Ray -
Thx for your insight. Below are my responses to your comments.
The hesitation occurs in park and in gear. The motor will not hold any
rpm above, or slightly above, idle. I inspected the duct work between
the AFM and throttle body, and see/hear no leaks. Also, the vac gauge
is rock steady at 22" at idle. I don't think my problem is a vac leak,
or I'd see some movement on the vac gauge, or a lower reading at idle.
I will check the vac gauge, when opening the throttle. The engine does
not rev, so this test probably won't help. I will test the EGR w/ my
Mighty Vac. Thx for that idea. I think it is a good idea (better MPG's)
to replace the O2 sensor given that it is the original part that is 23
years old w/ 154k miles. My replacement parts are all aftermarket. I
don't think the problem is ignition related. My feeling is that it is
air/fuel delivery related, or an exhaust restriction. If the EGR checks
out OK, I will disconnect the exhaust pipe at the exhaust manifold to
confirm/rule out an exhaust restriction. Maybe my aftermkt fuel filter
is bad, but highly unlikely. I will also hook up my fuel pressure
gauge. My elec fuel pump is noisy. Is this normal for this car, or
maybe an indicator that it's going bad??? I'd also like to test the AFM
voltage as you recommend. I just bought a Chilton's book for this car
on eBay. I hope this procedure is in the book. I'll also add some
injector cleaner to the gas tank.
- Glenn
Ray O wrote:[color=blue]
> <projman@optonline.net> wrote in message
> news:1158613698.709903.93390@k70g2000cwa.googlegroups.com...[color=green]
> >I have an '83 Cressida that I just inherited. The car has 154k miles,
> > 5MGE (2.8L) and AT. The car has been sitting for the past 5 years,
> > started 2-3 times, and never driven during that period.
> > I want to get this car back on the road. I replaced all the fluids, new
> > plugs, cap, rotor, wires, air filter and fuel filter. The engine starts
> > easily and idles very well. I measure 22" of manifold vacuum at idle
> > (rock steady on the vac gauge), and set the timing to 12 deg BTDC and
> > verified the ECU timing advance is OK.
> > The problem is a significant hesitation, and loss of power when the
> > throttle is opened. When in park, the motor won't stall, but attemtping
> > to drive the car, it willl stall, and will not get above 20 mph.
> >
> > Anyone have any ideas as to where to start to diagnose this? I'll
> > replace the O2 sensor, since it is original, and the motor will run
> > better, although I doubt this is the cause of the problem. I may
> > replace the TPS also, since it is also relatively inexpensive, and will
> > also make the motor run better.
> >[/color]
>
> I do not recommend replacing parts without first checking their function.
>
> Does the hesitation occur with the transmission in neutral or park or does
> the hesitation occur only under load?
>
> What happens to manifold vacuum when you rev the engine?
>
> When you replaced the cap, rotor, plugs, and wires, did you use OEM parts?
> I have seen problems like youa re describing with aftermarket ignition
> parts.
>
> Check the plastic intake tube between the air flow meter and the throttle
> body for cracks and holes.
>[color=green]
> > I don't want to replace the EGR or Air Flow Meter unless I am convinced
> > that either/both will solve the problem. These parts are both quire
> > expensive.
> >[/color]
>
> The EGR is relatively easy to check. With the engine idling, apply vacuum
> with a Mighty-Vac or by sucking on the vacuum hose leading to the EGR. The
> engine should start to stall if the EGR is functioning properly.
>
> The air flow meter is basically a potentiometer. As air flows past the door
> (flap), it pushes the door open, and as the door opens, it sends more
> voltage to the ECU. If you measure voltage as you move the door by hand,
> voltage should go up proportionately.
>[color=green]
> > I sprayed the throttle bottle w/ Gumout to remove buildup.
> >
> > Thank you.
> >
> > - Glenn
> >[/color]
>
> Since the car has sat for so long, there is the possibility that the
> injectors are gummed up. I would try either the Toyota branded fuel
> injector cleaner that the Toyota dealer sells or Chevron Techron. Follow
> the directions on the can. If the injectors are badly clogged, they can be
> professionally cleaned.
>
> If you have a fuel pressure gauge, you may want to check fuel pressure.
> --
>
> Ray O
> (correct punctuation to reply)[/color]
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