Computer not remembrring and setting all codes
Lots of electrical guessing
If it does not pass smog...
New plugs
Mass air meter
Fuel filter
Coolant and oil change
Battery
Runs like a jag should smoothly
Powerfully
Will not pass smog does not populate memory and reset sold random misfire code
Driven only 180 miles since new battery
Your thoughts?


1999 xk8 4.0

 

Would be nice to see the test results. HC readings, CO readings. My guess, car running too cool. If so, its not going into closed loop or it's coming out of closed loop during the test. Running too cool points first at a possibly stuck open thermostat. Are you saying it has new plugs? air meter, fuel filter and an oil change? Do you mean not resetting rather than setting ? Explain "sold" random misfire code.

 

I changed the coolant
Properly
Car has excellent hot air coming from. It
Warms up quickly
Gauge same place as before with dirty coolant
Somehow it shows a random misfire on EVERY CYL
Baffles me

 

Try OBD for codes and live data such as fuel trims. Should also show exactly which OBD monitors have not set. If no codes, look for old ones and pending ones. Don't clear them without a very good reason as it unsets ALL the monitors.

 

May or may not be related but there is a real issue with the new smog protocol that affects people who (1) have recently changed the battery and (2) don't drive a lot.

Last year my mom was in a panic when she took her 2004 Mercedes for a smog check and she didn't pass. The smog check guy didn't do a good job of communicating what the problem was but, rather, told her to drive a lot and come back. She asked me if I understood this so the first thing I did was google terms like "smog check" and "need to drive", etc. and came across a bunch of results of others with this issue.

It turns out the new smog checks here omit the usual hooking up of the car to an analyzer and running it at various speeds. All they do now is plug into the OBD port and take readings that are stored on the computer. If you recently changed the battery all of the previous readings are presumably lost and it takes a decent amount of driving to store the new required data.

My personal feeling has always been that this whole smog check thing is just another one of those typical government boondoggles that are no longer needed or justified given how clean the computer controlled cars are since the mid-1990s. Of course try and get rid of a government-mandated program, no matter how obsolete.

Doug

 

You will never pass until you figure out what is wrong and get the misfire code to clear.

 

What does this mean? Post the actual codes you are seeing.

 

i think Sesimic Guy understands what's up. I just have to drive it even more.

 

Seismic guy is partially correct in that a complete drive cycle must be completed for the car to test each system and then set a 'monitors ready' code. In the interim, other fault codes should not appear unless the car has a latent fault.

It's up to you whether you want assistance or not.

 

Mikey I think you understand as well. why else would i be here if not for assistance? It's been to a shop and they gave up after doing everything known to man. Smog place just says drive it, how long and how much? it's been a month!

 

Please supply the actual codes that the car is producing. If the car is running well with no faults there should be code P1000 and no others at this point.

 

I know I posted the codes in another thread on here. but essentially I have no check engine light...the engine shows ramdom misfires on all cyl and it must be a "soft code" yet to be reset when the car begins to populate and remember,which means a drive cycle which is now many miles or how many starts? Nobody knows.

I have replaced coil packs, plugs, mass air flow etc...fuel filter...the random misfire code came before i changed the battery which is only a week and 190 miles so i just need to drive the car more i suspect... thanks for all your help,it's not fuel or mechanical so it must be electric and i think the new battery will eventually sort it out????

 

No. You're chasing your tail.

 

Well Micky I thank you for your opinion and your assistance, you have made your point.

 

Drive cycle is something like this-
start from cold, idle 7 minutes.
Drive normal for like 10 minutes.
Drive steady throttle at 55-60mph for at least 15 minutes no slowing, no braking
Drive steady throttle at 35-39mph no braking, no slowing for about 3-5 minutes
Drive 55-60mph another 10 minutes or so

Works for me every time. I would also replace the battery as a matter of course if it is older than a year.

 

Please list the HC readings and CO readings from the test report. Does it fail at idle or higher RPM? I think the random mis fire code is a history code, not current because you say no check engine light stays on. The temp gauge is not entirely accurate. You need to verify with an infra red thermometer if its in fact, getting to 195/205 degrees F.

 

I don't believe the OP has had a tailpipe sniffer test, the smog station is reading the OBDII port, and finding codes as well as monitors not set. If so, he can drive to the moon and back and the problem will not go away until the underlying fault is cured.

 

I have trouble understanding what the OP is saying as I guess English is not their first language.

Without more, clearer, info I doubt we can help. Randomish statements are worse than useless IMO.

 

Thank you all for your opinions, it appears after the new battery and driving around for 300 plus miles and it passed smog!!!!!

 

Sounds like I guessed well regarding the changed battery issue. Either that or something else corrected itself. Either way you don't need to worry for another couple of years!

Doug