Easiest way to determine if car is firing on all 6.....

[jester911]

No you have to get cap from someone with porsche parts.
Dealers carry them if you need to get it locally. Our host has them as well.

When you remove the cap, first look at the rotor button.

You will see where the top of it makes contact with the cap.

YOu should be able to see whether there is wear on the cap and the rotor.

If you replace one, you should go ahead and get the other at the same time.

[svonkampen]

OK....looked inside the cap.........the contact points at the top look black....how do I clean them? (rexpose the copper)

need shopping list.

SvK

[jester911]

Look at the center post inside the cap to see how far down it is worn. If not making proper contact with the rotor cleaning it will not help.

Also check the copper on top of the rotor. Make sure it is not worn thru.

These may or may not be causing your problem but they are not expensive and should probably be replaced anyway.

[svonkampen]

what grade sand-paper / file do I buy...

anyone?

SvK

[svandamme]

dude, just scrap the dirt of the contacts, wirebrush or some metal sponge(you know , the kitching thing for old pots an pans) will do
if it doesn't help like that , buy another cap
it's 12 bucks or something

[svonkampen]

ok....when pulling / and replacing the 6 individual cables......the idle is NOT reduced by the same amount. In fact it varies wildly, depending on which ignition cable i pull....

What does that tell me?

SvK

[svandamme]

the one with the most change is running the best
the one with the least change is not running at all or marginally

start troubleshooting on the latter

wire , plugs , ...

[svonkampen]

Stijn,

Thanx for your patience, and advice ;-)

I don't know if you know this, but TRE motorsports, just overhauled my car. They put a 3.0 in her and used my Weber's instead of CIS....All my spark-plugs are new and my Carbs were rebuilt by Dave @ TRE.

When I picked her up from TRE, she was hell on wheels, for about a week......now she sounds like a Tractor and has no power. Anyhow, I'm whining. Monday she goes straight back to TRE......



SvK

[svandamme]

2 of these



i'm mellow and patient as can be...
i'll try Westmalle Triple next time i'm troubleshooting mine.. i'm never patient enough when messing around with my own engine

[RoninLB]

I confirm spark plugs were ok to start with. New NGK BP5ES is a good hot plug for tuning carbs, etc. Flip them out later if they're to hot for your normal operation.

carbs will foul plugs very easily and the eyeball can easily be fooled. It's difficult to compare to a CIS as the carbs run rich at low rpms which may be disturbing the fuel mix big time.

[Jandrews]

I'm with RoninLB. You said "steadily losing power" and "switched to webers" in the same post. I'd check to see if your plugs are gradually fouling. As RoninLB said, try a nice hot plug like a B6-ES or even a B5-ES. I think a lot of people underestimate the importance of proper plugs. I know I did.


JA

[jwetering]

Search the forum for weber*. You have yourself some plugged idle jets or sumthin'., I'm willing to wager your problems are not electrical.

[RoninLB]

Originally posted by jwetering

You have yourself some plugged idle jets or sumthin'., I'm willing to wager your problems are not electrical.

Exactly..


if it misses w/new hot plugs use air to clean everything. Measure the idle screw turns before pulling them so you can replace same.

or your current turns could have caused this situation or have been a contributing factor.

[cstreit]

Use an infared laser temp guage on each exhaust outlet... The cold one isn't firing.

[RoninLB]

Originally posted by Jandrews

I think a lot of people underestimate the importance of proper plugs.

Exactly

especially with carbs due to the low EGT's on a cold engine. If the carbs aren't right etc the plugs may never clean up with later proper operation. It don't take much to foul plugs.

[jwetering]

I dialled in the idle circuit on my webers WAY too rich once during one of my first "attempts" to tune them. One or more of the plugs foulled realyl badly and this manifested as a distinct miss which went away when I got on the loud pedal. Once I leaned the carbs out the the plugs cleaned themselves up just fine. I had many miles of happy motoring on those same plugs after that.

If the carbs are in good shape (ie no plugged jets or passages), then 2 - 3 full turns out from dead bottom on each idle screw should be good enough to have the car run relatively straight. There's a bit more to it to set them up for real, but that's a good baseline I've found.

I also had to pull my idle jets one day because of a really bad miss. Turns out there was a piece of o-ring stuck in one of them. Many years later I had a power loss under load, and I found more o-ring in one of the main air jets and in an emulsion tube. The only o-rings on the car live on the idle mixture screws, so I took them all out and I'm having the smoothest idle I've ever had. The moral? - ou don't need o-rings to seal the idle mixture screws.

Good luck.

[RoninLB]

Originally posted by jwetering
bad miss.

o-ring stuck in one of them.

more o-ring in one of the main air jets and in an emulsion tube.

so I took them all out and I'm having the smoothest idle

- you don't need o-rings to seal the idle mixture screws.

great story

[Hugh R]

Do you own a multimeter? Use the ohms function to test each end of each lead. Easier yet, fire it up, pull a plug wire (either end_ and touch it to ground it should zap with a fat blue spark repeatedly, if not, its a bad plug wire. Engines backfire especially on decelleration because the unburned fuel was too rich and it leans out into the combustible range as it hits the exhaust pipe and more oxygen is available to bring the mixture back into the explosive range.