be an easy fix.

The O2 sensor is a good place to test. Use the O2 sensor to check the bypass on the MAF...could be wildly off.

See a post I made following some emissions trouble...high NOX for me...

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/399639-failer-emissions-what-now.html#post3844584

The links to the Lambda sensor will probably be useful.

[dreamer944]

One thing I noted is when I have car running and I open oil cap it rev drop from 1k to 850- 800rp is that normal? and it run steadily !when I put cap back it run 1krp and run quiet! is that normal in 944 ! I will do a compression test tomorrow!! how is easiest way can show me how to check the o2 sensor?before I drop $150 for one in pelicans

pd can a friendly member post a good quality diagram of vacuum system in 944na

[HondaDustR]

There is a fuel quality switch inside the DME that is accessible through a little plastic plug. It is a three cornered screw, but a small hex wrench that's just the right size will work on it. You might be able to tweak it if you really need to pass emissions.
http://www.frwilk.com/944dme/ and go to "the FQS switch".



Dont waste your money on a factory sensor. Just follow this link. The hardest part is getting the old one out if it's rusted.
http://www.frwilk.com/the944/oxygen.htm

It's probably some vacuum leak lurking around, or something like that. It might also be worth checking the AFM. Just go to the AFM tab on the first link above.

[nynor]

there you go, no searching.

[dreamer944]

weel I will like sensor original or make for 944 ! I will not want to risk time money again I found this sensor that have the plug that my car has will this be fine and fare for the pricehttp://cgi.ebay.com/ebaymotors/Porsche-911-968-944-924-Oxygen-Sensor-88-89-90-91-92-93_W0QQcmdZViewItemQQcategoryZ33557QQihZ022QQitemZ 350048887338QQrdZ1QQsspagenameZWDVW

[dreamer944]

sorry es este sensor
http://cgi.ebay.com/ebaymotors/Porsche-911-968-944-924-Oxygen-Sensor-88-89-90-91-92-93_W0QQcmdZViewItemQQcategoryZ33557QQihZ022QQitemZ 350048887338QQrdZ1QQsspagenameZWDVW

[88BlueTSiQuest]

Originally Posted by dreamer944

weel I will like sensor original or make for 944 ! I will not want to risk time money again I found this sensor that have the plug that my car has will this be fine and fare for the price

An O2 sensor is just a sensor.... It doesn't matter if it's made for a Porsche, Lamborghini, Bugatti or a Pacer, the only difference is the plug and possibly the threading.

With that in mind, there are 2 ways you can spend money. The smart way, find a $30 sensor that works(the leg work is already done). The stupid way, buy one off of ebay for $100 + shipping.

Heck, I'll go yank my O2 off of my '83, and sell you a factory original for $80, you can't beat a Porsche factory original part!!

[DarylJ]

Originally Posted by 88BlueTSiQuest

An O2 sensor is just a sensor.... It doesn't matter if it's made for a Porsche, Lamborghini, Bugatti or a Pacer, the only difference is the plug and possibly the threading.

Sorry, that's just not true. While there are perfectly acceptable replacement for the 944 O2 sensor, there are many differences in other types, not the least of which are heater or no heater (1 wire of 3/4 wire), grounded or isolated (3 or 4 wire), the wattage of the heater, the type of ceramic used, and the protection tube style.

There have been several good discussion on this over at Rennlist, one with a Bosch O2 engineer participating: http://forums.rennlist.com/rennforums/showthread.php?t=42959

That being said, I have a Bosch Universal (that was recommended in that thread) and everything has been fine for the last 2k miles - much much better than with the dead old one in there. I know others have been running on the same model universal for years with no problems.

[hpservertech]

Your also idling too high. You should be idling around 850, not 1000

[dreamer944]

Ok I will do smart way can someone please llok in ebay for one sensro o2 by bosch universal that will work fine with my 944 86 and post the link here so I can buy it or give me the right part number ! thanks by why my car has a web cam not oem cam! maybe that why is idling 1k rpms

[Brando]

Don't use Bosch universal, use the right part. Sure it may seem like a lot but you'll spend less hunting down problems that aren't there.

Check the FQS (Fuel Quality Switch). Also check that your vacuum lines are run and connected properly (although that will more often cause leaner running).

If you can, post the numbers for your failed test, this will give some of us a determining point.

You are idling high. It should be a steady 900 ± 50 RPMs. Do you know if someone installed an aftermarket chip that changed the fuel mixture and timing? That could partly explain why a new O2 sensor had no effect -- some chips ignore the O2 system.

[88BlueTSiQuest]

Originally Posted by Brando

Don't use Bosch universal, use the right part. Sure it may seem like a lot but you'll spend less hunting down problems that aren't there.

But again, why spend 2 to 3 times more for a sensor, when a 'Bosch Engineer' recommended a sensor that should cost you ~$60.

Bosch 15725

[88BlueTSiQuest]

Originally Posted by DarylJ

Sorry, that's just not true. While there are perfectly acceptable replacement for the 944 O2 sensor, there are many differences in other types, not the least of which are heater or no heater (1 wire of 3/4 wire), grounded or isolated (3 or 4 wire), the wattage of the heater, the type of ceramic used, and the protection tube style.

And yes, I am aware that there are different wire count sensor. My statement was blanket, why spend so much money on a Porsche part, when there are suitable replacements for less.

[HondaDustR]

(To anyone that thinks this idea is stupid: )

There are a bunch of different types of O2 sensors, but not nearly as many types as there are cars. Lots of cars use the same O2 sensors. The only difference between the exact Porsche part # versus the equivalents are just different connectors, or lack of connectors (if universal). BTW, A "universal" sensor is only universal within it's basic construction, ie wire count, thread size, output parameters, ect.

Just go to the link ( http://www.frwilk.com/the944/oxygen.htm ), get the part number, hop down to the nearest autozone (or equivalent) and save yourself $100 (you'll no doubt need it for something else down the road, anyway )

I replaced mine with the 13953 and it runs fine. If you won't believe FRWilk, then who will you believe? I'm sure he figured it all out already.

[dreamer944]

ok I found one in ebay seems come with plug will this plug will be same in 944 so will be just plug in or I will have to cut wires and attach to my older o2 factory sensor plug!
http://cgi.ebay.com/ebaymotors/OXYGEN-SENSOR-BOSCH-13953-FORD-FOTZ-9F472-A_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQ categoryZ46097QQihZ010QQitemZ200206840944QQrdZ1QQs spagenameZWD1V

[hpservertech]

Just go to autozone or partsamerica and get the one that's in the cross refrence. you will have to cut wires, but that's ok.

why get it from ebay when i'm sure you have a local place you can get it cheaper and quicker...remember you pay for shipping too.