| Author |
Message |
Bill White (Nc_newbie)
New member
Username: Nc_newbie
Post Number: 10
Registered: 2-2003
| | Posted on Saturday, February 15, 2003 - 12:49 pm: | |
I'll pull the probe but it is a new control unit on the car.
The co/hc probe was too bit to fit into the test pipes so we adjusted it post cat by running co to 0 then back to 1ppm and set it at about .9 post cat and the car runs great now. HC was about 75-100 post cat. Prior to adjustment HC was about 150 and CO was 2.6 ppm. When disconnecting the o2 sensor not HC went up by abouit 50% but the CO did not really change much. I may still try to retest at another shop precat once I have a chance to measure 0-60 time.
BTW what is the throttle microswitch and how do I make sure it and the relay are working... I have been through everything else in the motor/FI system...
Also is it worth testing the advance on all cyclinders? The ECU and TDC sensor a just a couple of years old...
Thanks JRV... |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 944
Registered: 11-2002
| | Posted on Saturday, February 15, 2003 - 11:02 am: | |
>>However "Slow down" light still stays on all the time<<
Pull the thermal probe and check to see if it's melted. If the probe extension is intact the control unit is bad.
Did checking the numbers precat help? |
Bill White (Nc_newbie)
New member
Username: Nc_newbie
Post Number: 9
Registered: 2-2003
| | Posted on Saturday, February 15, 2003 - 8:52 am: | |
OK idle problem fixed - too problems corrected:
1. mixture
2. frequency valve relay
However "Slow down" light still stays on all the time... any ideas or anyone know what the resistance of the thermo couple should be?
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JRV (Jrvall)
Member
Username: Jrvall
Post Number: 882
Registered: 11-2002
| | Posted on Monday, February 10, 2003 - 10:30 am: | |
>>Any idea's on how to debug the "slowdown" light? <<
As soon as it stops running to rich the slow down light should stay off.
The test pipes are actually for testing individual cylinders for testing the individual FD injector function/settings.
Yes just unplug Oxy sensor wire.
Don't cross the temp sen. wires...that changes the timing...cold timing is retarded by computer for cleaner hotter burn...then it switches to normal timing advance.
Yes pull the AP belt if it's actually working as this can/will also dilute readings..
Gotta jump...hope this helps. |
Bill White (Nc_newbie)
New member
Username: Nc_newbie
Post Number: 4
Registered: 2-2003
| | Posted on Monday, February 10, 2003 - 10:21 am: | |
Thanks and understood on pre-cat testing!!!!
JRV, you da' man!
I would assume that the eight test pipes can be used as the Pre-cat test point and the oxy sensor can be left in place just disconnected? Disconnecting the O2 sensor and shorting the leads of the temperature sensor in the coolant tank (to close the cold start valve does the same thing and removing the airpump belt)?
Any idea's on how to debug the "slowdown" light? Anyone know what the ohm range should be for the thermocouple?
Bill |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 879
Registered: 11-2002
| | Posted on Monday, February 10, 2003 - 10:08 am: | |
All readings MUST be taken pre-cat...For Tuning!!!!
It is impossible to read engine emissions "for SETTING/TUNING" purposes after they have been changed/washed/burned by the cat. At the tailpipe you are reading DILUTED Numbers Not What The Engine is Producing. Are we clear on that point?
Under the rear there is a Pre-Cat test port on the Exhaust Pipe..somewhere arond the inlet side of the cat. This plug must be removed and special (fabricated) adapter inserted to read raw exhaust numbers. That is where a reading of 0.8% - 1.2% is neccesary...very small fine turns of the mixture screw inside the FD are required to bring CO within spec..with OXY Sensor Disconnected and Acces Hole Plugged While reading. Once 1% CO is achieved, by adjustments at the FD, then and only then are the air bleed/bypass screws to be turned to achieve proper idle "speed"...
Once the mixture and idle speed are correct and set...plug oxy sensor back in and recheck CO & HC's. The oxy sensor should then pull the CO to about 0.5 - 0.8 %....thru it's interaction with the computer and frequency valve. If the CO is still too high the OXY sensor will cause engine to surge or miss. The tuning procedure requires setting base parameters and then fine tuning to achieve the correct results.
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Bill White (Nc_newbie)
New member
Username: Nc_newbie
Post Number: 3
Registered: 2-2003
| | Posted on Monday, February 10, 2003 - 9:48 am: | |
Thanks and scheduled a trip to the shop...Unless someone has a cheap source for CO & HC meter and 3-way fuel pressure gauges?
JRV, Can you post the tuning procedure since the workshop manual is not clear on this.
It says first check all components for correct functioning and fuel pressures (adujusting fuel pressure if necessary). Then to adjust the Vacuum with bypass screw to be between 2.6-26mbar. Then to adjust idle mixture based with the airpump belt removed to be 1.2% CO & 100ppm HC.
It sounds like you may have a different procedure by disconnecting the O2 sensor which sounds much easier?
Bill |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 876
Registered: 11-2002
| | Posted on Monday, February 10, 2003 - 9:38 am: | |
>>>shop but a Porshce shop so they are familiar with Bosche K-Jet. <<<
Well, if they didn't tell you that after cat numbers are useless for tuning purposes ...Run Forest Run....Run Like the Wind Forest. |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 875
Registered: 11-2002
| | Posted on Monday, February 10, 2003 - 9:35 am: | |
Idle & CO% are married to each other...or better put siamese twins.
and tail pipe numbers for cars running cats are useless for tuning.
One without the other is like trying to change only the dirty part of the oil while leaving the clean part in. |
Bill White (Nc_newbie)
New member
Username: Nc_newbie
Post Number: 2
Registered: 2-2003
| | Posted on Monday, February 10, 2003 - 9:23 am: | |
Thanks,
I just got the car.
I had the HC and CO % checked at the tail pipe a couple of weeks ago and CO was about 3-4% (too high - should be about 1% I think) but HC was well below the legal limit since this is an emmission state (don't remember the exact number).
I replaced the Oxy sensor and was planning on adjusting the mixture to bring it to 1% at the tail pipe. However, I noticed the idle problem and wanted to fix that first.
Since that is all of the info I have and I don't have a HC or CO tester I've scheduled with a shop to do the test you asked for along with measuring the Cold and warm pressure and to check for fuel pressure hold/leaking pressure. They are not a Ferrari shop but a Porshce shop so they are familiar with Bosche K-Jet. I'm only going to have them make the measurements and not do anything else.
Bill |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 872
Registered: 11-2002
| | Posted on Monday, February 10, 2003 - 9:11 am: | |
What are the CO% & HC readings before the cat cold & hot & hot with oxy sensor plugged & unplugged?
Without those numbers an accurate determination of possible problems & solutions is a whole lot of guesswork. |
Bill White (Nc_newbie)
New member
Username: Nc_newbie
Post Number: 1
Registered: 2-2003
| | Posted on Monday, February 10, 2003 - 8:09 am: | |
Two questions:
1) Slowdown light on or blinks. I changed the "cat control box" with a new one because it stayed on all the time and the old one was burnt up. It was ok for a couple of days after installing the new control box but now the light is back on all of the time. It appears that all voltages going to the box are correct and the resistance of the thermocoupler is about 1 ohm cold and goes up (it was 4 ohms after about 5 minutes of running) as the engine warms?
2) Idle speed problem.
Symptoms:
- Cold engine - idles too low (<500 rpm)
- Warm enginer after running a few minutes - fine (1000 rpm)
- crank a warm engine after several minutes - fine (2000 rpm until Aux air device closes then 1000).
- Crank a warm engine after just a minute or so beeing off - too low
Diagnosis so far:
- I checked the aux air device and open about 1/2 way cold and closes completely
- cold start valve firing for about 5 seconds and no drips
- no vacuum leaks (I think)
- cleaned and oiled butterfly and airmetering valve appears to operate and be adjusted correctly
- I noticed that I get a change in engine speed on when connecting and removing the wires on the thermal switch in the cooling reservoir that operates the vaccum controlled cold air valve - should this have an inpact on idle speed?
So, I at this point I think I have a problem with the warm up regulator. But before I go out and buy a full set of three way fuel presure gauges I thought I would ask.
Bill |