AT WITS END (1 Viewer)

[dani cee]

The tach is fed from the igniter. It's all 1 system. The FSM tells you what resistance you should see across the distributor pick up coils. You can make those tests right on the ECU connector or on the distributor connector. If you have a bad pick up coil, the ECU will shut the system down.

thats what one of the mechanics said "bad pickup coil" so i replaced the distributor.....no spark....unless the distributor i replaced it with was bad. the engineer in japan said always get a new distributor.......so i am waiting on a new one........i will let you all know what happened......

 

[jonheld]

so your saying the distributor might be bad?

I didn't say that. I'm not there with you testing the system components. That's your job. I'm just yelling from the bleachers.

 

[BILT4ME]

I'm sorry, but I can't stand to watch people throw money at part after part after part just because they "think" that's what it COULD be.

Follow a troubleshooting checklist in an orderly fashion, making sure that all "i's" are dotted and "t's" are crossed.

Listen to jonheld. He knows what he's doing. Don't jump around and be all ADHD on it. jonheld will guide you through this, but you have to be patient enough to listen and follow along.

You said "Toyota will charge thousands". By the time you're done doing it your way, YOU will spend thousands....

I'm not TRYING to be a dick (it comes naturally according to my wife), it's just that I want you to get through this in a logical fashion. I understand the frustration. Listen to those in the know here. JONHELD. Did I mention @jonheld ?

BTW, @jonheld can help you.... He's actually more like the coach on this one and he's giving you the plays, but you're throwing the ball to the wrong guy.....

 

[dani cee]

I'm sorry, but I can't stand to watch people throw money at part after part after part just because they "think" that's what it COULD be.

Follow a troubleshooting checklist in an orderly fashion, making sure that all "i's" are dotted and "t's" are crossed.

Listen to jonheld. He knows what he's doing. Don't jump around and be all ADHD on it. jonheld will guide you through this, but you have to be patient enough to listen and follow along.

You said "Toyota will charge thousands". By the time you're done doing it your way, YOU will spend thousands....

I'm not TRYING to be a dick (it comes naturally according to my wife), it's just that I want you to get through this in a logical fashion. I understand the frustration. Listen to those in the know here. JONHELD. Did I mention @jonheld ?

BTW, @jonheld can help you.... He's actually more like the coach on this one and he's giving you the plays, but you're throwing the ball to the wrong guy.....

well for the first 3 mechanics....they were very professional and did not jump around......followed the book......but they all did the same thing i did.......after following step by step everything and replacing 3 of the same parts four or five times you naturally will start to jump around a bit. i know what jon is saying.....but it all has been done 3 times over by different mechanics........thats why i have automotive engineers from nissan on it now......i have studied the service manual for three months and now know it like the back of my hand...........going to get a new dizzy and see if that is it......it has to be a component..........i know for a fact 5 times over it is not a short.....

 

[Reelitchy]

I have many flaws and right now I can't seem to stop my fingers from hacking away here at the keyboard. You can buy a new distributor but I would say most likely you will still be in the same boat. A lot of mechanics are parts changers -- troubleshooting takes a long time and patience and obd1 gives you less help. The ecm would tell you if its the distributor... code 12 or 13. Code 14 only registers if code 12 and 13 are ok. You do have a CEL so that is a big plus.
I see you have said continuity in wires is ok... well we don't know how you are measuring that also. The ends of a wire will always have continuity if they are shorted to ground somewhere. Did you isolate them and check them to ground? Just to humor me could you disconnect the connector with the igf and igt wires( on the igniter, set your meter to low voltage and see if you have less than 2 volts on the igf side of the igniter. Then check the low voltage of the igt wire on the connector (coming from the ecu) while someone is cranking the engine. You should get pulses (quick ones). If you do then the ecu is pulsing the igniter so you have to hook the connector back up and find a way to check the pulses coming off the igf wire to the ecu (use a jumper stuck in the connector or check it right at the ecu and have someone crank it. The ecu is telling you it is not getting the right reading from the igniter.
Really want to see you get this rig running.

 

[Pin_Head]

The one thing you haven't replaced is the wiring harness and you keep assuming it is OK. It can have continuity and have 12V, but it could still be bad. It could have high impedance or be shorted to another wire, but you keep ignoring this possibility.

 

[jonheld]

The one thing you haven't replaced is the wiring harness and you keep assuming it is OK. It can have continuity and have 12V, but it could still be bad. It could have high impedance or be shorted to another wire, but you keep ignoring this possibility.

@Pin_Head is correct, as usual.

The Toyota FSM has tests for every component in the system except the igniter. Essentially you're measuring resistance across coils. The 2 pick up coils in the distributor; the primary and secondary windings in the ignition coil. The FSM goes on to specify the air gap between the rotor shaft magnets and pick up coils. If these parts test within specification then I would call them good. Coils can open and coils can short. Both of these conditions can be read with a meter. Either they're in spec or they're not. A visual inspection of the solder landings of the distributor pick up coils can reveal potential issues.

If the parts of the system are all within spec and the truck does not fire, then look elsewhere. As posted by several others, wires can have all sorts of issues regardless of length. I would be looking at the actual pins inside the connectors, I would be sistering in jumper wires, I would have the cover off the ECU and try to get to the actual solder point landings where the connector pins mate to the PCB.

MAYBE a pin is bent/broken inside one of the ECU connectors.
MAYBE there is enough corrosion on the crimp of one of the ECU connectors to add enough capacitance to totally round off the pulses coming back. That would still read good with a meter (maybe).
Igniter ground is through the chassis mount. MAYBE there's enough corrosion to prevent a good ground to the igniter.

There are 4 parts to this system and 7 freakin wires. 1986 technology. All analog, all the time.

 

[dani cee]

all of you are fantastic.........i am looking foreword to trying all of these steps.......too bad it is raining today........but tomorrow i will be out there checking..........and i WILL get this truck running......i feel i will be an expert fj80 troubleshooter after this whole thing is over.........lol
thank you all again.....

 

[cahilc]

Doesn't take a lot of corrosion/ resistance to shutdown an ECU. Take a really hard look at the connectors and wires. We're looking for less than 5 ohms of resistance. Trivial to meter when testing on volts or ohms but not to a running circuit.

My 2¢ ...

 

[dani cee]

I have many flaws and right now I can't seem to stop my fingers from hacking away here at the keyboard. You can buy a new distributor but I would say most likely you will still be in the same boat. A lot of mechanics are parts changers -- troubleshooting takes a long time and patience and obd1 gives you less help. The ecm would tell you if its the distributor... code 12 or 13. Code 14 only registers if code 12 and 13 are ok. You do have a CEL so that is a big plus.
I see you have said continuity in wires is ok... well we don't know how you are measuring that also. The ends of a wire will always have continuity if they are shorted to ground somewhere. Did you isolate them and check them to ground? Just to humor me could you disconnect the connector with the igf and igt wires( on the igniter, set your meter to low voltage and see if you have less than 2 volts on the igf side of the igniter. Then check the low voltage of the igt wire on the connector (coming from the ecu) while someone is cranking the engine. You should get pulses (quick ones). If you do then the ecu is pulsing the igniter so you have to hook the connector back up and find a way to check the pulses coming off the igf wire to the ecu (use a jumper stuck in the connector or check it right at the ecu and have someone crank it. The ecu is telling you it is not getting the right reading from the igniter.
Really want to see you get this rig running.

so what do i do if i dont get any pulsing or if i do get pulsing from the igniter...
i know for a FACT the igniter is good.....all three igniters i have tried are good....isolated both wires coming from the igniter.....black/light green...black/green....pulled ECU put tester on end of wire...put other end of tester on wire from igniter plug.....i know for a fact both wires are GOOD....so we have two units (igniter, ECU) i have replaced both.......then we have two wires that have been isolated and checked and they are also good............is there anything else i could check? i have checked these parts over and over again hoping that maybe i made a mistake, but i didnt.

 

[Dirty Koala]

There are some of the most knowledge 80 series electrical gurus giving you guidance in this thread, do yourself a favor and listen to what they are telling you.

Don't assume your wires are good because they have continuity and 12v.

Also, how much experience do you expect the Nissan techs have on 20 year old Toyotas?

 

[Twinair]

You've replaced everything except the wires. Replace the wires. It's only 7 wires. You may be reading proper voltages but you may not be flowing enough current to satisfy the ECU. Voltage is only one part of the signal. You need that voltage to flow. A bad wire can show proper voltage, also known as potential, without being able to flow the required current to do any useful work. Picture a bucket of water. That bucket is full of potential energy that can be measured. The potential energy can not be realized until you tip the bucket over to get the water to flow out. It seems your bucket has a lid on it. Replace your bucket with one that doesn't have a lid.

 

[Reelitchy]

Just looked at the wiring diagram again and may have (hopefully) found what your problem could be.... fingers crossed. I am using my 94 manual but should be the same.
The igniter is case ground- notice there are no ground wires on it for the primary coil. Check for continuity between the igniter case and ground. Take the braket off and the igniter off the bracket then clean the surfaces and remount. This needs a good current path. Hook up your connectors and try to fire it up. No ground on the case means no spark.

 

[dani cee]

There are some of the most knowledge 80 series electrical gurus giving you guidance in this thread, do yourself a favor and listen to what they are telling you.

Don't assume your wires are good because they have continuity and 12v.

Also, how much experience do you expect the Nissan techs have on 20 year old Toyotas?

oh yes i am following their instructions....and i appreciate it greatly
these are not nissan techs......these are nissan engineers.....they designed this circuit.....nissans have identical circuit.
they are the guys who had me check the individual wires.....the one in japan knew all the colors of each wire without having to look....
i think with the help on here and engineers from japan i have a pretty good team and we can figure this out..........LOL

 

[dani cee]

Just looked at the wiring diagram again and may have (hopefully) found what your problem could be.... fingers crossed. I am using my 94 manual but should be the same.
The igniter is case ground- notice there are no ground wires on it for the primary coil. Check for continuity between the igniter case and ground. Take the braket off and the igniter off the bracket then clean the surfaces and remount. This needs a good current path. Hook up your connectors and try to fire it up. No ground on the case means no spark.

thanks....going to try this right now............will update

 

[Stumpalama]

With all this build up, there should be a prize for the one whose advice solves the problem.

 

[wrongway around]

It has to be the ground.

 

[jonheld]

Why do I bother writing this stuff if no one reads it?

 

[NLXTACY]

Why do I bother writing this stuff if no one reads it?

Oh shoot there you are. Was wondering when you were going to post

 

[dani cee]

thanks....going to try this right now............will update

if i take the tester and put black end in negative terminal on battery and put red end on the case of the igniter i get continuity also if i touch red end to igniter bracket i also get continuity...........does that mean the ground is ok?