jerybak

Since we have been putting more miles on the car as a daily driver its has presented with several issues. Currently it is burning about 1qrt of oil/ 500-750 miles, the car doesn’t leave a drop on the floor or anyplace on the engine, every once in a while it will produce a more noticeable small puff of blue smoke at startup. It is oil fouling out plug no.6 about every 500-1000 miles, I have installed a new plug twice now and it again fouled it out within 750 miles each time. I know she runs rich from a dyno.

Did a compression test and found the following psi:
180,183,187,190,190,185,190,178 (178psi was not on Cylinder No.6)

• Plugs have less than 3500 miles, and cylinder no6 has had 2 new ones installed
• New Beru plug wires
• Running both Kens chips, & WR5DC+ plugs
• X Pipe, no cats or smog pump
• Roger’s 24lb Injectors
• Car does spit black soot from tailpipe on startup (garage floor shows this)


Thinking about replacing caps and rotors and doing a leak down test, just wanted to throw this out and see if anyone has some other ideas before we start in and order parts. Coils look original, wondering if I should change them, but most folks say coils wouldn’t give an issue to only cylinder, as all the other plugs looked good when we pulled them for the compression test. Miles on car are 63k, fuel mileage is about 13miles/gal

Kevin in Atlanta

What is the known mileage? Start with a leak down test. No expert on compression, but i thought I read they should be within 10% of each other. I get blue smoke on startup and the fouling with my 87 - but I know I need to replace the valve stem seals. My fouling clears up after an italian tune-up only to return the next time I start the car and then I have to drive it hard again - a vicious cycle.

jerybak

updated post, miles are 63k

jerybak

fuel mileage is about 13miles/gal

granprixweiss928

Worn valve guides and/or seals.

my plugs were quite fouled as well and it was due to this.

I also had only 60K miles- but lots of short trips and cold starts over the last 35 years wore the guides... and many other things

zekgb

Yes most likely stem seals and guides. My car was burning about a qt/1k miles and was oil fouling 8 and 7 on the regular with periodic blue smoke on startup which I assume had some connection to the eventual burnt valve in my avatar in 8. Definitely should do the leakdown test and report back with results.

As for spitting soot and the lousy MPG is the MAF original?

Speedtoys

Hotter plugs may help in the mean time.

jerybak

yes MAF is original, LH & EZK have not been rebuilt.

Which plugs do you recommend? I also read that making the plug gap smaller helps.....

safulop

I think that, aside from the plug fouling issue, the MAF is a likely cause of poor mileage. But really 13 mpg is not too bad for an S4 in all-city driving. I did 12-13 for the past 5 years on mine.

jcorenman

I don't think this can be an ignition issue. I would check the #6 plug wire (do an end-to-end restistance test compared to e.g. #7) and skip the rest for now.

Is this a new problem, or has it been rich since changing the chips? Was it running rich prior to that, with stock chips?

Is the 13 mpg highway, or city driving? You should expect around 20 on the highway, city can be all over the map.

Most of the symptoms are hollering "Rich mixture!!" yet you seem to be looking elsewhere. Resolve that first. Unless the O2 sensor has been recently changed, replace it. They don't last much past 60K miles in any event, Bosch 13048.

An aged MAF tends to make the mixture leaner, not richer. A failing LH can do lots of strange things, and will eventually leave you stranded unless you get it rebuilt. I would put a rebuilt LH high on the list.

WR5DC+ plugs are two steps colder than stock, they work fine if everything else is OK but I would go back to stock WR7DC+ plugs until the issues are sorted.

Oil consumption may well be a completely separate issue. What is the history on this? Always been an issue, or recent? With only 63K valve neither rings nor valve guides/seals should be an issue. A leakdown would provide some good info here.

Is the 63K actual miles? Or was the odo maybe broken for a long period?

jerybak

Got the car last Nov after sitting for 3+ years, we have put about 6k miles on it since then, never saw any issues prior to the fuel chip(installed the ignition chip with stock injectors for first 3k miles) & cooler plugs. Ran without fouling plug for the first 3k miles, but the last 3k miles and since we installed the fuel chip, cooler plugs, and 24lb injectors is when the plug fouling started to show up. Also first 3k miles were over about 5 month period, the last 3k miles have been about 2.5 months so its getting driven more now also and I just started tracking, oil, fuel usage the past month.

All city miles, little to zero highway, short trips lots of starts.

O2 sensor has not been changed, was planning to order with caps and rotors ( i have a maint record from PO that shows caps & rotors changed 10k miles ago.

I good friend has a chipped LH/EZK he is willing to install and test, should I install an AFM gauge?

Will those plugs be ok with kens chips installed? I assume I should change all plugs and just the No.6

63k miles are verified, from carfax and PO records, I knew the immediate prior to me owner of the car, and because I am a straight nut job I researched and contacted (2) of the other POs of the car. These (2) guys had the car the longest and shown on carfax 2 pages of various service work.

GlenL

If it started when you made those mods then take out the mods and see if it goes away

Besides that, 1qt in 500 miles is far above acceptable for that model and in city driving.

I actually suspect that there are two or more problems with the car. One is causing oil consumption. One or more problems are creating excessive richness.

Imo000

1gt in 500 miles is highly uikely to be the valve guide seals. Probably worn rings and/or cylinders. Get a proper leakdown test.

Cosmo Kramer

How is your driving style, do you bring it to high rpm often? 32v cars tend to have some oil injestion issues into the intake at high rpm. Do you get blue smoke on startup and deceleration? That would signify worn valve guides and seals. Blue smoke on acceleration is usually from worn or stuck rings or bad crankcase ventilation that throws oil mist into the intake.

jcorenman

Was anything else done at the same time as the chips and injectors?

OK, then 13 mpg may not be unreasonable. But the dyno showed rich, plus the soot from the exhaust. What was the AFR on the dyno?

I would definitely change the O2 sensor. Caps and rotors last a long time, so unless something got broken or cracked then that seems unlikely.

Swapping LH would be a good test, EZK (almost) never fails. But I would still go for a rebuilt LH as budget allows, it will fail at some point.

Yes, chips effect timing and don't care much about the plug's heat range. Colder plugs tend to reduce detonation but also foul more easily. I would change them all to stock plugs until this is sorted, just to reduce the number of variables.

Too young to have worn valve guides and seals, or ring or bore wear. At 263K yes, but not 63K. The problem is that I don't know what would link oil consumption / plug fouling and running rich, so maybe two separate issues-- but that seems odd, if they both started around the same time.

It would also be good to stick a borescope down the #6 plug hole and see what the piston/cylinder walls look like, compared to the others.