Huelsmaniac

I made the mistake of trying to fix something that wasn't broken.
I decided to do some preventive maintenance by replacing my spark plugs and high tension cords. Worked totally fine before this. Now, for some reason, it doesn't get spark.
I've already replaced my ignition coil, and checked my MAF (read something about a bad MAF can prevent spark, something with the ecu). Thoughts?

Huelsmaniac

So, I have ruled out anything that has to do with the ecu. Probably just a loose connection somewhere. Does anyone know a good thread about what kind of voltages I should be getting and where?

Huelsmaniac

Checked Distributor specs according to FSM, seems good

superex87

Coil/ igniter need to be plugged in and the bracket that holds them needs to be grounded to the fender. Double check all the wires on the distributor plug are seated. No signal from distributor means no spark. Same goes for the coil and igniter.

crawlpotato

I just went through a no spark nightmare on my 1991 3vze pickup. Turned out I had loose ground connection from ECM to engine cam bearing cap, and a loose connection from the passenger kick panel harness plug for the EGR...and a short in my MAF...all of which I figured after I replaced the distributor, coil, igniter, plugs, and wires and noticed my check engine light intermittently illuminated with my key "on".

Let me know what you find.

Here's how I found them:

1) Do you get a check engine light when key is turned to "On"?
If NO:
-Check your grounds (a) behind top of plenum to body, b) exhaust to fender, c) coil base to exhaust, d) battery negative to fender, e) ECM wiring harness has 3 brown wires that will all mount to the passenger side rear camshaft bearing cap under the plenum.
-The MAF may have an intermittent short from the sensor connectors under the black cover, mine did. IMPORTANT: Remember not to remove the screws from the sensor plug (if you pull the base of the female plug from the MAF it will break the connections in the sensor) ONLY REMOVE THE WIRE CLIP.
-Gently wiggle your ECM connections and harness plugs under passenger side of dash with the key "On" (I noticed my EGR valve clicked on and off and traced the wire to a bad harness plug)

If YES:
-Wiggle your harness and connectors to see if the Check Engine Light illuminates
-Check resistance of your distributor plugs, and ignition coil
Tech Tip: No Spark and/or No Injector Pulse on Toyota

Application: 1989-1995 Toyota Pickup & 4-Runner with 3VZE Engine.

Symptom: No Start.

Theory: The Ignition system on this engine uses a Distributor with three
Pick-up Coils inside and an external Igniter and Coil. The ECM uses the
signals generated by the three Pick-ups to control the Igniter, which
controls the negative side of the Coil for spark. The Igniter also sends a
signal back to the ECM for injector pulse.

The Test: The first place to start is to check the Pick-ups inside the
Distributor. If any of them are defective, nothing else is going to work,
not even the tap-test we're going to do later. The first step is to test
resistance on each of the three Pick-ups. You'll want to check them with
the harness unplugged from the Distributor. Identify the terminals on the
Distributor connector using the wire colors on the harness side.

Terminal-1: White..NE signal
Terminal-2: Red..G1 signal
Terminal-3: Black..G2 signal
Terminal-4: Green..G- signal

Between G- and G1, it should be 125 & 200 ohms. Between G- and G2, it
should also be 125 to 200 ohms. Between G- and NE, it should 155 to 250
ohms. All of these resistance specs are at ambient temperature. If checked
on a hot engine, the tolerances go up about 30 ohms. If any one Pick-up
fails the test, it needs to be replaced before any further testing. If all
three Pick-ups pass, we need to do a "tap-test" at the Igniter. Make sure
the connector is plugged back in at the Distributor. Go to the Igniter,
which should be mounted at the Coil. On the Igniter connector, locate the
Black/Blue wire and probe into it with a test-light. With the key on, tap
the alligator clip of the test-light on battery negative and watch for
spark out of the Coil. If you get no response, try tapping the alligator
clip on battery positive, again watching for spark out of the Coil. If
there's no spark in either case, check for battery voltage at the positive
side of the Coil. If that's okay, attach a second test-light from ground to
the negative side of the Coil and redo the tap-test at the Igniter. If the
test-light on Coil negative flashes during the tap-test, and you had
voltage on the positive side, you have a bad Coil. If the second test-light
did not flash on Coil negative, we need to check the remaining wires at the
Igniter. Make sure you have battery voltage on the Black/Red wire at the
Igniter with the key on. If that's okay, make sure you have continuity on
the Black/White wire between the Igniter connector and the negative side of
the Coil. Make sure the Igniter itself is grounded properly to its mounting
surface on the truck, no rust or corrosion. The last check will be to make
sure the Black wire does not show full continuity to ground. This wire goes
to the Tachometer, and if grounded somewhere in the harness, will keep the
Igniter from working. If all of these things pass inspection, chances are
good you have a defective Igniter. Be sure you check resistance on the Coil
to be sure we don't damage a new Igniter. The primary side should be 0.4 to
0.6 ohms. Secondary should be 10,200 to 13,800 ohms.

The Fix: Replace the defective parts determined by the above testing. Don't
forget, if you do end up replacing the Igniter, double check Coil
resistance to avoid damaging a new Igniter.