94 Camry won't start. No spark. Headlight fuse blowing

Hi,

I’ve been trying to work out why my 94 Camry isn’t starting, and was hoping I could run a few things by you all and see if you think I’m headed in the right direction. So, here’s the situation so far.

No leading-up issues of any kind. Just passed a (real) PA inspection and runs great. The car was parked just overnight, running fine the day before. The next day, it wouldn’t start at all. Strong turn-over. No attempt to start. I tested a working spark plug by connecting it to the car (pulled out), and then connecting the threads to the negative terminal of the battery. While turning over, there was no spark. I then pulled the distributor cap and rotor. It appears some oil (definitely engine oil) had gotten inside from a previous known leak. The rotor contact was not super clean and looked to have some burnt up oil on it. I cleaned up all the contact points and reassembled. Nothing. Took the cap back off and tested the coil with an ohmmeter, which was all within spec. I have not tested individual terminal from the distributor, because a) I’m not entirely sure of a good way to do this and b) I doubt all four cables went bad at the same time, and if some were firing, it should be attempting to start, no? I suspect it’s an issue from the distributor or before.

I had read that a coil with good ohmmeter readings may still be bad, so I ordered a new one. Should be here tomorrow.

Is there anything else I should test or look into? Oh, and is it weird that the headlight fuse keep blowing when I attempt to start the car? Does that give any clues as to the source of the problem?

Thanks in advance.

Using a test light probe, check to see if power is getting to the plus side of the ignition coil when you turn the ignition switch to the RUN position. If that is okay then check to see if power turns on and off while cranking the engine and the probe is on the minus side of the coil. If that is good then the points are working and you should have spark unless the main coil lead going to the disty is bad. See if the light fuse doesn’t blow out and you have power to the coil by just turning the ignition ON and not to the START position.

The blowing headlight fuse may very well be a clue to the problem but unless it is also connected to the ignition somehow I’m not sure how it ties in. Does the fuse still blow if the lights are OFF?

The distributor doesn’t have points in the traditional sense; instead, it probably has a signal generator (it may go by a different name), a gizmo that gives an electronic signal to the coil telling it when to fire. Points are (were) an on-off switch that actually opens and closes as the lobed distributor shaft rotates. In your car, the dist shaft has 4 or 6 projections like blades on a paddle wheel. The gizmo magnetically senses when a lobe comes near, and signals the coil to fire a spark. When this part fails you get no spark, or weak and erratic spark.

The headlight fuse is a puzzle to me; a close look at a wiring diagram may disclose a connection between the headlights and the ignition system. Any other systems affected?

I didn’t pick the schematic apart but there’s a couple of fuses involved in creating a spark. One is an EFI 15 amp fuse and the other a 7.5 amp ignition fuse. With the key in the START and RUN positions the red/white wire at the coil should have power.

Have you checked those fuses? At this point I did not dig into any ties to the lighting circuit although there is a diode pack involving the tail lights in the START and RUN positions.

Does the distributor rotor rotate when cranking the engine? I wonder if the timing belt broke.

On my Corolla of similar vintage the fuses OK mentions are in the engine compartment as I recall. There’s an engine main relay involved too I think. If the ignition rotor is going round and round during cranking as Nevada suggest to check, then probably what I’d do first is make sure all the basic power test points which supply power to the ignition module are correct. I’d do this by looking at the engine wiring schematic while probing the test points with my DVM.

If looking at schematics and probing with DVM’s isn’t your thing … hmmm … if the fuses seem to be ok, and the air gap between the ignition rotor and the associated sensor measures to spec , next I’d probably replace the ignition module. On my Corolla that part is inside the distributor. I think it might be called the “igniter” in Toyota’s nomenclature.

The gizmo inside the Toyota dist is (was) called a pickup coil, or signal generator. Ignition module is probably another name for that part. The igniter is (was) a separate larger piece, about the size of a couple packs of cigarettes (remember those?) mounted, say, on the wheel well. In my experience with 1979 and 1983 Toyotas, the pickup coil / signal generator was the more likely failure point.

On my early 90’s Corolla anyway, the igniter is inside the distributor, along with the coil and the pickup. Can’t speak to the configuration of the 94 Camry though. But any of those parts could be the culprit.

How sure are you that it’s the headlight fuse that’s blowing and that you’re not misreading the label? Could it be an ignition fuse that’s blowing?

George, thinking about it I remember the igniter being a separate device, mounted on the wheel well on my 1979 Toyota pickup, but I don’t remember where it was on my 1985 Corolla - perhaps inside the dist as you saw.

Igniter?

On all the older Toyotas I’ve encountered, the igniter was NOT inside the distributor

It was near the shock tower. Seem to remember it had an aluminum housing, with some heat sink

igniter = ignition control module

location

Doesn’t apply to the OP’s vehicle, but for those curious, here’s how the coil, condenser, and igniter are all packed together inside the distributor on Toyota’s 4AFE 1.6L engine.

http://www.toyotaguru.us/corolla-e11-workshop/i-i-pus.html