Stalls after fixed time - second go 'round

Last week I posted about the 1992 Acclaim (4 cyl, 124k miles) that stalls
after exactly 20 minutes at highway speed. Anything over 40 mph seems to do
it.

My mechanic couldn't test drive it long enough (he's not very near a
highway) to recreate the problem. He said the hall effect sensor had a
fluctuating resistance and replaced it. No difference though.

Some people here suggested the gas cap was not allowing air into the tank.
When next it stalled I removed the cap for a few seconds to let the pressure
equalize. There was no sound of air rushing in. It still wouldn't start
until it sat for 5 minutes just like before.

 

Sounds like something in the ignition circuit is getting hot and
creating an open circuit.
Possibly the coil.

 

Did he test the primary resistance of the ignition coil?

 

I once had a similar symptom that turned out to be a clogged fuel filter. Of
course, at lower speeds it ran longer before stalling.

Just a thought for what it's worth.

 

A week before this began, it wouldn't start at all, and was fixed by
replacing the fuel pump. When replacing the pump he checked the filter,
then after a few days I noticed this behavior.

 

I don't know, but I'll ask. Thanks.

 

Maybe that would create the same behavior, but I thought it "feels" more
like a fuel problem because it sputters with gradually increasing severity
for almost a minute before it stalls completely.

 

Can you borrow a timing light?
Test it by connecting to battery and clip around a sparkplug wire.
Start the car. When you pull the light trigger, you will see a bright
flash out the end indicating the presence of power to that plug.
When your symptom recurs, have a friend crank the car while you check
for a spark using the timing light. (Stand to the side of the car, please.)

Or route the timing light wires so you can do this as a one-person
operation.

If it won't start and you are getting your normal spark power, you can
suspect that it probably is something other than the ignition system.
If on the other hand, you see no spark power as you did during the
time the car was running, you can suspect something in the ignition
circuit. (Distributor, Coil, Ignitor, Fuse, Ignition switch, wire, etc.)

--Winston

 

Thanks. I would have to do it that way, since this only happens when I'm
alone on the side of the road. I do have a current clamp for my
multimeters. I can extend the wires if it's possible to use one of those.

 

I don't think your multimeter is going to be fast enough to catch
the pulse in which we are interested. You really need to use a
timing light or scope.

Quite a few servicable timing lights sold on ebay recently for less than
US$20 each. Like:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4122&item=6184181555&rd=1&ssPageName=WDVW>

--Winston

 

A coil breaking down when hot can exhibit the same symptoms, but in my
experience (with much older cars) it usually is fuel; either the fuel
pump or rust flakes in the gas tank (and you shouldn't have either)

actually pretty much ANY electronic component could cause this, but I'd
suspect the analog ones (i.e. coil) first.

nate

 

That could just as easily be the ignition getting weaker and weaker and
more intermittent.

Is there any spark at the coil or plugs when you test it immediately
after one of these stalling incidents?

 

I was ill-equipped to do much testing at those times. I'll try to obtain a
timing light. Is there anything else I can try when nobody else is around?

 

I've had good results with just pulling the spark plug boot, taking a
screwdriver and inserting it in the boot and then placing it (the metal
shaft of the screwdriver) close to something that is grounded. If a spark
jumps, you'll know that the ignition system is working. Then you need to
determine if the spark is good or not. You won't have to buy a timing
light.

-Bruce

 

just push the boot back and hold the wire so the exposed terminal is
near something grounded. WARNING: if you do this with a spark plug
wire that's 30 years old you might get a little jolt up your arm. Or
so I've heard.

nate

 

Fuel pressure gauge and a can of starter fluid. Beware! A poorly fitted
fuel pressure gauge can cause your present car problem to be a non - issue.
Be Careful With Gasoline!

Car konks but has spark. Fuel pressure gauge reads good but car starts
using starting fluid. Ah HAH! Maybe a blockage at Mr. Carburator or
Mr. Throttle Body.

Car konks but has spark. Fuel pressure is non-existant. Ah HAH!
Suspect fuel pump or blockage at filter or in line.

Car konks, no spark but fuel pressure is within manufacturer's spec.
Ah HAH! Ignition problem as pondered before.

Ideally, you could have the car completely instrumented.

By the way, when you tested the On Board Diagnostics, what codes were
revealed?

--Winston

 

Thanks but that's too incautious for me.

From the first time it happened the code was 55, which is no codes. After
the hall effect sensor was replaced I got 12 55 for a few days (battery
recently disconnected), then just 55 a few days later.

 

No joy there, then.

This sounds like an ignitor bug, but we need more info.
Looking forward to the results of your 'timing light' test, Tom.

--Winston

 

The very next day, before I could get a timing light, it wouldn't start at
all. Not the usual stall after 20 minutes on the highway.

It was reluctant to start one day last week -- also a hot day -- but I got
it started. Apparently the problem takes time on cool days, but on hot days
it never wants to start.

It would turn over for a second, then stall. Same on the second attempt.
Then on the third attempt, nothing. Clearly this looked like fuel and not
ignition. Starter fluid let it run for a few good seconds, with another 5
seconds of sputtering (during which it was really quite valiant in its
effort to keep going). Obviously it had a good spark.

Tuesday night I had it towed back to the shop that replaced the fuel pump
just days before this problem started. I don't think they got to it
Wednesday, but I know they did yesterday and I expect to get a verdict this
morning.

Much thanks. I'll post later when I learn more.

 

Oh well, it's back to intermittent. Today was cooler and the mechanic said
it started right up. I let him drive it home so he could have it long
enough to make it stall.

There is no longer any doubt that it is a fuel problem and not ignition.
Ever hear of a brand new fuel pump that stops after running for a while, or
when it's over 80 degrees?