91 Died while driving - timing belt, fuel, spark OK

[sketchmobile]

My girlfriend's '91 4cyl sohc auto wagon died on the highway the other day. Simply turned off while cruising at 55. Nothing violent, no warning, nothing.

It has spark. Pulled a plug wire, and though it won't arc to the block, if I insert an in-line spark checker that does light up. Should the spark be able to arc to ground from deep within the plug boot and mine is weak? Or is spark likely fine?

It seems to have fuel (yes, tank is full) - can't hear the pump running with the key in the acc position (should I? don't recall hearing it on this car before), but if I pull a plug and crank it, I can smell fuel. Cranking with plugs in hardly yields any fuel smell by comparison, so I don't think there's an engine bay leak. Any further ways to check on this?

Has sufficient compression that there's a nice difference between cranking with and without plugs. With one plug out there's a distinct difference every 4th stroke. I would say it's fine, haven't compression tested it though.

Timing belt is good, was new a year ago when I did the water pump. I took the top timing cover off, aligned the crank timing mark, and the cam mark is dead on. Belt is also nice and tight as I remember it being when I put it in.

So, any advice or ideas before I head off to rent or buy a compression test kit and/or fuel pressure tester?

Will try to start it on starter fluid/ether later tonight, but looking for advice before I start doing more dangerous stuff

Thanks!

[fredk]

it just shutting off sounds electrical, if you smell gas and if your plugs are wet and timing belt is ok sounds like spark troubles

[new echo owner]

Check the ignition coil and pickup coil in the distributor.

Fuel pump doesn't run except when cranking or when the ECU gets a signal to power the Circuit Open relay.

N.E.O.

[sketchmobile]

Ignition coil is brand new about a month and a half ago (due to stumbling when wet - it fixed the problem). I'll end up pulling it and checking resistances again I guess.

[new echo owner]

Won't hurt checking the resistance again! Don't forget the pickup coil though.

N.E.O.

[Doctor J]

Try new rotor for distributor; had similar problem with my car: it have had weak spark [caused flashing of timing light and spark tester too. The car fired right up when I changed the rotor.
Make sure you have power [at least 9 v on the fuel pump connector while cranking];
if not short FP and B+ terminals in the diagnostic box and attempt to start the engine.
Also: check the trouble codes [the bad pick-up coil or igniter will set codes even if CEL is not on]

[sketchmobile]

Cap and rotor were also new with the coil. I'll grab a new rotor today for a whole 6 bucks, and put the old cap (was only a year old) on and give it a try with that too to be sure. Has new wires too. I know just cause it's new doesn't mean it works, I'm just sayin'

If it starts with FP and B+ shorted, what does that mean?

Where's the fuel pump connector? I don't know much about this car, I just fix it when it breaks. Well, until this time

Thanks folks. I'll update tonight.

[new echo owner]

In the diagnostic connector under the hood.

N.E.O.

[Doctor J]

The fuel pump connector is under back seat driver side blue and white wires [blue is hot in start and run, white is a ground]
The diagnostic terminal is black or gray box about one by two inches with lid on the driver side strut tower under hood; the terminals are labeled on the underside of the lid

[Mike Gerber]

"Will try to start it on starter fluid/ether later tonight, but looking for advice before I start doing more dangerous stuff "

Use O2 safe carb cleaner instead of starting fluid. If lack of fuel is your problem, the carb cleaner will at least make it sputter and it is much safer to use than starting fluid.

Mike

[sketchmobile]

New cap and rotor. No difference.

Coil is within spec for both primary and secondary resistance and does not look burned like the old one did.

Jumped Fp & B+, now can hear the fuel pump running quite clearly whenever key is in acc position, but still no start even with those two plugs shorted.

Tried starting it on starting fluid (before reading your post, mike...eh, nothing blew up), it didn't even pop, sputter, or anything. Worked up to *plenty* of fluid, it should have done something.

So...purely a spark issue? Where to go next? Distributor?

At this point we're thinking of taking it to a shop and letting a professional diagnose it.

[new echo owner]

Did you check the pickup coil?

N.E.O.

[sketchmobile]

I did not check the pickup coil - but a quick search looks promising that that might indicate a distributor for sure. Am I correct that the pickup coil is checked by checking resistance between G+ and G- and between G- and NE prongs of the plug on the dist.? Any further details?

[new echo owner]

G+ to G-: 205 - 255 Ohm
NE+ to NE- : 205-255 Ohm

N.E.O.

[sketchmobile]

219 and 246 ohms. Within your range, and according to my crappy repair manual, the range is 140-180 for all models except 1991 4-cylinder cars, for which it says 205 to 265.

So...yeah.

However, aftermarket distributors all say they fit '87 to '91, so is it possible those units would have lower resistance, and this car has had its distributor replaced at some point?

What was your range from? I'm guessing an equally reliable source, so, sigh, what to do.

Think it's worth a 150 dollar distributor before having it towed to a shop? I'm thinking so. Unless there's anything I haven't checked outside the dist. that could be causing a lack of or incorrect timing of spark.