R. Santore

this is depressing.. the first two times i had left it in 2 separate spring storms and i thought that might be some kind of contribution, but this time no rain, and its on its way to fouling another 6.. the first time i self diagnosed it and changed them, the second a shop did, and now for the third(my tuner suggested it would probably happen again, but i was ever the optimist haha).. i just wish i knew why its doing this.. i have a 3.0 turbo with K27, 1 bar spring, intercooler, electromotive ignition. every time i change plugs, it fires up and it runs like a champ for about 3 days.. but then after i let it sit for a day and try to fire it up, its fouled.. its almost like its fouling them while its sitting there... anyone have any insight as to what could be doing this? thanks for any help!
Rob
1974 Carrera

Steve Weiner-Rennsport Systems

Hi Rob:

Plug fouling is due to 3 things:

1) Ignition performance problems. This can be caused by insufficent operating voltage or a design issue.

2) Mixture too rich. What is your idle CO; hot & cold??

3) Wrong spark plug heat range. What are you using?

FWIW,..........I'm no fan of Electromotive ignitions for these very reasons. They simply do not possess the "oomph" to clear a fouled plug and MSD's are FAR better in this (and other) Sometimes one simply has no other alternatives on a 930 and some other measures may be needed to compensate.

R. Santore

Thanks for the advice steve, i am not sure of the CO but the plugs are bosch platinums part no# W3DPO. When you mean a design issue, what are you referring to? The bracket that holds the ignition mount broke off so it was loose in the car for a while and it has since been tie wrapped until it can be soft mounted. Do you think its fouling the plugs as its driving, or sitting, or immedieately when i'm trying to start it??

willard

Blown oil seal on the compression side of the turbo?

Steve Weiner-Rennsport Systems

Rob:

IMHO, those W3DPO's are far too cold for street driving. Those foul very easy and I'd be inclined to use either a W5DS, W5DC, or equivalent NGK unless you are on the track.

Willard suggested perhaps a blown turbocharger and I assumed that your car is not smoking,...............?

You must find out what the CO is as this plays a role in determining why this is happening.

Electromotive ignitions simply do not have the power to keep plugs clear below 4000 RPM. These things cannot fire the wide plug gaps (.040) that keep plugs clear, enable best drivability, and the best power.

If your car is not twin-ignition, you'd do lot better by using the Turbo distributor with an MSD 6AL and MSD High-Vibration Blaster coil. This setup will not foul plugs and you can open up those gaps for best idle and best HP.

wwest

Almost has to be oil pooling somewhere in the intake system while it's parked for long(er) periods.

R. Santore

what do i need to do to check the CO? i am not famliar with that, and how the car is running now it will need to find the shop for them to check it. Do you think just using the different plugs might help? And also, out of curiousity, how much would the MSD setup you were speaking of run me if i chose to switch.. There is no smoke at all, and the turbo isnt blown as far as i can tell(while it was running good for the 2 days i had it, it was running REAL good <img border="0" title="" alt="[Wink]" src="wink.gif" /> so i'm left to assume its something within the ignition.. I've contacted my tuner and i'm sure he will fix it perfectly, just trying to get some ideas!
Rob

PorschePhD

All due respect I disagree with Steve in this case. My first setup with an HPV-1 with bought from Steve. Since then I have had one failure due to a customer jumping his car with a 100 amp charger. In all we have built and installed over 75 of these units and the HPX has proven even better with a map retard function. I personally ran one for nearly 4 years without issue. Several on the board here run our motors and this ignition without issue.

The MSD we have had multiple failures on several cars. As well as many friends in the industry.

I suggest that some simple things be checked first. This is an early CIS system with lord knows how many miles, injectors can leak down with time. The first thing that should be done is check the injectors for this. A system test on the pressure would also show such a problem. The older these cars get the more we see this. I have also seen several cases where the cold start injector was leaking. This is not only a problem with the turbo, but on the SC as well. The WUR should be checked for proper pressure when cold and hot. Lastly if the CO is out of wack it too will create havoc. I am seeing more and more the CO vary due to age and typical wear of the heads. After all the system is no less than 24 years old. I now have seen several C2T with worn fuel heads. They are the youngest of the bunch. The fact that there is a resident fuel smell after the car sits leads me to believe something is leaking down in the system. <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />

Steve Weiner-Rennsport Systems

Hi;

Ahhhh, diversity,....that's what makes these Forums both interesting and educational. Differing and sometime conflicting opinions are healthy.

I'd like to share a few more thoughts on this subject if I might be permitted,.........

1) I too, have sold and installed a lot of Electromotive ignitions starting in 1987. They have all worked flawlessly in the reliability dept and no car with these systems has ever left its owner stranded. Decent quality stuff, no question about it. Back then, pump gas was FAR more volatile than it is today and plug fouling, even with cold heat ranges and small gaps (.028-.030), was not an issue. Even rich running engines such as MFI'ed or Weber'ed ones had little problems.

Several years ago, the EPA mandated changes in pump fuel that has resulted in a formulation that doesn't evaporate hardly at all and easily "wets" a plug. With modern engine management such as Motronic, Motec and things like that, its not as big a concern since fueling is very carefully controlled. With less precise fuel control like MFI, carbs and 930's with properly adjusted FD's (kinda rich), this becomes a concern, at least to me. Its no fun to change 6 plugs, much less 12, when the ignition will not clear a fuel or oil fouled one.

One way to help prevent fouled plugs is by using wide gaps that create a large, very hot spark kernel that makes much better combustion. Unfortunately, this requires a large reserve of voltage AND current to strike and sustain that spark gap, and inductively fired ignitions operated at bus voltage (12-14.2VDC) simply cannot manage that. You cannot get something for nothing.

If you doubt me (and you should), try this for yourself. Open the gaps to .040 on any Electromotive-ignitioned car and drive it for a bit. You'll see what I mean. Then close 'em up to .028 and try it again. Big difference.

2) I've also installed a few hundred MSD's (with MSD coils) over the past 30 years on many vehicles, including the somewhat cantankerous 3.0 RSR, 934 and 935 variants. In all cases, after opening the plug gaps to .040-.045, these cars ran FAR better and made more HP. Following that example, I did the same things to various MFI'ed, carb'ed, and CIS cars with similar results. All of them ran better and our engine dyno showed more HP, everywhere in the RPM range. Both drivability and idle quality were flawless. The toughest tests were on a '78 935 twin turbo and a 917/10 (5.4 litre 1100HP) that we had here. Both cars would not idle for long without plug fouling and the Bosch ignitions would not clear it. New plug time.

Installing MSD's on these cars, even with plugs that had NO side electrodes at all, resulted in a CIS-smooth idle for as long as you had fuel to burn,...

I've never had an MSD failure as long as the units were installed and wired properly. This means excellent voltage supply with the proper current capacity and perfect grounding. These things draw lots of current and both paths must be first-rate. MSD's do not tolerate any sloppiness nor errors. I've seen many installations that resulted in ignition failure and it would be unfair to blame the component on a poor installation, IMHO.

Lastly, several cars here with Electromotive ignitions all made more power on the dyno when converted back to an MSD system and those wider plug gaps. Please don't take my word as gospel here; try this for yourself if you get the opportunity. Its both amazing and educational.

My deepest apologies for being so wordy, but this subject is one of my passions and I deplore changing plugs unneccessarily. Try doing that in the 917/10 (24 plugs) and you soon know why one really wants the best ignition system that money can buy,....

Stephen's suggestions to Rob about leaking injectors and fuel distributors was right on the money. Those are easy to test and if they are dripping, its time for new ones.

PorschePhD

Agreed, civil discussions are always a welcome as well as an educational process for the spectators.

You points are good ones, yet several things I would encourage you to consider.

I ran your test as you described some time ago to verify whether Electromotive claims were valid. I found absolutely no difference in drivability nor dyno numbers when compared to the MSD. In fact I have set almost every car we have done @.40 and never have found this to be an issue. I have some cars that now have been running this way as track and street car for nearly 5 years. Perhaps that the difference is several variables not limited to nor excluding octane?

Interesting enough though we have many customers with our motors on 91 octane in CA. All of my test were done on 93.

When I last spoke to your wrench in the fall he was unaware that Electromotive had come out with yet a new unit. In fact he had indicated that he really hadn't paid attention to the the line up and was even unaware that the TEC I had gone through 2 software updates including the self leveling VE table and then on to the TECIII units. If you guys still have not tried the new units I encourage you to do so. The industry has changed a lot in 30 years as well within in the last 6 moths to a year. To condemn a product based on experience even 5 years ago is not fair nor approriate. I suspect that the number of people running Electromotive units in the Porsche community far out weigh the crowd with MSD. When I had spoken to Jeff he also had indicated that he had seen a few failures with the MSD. Like the MSD, although I assure you my installs where not an issue, it too is finicky to grounds, power, placement, gap etc. Electromotive has changed their entire unit right down to the Map option and the pickup. A good example of support is a 3.8 TT we built. The unit is still using the same DFUs as the HPX yet on this we are using 106# injectors. The car has run flawlessly on .40 gap and has turned 30K miles this past year. All this without a plug change I might add. The TecI I have also dealt with using the same configuration as well as DFUs, even on my own car...No problem. I suspect that perhaps the difference in data are the variables.

RJay

All this is very, very interesting. In the comments about gapping plugs you didn't mention plug types. I forwarded my mechanic the comments on gapping, he replied that I should ask what you gentlemen might recommend one increase the gap to for the bosch W5DPO plugs? I should probably mention that the engine is 2.4E with S heads and cams, MFI with a 2.7RS pump. Thanks for any insights you might provide!

Steve Weiner-Rennsport Systems

RJay:

Bosch does not recommend regapping those particular platinum plugs. The DPO's should be run, as they come since its possible to dislodge the side electrode and have it fall out into the engine.

For that reason, I usually use the regappable Bosh Silvers (W5DS) which have a very wide heat range and last a long time. You may also use the resistor version of this without reservations.