Hi Guys, need abit of guidance here please. Have just changed the spark plugs on my 3.2 jag, all good started ok. Then decided to clean the throttle body. stripped cleaned ,also cleaned the air filter assembly,refitted now she turns over fires but wont pick up!! Removed the air flow meter and started the car but not running too well, then whilst running refitted the airflow and air filter assembly , car kept running but soon as turned off would not start again. Unfortunately cannot get into my local indie till next week(fully Booked) so stuck with a car that wont go , suggestions please!

 

Did you check that any electrical plugs on the Air Meter etc. were cleaned and replaced securely? Often when we dismantle something, it's very easy to forget to do so. Worth a look as it seems your issue changed course somewhat after you investigated the above.

 

yes connections all good, no corrosion, will start with the breather pipe from the rocker cover disconnected and the air flow sensor disconnected. Removed the breather pipe and cleaned all clear , refitted but will fire but not pick up. Disconnected again and starts up !!

 

Hi bigriz,

One possibility that comes to mind is either contamination of, or misadjustment of, the Throttle Position Sensor, which is mounted to the throttle body (TB). When you stripped and cleaned the TB, did you disconnect the TPS from the TB? If so, is it possible that it was not reinstalled in exactly the same position?

Is it possible that whatever cleaning fluid you used to clean the TB may have contaminated the TPS or its electrical connector?

What about the Idle Air Control Valve and its electrical connector?

Did you by chance disconnect the O2 sensor electrical connectors? If so, is it possible you inadvertently swapped the connectors for two or more sensors?

Have you scanned the system for any stored Diagnostic Trouble Codes (DTCs)? The kinds of symptoms you describe are likely to have triggered at least one code.

Please keep us informed.

Cheers,

Don

 

thanks for the reply Don, have taken the car down to the local garage, they have managed to get the car started but it seems to be over fueling. Apparently no codes have come up on his scanner. They have closed for the weekend so will have no further joy until monday. Wonder if i have made an error in not waiting till the euro specialist garage was available!!!!

 

garage thinks it could be the air flow meter, so have one arriving soon to test, hopefully this sorts the problem , next will be the tps.

 

Hi bigriz,

Without a fault code to indicate a problem with the Mass Air Flow sensor (MAFS) or its circuit, it sounds like the garage is just guessing. If so, that is a very expensive way to diagnose malfunctions...

You mentioned "over fueling" in your previous post. If you mean the engine is running rich, the O2 sensors and Coolant Temperature Sensor should also be checked. Also, if the diaphragm in the Fuel Pressure Regulator fails, raw unmetered fuel is inhaled directly into the intake manifold via the FPR's vacuum hose, causing rich running that the ECM can't correct.

Cheers,

Don

 

thanks for the reply Don.Got the call from the garage, car ready to pick up, all good apart from a very slight missfire. Great i thought, pays my money ,jump in the car starts and gets me to the fuel pump (approx 20 metres) and stalls! Put in petrol showing empty,startup and drive away and stalls in the middle of the road!! Started again drove round the corner back to the garage and stalled again.Left with them!! Apparently checked fuel pressure, injector spray pattern,removed throttle body for correct throttle positionsensor fitment &adjustment,checked ecu all good apparently,fitted another air flow meter and here we are at status quo.!!