coil pack Hotwire DIY.

[fastbikes76]

Got the car back together yesterday and did some driving. Haven't had a single spark blowout so far.

As expected Since doing this I have never experianced any either even at 24+psi.

Just think, You could have spent £500 GBP on a HKS DLI...or 10 bucks on a 30amp relay
http://www.amber-performance.co.uk/p...php?xProd=7624

[murphys_law]

Ordered


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[Jesters Deadd]

FYI
I have read there is a 7 amp limititaion on the PTU in a couple locations but can't find the sources now.
I have done some testing on a stock ignition and found that you can add 25% dwell time to the ignition without seeing a platue in the current rise. I reflashed my ecu with the 25% ignition dwell time and I don't see blow out, and I have run e85 to 30 psi.
I have run it like this for 3 years now. So stock coils retain their reliability at the increased dwell time.
I bet with this hotwire mod and an increased ignition dwell on a stock setup you would be set for ignition.

Good stuff guys, anyone else care to answer this one. I personally don't believe the voltage has dropped more than 1/10 or 2/10 of a volt with age and corrosion. IMO they skimped out on wire sizing from the factory on a lot of the wire harness'.

Waiting to hear more on a possible ptu current limitation but I have no doubt this mod will help out!

[jras312]

The other thing we need to wire around is the one set of cylinders that loops over to the tachometer test point near the battery. Does anyone know the correct fix for this?

Are you talking about just removing that wire that's used for testing? It is just a splice from the 3rd signal on the PTU out of the 3 sent to the coil pack.

[ChargerX3]

Solid thread. Nice walk through. Jester brings up a good point with the software side. Might have to go that route first.

[bradrs]

FYI
I have read there is a 7 amp limititaion on the PTU in a couple locations but can't find the sources now.
I have done some testing on a stock ignition and found that you can add 25% dwell time to the ignition without seeing a platue in the current rise. I reflashed my ecu with the 25% ignition dwell time and I don't see blow out, and I have run e85 to 30 psi.
I have run it like this for 3 years now. So stock coils retain their reliability at the increased dwell time.
I bet with this hotwire mod and an increased ignition dwell on a stock setup you would be set for ignition.

Here is where the current limit on the stock PTU is mentioned:

Stealth 316 - Power Transistor Unit

Which is a very similar result to what I found on the DSM PTU when I tested it years ago.

FWIW, NONE of you guys are experiencing a "spark blowout". Your spark isn't starting because the voltage at the plug is inadequate to bridge the gap. The spark isn't "blowing out" after it starts. A better term would be to call it a "misfire"

The only thing to keep in mind with your +25% dwell, and the voltage mod, is both are increasing coil current. So you will be more likely to hit that current limit. Assuming your system is like the DSM, dwell will drop with RPM, so this may give you higher current for a longer time, but it might also overheat the PTU. Was your current testing done at idle? Did you recheck your values at high RPM?

Someone in a thread on another forum was mentioning the advantage of a dual PTU setup, which would help a little in that case. At 6-7A, with the stock coilpack, you should be getting nearly 100mJ of spark energy, and a nice spark. Beyond that, you may need to look at other coils too, not just increasing the current to them.

[murphys_law]

This seems like a good idea, and should help with misfires.

A few suggestions on the installation though. There are many places that sell sealed relays, so that they are sealed connections, not exposed. Or if you want to go with a standard unsealed, many companies make a connector where you can get the terminals and crimp them onto the wiring yourself. This would eliminate several splices in your harness.

And at the coilpack, you could do this wiring job without having to cut any wires. You could depin that black/white wire and put it into a 1 pin connector that uses the same terminals like this:




Or you should be able to unbolt the 12V wire at the coils, and just replace that with new wire/ring terminals.

I think I'll be using this solution as it's 100% reversible. Thanks.

[Chris@Rvengeperformance]

Are you talking about just removing that wire that's used for testing? It is just a splice from the 3rd signal on the PTU out of the 3 sent to the coil pack.

yes, grayson was saying once it can cause some misfires as I recall.

[Unlogic]

Haven't had much time for the car lately but yesterday I finally managed to sort out the boost compensation tables in the ECU so they work properly with my new boost solenoid. I'm now getting about 1.22 bar (17-18 psi) of boost all the way to redline now however above 5500 rpm I'm getting some spark blowout again.

I'm gonna try to increase the dwell time in the ECU as per Jesters advice. If that doesn't work I'll have to pull out the plugs and check the gap on them.

[fastbikes76]

Seems strange, never encountered anyone who's issues have not been permanently cured via this method. Saying that it's a help for weak spark at high loads, not a band aid for failing ignition components. Could be bad leads or failing coil packs I guess.

Hope you find the issue.


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