my poor R motor consistently breaks/melts the electrode off the sparkplug in cylinder #3

this is a stock R motor with a toda header, smsp cat, and the milk jug removed from the stock intake. the other plugs are white (lean?), but don't have any other issues. the fuel filter is new and i moved the injectors around (assuming clogged injector), but the problem remains with cylinder #3.

the motor's compression is fine, cylinder #3 is probably the best of the bunch. is it possible the piston could contact the sparkplug, but not damage the valves?

i do the valve adjustments myself and the problem occurred before the adjustment and remains afterwards. the distributor timing was checked and is at stock 16deg btdc, but i plan to get it rechecked.

what haven't i thought of? what could cause this problem?

i've heard that a header can cause a motor to run lean and cylinder #3 already is the "hottest" one, but i've never heard of anyone else having this problem.

 

take it to someone that has a wideband to see if it is running lean. Could be that the wiring is bad, or if you are running aftermarket injectors, the wiring could be backwards on that injector harness...or the injector driver in the ECU is bad for #3, you could check that by plugging in another ECU (if you know someone that has one..)

 

intake manifold clogged?

 

also try resetting ecu...although it's probably something more major

 

have you tried a one step colder plug?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boost psycho &raquo;</TD></TR><TR><TD CLASS="quote">take it to someone that has a wideband to see if it is running lean. Could be that the wiring is bad, or if you are running aftermarket injectors, the wiring could be backwards on that injector harness...or the injector driver in the ECU is bad for #3, you could check that by plugging in another ECU (if you know someone that has one..)</TD></TR></TABLE>

His injectors are stock. Like already said, you should get your A/F ratio checked. Maybe a colder step spark plug will help also.. Just ideas.. Good luck..

 

i hope to take it to a dyno shop this week to get tested with a wide-band and get the distributor timing checked. i also have a vafc that i'll get tuned; it's not currently plugged onto the ecu.

i'm going to look into running plugs that are 1 step colder.

how would a lean/hot motor be indicative of a clogged intake manifold? wouldn't lack of o2 cause it to run rich? i haven't pulled off the intake manifold, but the throttle body is spotless; i would assume that for something to get into the intake manifold it would have to leave residue on the throttle body.

 

My suggestion would be to get it tuned with a wideband, which you appear to be planning. Sounds like the motor is running extremely lean.

 

what kind of spark plug and how many miles?

 

i have moved the injectors around and the problem remains with cylinder #3.

the car has oem injectors, wires, & sparkplugs; 62k miles on the odo.

could the spark wires for cylinder #3 be damaged causing poor spark? i guess it doesn't explain leaness.

 

i guess it woulnd't hurt to replace all simple things.. so replace wires if they have 62K miles on them, replace your dist. rotor if you haven't yet for these 62k miles. then see if you still have that problem. i'm not sure about piston/valve damage from this.

and how many miles do your sparks last until this happens? usual boltons without tuning will make the car run leaner, but i wouldn't expect all this to happen.

 

Sounds like a lazy primary O2 sensor. Pull it out, bench test it and replace if necessary.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stumpyf4 &raquo;</TD></TR><TR><TD CLASS="quote">Sounds like a lazy primary O2 sensor. Pull it out, bench test it and replace if necessary. </TD></TR></TABLE>

could it cause this? good idea, i'll just buy a new one in hope that it fixes it. do new o2 sensors need to be spliced/soldered onto the existing wire?

the cap/rotor were just replaced. the plug seems to last around 5k miles. once the plug breaks, there is an occassional intermittent stutter at idle but it's seems to run fine at partial throttle/wot.

one would wonder where the 3 previous electrodes have gone, but the compression checks out fine. i believe it slowly melts away and the metal bits are ejected through the exhaust valves. i poked a magnetic wand through the spark plug well and rubbed it around on the piston and didn't pick up any metal.

 

bad O2 sensor can cause both lean and rich condition, only other thing i can think of is to check the gap, and replace spark plug wires if you suspect one of them isn't good.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtec.dc2 &raquo;</TD></TR><TR><TD CLASS="quote">bad O2 sensor can cause both lean and rich condition, only other thing i can think of is to check the gap, and replace spark plug wires if you suspect one of them isn't good.</TD></TR></TABLE>

gap on oem plugs is set at 1.1mm. i'm going to chase down the distributor timing and replace the o2 sensor asap.

 

honda guru rodney thinks i might have a faulty fuel pressure regulator. he felt it was unlikely the o2 sensor because the car has not (but should have) thrown a code.

 

Get a fuel pressure gauge?

 

i'm going to the jeimports dyno in maryland on wednesday morning. they will check the fuel pressure (and they have an aem fuel regulator in stock), dyno tune the vafc, and check the distributor timing. i've got my fingers crossed!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by magic hat #9 &raquo;</TD></TR><TR><TD CLASS="quote">i'm going to the jeimports dyno in maryland on wednesday morning. they will check the fuel pressure (and they have an aem fuel regulator in stock), dyno tune the vafc, and check the distributor timing. i've got my fingers crossed!</TD></TR></TABLE>

Sounds like a good plan.
I was going to suggest an FPR for use with the VAFC (FPR to up the pressure and VAFC to trim it out where needed).

At least you noticed this before it ended up with a burnt piston or worse.

P.S. Where's J E Imports located?
I'll be on the road Weds making my way north and ...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zygspeed &raquo;</TD></TR><TR><TD CLASS="quote">

P.S. Where's J E Imports located?
I'll be on the road Weds making my way north and ...</TD></TR></TABLE>

je is in parkton maryland, i bit north of baltimore. i'll be there from 10-12ish - come on by!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by magic hat #9 &raquo;</TD></TR><TR><TD CLASS="quote">

je is in parkton maryland, i bit north of baltimore. i'll be there from 10-12ish - come on by!</TD></TR></TABLE>

http://www.jeimportperformance.com/interface.html

 

Thanks guys.

 

The primary O2 sensor is only feed back to the ECU on the lean/rich mixture. If it detects a lean condition and asks for a enrichment and doesn't see any enrichment it will set a trouble code for too lean. My feeling is since you're not seeing a MIL light it's the O2 sensor being lazy... not reading correctly. The sensor voltage is not outside parameters (if outside parameters it will set a MIL light for O2 sensor) just not reading the rich/lean condition as it should. Just my $0.02, good luck with the diagonis.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stumpyf4 &raquo;</TD></TR><TR><TD CLASS="quote">The primary O2 sensor is only feed back to the ECU on the lean/rich mixture. If it detects a lean condition and asks for a enrichment and doesn't see any enrichment it will set a trouble code for too lean. My feeling is since you're not seeing a MIL light it's the O2 sensor being lazy... not reading correctly. The sensor voltage is not outside parameters (if outside parameters it will set a MIL light for O2 sensor) just not reading the rich/lean condition as it should. Just my $0.02, good luck with the diagonis.</TD></TR></TABLE>

doesn't really make sense the o2 could be so "lazy" that the motor is running lean enough to melt spark plugs but doesn't pop a cel. i'm going to the dyno shop tomorrow, they are going to check the fuel pressure and perhaps we'll narrow this down to a busted fuel pump or a broken fuel pressure riser.

 

good luck tomorrow aaron