Mechanics

NEED HELP TO REPAIR ROUGH IDLEWHEN COLD AND ENGIND CODES THAT KEEP COMING BACK P0170 AND P1188

1998 BMW Z3 • 15,500 miles

Working on a 1998 bmw z3 roadster with a2.8 engine and the check engine light comes on the codes are p0170 and P1188, when the car starts up cold it runs rough and when it goes into closed loop it smothes out and runs fine. The intake and vac lines were smoke tested and leakes repaired. New plugs, fuel filter and ccvv/oil seperator was replaced, idle air valve cleaned, air felter cleaned. Data on a scane tool first time the front o2 sensor read 0% at.92volts and o2 sensir after the cat read 99.2 at.96 volt, replaced the front o2 sencer and rechecked date and the voltage on the front o2 sensor started to go up and down as needed.79 volt to.98 volts and read 25% rear sencer stayed at 99.2 % the car still runs rough at cold idle. Maf was changed not differance. Air control valve was changed no differance checked fuel pressure with 3 different gauges fuel pressure was 44 to 51 PSI depending on what gauge was used. Tps reads 17 to 18 on at idle. With the reading of the o2 sensors is the fuel pump not putting out enough pressure. The car at times will have blacke smoke. Your help or answer on this matter will be very helpfull. If it is the pump how do you get to it.
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Texasdawg2003
June 18, 2012.




If more information please ask I well get information needed to repair car as needed. To repair codes and cold starts


Tiny
Texasdawg2003
Jun 18, 2012.
Both codes are related to long term tirms out of range.

Possible causes are vacuum leaks, low fuel pressure, pcv system, mass air flow sensor. All these need to be verifed by a shop with a scan tool that can monitor these systems.

Roy


ASEMaster6371
Jun 19, 2012.
The intake was smoke tested for leaks. Ccvv was replaced, mas air flow was replaced and no differance what should fuel presssure be and numbers do you need to see from the monitor


Tiny
Texasdawg2003
Jun 19, 2012.
Was the smoke test done cold when the issue occured. When it gets hot and runs better, the seals expand and seal off vacuum leaks.

Roy


ASEMaster6371
Jun 19, 2012.
The test was done cold I did another test I took off the pcv hose and pluged it and it ran fine cold and worm is there an air reductucting valve in the valvle cover or tubing. Someone else changed the valve cover gasket so I dont know if there is one or not it did not run rough or set the pending codes like it did before I pluted the line is the spark plug tube seals leaking+


Tiny
Texasdawg2003
Jun 22, 2012.
If you leave it plugged, it will not allow the crankcase pressure to vent and you will create oil leaks. Just replace the valve.

Roy


ASEMaster6371
Jun 22, 2012.
Ccv has already been replaced it was doing the same thing before it was replaced it olny idles rough when cold as soon as it goes into cloased loop it runs fine


Tiny
Texasdawg2003
Jun 22, 2012.
I hear you but I still feel you have vacuum issues when cold and they seal when warm. The people working on the car, are they bmw techs?

Roy


ASEMaster6371
Jun 23, 2012.
Spark plug tube seals and valve cover was replaced again one the first start it did not run rough on start I will see it it runs better on next start it looks like was not holding vacume in eng what should the o2's read while runing
AD


Tiny
Texasdawg2003
Jun 23, 2012.
You need a scan tool to read this as they are fuel ratio sensors. The trims are important as they should be under 5%

Roy


ASEMaster6371
Jun 23, 2012.

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