ECU or bad tune-up?

[alex673]

Hey guys,

I have a '95 VS series I with about 249,000KM's on the clock. It's a bit tired, looks a bit shabby, but has been extremely reliable. (Most of the km's are highway)

Anyway, I had a major service and tune up done a few months back, and have noticed 2 distinct problems...

1. The fuel economy has gone up the sh**! I used to get about 450km in the city prior to this service, and now am lucky to get 250. My driving habits haven't changed, and the only difference post service is a new battery

2. The trans slams into gear late, and no matter how you drive, it is no longer smooth in changing gear. The only plus is that it goes a lot quicker on takeoff...

My feeling is that the mechanic has somehow stuffed up the standard tune of the car, and it is running extremely rich, thus the crap fuel economy and the extra power on take off. Does this sound feasible, or am I just thinking too much into it?

A friend of mine suggested that I reset the ECU with the battery disconnect, then crank it and rev to 3000RPM for 10 Seconds... Tried it, but didn't seem to make any difference.

Any advice would be appreciated.

Cheers

Alex

[danja]

The tune is electronic, you can't screw with it accidentally

Possibly he's screwed up a sensor? Have you checked out your MAF, O2, TPS sensors?

[ephect]

the delayed gear changes dont sound health, and will hamper fuel econ, its prolly due for a trans service or reco. generally o2 sensors as danja meantioned, often are overlooked and havent been changed since rolling off the factory.

whats been serviced lately, replaced, or changed?

[alex673]

the delayed gear changes dont sound health, and will hamper fuel econ, its prolly due for a trans service or reco. generally o2 sensors as danja meantioned, often are overlooked and havent been changed since rolling off the factory.

whats been serviced lately, replaced, or changed?

The only thing that has been changed lately is the battery. I watched the mechanic spray some sort of hi octane cleaning fluid through the plenum and intake, and bucket loads of carbon build up came out, but apart from that it was just a normal service and tune up.

Don't know if the above is relevant though...

Cheers

Alex

[ephect]

i would start with checking error codes, located in the how-to section, this should point you in the right direction and tell you if its logged anything thats failed.

o2 sensors would be next on the list, get new ones on there, combine that with a service including air, fuel and oil filter. change plugs and leads.

Free Stuff: remove the throttle body and its sensors and giving it a good hit with some carby cleaner. Check all hoses for cracks or vacuum leaks.

all listed above should get your engine running smoothly.

if the oil hasnt been changed in a while, i would change it and the filter, and after 1000kms do it again filter included, kinda like a flush out, its might seam a waste but will ensure its clean. i believe there is a product you can buy to add/replace that flushes the oil system

[aceventura]

I watched the mechanic spray some sort of hi octane cleaning fluid through the plenum and intake, and bucket loads of carbon build up came out, but apart from that it was just a normal service and tune up.

Can't some of these cleaning compounds foul the O2 sensors, maybe even the carbon build up the cleaner dislodge is fouling the sensors?????

Just a thought

[sircruisealotVS]

there is no such thing as a "tune-up" on a modern car, thats a term used for carby engines.
so get that idea out of your head, there's nothing your mechanic could have done to the tune. its all set and electronic and can't be changed without tuning on a dyno with a program like kalmaker.
its more than likely just a coinicidence that something has gone and started playing up after your service.
the fact that you changed the battery also would play a part in your cars change. it would have reset the pcm and would now be running off base tables from the factory tune till it starts to self learn a bit and get where it needs to be.

[ianf]

"your sorry, what about her?"...

[Not_An_Abba_Fan]

The only thing that has been changed lately is the battery. I watched the mechanic spray some sort of hi octane cleaning fluid through the plenum and intake, and bucket loads of carbon build up came out, but apart from that it was just a normal service and tune up.

Don't know if the above is relevant though...

Cheers

Alex

Very relevant. I'd say the crap that the cleaner has dislodged has blocked the idle air control ports in the throttle body. Take the throttle body off the car for a proper clean.

[Munz]

hopefully he would have sorted it by now abba.......lol


they got you good!!!

[Not_An_Abba_Fan]

Shit.....I always do that.....I never check the posting date.

[Munz]

Thats alright still good info about the iac, I'm sure it will help someone out