3S-FE Engine Problems - cutting out under load

[Disturbed1]

Gents,
We have a '91 model Corona with a 3S-FE giving us some grief.

Early on it would hesitate occasionally accelerating from idle. The hesitation became progressively worse to the point where it will now idle fine, but under load it cut's out and die's completely.

It idles fine, and will rev up fine without load - and if I rev it in drive on the brake verry slowly it will build revs however if I do the same thing but rev it quickly it coughs and won't rev.

The fuel filter was almost completely blocked so that was replaced and the car drove fine immediately after (short lap around the block). On the next start the problems returned so we assumed the pump must have given up so it was replaced. Again, it test drove fine around the block but on the next start it we had the exact same problem.

I've loaded it up on the brake and shut it down while miss-firing to check the plugs and they were completely dry.

Any suggestions??

[beerhead]

Is the regulator holding pressure? Try clamping the return line a bit to increase the fuel pressure and see what happens.

Injectors could be clogged too, brass punch and tap them as someone is cranking and sometimes they'll un-stick.

The other thing it could be is a sticky AFM not registering that there's the right amount of air coming in the motor, maybe clean it up or swap out for another one if all else fails.

[horse]

take off return line from hard line, put into bucket
take off intake pipe before afm
turn engine to on (don't start)
push flap in afm wide open.
Check that fuel flows constant. if so then that is all good

have you checked ignition components, eg dizzy cap and rotor button?

[beerhead]

If the regulator isn't holding pressure it'll flow petrol either way - all that taking the return off and pouring into a bucket tests is whether your pump is operating (which has already been replaced), and if you measure the volume of fuel after a minute, how much fuel your pump can pump.

Without installing a T piece and a pressure gauge in the line feeding the rail the simple way to test your regulator is what I said above, which creates a restriction after the rail and will increase pressure, and fuel delivery to the motor.

Out of interest, is the fuel pump coming on when you crank the motor when it doesn't fire? AFM flap isn't stuck?

[Disturbed1]

The motor is map, no afm.
I have cranked with the return line removed and there was flow, thought there is no audible priming sound.
Disconnecting the map changes the idle, whereas disconnecting the fpr vac line doesn't make a difference. After fiddling around with the fpr vac line (on/off etc) it won't start at all now so I suspect I'm on the right track.

Thanks for the tip beerhead -I'll restrict the return line and see if that helps get some fuel into the motor.

[Disturbed1]

All sorted, Corona now runs an aeromotive reg borrowed from the race car Thanks for the tips/recommendations.

Nick

[beerhead]

Glad to hear you got it going! Didn't realise there were any early map 3SFE's too many bloody toyota's out there!

[horse]

that'd be the late model 3sfe's with square spark plugs leads. more power in those then the camry ones.

Good to hear it's all sorted mate.