Ignition Coil Corrosion..and chasing other demons for fun
 

Impossible to get a photo..but...

HOW much corrosion in there is 'bad'?

Cant say..ive seen any in any other car ive had, but on the drivers side, there is some in there..its just very very hard to get a clear view, but theres nothing shiny in there if you follow, some white and light brown crust..

Im chasing down an all-rpm ignition miss, might just get me -2- new coils tomorrow, and see what happens.

I would guess ANY corrosion there is bad. Any sign of sparks when run in the dark? How old are the plug leads, plugs, caps, rotors?
jp 83 Euro S AT 52k

No visible sparkin that I can see out in total darkness.

Wires, 1mo old, Beru.


The rest, unknown, and I have all but new coils on-hand for replacement.

928 coils rarely fail - just give the connector a good scrub with the bristles of a brass wire brush and some contact cleaner. If you want to really be thorough, de-oxit spray is good too - spray in there, leave overnight, and wash out with contact cleaner.

Here was mine last spring....
https://rennlist.com/forums/members/...il-contact.jpg

Also, make sure to inspect the in-feed power and grounds for corrosion and tightness.

I notice you have started individual threads of similarly related items, ie clean corrosion, clean grounds, clean connectors....
created a master thread for my car call Jadz928's Perl Blog, and have been using that thread to keep track of maintenance, ask questions, and keep people updated.

I like your threads and enthusiam very much! Just hard to keep track of ya... ;)

The wires have spring electrodes.
They need to contact the inside of the coil.
I had to gently bend a set with needlenosed pliers, because they were not making contact.

The plastic cap can be taken off the end of coil for a little better view.
Coils are not that hard to remove and inspect.
Or use a compact mirror and a flashlight.

I changed my coils this spring and still have the old ones if you'd like them. PM if interested ,,,

If you have any corrosion there you need new ones and coil wires.

The coil wire itself, couldnt be cleaner, as its brand new.

If you have ever installed it make sure it is REALLY clean before you put it in a new coil.

I did not install them, PO did after breaking some wires doing a PPI compression check..so -they- carried that $500 tab.

No idea what the old wire looked like.

The feed/ground wires to both, appear well intact.


Just wondering what I have 'round the house right now, that could brush up in there a little. ;)

Although it has a nice snug boot around it, those connections, both ends, are very prone to corrosion; first place to look.

I would just replace them. Corrosion is a bad thing. However, coils are simple - they either work or they don't. It wouldn't hurt to clean the corrosion out of them.

At close to $100ea, we'll try cleanin first.

BUT...I was able to get emory paper in the drivers side one, then use a flat blade screwdriver in the bore to help rotate it..and its all shiny clean in there now.


Drove to work..

Ya..theres a difference there!!

I hear a whole new whoop-ass under the hood at high RPMs that wasnt there before.

Cant wait to tear down to get to the pass side coil this evening.


..and..can you do the dist caps/rotors with the cam covers in place? I havent looked closely enough, yet.


Thanks!

Yes you can remove the dist caps and rotors with the cam covers in place.

I'd also take the chance to remove the right-side cover and check the timing belt tension while you're at it. Don't trust the belt tension to previous work done.

Also inspect the timing belt warning system while the cover is off - it should attach to a tab on the nose of the tensioner, so that it actually works and warns you of low tension (I've seen cars where this was defeated as the tab had broken, and they'd "fixed" the warning light by grounding the signal wire permanently).

Wilco.

I've used a Dremel with a stiff nylon brush bit to clean minor corrosion off the wire ends and/or ignition coil pins before.

Make sure you get the metal shiny and clean, though. If you can't, then it's time to replace the part.

After cleaning, put a bunch of DeoxIT® (I recommend the 100% D100L) on the metal connection point to keep corrosion at bay.

I'm startin to like you. ;] Bruce

Fiddled with my coils for a few days, then bought a used one from 928Intl and swapped it and troubles gone. Old coil still measured good, no clue on what the issues was, but problem solved.

I have two on standby locally, some new Bosch ones.


And..my water pump week became a water pump fast drip yesterday.


SO..now to work out between about one million posts, which one to get..but I can clearly state, im not payin $1k for a dealer one. ;)

That's easy... any of the ones that Ed modifies with his new bearing/drive system:
https://rennlist.com/forums/928-foru...ater-pump.html
:cheers:

New Laso or one with the fancy reworked bearing.
https://rennlist.com/forums/928-foru...ics-added.html

Heck, that saves exactly 999 threads.


Im on it.

Bought the two new coils..here was the testing on the old ones:

Drivers side:
Primary: 1.3ohm
Secondary: 6.1Kohms

Pass side:
Primary: 1.3ohm
Secondary: 5.88Kohms


NOT to spec, which is:

Ignition Coil Primary .33 - .46 ohms
Ignition Coil Secondary 7 - 12k ohms



SO..changed out the plugs, where were Bosch Plat +4's, the caps and rotors (which had some scarring), found that the heater return hose had now started a split ALONG the hose under where it connects to the water bridge (some hose for a GM was a dang close fit, using it until I can get a proper one)..and that solves the fun steady leak that developed on the way home last night..there were no abnormal temps involved.

Found the A/C leak on the output of the dryer, thats now tight..and I THINK the R134a system is fully charged. Its hard to get a guage on the low side, due to a PS hose being "right there" and mostly immobile. But the rear A/C blows out penguins, and the front is "cool" as it fights the heater core heat..cuz that valve under the hood is unresponsive.


Tomorrow, initial vacum tests, Temp2 checking, and that heater valve...and if I can find it, why my oil pressure sender is pegged to the top.

Oil pressure pegged.... good thing. These beasts run 5 bar at full tilt, 2-3 bar @ idle depending on temp.

Mike
84 black
80 white

Roger Tyson is your friend.
 

Lots of threads here on what you're looking for. The heater valve is a very common failure point. They're not very heat resistant....plan on regular replacement. My experience says every three years. (Assuming it's getting vacuum). Temporary fix can be as simple as a wire tie. However, where you live, you'll want to get it working properly soon.....:D
Oil pressure issue also common. If it's pegging with power on and the engine not running, it's either the wires, (Check first), or the sender itself. Bit of a PITA to get to and change out, but really not that difficult.
The DeOxit suggestion is a good one. Never heard of the stuff prior to 928 ownership, and swear by it now. Also highly effective in removing errant dash warning lights, especially for air bag systems....:p

But..with they key on at 0rpm?


:)

Spark Plugs
 

And, no point in getting fancy with high tech spark plugs....the ones that seem to work the best are the Bosche coppers. I think the part # is 7900.

7900 = WR7DC thats the plug to use
replace the water bridge hoses all of them,
replace the HCV and the short hose its special.
Vacuum testing will probably show one or more of the console pods are leaking if so thats why the HCV wont close,
so fix the leaks then the HCV will operate as advertised.
Swap out the coils make sure the new coil wires are not touching any metal or any other parts as they will soon abrade and fail.
Make sure both of the coils have a thick wire connected to the securing bolt then the other end connects to the head to ground the coil to the head

to test the oil pressure sender just swap the wires if the wire swap doesnt show any changes , OR the sender has a plug on type connector that can only go on one way, then you need a new sender

Oil pressure sender goes thru the 14 pin.
Check for corrosion or broken/suspect solder joints.

First peeks..

Vac line was completely off the rear fuel damper
Flappy port vac line, was broken 6" from the solenoid
Cant hold vac behind the dash *duh*
Front knock sensor wire to the sensor from the plug is _hammered_
The A/C compressor just threw it belt on a test start (idles better with the damper plugged in)
AFM ya..able to pull right out, and have adjusted cable to just hear the off-idle TPS click now.

Well..now I know what im saving up parts for now. :)

factory bosch replacement O2 sensor available on Amazon for 63.00

Went to peek at the hatch release..why doesnt it work..well, there IS no hatch release motor in the mount in the back. Yup, there's the problem.

;)

Don't worry too much, they usually don't work any better with a motor.

Ya..I read a thread about that. :)

However, these were the plugs I pulled out.

http://www.speedtoys.com/~gemohler/plugs.jpg

Seven of them looked like the plug on the right.

The rear plug, drivers side, was the plug on the left.

either leaking injector, bad spark plug wire or low compression for #8 plug

Ko..probly wont get into those diagnosis..until the top end tear down this Nov/Dev/Jan.


I dont have -a- spare plug wire to test with, dunno if I have a comp tester...or a spare injector...and dont wanna disturb the fuel rail of unknown age/condition until its time

Or possibly a poor spark plug? (wrong gap etc.)

Replace those fancy things with some Bosch WR7DC copper single-electrode ones, correctly gapped (memory says 0.86mm, but check the owners manual for correct spec). Plenty of reports here of curing ignition stumbles by reverting to the factory-recommended plugs.

Yup, proper plugs are in there, gapped to .7mm, +/- .1 by spec. But they all fit my .71mm wire tightly.

Might just pull the back two on that side, and re-assess.

Yep.

So..I sealed out the vac leak that the flappy valve had been, put the fuel damper vac hose back -on- that was off, and the result was threefold.

1) Runs MUCH better, but still not right.
2) Tranny shifts as it should, perfect.
3) Runs rich as heeeell. I have a brown bumper above the exhaust now.


Wasnt -that- bad with all the leaks.


Granted, I still have leaks..for sure...just much less of a 'leak'.

Vac hose is for safety if internals of dampner leak -- leaked fuel then gets sucked into manifold.

So any runnability improvement would be from reducing the vac leak from the open ended hose.

Why would it be so much more rich than it was before? Granted...it has lottsa issues to resolve. :)

Likely now running rich as a result of the LH adaption routines having previously compensated for the unmetered air leak(s).

The O2 sensor input would have caused the LH brain to increase fuelling until the detected mixture was correct rather than lean.. and those memory tables are persistent between starts of the car, as they're stored in flash.

Disconnect the battery for a min to wipe the flash memory in the LH, and then reconnect. It'll take 10 mins or so of driving for the LH to re-adapt the idle speed and idle mixture to correct parameters based on inputs, after which it should be more normal (idle will hunt up and down during the adaption routine).

I considered that, and pulled the wing-nut ground strap under the tool tray for 2min this AM before leaving for work.

I was Mr Brown Bumper today from the richness.


PS: The car idled just fine after I reconnected...maybe I should go pull that for the night...