Jeff928S4

Just got back from the mechanic who did my timing belt. After everything was put back together, the car runs very rough.

Thing is, when I first test drove it - the battery was dead and it took about 10 minutes of starting and stalling and a bad idle and then all of a sudden, it ran great. I figured the brain needed to "re-set" itself after the battery was unhooked.

The battery was unhooked again for the belt (and other stuff). The mechanic took off the air intake hoses and I remined him it was a hotwire system and he put the hoses back on and it idled great - but if you give it gas....nothing.

He took the hoses off again and put his hand over the air intake screen and it ran perfect - took the gas and everything. He thinks it's the air sensor, but I still think it just needs to re-set itself.

What do you all think? That sensor is costly and I don't want to get it put on if it's not needed. Anyway to check it or is there a procedure upon re-starting the car after the battery was unhooked?

Thanks,
Jeff

Garth S

I guess a MAF (air flow ) could die at any time, but I'd start by going back over all the things touched/disturbed/opened during the TB procedure.
There are the usual sensor connectors, as on top of the thermostat housing. Perhaps the more critical is the 14 Pin connector of the front engine harness as it engages it's male socket just behind the hot terminal on the right fender ( this was opened in the procedure).
The LH & MAF Guru's frequently recommend disconnecting the MAF harness and restarting the car: if it runs better in a 'limp home mode', the MAF is suspect. From the "test drive" experience, the MAF connector may also need to be cleaned up. ie., you're seeing the same (intermittant) experience again.

worf928

There is no reason to disturb the MAS (Mass-Air Sensor) during a timing belt change.

Garth's idea of checking all the stuff that was disturbed by your (ex-)mechanic is a good one. Go to Pirtle's site:

http://members.rennlist.com/pirtle/

and use his excellent timing belt change procedure as a guide to what you need to check.

Quote:

Anyway to check it or is there a procedure upon re-starting the car after the battery was unhooked?

The idle controller is adaptive and adapts - effectively - to wear and tear. The adaptation requirements are stored in the ECUs and are cleared when the battery is disconnected. There is a factory procedure for quickly re-adapting the idle with the Bosch Hammer. The 'standard' way for those of us without a factory $2500+ tool is to simply let the idle re-adapt at its normal pace - which could take a while (hours of driving and many minutes of idling interspersed) if your car needs a lot of 'adaptation' due to old rubber and vac lines, etc.