Posts ref Alarm wire blowing engines.

[richard cash]

as mentioned a few posts above tim doesnt remap ecu\'s so thats why i used the two companies. RX motors is closer to me and was much cheaper for the rebuild and porting. They also were very highly reccomended and on the phone tim and mat were very helpful. When it came to mapping i was going to go with a guy called greg in bristol who tim reccomended but around this time i wanted it done i couldnt get hold of him (email problem) so decided to go with reworx as they could fit me in quickly.

[Jonathan_F]

Here we go....

I have been doing some testing at work..bikes I know but its all the same 4 stroke cycle.

We use twin plugs to get an even burn because of the large piston diameters on this particular engine. The testing has been to run with only one plug at low RPM\'s to slow down the burn and improve the torque. This has worked but we are now CLOSER TO DETONATION.

My theory: A reduction in the supply voltage to the coil packs of alarmed vehicles leads to missfire of either of the plugs. This causes detonation and the engine pops a seal. This explains why it happened at normal driving speeds as we all know from experience: Detonation is much worse at lower RPM\'s.

Also, the statements that carbon build up from missfire would take too long are false. I\'ve had apart many a cylinder head after a short duration test and carbon can build on the plugs and in pockets etc very quickly.

[onelastpost]

???confused???

Are we saying that having an alarm could cause my engine to pop a seal?

[Prof]

I don\'t think anyone on this thread is saying it does - I think some, including myself, said it could be possible.
 
As for Richards motor - until it\'s apart no one is going to know.
 
It has to be said, and from what Trex has posted, that if it has happened then it will be a pretty infrequent occurrence.
 
It would never hurt to check the wiring in any case - I had some awful wiring around the alarm / immobiliser on my car - and some twist together bodges in the engine bay and around the loom at the front where the lights are.  You buy an old car you might have had cowboys in :bandit

[richard cash]

Prof, its been apart, repaired, backtogether, ran in and mapped again, lol. The ignition loom is completly standard now and engine loom renewed. There was no definate answer to why it blew but everything that could have blew it (alarm and other bits on ign. loom and engine loom) has been rectified. its putting out the same power again and all is good.

[BlitzBoy]

Here we go....

I have been doing some testing at work..bikes I know but its all the same 4 stroke cycle.

We use twin plugs to get an even burn because of the large piston diameters on this particular engine. The testing has been to run with only one plug at low RPM\'s to slow down the burn and improve the torque. This has worked but we are now CLOSER TO DETONATION.

My theory: A reduction in the supply voltage to the coil packs of alarmed vehicles leads to missfire of either of the plugs. This causes detonation and the engine pops a seal. This explains why it happened at normal driving speeds as we all know from experience: Detonation is much worse at lower RPM\'s.

Also, the statements that carbon build up from missfire would take too long are false. I\'ve had apart many a cylinder head after a short duration test and carbon can build on the plugs and in pockets etc very quickly.

Sounds like you got a cool Job Jon who do you work for?

Richard I am glad you are up and running :Thumbs-up nice when you are rolling about in and FD thats working correctly

[Timrxmotors]

If you have 12v at your igniter,it will send 40v to the coil,which at 100 turns to 1 will give 40,000 volts at the spark plug.
Now if the alarm wiring only allows the igniter to see 11v,the igniter only sends 33.3v to the coil,100:1,gives 33,300 volts at the spark plug.
That is a loss of 6,700 volts to the spark plug,of course you will have a weaker spark.Misfiring is now much more likely,especially on high boost,because under boost a much stronger spark is needed to ignite the mixture.
This misfire,if it occurs is not detonation.If the fuel pump sees lower than the already lower than 12v (standard wiring),then it is very likely the fuel pump will not be able to maintain the pressure required under boost,mixture goes lean,engine goes pop.
Point is you should aim for 14v at the igniter,and at the fuel pump,so cutting wiring and adding any alarm wiring is a very bad idea if you want to run more than stock power.

[Martiny]

Yay !
TIm explained the whole thing in a few sentences ! And he agrees with Miguel.

[FD3UK]

Instead of ripping out the alarm wiring and voiding insurance. Fitting a fused line from the battery to the igniter via a relay which is switched on by the old igniter wiring will solve both problems. This should keep imoboliser in place and give the igniter a good supply.

[iaint]

Yay !
TIm explained the whole thing in a few sentences ! And he agrees with Miguel.

Interestingly though, if read in conjunction with Johnathan F\'s post you can see how weak spark could cause det.  Tim also says that lower power to the fuel pump could cause lean running & det...

Glad this is such a simple problem, otherwise we\'d be here for weeks arguing :Giggle

[Warthog]

Link which may be of interest.

http://www.mazdarotaryclub.com/forums/showthread.php?p=305641#post305641

[Cally]

Q. SHould I not get my alarm fitted at xmas then? Is it gonna cause problems?

[A7NTY]

I think its amazing some of the opinions displayed from those questioning this problem when they clearly dont have a god damn clue in reality.

I will leave it at that.

[rx7veilside]

cally u will have to have an alarm for ins..get good quality alarm and ask them to use as thick a wire as poss for ignition cut..

[iaint]

Q. SHould I not get my alarm fitted at xmas then? Is it gonna cause problems?

Have it fitted but talk to the fitter and explain the issue!