NO SPARK: 88 4Runner

parked for two hours and it was about

started. It ran extremely rough for about 10 seconds and then died. The engine cranks over with ease and is not frozen. It will sputter a little bit but not much.

connections and made sure they were tight and inplace....visually everything seems ok.

is it related to the frigid cold temperatures. And obviously...what can I do to get my truck running again.

My money is on your ignitor. If not that, your coil is the next in line as the culprit.

Check the diagnosis system. If the problem is with your ignitor or coil, it will have at least one code 14 stored in memory, meaning the ignitor failed to signal the ECU several times running.

I have had two Toyotas go dead as doornails as you have described (no fire) and, both times, it was the ignitor. But, check the code first to be sure, this part is expensive and they either work or they don't. BTW, if you have to replace it, go with a junkyard - you will get it for half the price and it could last as long as a new one.

Luther

Maybe you'll get lucky and it'll just be a bad distributor cap and/or rotor. No harm in checking out the easy stuff first.

Chris

That's what I thought, when my '89 3VZN wouldn't spark/start! Now I have a spare ignitor ($70, "used").

After the $pendy ignitor didn't make it run, I applied systematic diagnosis: I started unplugging stuff! With the Air Mass Meter and Throttle Position Sensor disconnected, it STARTED! I had a shorted-out Air Mass Meter! I got one from a Toyota sedan at UPullIt for $15, and good-to-go ever since!

the details: the 3VZN AFM's are different than the RN Series, and are difficult to locate, used ("new" is out-of-the-question!). I found the ohm specs in the FSM and kept scrounging (ohming-out units at UPullIt) until I found the right one. They ALL look the same,even Subraru, just different ducting, and resistance specs, of course. And, there were NO codes generated by this problem! So much for OBD-I! Apparently there is one wire that carries a reference voltage from the ECU to the AFM and TPS, and if it is grounded out, you lose spark, without codes generated.

Good luck! (NO fun working in f**king freezing weather!!)

He asked for the most probable cause and I gave my best guess based on the fact that it just quit and he has no fire.

But that was just a SWAG. The important part of my advice was that -- before buying anything -- he should CHECK THE DIAGNOSIS SYSTEM (ie -short out terminals T and E1 on the check connector and count the number of times the "check engine" light blinks.) In situations involving no ignition, this system is excellent at pointing out the culprit. As a matter of fact, it should have diagnosed your faulty air flow meter as well (code 31 or 32), saving you the $70 on an ignitor you didn't need.

The diagnosis system can only help us if we ask it to.

Luther

I totally agree, Luther.

In my ("rare occurrence") case, though, I was stymied by the LACK of error codes. The AFM "may" have clobbered my IDL input. (Sensing an open throttle switch will prevent the ECU from running self diagnostics.) But that's a guess...

Right! CHECK FOR ERROR CODES FIRST!

Jeff

Too bad you couldn't get any codes. Touché on your diagnosis and repair of the problem, however. Your approach was impressive.

I have heard others say they cannot get codes out of their vehicles. Strange - mine spits 'em out like there's no tomorrow. It told me just yesterday that my a/c switch circuit was open - I knew that anyway, but was appreciative on the heads-up nonetheless.

So Cory, what was the verdict?? You've got my curiosity up.

Luther

I couldnt get any codes out of the diagnosis system. I thought it might be a bad ground so I grounded t to the negative batt terminal and still nothing (shit). I took out my multi-meter and went crazy testing every possible thing i could.....still nothing.

I do recall a while back trying to set my timing and jumping t and e1 did not seem to have an affect on my engine idle...although the timing seems to be perfect. I am skeptical about the diagnosis system. At this point I am running out of ideas.

Any thoughts???

thanks

Here is excerpt from an SMP Technical Note:

TOYOTA PRE-OBD II-CHECK ENGINE LIGHT ON-CANNOT FLASH TROUBLE CODES Normally, diagnosing a Toyota vehicle that has a Check Engine light illuminated is a straight-forward procedure. Typically, we jumper the appropriate terminals to read the flashes of the light on the dash. But what should we do if the light does not flash?

Let's review how the system operates. The check-connector on early models were typically two wire connectors located in the engine compartment. The two wires are designated: T and E1. T is the test terminal that is connected to the computer. The E1 terminal is a ground. On later systems, these two wires are located in a multi-pin connector, labeled "Diagnosis", located by the front strut tower. This connector has a flip-up cover that has a label for terminal identification. This connector contains the T or TE1 terminal, along with an E1 terminal.Voltage on the T or TE1 terminal should be 5 or 12 volts with the ignition key in the "On" position. The absence of a voltage reading is an indication of an open circuit between the connector and the ECM, or a bad ECM.

If we have the proper voltage at T or TE1, then the next step is to ground this terminal directly to the E1 terminal. If the light does not flash, then try the battery negative terminal instead. If the light now flashes, then terminal E1 is not grounded properly.At this point, if we still cannot get the light to flash, then we must check the Check Engine light circuit itself.First, locate the ECM and disconnect its connectors. Next, turn the ignition key to the "On" position. The light should not be illuminated. If the light is illuminated, then the circuit has a short to ground that must be repaired.The last item to check is the IDL input to the ECM. The IDL input informs the ECM when the throttle is opened or closed. This IDL input comes from the throttle switch that is basically an "On-Off" switch. The throttle switch is a black box assembly on the throttle body, opposite of the mechanical linkage. It is attached with two screws, and it is adjustable. The ECM will supply a voltage signal (5,9,10, or 12 depending on the system) on the IDL wire. The switch will ground this signal at closed throttle. The voltage value is not critical, however the switching is. Self diagnostics will not be allowed if the throttle switch is open. A quick check with a voltmeter will reveal if that switch is closed. If you measure zero volts, then the switch is closed. You should measure voltage when the throttle is opened.

Items that prevent the proper input to the ECM are: dirty throttle bodies that prevent the throttle from closing, improperly adjusted throttle linkage, sticking dash-pots, or an out of adjustment throttle switch itself.One other point to keep in mind is that the same terminals you use to check codes, are the same needed to set basic ignition timing. Proper IDL input is also needed, otherwise, basic ignition timing cannot be properly set. A couple of points to keep in mind when setting basic timing are: when you jumper the T or TE1 terminals to E1, you should see a reduction in engine speed and the Check Engine light should be flashing.If you do not see this, ignition base timing will not be set properly.

John Rogers Asian Specialist (From: SMP, Inc. "Engine Controls and Fuel Systems Fall 2002)

a bad ground so I grounded t to the negative batt terminal and still nothing (shit). I took out my multi-meter and went crazy testing every possible thing i could.....still nothing.

not seem to have an affect on my engine idle...although the timing seems to be perfect. I am skeptical about the diagnosis system. At this point I am running out of ideas.

I just checked my timing and jumping T and E1 didn't do squat for me either (at least that I could tell); so that may not necessarily be an indication that the system will not output a code. Here is the procedure from the manual - it's straightforward, but maybe the order of steps is important:

OUTPUT OF DIAGNOSIS CODES

1. Initial Conditions

(a) Battery voltage above 11 volts (b) Throttle valve fully closed (throttle position sensor IDL points closed). (c) Transmission in Neutral position (d) Accessory switches OFF

1. Turn the ignition switch to ON. Do not start the engine.

1. Short terminals T and E1 of the check connector

NOTE: The check connector is located near the no. 2 relay block.

1. Read the diagnosis code as indicated by the number of flashes of the "CHECK ENGINE" warning light.

(a) Normal System Operation

The light will blink once every 0.25 seconds

(b) Malfunction Code Indication

The light will blink a number of times equal to the malfunction code indication as follows:

1. Between the first digit and second digit: 1.5 seconds 2. Between code and code: 2.5 seconds 3. Between all malfunction codes: 4.5 seconds

The diagnostic code series will be repeated as long as the check connector terminals T and E1 are shorted.

NOTE: In event of a number of troube codes, indication will begin from the small value and continue to the larger in order

1. After the diagnostic check, unshort the check connector.

******* END OF MANUAL INFORMATION ********

Good Luck,

Luther

Well...I followed the steps exactly as described and I am still not getting any response from the system. I dont even get the blink every .25 seconds indicating normal system operation. I'm not sure what the problem could be with the diagnosis system.

But...At this point I think I am going to take my chances and buy an igniter that I found used for $45. All the other ignition components seem to be good. System diagnosis or not..I guess I will just have to take my chances.(fingers crossed)

I appreciate everyones help and will let you know how it goes.

P.S. If anyone knows why I cant draw any codes...please let me know.

Cory

Just a thought

Could it be a problem with the ECU???

Absolutely, these symptoms could be caused by the ECU. However, the standard rule of thumb is that the ECU is the last thing to eliminate as the cause for no ignition spark for two reasons: (1) the ECU units rarely go bad and (2) they are very expensive to replace.

It really sucks rocks that you can't get the codes out. You may try calling the Toyota shop and asking them what could cause this. The guys here in town are pretty nice about answering my questions.

Luther

Waiting for the Big Gun Techs (like Rick) to chime in, but I recall that there's a Regulated 5V line from the computer that will kill the whole ECU system if it gets grounded out. IIRC it goes to the Airflow Meter and the Oxygen Sensors on the exhaust system (pre and post catalyst), the distributor, and a few other places.

Get the list, and unplug the sensors one at a time until you see some signs of life. Worst case, none of them work because that line is grounded out somewhere in the wiring harness, and you'll have to hunt for it.

Of course I could be wrong, so don't do anything permanent. ;-)

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Does your Check Engine light come on when the ignition is on? If not, you could have several problems. The bulb could be bad or the 15A fuse between the ignition switch and the warning light could be bad. You can eliminate both of these by grouding ECU terminal W to the body. If this makes the light come on, then you either have a bad ECU or E1 is not grounded properly. Time to try another ECU.

You've got two different problems here: (a) no spark and (b) you cannot get a diagnostic signal. Before I started convincing myself that the ECU is bad, I would get the motor running. No spark normally means distributor, coil, or ignitor. First, check to make sure you have battery voltage at the coil's positive terminal. If that's okay, then check the resitance of the coil: primary should be 0.5-0.7 ohms and secondary 11.4-15.6 ohms. If those numbers are okay, your coil is good and it's probably either the distributor or the ignitor. If the problem is with the ingitor, you will probably not see voltage between the ECU (IGt) and E1 (or ground) when cranking the motor. Normally it would be slightly less than a volt. If you don't see voltage, it would be a safe bet to try another ignitor.

As info, IGt is third terminal from the left on the bottom of the ECU wiring harness, E1 is right beside it (fourth terminal), and W is seventh from the right (bottom row). You can remove the right kick panel and pull the ECU out with the harness still attached and make these checks with a multimeter.

Luther