1995 V6 cranks but won't start, yet another no starting thread

[The Desert Rat]

Ok, did a search and it seems the problem is common but the solutions are all over the board. My 1995 V6 4Runner has 110K miles, so not bad mileage. It has been running fine up until a couple of days ago. I go to start it and it cranks over no problem but won't fire. It has a brand new cap and rotor, new plugs, new wires, all fuses are intact, air filter is new, new battery and no water or condensation in the cap. All lights go on, and everything electrical inside works fine.

So, I start fiddling around with everything under the hood starting with checking for spark. I pull the coil wire and fire it up to see if I can get an arc. No arc from the coil so I figure it must be a bad coil even though it is only 3 months or so old. I pick up a new coil and install it. It fires right away and runs for a few days no problem. Today I drive it to the store and when I come out, crank but no start.

I don't have any tools so I start checking all vacuum hoses and ground and other wires that I can see. After tugging and wiggling wires and hoses, then trying to start it takes about 10 times and somewhere along the line I must have jiggled the right thing because it finally fires up. So, what could the problem be? A bad ground somewhere? Some vacuum hoses split that are hard to see? A relay slowly going bad? A fuel pump going bad?

 

[Footofgod]

Ok, did a search and it seems the problem is common but the solutions are all over the board. My 1995 V6 4Runner has 110K miles, so not bad mileage. It has been running fine up until a couple of days ago. I go to start it and it cranks over no problem but won't fire. It has a brand new cap and rotor, new plugs, new wires, all fuses are intact, air filter is new, new battery and no water or condensation in the cap. All lights go on, and everything electrical inside works fine.

So, I start fiddling around with everything under the hood starting with checking for spark. I pull the coil wire and fire it up to see if I can get an arc. No arc from the coil so I figure it must be a bad coil even though it is only 3 months or so old. I pick up a new coil and install it. It fires right away and runs for a few days no problem. Today I drive it to the store and when I come out, crank but no start.

I don't have any tools so I start checking all vacuum hoses and ground and other wires that I can see. After tugging and wiggling wires and hoses, then trying to start it takes about 10 times and somewhere along the line I must have jiggled the right thing because it finally fires up. So, what could the problem be? A bad ground somewhere? Some vacuum hoses split that are hard to see? A relay slowly going bad? A fuel pump going bad?

It's safe to say that your starter is good. I have learned way to much about this lately. Start with Spark. If all your wires have good spark and the coil is good, move on to fuel. You might want to get a pressure guage (borrow from parts store) and make sure you are getting enough fuel to the rail and also check the injectors. Once you have eliminated fuel, move on to air. Check all the hoses coming from the Air Flow Meter (AFM not MAF). There is a test in the Factory Service Manual to make sure it is working right. Do a Google search on how to clean it. Clean your throttle body.

When all that has been checked and re-checked, check your timing belt and ignition timing. Two weeks worth of foolong with stuff and finally got mine going.

 

[SV_Dude]

I have learned way to much about this lately.

You should be a pro on the 3vze

Even myself, not having a 3vze I feel like I know way too much about your motor.

 

[ToyoTech]

its common to have the ignitor/ignition modular fail. but you said you were messing with some wires. i would say you have a loose wire somewhere.

 

[KidVermicious]

its common to have the ignitor/ignition modular fail. but you said you were messing with some wires. i would say you have a loose wire somewhere.

This. I don't know much about the coil, but I'm guessing you've a bad gound connection...

a) no spark from original coil
b) cleared when you replaced it
c) trouble came back
d) cleared spontaneously

That's a classic wiring problem - bad connection or a wire broken in the sheath somewhere.

 

[The Desert Rat]

My best guess was something shorting out. Since fiddling with everything results in it eventually starting, fuel shouldn't be an issue. Once it fires, it runs just fine. Clogged injectors, MAF, fuel pump, etc. would cause it to run poorly but it runs perfectly once it actually runs. Then again, there is a fuel pressure regulator, of course under the manifold on a V6, that I suppose could be sticking?

A short on the other hand would be an all on or all off situation. The problem is, what is shorting and where is it? I checked the ground on the coil and it looks good. Could the ECM be going bad?

 

[The Desert Rat]

its common to have the ignitor/ignition modular fail.

That would suck since it appears that even at O'Reillys they are $170 - $325. This sounds like it could be the problem but would it fail intermittently?

 

[SV_Dude]

I would double check all of your plugs and make sure that they're securely fastened. Check your grounds and make sure they are in good shape. Once you've done that, remove the coil input from the distributor and hold it close to the engine or something metallic. Have someone try and start the engine while you're looking for spark. If you have spark then you need to start looking for fuel issues. If you do not have spark, see the FSM for ignition related issues.

If you do have spark, check for fuel pressure. Crack the fuel line going into your fuel rail and have someone try to start your engine. The fuel line on the driver side of the engine is the easiest to get to. If fuel sprays into the engine bay, then you have good enough fuel pressure. After that, get some noid lights and check for signal going to your injectors.

After you verify that you have fuel and spark, then you need to look into timing.

Odds are that your problem lies within spark though.

Good luck!

 

[The Desert Rat]

I would assume I have plenty of fuel pressure since when it fires, it runs fine. Although, I suppose if the fuel pump was going out and isn't always running that could be an issue. Again, obviously when it runs it has spark but when it won't fire, I've pulled the coil wire and turned it over. During the times it isn't starting there is no spark from the coil wire. Would this indicate that the ignition control module isn't working during these times but at some point will kick in?

 

[SV_Dude]

Check with the FSM to be sure. There could be some other sensor that is telling the ECU to not send power to the ignition/ignitor. You could have a bad wire somewhere too. There is a task in the FSM to check for power and signal to the ignitor though.

 

[The Desert Rat]

I guess the smart thing to do is to make sure there is no short anywhere before I kick down the bucks for the module. I'd hate to fork over the $200 and have it happen again anyway. I am pretty proficient with mechanical stuff but electrical issues just aren't my forte.

 

[SV_Dude]

Open up the factory service manual. It will tell you everything you need to know.

 

[ToyoTech]

another common problem with the 3.0 is the circuit opening relay. seems like your runner works after a while. so maybe the relay is getting to hot or a bad connection to the C/O relay. relays can stick sometimes too. you should be able to here this click on when turning the key to on. get the runner to act up (wont start) than go to this relay and turn key on to see if you hear it click. its just one click when the key goes to on and thats it. its a decent test but than again these relay can stick or have poor contact inside. its located on the passenger kick panel area but kinda up high.

heres a picture i found online

 

[The Desert Rat]

Where is it located? I could see that being a possibility too since maybe I've been jiggling it just right once in a while.

 

[ToyoTech]

Passenger kick panel

 

[The Desert Rat]

Well that rules out my jiggling the wire since I haven't been there yet, but I will check the connection.

 

[ToyoTech]

but that relay is what turns on the fuel and ignition that is happening under the hood.

 

[The Desert Rat]

Well now this is odd. I can't duplicate the problem and it is running fine now for a couple of days. I did the reverse and left it running. I then went around and jiggled all the wire connections including those to the ignition control module, volume air flow meter, all the relays and every electrical connection I could see. None of them killed the engine, or even made it skip a bit.

I did notice a hissing noise coming from the area around the EGR valve though. I jiggled all of the multitudes of vacuum hoses but no change in sound. If that was sticking, or leaking it wouldn't effect starting I would think. Maybe run rough but no starting at all?

 

[ToyoTech]

EGR can cause a hard, maybe a no start. it is recirculating exhaust gases back in to the intake manifold. there shouldnt be any hissing sound, should fix it tho

 

[Footofgod]

Grab a multi meter and start checking wires and electrical parts. I was told once (Scotty at Addicted Offroad) that if you have the 3.0 (which I do), be prepared to get VERY intimate with that engine and a multimeter.