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No fire no start...! lil help please

I have a highly (bolt on) modified 94 supra, stock internals. I recently broke the cam belt tensioner. when I replaced it I had thought there was trouble with timing. come to find out I was experiecing a melting spark plug. As the plug became worse the car ran worse until it did not run. I have since replace the plugs and can not get the car to star. I have spark on the number 2 cylinder but nothing on 1 3 5 have not tested 4 yet and 6 is a pain to get to... any ideas?

I am leaning towards the crank positoin sensor...

Drew

Quote:

Originally Posted by 94T88Widebody

This may be a dumb question, but I just want to make sure. Did you gap the plugs or are the pre gaped? Also did you check your plug wires to make sure they are still good? Sometimes the plug wires will where out and one will work and the rest dont. I hope that helps or if it didnt at least we ruled out those possibilities.

Quote:

Originally Posted by 94T88Widebody

To begin with, I'd assume your '94 Supra is (was) a TT. If this is not the case, please post.

The problem you describe is unusual, and might possibly be related to a bad ignitor. I'd also suggest we treat this as (possibly) two separate problems:
1) Why did your sparkplug melt in the first place?
2) Why aren't you getting spark in 1,3&5?

...however, before we go too much further please post a bit more about your exact setup (i.e. your complete mods list), as well as the methodology you're using to test spark.

Dual Fuel lines, T88 turbo, Virtual Works intake, 1600cc injectors, AEM, custom 5 inch exhaust, Block is unmodified at this time.

I do not know why the plug melted.. it was in the #4 cylinder. At this time 2 is the only verified working. I swapped out coils and pugs all into number 2 so that I could check each coil and plug on #2. 1235 coils and plugs all work I have not checked 4 and 6. if I move them to thier respective plugs the no longer work...

I am testing spark by threading a conductor onto the plug and then grounding the out side of the plug with that.. turn the coil upside down and crank over.. like I said.. I get great spark on each coil and plug if I a plug into the number 2 plug..

Plugs are gapped properly

Hmmm.... so let me get this straight. You have checked each coil and plug on the number 2 cylinder and 1235 work? But when you place the coils and plugs back to their respected places they no longer work? Am I reading this correctly?

Quote:

I get great spark on each coil and plug if I a plug into the number 2 plug..

Huh? The number 2 spark plug or number 2 cylinder? You said before

Quote:

At this time 2 is the only verified working. I swapped out coils and pugs all into number 2 so that I could check each coil and plug on #2.

Im assuming when you referred to 2 earlier that it was the cylinder not the plug itself.

Now from what pwpanas has said I think he is on the right track here. First we need to ask ourselves why did the number 4 plug melt in the first place? Have you ever used nitrous? What type of fuel management do you have other than the 1400cc injectors? How long have you had this turbo kit on? And what exactly kind of plugs do you have? IMO you should put a bit colder plugs on if you are running that kind of kit with 1600cc injectors. A hot plug will melt.

However, IMO if all you have is a t88 turbo with log style manifold(which causes unequal airflow) and 1600cc injectors without a better fuel pump and fpr and without any better engine management on shabby fuel then I can see why you are melting plugs. How many pounds are you boosting?

IMHO, I think this problem is due to improper engine management and the motors unability to cope with such a thing. Now I am probably maybe wrong here but if the coils are working on the number 2 cylinder and they arent working in their respected positions then their is something seriosuly wrong with this picture here.

I turn this over to pwpanas for he is more knowledgeable about this car than I am. I am sure as long as you are informative to pwpanas he will be able to diagnose and properly aid you in what you need to do to fix it.

Sorry I couldnt be more helpful.

Quote:

Originally Posted by 94T88Widebody

If you don't mind my curiosity, why haven't you checked #4 and #6 yet? Since you changed your #6 sparkplug (according to your earlier post), you'd have already had your #6 coilpack off. I'd suggest it's important we get a full overall picture of what's going on before we decide on a troubleshooting process.

That said, I'd still suggest you try swapping your ignitor if you can find another Mkiv Supra owner in the area. If your ignitor is good, our next step will be to find out if all of your AEM's ignition channels are still good.

Also, are you running an ignition amplifier of any sort (CDI or DLI)? And is your AEM set up to use waste spark ignition? If so, note that your #2 and #5 ignition signals are driven out of the same AEM output...which means that your #5 coil & plug should fire at the same time as #2. This is another reason I suspect your ignitor may be related to the problem.

...and even after your ingition starts working again, we still need to figure out why your plug melted (in order to proactively and positively make sure this same set of problems doesn't happen again).

I appologize..Let me explain better.

From the begining...

I was driving and noticed the car had less power and sounded different (misfiring)

On my way home I broke the cam belt tesnioner throwing the car out of time but still able to run enough to get me home. (one time its good to still have a stock block)

I replaced the tensioner with a billet one. put the car back in time and it ran again with the same lack of power and still sounding differnt.

I decided to put fresh fuel in the car (91octane) and take it for a spin (I know I need race fuel!)

while driving the car spit sputters and threw a bomb out the back end ran for a few seconds more and then died.

I towed the car back to my house and began to troubleshoot.... and now here is what I found.....

Number 4 plug electrode was melted away:
I replaced the nuber 4 plug only and gapped it according to what 1 2 3 were gapped. I tried to start the car and would not start.

At that point I decided to check spark:
Pulled #2 plug and coil pack (#2 is super easy to get to thats why)
It sparked..

Pulled number 1 plug and coil pack. No spark

I took plug from 1 and checked with number 2 coil pack on number 2 harness connection... I had spark.... good plug!

I then moved number 1 plug and number 1 coil pack to the number 2 harness connection and checked for spark..... I have spark!

These are the same symptoms for 1 3 4 5 6! Good plugs, Good coils.. no spark.

Basically I am only getting signal to the number 2 harness plug to initiate the spark.

All modifications were completed by Ryan Woon at WOTM. As of now I have no reason to doubt his desgn. His only recomendation to me was to run with race fuel as much as possible. Boost is as low as the controller will allow me to go.. roughly 16psi. Plugs are a 7 heat range NGK VPOWER

Quote:

Originally Posted by 94T88Widebody

Again, are you running an ignition amplifier of any sort (CDI or DLI)? And is your AEM set up to use waste spark ignition? If so, note that your #2 and #5 ignition signals are driven out of the same AEM output...which means that your #5 coil & plug should fire at the same time as #2. This is another reason I suspect your ignitor (and/or your ignition amplifier, if any) may be related to the problem.

Your broken tensioner bracket could still have caused valve(s) to be bent if your head were decked and if you're running 272 or 280 cams (are you? ...or are you running stock cams too? )...but either way a failure in the cam timing should not have any effect on the ignition. About the only semi-related item is the 'toothed' crank position sensor gear attached to the crankshaft's timing belt gear. When you plug a laptop into your AEM are you getting an accurate RPM signal while trying to start the engine?

Another troubleshooting step you should take (imo) is a compression test. Although this is not directly related to the ignition problem, it can help determine if you have either bent valves or scored cylinder walls (from spark plug debris).

Quote:

Originally Posted by pwpanas

Your broken tensioner bracket could still have caused valve(s) to be bent if your head were decked and if you're running 272 or 280 cams (are you? ...or are you running stock cams too? )

I have a completely stock block... The car was running as good as it was before the tesioner broke.

Quote:

Originally Posted by pwpanas

About the only semi-related item is the 'toothed' crank position sensor gear attached to the crankshaft's timing belt gear. When you plug a laptop into your AEM are you getting an accurate RPM signal while trying to start the engine?

I will check.

Quote:

Originally Posted by pwpanas

Another troubleshooting step you should take (imo) is a compression test. Although this is not directly related to the ignition problem, it can help determine if you have either bent valves or scored cylinder walls (from spark plug debris).

I checked this in the begining... I have 100 -120 psi depending on wich cyinder

Again, are you running an ignition amplifier of any sort (CDI or DLI)?

It all appears to be stock "Toyota Denso part numbers"

And is your AEM set up to use waste spark ignition?

I do not know... I will find out as soon as Ryan answers his phone!

Okay...I thimk we may be getting somewhere..... I hooked into the AEM .......no Engine RPM...

Would this be a good time to assume my CPS system has a problem...?