eric951turbo

So the car is going better, fixed a lot of things since spring.

The only problem left that I'm trying to find is the exhaust popping when I let go the throttle, and in between shifts.

So far, I have :
- adjusted the idle / tps... I have a really nice, steady idle now
- all new vacuum lines
- Cleaned the ISV
- new spark wires
- new coil
- new rotor and dist. cap
- new temp sensor
- i some water problems with the dme... all is fixed

Now I had 3 things left to do :
- new sparks plug (I changed them 2 months ago)
- swap the dme with a good one
- fuel pump and fuel filter

I have an almost brand new (2 years old) Vitesse Stage 1 kit,
that I still haven't had success with, because of a tons of other problems.
So I may have 4K miles on it (all parts), still no track days.
- Maf
- 3 bar fpr
- 83 pounds injectors
- stage 1 turbo

So I started tonight with the plugs, decided to try the NGK bpr7es,
here's what I found ??????????

In my books, this mean a ''very'' lean condition... no?

With the exhaust popping, backfiring, missing, I was 100% sure I had a ''rich'' condition.

It looks like carbon deposit, that became White??????????

I'm even more confused now, please help.

bonus12

Those heavy tannish deposits in the 4th cyl may indicate oil leakage into cylinder or gasoline additive buildup. But the grayish color with small amount of electrode wear looks normal to me.

shortyboy

Check injectors and fpr. mine has been doing the same for a while some backfiring on deaccelleration.I'm suspecting my injectors or fpr because my gauge is pulsing 50-60 and almost to 80psi when o shut the engine off.then 20psi the next morning.those plugs look pretty normal to me.

mytrplseven

Plugs appear to be very clean. I'm wondering if that's not necessarily a good thing. I'd expect a touch of tan color indicating a healthy fuel burn. My Harley really pops when it is backing down. This is indicative of a lean mixture (caused by installing a K&N free flow air cleaner and exhaust pipes that reduced back pressure). Bottom line: more air through the engine vs proper fuel/air ratio, i.e., too lean. Had to re-jet the carb to a richer jet to stop the popping.

shortyboy

do you have a wideband O2 sensor?what do your AFRs look like at idle, partial throttle and full WOT?

eric951turbo

Nope, I don't have a wideband, that's a thing added to my list.

I'm trying to fix the things that are suspicious for now, with less $ involve. So far, i've:
- reajusted my fabspeed exhaust (had two tiny leaks)
- changed the water cooler fluid (I had to make sure no oil in it)
- reajusted the idle....

I adjusted the idle higher, almost at 1000rmp, and realized that the popping is almost gone?

But now I just came back from a ride, and my isv is making a lot of noise, and with the engine hot, I won't do anything if I play with the idle screw. Doesn't even do anything if I pinch the isv hose.

I also ordered a new fuel filter, check valve, and o2 sensor (universal, cheaper).

shortyboy

you shouldnt be able to hear the isv. i would remove it, clean and pressure test.ive recently had the same problem, i took it out, and plugged the ports on the intake manifold and intercooler pipe and adjusted my idle set screw on the side of the throttle body.

krystar

by the blackness on the base, either too rich at idle or burning oil.

porcelain seems to be a bit too white...indicating lean under load.

if you haven't done so, go get a wideband dyno. that'll tell how lean you're running under load.