57 twin turbos on a 98 gt. Have changed out the coil packs plugs and wires. In addition have added a Boost a Spark to it. The car only makes 10lbs of boost then the spark goes out. I have two tunners tell me the same thing. One thinks its the PCM sending a bad signal/electrical signal not enough voltage and the other thinks it RF waves from the alternator. All i know is I keep spending money for Dyno time with the same results. The car with the plugs gap from 30 all way down to 18 will only due 4700 rpms at 10psi. If you back it down to 9psi it will do 6500rpm no problems.

Any help?????????

 

Get a more powerful coil or use two coils to get more time for it to charge before next discharge.
What kind of plugs are you using?

electrons are traveling quite fast so I doubt that the spark can be blown out. I think it's rather a question about that the mass in the cylinder become so great that the heat the spark produce is not enough to ignite the charge.

 

Its not literally being blown out, it is when the pressure in the cylinder becomes so great that the coils can't produce enough voltage to make the spark jump the gap. What kind of coils do you have? The individual coil packs or just one? Typically I've heard of it happening single coil setups...im not really familiar with mod motors though...maybe someone else can chip in that has a similar setup

 

IT has the MSD coil packs (2). Now they think it may be the TPS sensor or the fuel pump. Something about the duty cycle stays continues until 10 psi then the pump turns it selve up. running 80lb injectors and trying to remember the name of the fuel pump. In addition when he went down the road the car fell over on its nose at 4700rpm several times then he did it again got out of the gas and stuck it to the floor again and it pulled fine. He thinks to much full so going to take some fuel out with the tune now.

 

What is the theory behind this?
I can't see a reason why it can't jump the gap when the densety of the charge increase.

 

The spark has to jump the gap (which has resistance) and higher cylinder pressure has more resistance. Welders experience a similar issue when welding with different gases as well.

 

Not trying to insult your tuner...but he has a problem with the car...so he goes out on the road and full throttles it a few times...and then guesses it has too much fuel? Do you have a wideband? Does he have a wideband to tune it with? If he keeps guessing random parts you are going to end up with a lot of money in the hole...

Stian, losing spark at high pressure is a common problem on boosted cars, and it is a proven fact that higher pressure equals higher resistance. Too much resistance and the spark simply won't jump at all. So you go from no problems at x rpm, and then when you hit that threshold with too much pressure and not enough voltage, you lose spark completely, engine rpm drops back down, you get spark again. That's what the boost a spark was designed to fix...I've never used one, but the theory sounds good...whether or not the product delivers is something I can't say...
http://www.kennebell.net/accessories/boostaspark/boostaspark.htm

How do you have the ignition wired? Two coils and a boost a spark??

 

Maybe valve float, are your heads new or do they have alot of miles on them, spring could be weak! although that isnt much boost.

 

Not trying to argue here, but I would like to get this straight.
From where have you gotten the proven fact that higher pressure equals higher resistance?
Higher temperature equals higher resistance I know, but newer heard the same about pressure.
From my point of view higher pressure should result in increased density and should create a environment with better conductivity than air witch is a excellent insulator.
Did anyone actually conduct a experiment where they measure the amps trough the plug wires when this is happening?
I always found the theory that the spark is blown out as bull because it did not make sense and I'm in doubt about this one as well.

Sorry for my attempts to hijack this thread.

 

Increase in pressure causes increase in heat....high density air is still air....just more of it. You ever driven a car that had a coil going bad? It always skips when you accelerate, typically they are okay at cruise. Same rpm, different load. Higher load has a larger air/fuel charge being drawn into the cylinder. Using your theory, cars with weak ignition systems should run better at wot than at cruise...which simply isn't the case. I've worked on cars 6 years now, and weak ignition systems always act up under high load. Maybe its not directly the pressure, but the heat caused by it....in any case, adding boost to a car stresses the ignition system, and many people have fixed their" spark blowing out" issues by running a smaller spark gap, or using stronger or multiple coils...I might have the theory slightly off, but its not a made up situation no one has come across and fixed

 

Using my theory cars with weak ignition will fail to develop enough heat to ignite the charge at WOT.
The higher the mass the higher the amount of energy is needed to ignite it.
Just like it's easier to ignite a thin piece of wood than a thick one using just a match.
From a quick google i found out that

Code:

air ranges from around 4 x 10^13 ohm meters at sea level, to around 1.3 x 10^16 at 12km elevation

http://answers.yahoo.com/question/index?qid=20080214200945AA3RSQd
So if I should trust google your theory is slightly wrong regarding resistance increasing, but I'm open to explanations.

 

....using your theory, closing the spark gap on a car with this issue wont change anything. Do a search, tons of people have had.this problem and fixed it by closing the gap. You are completely ignoring all other facts besides density...higher pressure causes.higher heat. Higher heat causes more resistance. I never said more air fuel charge doesn't need more energy. You can't look at only one aspect. Do a turboforums search instead of google, and find people who have experience with turbocharged car. Look at the recommended spark gap for a factory boosted car as opposed to a n/a car. Boosted cars typically use a smaller gap. A smaller gap has no effect on the energy in the cylinder, but it does fix the problem a lot of times. If you don't want to believe me you don't have to. I don't know how else to explain something that has been done over and over....

 

Tons of people will also tell you that you need back pressure in the exhaust in order to get the engine to perform well witch is also untrue.
Maybe you should look a little at your own comment about "completely ignoring all other facts"
According to ohms laws reducing the spark gap would reduce resistance and reduced resistance with same voltage would increase the current witch would increase the heat developed.
If only resistance was a problem why is the hight performance systems like boostaspark delivering 2amps? Only increasing the voltage alone would be enough according to your theory.

 

couple of things to check...
1. voltage @ the battery and amps from the alternater..... you can have a phase out inside the windings of the alternater, and have volts and not enough amps..
2. earth from chassie/ battery / engine

 

This statement is false.


If you would like to discuss your opinions of this spark issue further start another thread. No need to hijack a thread.

 

If you have msd coils a boost a spark and closed up the gap stop chasin spark blowout. You should be producing more than enough kVs to get the job done. Either your running a sensor out of its parameters which a tuner that isnt mentally disabled should notice. Or your floatin the valves.

 

Why? It's easy to say something is false, when you don't have to explain it is it not?

I would welcome a moderator to split this thread.

 

Check for weak valve springs. DBM

 

Back to the wideband question.. Is there one being used? FP gauge? I know WB 02 sensors kinda suck for this type of problem but you said your tuner thought it might be going pig rich at the top? You said he "THINKS" to much fuel. He shouldn't be thinking. He should be knowing these things.

If spark is blowing out than the wideband will read lean. If valves are floating it will read lean. Any time there is some sort of misfire a wideband will supposedly read lean.