VX getting lousy FE lately, what are the causes?

[silversol]

I am in georgia also, I have a almost brand new set of cv axles i was saving for whenever my civic needed them. Let me know if you would be intrested in them.

[add|ct]

If these 'new' ones I have go out short of 3-4 years, minimum, I'll be overpaying for Honda originals next time.

[add|ct]

Update:

Yesterday, while waiting at an extreme incline(car front facing UPHILL) of at least 20-25 degrees, the car suddenly stalled upon attempt to move once the light turned green. I had the AC on, blower set to max. Maybe I should have ridden the clutch a little longer? ...but it seemed to die very easily, in any event.

My last tank yielded about 36 MPG, by the way, the vast majority of run time with the AC of course, this after about 43 on a highway trip out of town(pretty lame for mostly highway if you ask me, some stop and go). It feels like the car wants to die at slow speeds, especially with AC on...and if I press on the clutch pedal to early coming to a stop(while the engine is starting to brake itself), I feel a 'shudder', strange 'pop' like sound at the same time. This is just on occasion, though.

Suspicion: I wish I could replace both the tires and the clutch, but I may have to eat taking worse MPG on these older tires for the sake of a clutch replacement due to the need of functionality in a populated area/safety concerns with my wife needing to drive it. This should improve MPG, too, though.

I just have this strange feeling as if something fuel related is an issue, but I do believe a new clutch would fix my issue(I hope my cat isn't starting to clog?) Emissions testing is in a month or two, so I'll report back soon regarding that. I also had the car die while trying to move in reverse a few weeks ago at night, the car was facing downhill slightly(5-10 degrees). I was on the grass there, the stall yesterday was leaving a parking lot on a crazy incline. Not sure, but it could have well been closer to 30 degrees, no joking.

[benfrogg]

Hmm. Your comment about the "pop"sound and shudder sounds a bit like spark knock to me. That would account for bad FE as if it's knocking the timing isn't adjust correctly (or the advance/related systems are malfunctioning). That might also account for lower rpm reduced power/stalling. I recall a while back we discussed timing in your car... I think? What ever came of it? Have you seen the youtube video and heard the sound of knock/ping? It has a very distinct sound you wont forget. I believe Holy Cow embedded it last time.
It sounds like the timing is either set to far advanced or the timing advance isn't working right. Too far advancing timing will hurt FE just as much as too far retarded. Those marks on the plastic case are tricky to look down and get line of sight on. It's a bit like lining up the crosshairs to the circle on and old gun, then looking up down 3" to marks on the harmonic balancer.

I think replacing the clutch will only help FE if there is a significant amount of clutch slippage. If, OTOH, the associated bearings are failing and will be replaced when the clutch is replaced, FE would likely improve.

It is my understanding that extreme angles will make the engine lack lubrication because the pickup for the oil pump can become no longer submerged, if only for a brief period. That could do some funny things.

One other thing-
Pull your plugs and take photos of them. Make sure you label which one came from what cylinder while you do it. Post the photos here... if there's a major difference in plugs or they don't look just right, it may give some clues about what's going on. For several months my VX had the number one plug always much whiter than the rest.... then I cleaned the injectors in the shop... and even color across all four after that.
B

[add|ct]

Thanks for the tips ben. The sound I was describing seems to be related to the clutch, the sound itself/feel I get. It is only occasionally and typically happens with the AC on which causes start and go drive-ability to be lugged, etc...for instance, I start moving in 1st gear with AC on and the car feels like it's either wanting more power or wants to die, so sometimes I come back onto the clutch pedal too hard or fast and the preceding symptoms/sounds etc happen at that moment.

The extreme angle makes some sense, I think it might be this clutch making it harder(slipping when I need to ride it more?)...I do plan on replacing at least the ISB, but overall I think the transmission is just fine otherwise.

I will pull the plugs soon on and see what's up, compare each one to the other. When I first pulled the plugs to 'check' them, the old ones also original NGK p/n, I noticed cylinder 1 had more carbon around the threads. I'm afraid of pulling cylinder #4 since it was being difficult compared to the other 3 cylinders when installing the new replacement plugs, back in the end of May.

I also have thought that perhaps my injectors aren't operating optimally, as the ticking from them seems noisy/sporadic. Would it be worth it to use the old screw driver or mechanics stethoscope on each injector to listen for any differences? I did use a bottle of Red Line SI-1, the full bottle, on a full tank. I realize now this was over-treatment, maybe it did 'too' well and gummed up an injector slightly? IDK.

I wish I could find out where to test the fuel pressure on the VX(fuel test port?), I'd buy a pressure gauge and do that in a heartbeat.

Back to the plugs, they seemed to be alright when pulled before. #1 seemed a little 'cruddy', with some of the carbon and all, but when I checked the other 3, they appeared 'normal'. Of course, turning white on the arm but not 'terrible', it seemed like normal wear for a lean burn chamber to me. I'll see what these 'new' ones I installed look like and take pictures if worth it. Maybe I added too much anti-seize?

[benfrogg]

You could use a long screw driver touching an injector and your ear with the car running (carefully with the pointy end on the injector) to listen for clicking. It should be nice and even, no "misses." Check each one. They should all sound similar/the same at the same RPM.
If one is particularly louder than the others, you might have an issue. It would be acute though. More likely, you'd find one that was more faint than the others.
More carbon build up could be an indication of something... could also be related to FE type driving. If pulling #4 is precarious, you may wait until you don't need the car for a weekend or something. That way if you have bad threads to deal with, you'd have some time/money to take care of it.
When you do pull them, try cleaning off the antiseize from the plugs. They'll still be some left in the head so you wont have to worry about them seizing on you.
The VX fuel test port is supposed to be on the fuel line that attaches to the fuel filter on the top. It has a larger bolt head that goes into the filter and then a much smaller bolt head on top. The smaller one threads out and you put your FPG there.
B

[add|ct]

Similar patterns on all 4 injectors, but once warm I could tell a 'slight' dullness in cylinder 4 compared to cylinder 1, cylinder 1 sounding slightly 'raspier' and cylinder 4 being ever so slightly more faint than the other cylinders. Either way, I'll probably wipe off some of the anti-seize.

I'll probably pull #1 and then perhaps all expect #4 when I have a couple days off in a row in the event of an issue, if I decide to pull all including #4. So, we'll see.

I also noticed the wire that comes out of the VTEC solenoid lately has oil on it(it may have done this before), I had previously lost oil from either the housing or the top part, replacing both gaskets already. Maybe it's leaking internally? No codes as of yet.

The VX fuel test port location, that sounds plausible, but wouldn't that only detect pressure post-filtration, perhaps telling you if you had a clogged fuel filter or not? I have replaced my fuel filter twice, one upon getting the car and then 20,000 miles later with a Purolator. I'm considering going with a Mann, Hengst, or Wix/Napa Gold next time.

I suppose if it failed a pressure test ever so slightly and replacing the filter didn't see a spike with pressure, a fuel pump would be the suspected culprit in the end? This wouldn't test for FPR functionality, though if I'm understanding things right.

[benfrogg]

If you are hearing differences in your injector sounds, it would definitely be worth a cleaning. It isn't all that hard to do, really. You need a couple of jumper wires with gator clips, a 9v battery (or car battery), a length of hose that fits the end of injector tightly, spray throttle body cleaner, and something to block the other end of the hose with like a bolt.
I doubt oil around the vtec solenoid will have much effect on anything other than leaking oil. Besides, I suspect you rarely get above 2300 rpm anyway.
Yes, you are right, the test location is pre-filter, I think. I'll have to look at the routing on mine to confirm this. You can test there, then replace the filter... if the pressure goes down, the filter was clogged. If the pressure is then under spec/inconsistent, you can suspect FPR or pump. There's a procedure for testing the FPR, it involves pulling the vac line and inspecting for fuel (which there should be none), then providing a vacuum on the line, or not, and checking to see that pressure changes when you do so. If the pressure doesn't change at all or there is fuel in the vac line, replace the FPR. If it is functional and the pressure is still low, replace the fuel pump.
B

[theholycow]

It sounds like you replace your fuel filter often enough. You'd have to have a severe sediment problem to clog a filter enough to cause insufficient pressure at idle...and then I imagine you would have severe lack of power, like, can't get over 2000rpm or 20mph. I wouldn't recommend worrying too much about location of the test port, as long as it's somewhere between the fuel pump and the injectors.

[add|ct]

Yes, I do replace the fuel filter often enough(twice since owning the car in about 35,000 to avoid such a 'clogged' filter after bringing the car up on maintenance)...

I took out plugs from cylinders 1, 2, & 3 today. Here are some pictures. The one on the left, in the pictures, is from #2.

The plug on the right is from #1, and #3 looked similar to #1...(#3 not pictured)...what do you think guys? I did add lubro moly Mos2 and used a full bottle of Red Line SI-1 fuel system cleaner after these plugs were put on about 4,000 miles ago, I think I may have used too much anti-seize as well:

http://img153.imageshack.us/img153/3654/1003550.jpg

http://img854.imageshack.us/img854/8595/1003553d.jpg

http://img828.imageshack.us/img828/1763/1003554.jpg

Gap for #2 was slightly larger than the spec'd .043 gap, but #1 and #3 were just under .042 gap or so.