gunlover05

Well, I just did my first valve adjustment, replaced plugs, air filter, oil+filter. All my old plugs looked the same (sparkplug1-5 pic) EXCEPT for cylinder #6 (sparkplug6) - which didn't look right. Also, the gap on the old plugs are around 1mm or .038" - which is bigger than spec by a good bit. My new setup seems to idle smother, but I don't feel any power increase really and maybe even slightly less "rawness" - as the car ran quite strong before.

Any thoughts as to what the condition of plug #6 tells me about that cylinder?

gunlover05

Top picture represents plugs 1-5, 2nd picture is plug #6.

Chris57

Dont know how long the plugs were in the motor but it looks like number six is burning some oil.

Daniel Dudley

Why don't you pull the new plugs after 500 miles and check them. Also consider replacing the cap and rotor, and wires too, if you don't know how old they are. Do you have an O2 sensor ?

That plug may be a sign of oiling, I would rather be optimistic and say faulty or weak spark. Does it smoke at start up ? Also, it may sound silly, but some oils burn much cleaner than others. Oil coming from a worn valve guide is not much of a problem. Low compression is a problem.

gunlover05

yes, sorry i didn't say before but I also replace the cap and rotor...I did replace the wires with clewetts, but have to send them back..something is wrong with them, the car ran like crap with them and I was getting shocked at the cap, I put the old wires back on and runs fine until i can get another new set.

good advice, I will pull the plug in 500 miles or so and check it, maybe I will just hold the new wires to put on then. I hope there is not a compression problem, just a leaky valve guide maybe? The PO said he had compression test done about a 1.5 yyears ago and things were fine then (no records though).

gunlover05

oh yes, i have an oxygen sensor and just bought a new one, plan to put the new one on when i put in a cat bypass in a few weeks ;-))

MDL

Check this out.

http://www.ngksparkplugs.com/techinf...q/faqread2.asp

Dan.

Hladun1

I put Clewetts on my 78SC and got sparking at the coil until I put on a coil boot.

http://www.pelicanparts.com/catalog/...pg8.htm#item33

Also the Clewett rubber sleeves that go over the plugs seemed hard and were difficult to get to seat properly. I finally ended up using the old wire set sleeves. It now runs fine and does not spark at the coil. I won't say that I'm unhappy with the Clewetts, but I wouldn't recommend them either.

The bad plug looks like an ignition or richness (injector) problem to me.

ron mcatee

I had four plugs that looked similar to yours. #2, #4, #5, and #6. I also had a problem with the car idling a little rough and sounding like there was carbon hung-up on a valve. Kind of a hollow sound, but not a missfire. I had done the cap, rotor, wires, O2 sensor, new plugs, etc. So I decided to pull the injectors and have them flowed and cleaned. As I suspected, the injectors for those respective plugs were either clogged or had erratic spray patterns. One was so clogged that all it did was drip even when in the rpm cycle. All is back together and the car runs great. If in doubt, check those injectors. I had them cleaned, flowed, new parts (0-rings,etc) for $120. You may have a similar problem on that one injector or the injector could be bad. Just be aware it could be the culprit.

Mike Murphy

Truthfully, it is strange to see just 1 cylinder look like that, with those deposits on there, while the others are so clean/normal. It could be that someone forgot to change that plug when they were doing all 6 for routine maintenance. It could be a defective plug. That said, if the plug is new and is the same heat range as the others, I would check to make sure that you're not running lean in that cylinder. Pull and check the fuel injector. Also, check the intake for vacuum leaks around that cylinder.

gunlover05

I hate to ask, but how do you pull and check an injector? I've never pulled/checked an injector....seems a few think it might be injector related....also, how do you check to see if you are running lean on a particular cylinder?

as far as checking intake leaks, do you spray something around the intake manifold on that cylinder to see if there is a change in the engine speed/reaction at idle?

thanks for the advise guys!

ron mcatee

Gunlover05, On my 88 Carrera and the 84-89 Carrera's, the top end of the injectors have an O-ring that is press fit into the fuel rail and held in place by a clip. This how they are installed in the fuel runners on each side of the manifold. The bottom end has an O-ring that press fits into the intake manifold and is held in place with two 10mm head bolts (front and back of manifold). There is a fuel line coming from the fuel filter and connects to the left rail which provides fuel to both rails. I just removed the lines (1 in rear, and 1 in front, and the rubber fuel supply line) and pulled up on the fuel rail. You'll need to plug the fuel supply line or fuel will go all over the place. You'll need 15mm, 17mm, and a 19mm open end wrenches to get the hard fuel lines loose. On the left side, I remove the heater blower motor and the black heater tube for more room to work. There is a bracket bolted on the manifold on the left side with plugs. I suggest you remove the two 10mm head bolts holding it to the manifold and wire it up out of the way. The right side is done the same way. Once the rails are off, you can then take the rails and the injectors as an assembly and have them flow checked. If they flow OK, you may want to have them cleaned prior to putting back in. You'll need new O-rings also. When putting the injectors back in the manifold, be sure to lube the new O-rings to prevent cutting them. O-ring kits were to cost me approximately $7 apiece, so i decided to have the injectors cleaned, flowed and new seals put in for $120. That way I was sure they were in good shape.

gunlover05

great instructions on the injector disassembly Spider911! much appreciated!

Mike Murphy

There are many ways to find a vacuum leak. I would first look at the fuel injector on that cylinder, but if you want to try the propane torch approach, it is the easiest. See the following link for more information: http://www.aa1car.com/library/vacleak.htm.

Now that I think about it, there may be a couple other things to look for. One thing would be to see if a friend or mechanic has a temperature gun. See if that cylinder runs at a different temperature than the others. If it is hotter, it is probably running leaner. Or if it is running hotter, there may be a blockage above the cooling fins on that cylinder. I've heard stories of material lodging itself inside the cooling fins and causing damage. It's not easy to find, since you have to take the top of the engine (fan shroud, intake manifold, etc.), but it is the only way to check.

Finally, does the heat exchanger look any different on that cylinder? You have to get under the car, but if there is a crack or bend in that particular tube off that cylinder, it could have an effect on the mixture and/or temperature.