91 metro 3cyl floods

[pnguine]

Hi all - great site.

My 91 3yl metro (Pontiac Firefly here in Canada) floods instantly when I try to start it. I have just had the injector tested/cleaned with no effect. I belive it's flooding because the throttle body is full of gas when I look in it and if I disconect the electrical connector to the injector and then turn the key and hold the gas peddal down it tries to start (until the fuel is burned off). Then if I reconnect it it fires fine the first second of cranking then dies and the throttle body is again filled with fuel. It's as if the ecm thinks that no throttle is full throttle or something. I'm going to the scrap yard tomorrow to see if I can get a new ecm. Anyone have any ideas?

TIA

[geozukigti]

Pick up a new intake manifold w/injector while you're at it. Sounds like you have a bad injector that's leaking bad

[pnguine]

I thought of that so I took the injector to a local shop and he ran flow/leakage tests on it, cleaned it, put in new 'O' rings and gave it a clean bill of health - didn't help.

Looks like I have more serious internal problems - ie. one dead cylinder and low vacuum. According to another web site the low vacuum causes the MAP sensor to send a signal to the ECM that makes it think it needs to pump more fuel!

So I'm just pulling the head now and will add more to the thread later to keep it intact.

[pnguine]

the saga continues:

Pulled head - whoa! same problem as old one - cookie monster's been eating my middle ex. valve. Get valve from old head - lap all valves - reinstall head. 180 in #3, 180 in #2, 0 in #1! arrrgh. car starts - very, very noisy lifter - chug about for a week - lifter goes quiet -start checking again - 150 in #1 but still runs same!!!! nearly new (2 - 3,000 kms) #1 plug damp, no sign of life - inspect plug lead, cap - nearly new - pull lead off while engine running - do the high tension shuffle - get better insulated pliers, try again - lead gets an inch from plug and it starts to fire!!! - engine runs on all three!!! replace plug with old one - runs better than ever - (burns oil like crazy)

now for some tweaking to get rid of the lag - like turbo lag or broken accelerator pump - then it's buzz, buzz, buzz. (in my dreams)

[pind]

cookie monster you mention goes by the name of catalytic converter. too much backpressure on these engines. i did several valve jobs on them prior to discovering this.
I also had a flooding issue on an 89, turned out that the o-ring under the injector had gone bad, swelled up, forcing the injector off its seat and puking raw fuel onto the throttle plate. new o-ring cured it.
currently building a 91 chevy sprint, metro, whatever. will be interesting to see how it runs.