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Re: stalls under load (update)
Posted by Charles Christacopoulos (more from Charles Christacopoulos) on Sat, 28 Oct 2000 09:33:59
In Reply to: stalls under load (update), Veeate, Fri, 27 Oct 2000 18:19:13
> I'm not sure what else to look for.
Hold on. It is a V4 right ? :-)
OK. I had the same car (a bit older with twin carbs)
> Well, today I looked it over for vacuum leaks and found none. Where I
> could I cliped the hose ends and refitted them for a better seal just in
> case. It has always idled just fine though, even when the problem is
> happening. Wouldn't a vacuum leak mess up the idle all the time?
Not really. You'll find a car may idle reasonably well whilst you just
listen to it, but may be completely unable to move under load.
Vacuum leaks with your your distributor should affect accelaration (ie. no
accelaration). Vacuum leaks for the air the engine sucks should result in
weak mixture (too much air too little fuel).
> Cap and rotor in good shape. The plugs and wires have been replaced
> recently, but not the coil. I have had problems with a coil shorting out
> when hot on my ford Falcon before but then it would start at all till cool.
> This one will start, but stall only while in gear.
I only replaced a coil once. The car was getting very difficult to start.
checking the 'brightness' of the sparking plug with one of those light things
(they fit between lead and sparking plug) and doing the same eye test on a
good car showed a very weak spark. Once it started it seemed to run OK
though.
> As for the pressure accumulator, could this be the problem even if it is
> easy to start?
> Or the fuel pump? Could it have enough gas pressure to run and rev untill
> under load?
I am not very good with injection ... but plainly the car needs to maintain a
certain fuel supply and under load (accelarating as opposed to cruising) it
needs a higher supply. However, all pumps (injection or mechanical for
carburetors) are supposed to supply more fuel that is needed and the excess
is returned to the tank.
> Perhaps it doesn't have enough power somehow to run under load.
What else > could cause this?
I think this is what I am afraid of.
See end of message.
> The book I have suggests I check the fuel injection leads in the
> distributor but then give not details on how this is done. Could that be
> it? What do I look for?
>
> Someone suggested I disconect the amm. I still can't figure out where it
> is though, or even if this car has one? Next time it happens I am going to
> disconnect the O2 sensor to see if its the fuel injectors.
Injectors can get dirty with age. When I had injector problems in an older
saab, it would never start on a warm engine. A bottle of cleaning fluid did
the trick. From memory though, the cleaning fluid was not meant to be used
more than twice on the lifetime of an engine.
> I also got a tip to look at the tach when it happens. If it doesn't
> register it could be the crank sensor that tells the fuel and distributor
> what to do. I still can't figure out if my car has one though. The book
> is totally unhelpful with this.
>
> I did find out that only one of the electric fans is working. I am going
> to look around the local pull-a-part for a replacement motor tomarrow.
> This should help keep it cooler. (I know its the motor because of the
> awfull screeching noise it made once i got it to work at all. Ouch!)
The checks here are cheap, I make no comment on injection as I do not know.
Assume the engine cannot pull. Basically mechanical problem.
Do a compression test.
- Remove all sparking plugs.
- REmove fuse for fuel pump so you get no fuel coming in.
- Get assistant to press clutch pedal and (maybe) accelarator to increase the
aid intake of the engine. (If paranoid) remove the air intake from the
filter to allow for more air to get in the engine.
- Keep leads or exposed ends of any wires which may spark during rotation
pointing away from the fuel pump etc.
Check each cylinder in turn with the assistant cranking the engine. The
needle of the compression tester should jump high on the first crank and less
in subsequent cranks. See that all cylinders reach the same level and in
approximately the same increments. My experience with old engines they take
5-7 cranks to reach maximum compression and after that it is a waste time.
-----------------------
Once you got all your compression tests look for irregularities. Two
adjacent cylinders being low indicate blown gasket. One low cylinder may
indicate gasket or valve problems.
WATCH OUT FOR CYLINDER NO 3. THE HEAD CRACKS IN LINE WITH THE (inlet or
exhaust valve, can't remember). ARE YOU LOOSING COOLANT???
The valve sims may need adjusting (I don't think your car uses hydrolic
valves).
===================
I did have a cracked head. It is not repairable don't let anyone tell you
otherwise. If the car has had the head removed and not refaced, then you
will not get that many miles before the gasket gives up.
I am sorry to be bringing bad news. I do hope it is injection probably easier
to fix but not necessarily cheaper.
REgards
Charles
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