In the past 3-4 weeks my engine has completely changed it's behavior. No work or mod was done to it other then changing the exhaust, but it started a few days before that.

When the engine is cold, it will start up and just idle very poorly. Bogs, sometimes dies, I normally have to threat it like a carbed engine and give it a shot of gas before and after, and sometimes maintain the gas for a few seconds after my start up.

After 30-45 seconds of running, it will run normal as if there was no issue at all, the only time I can enjoy my car.

Once the engine reachs operating temp, the weird problems happen. The engine will feel and act gutless. You have to ride the clutch or else it will bog and possibly stall from being so weak when moving from a stop light. It will back fire and miss like crazy aswell, in all gears from idle all the way to 4000rpm. It will even backfire and miss at idle. This is all on partial throttle.

Once it hits 4000rpm, the engine, regardless of it's throttle, will behave and drive fine. Very comfortable and responsive just the way I like it. Unfortunatly it's hard on gas and I'm not all for that.

When giving WOT, the engine will be aggressive, but once it reachs 4000rpm it gets an extra boost of power. My brother has dubbed this issue my LS VTEC cause it sounds/acts exactly like vtec would powerwise and efficiency wise. The ECU isn't throwing any CEL anymore either. The fuel consumption is terrible. I say 300kms for a full tank of gas, the reason I bought a honda was for fuel efficiency and it bites my *** that it doesn't have that anymore. I don't beat on it nor leave it in high rpms. That's why this problem is buggin me so much, it only effects the range I like to be in, partial throttle and low rpms.

90 Civic
B18A1 w/ YS1 w/ LSD
OBD1 P06 ECU (ran the engine fine for 3 months before any issues)
Stock everything else
VTEC dizzy

Things I've replaced and checked:
- Dizzy, it died, new one works perfect on my friends car aswell.
- ECU, swapped it to be safe with other P06, same deal.
- General tune up parts, you name it it's been done.
- Timed, we timed it again for the 4th time last night, it's perfect.
- Checked the wiring for my dizzy. I was throwing code 8 (TDC, important for injector operation) but it's fixed now.
- Checked all my hosing, it's all good.

I'm suspecting my valve seals themselves have either buildup or are burnt out causing a leak. But why would it not happen at 4000rpm?

Both myself (experienced honda tech) and my brother (worked 5 years as a honda tech) are troubled with this. Does anyone have any suggestions?

 

That sounds like it sucks . What about a fuel pump or FPR problem? Just ideas....good luck man thats about all I can think of

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FastAsleep &raquo;</TD></TR><TR><TD CLASS="quote">what head are you using? stock injectors?
have you checked your fuel pressure? fuel volume? injector pulse? </TD></TR></TABLE>

Stock head. Stock injectors, sotck fuel pressure regulator, stock pulse. Car is timed.

As noted in the first post when I said EVERYTHING is stock other then what's listed.

 

have you tried disconnecting the MAP sensor? what about iacv? are you sure the vtec dizzy isn't a culprit? also, test the TPS.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DustinM &raquo;</TD></TR><TR><TD CLASS="quote">have you tried disconnecting the MAP sensor? what about iacv? are you sure the vtec dizzy isn't a culprit? also, test the TPS.</TD></TR></TABLE>

Disconnecting the map sensor should make it run horribly rich, that's what I think is the issue, too much fuel not enough timing. IACV is in good shape and has been replaced, forgot to right that. TPS was calibrate to 0.5 at idle. VTEC dizzy gave no issues for the first 3 months I ran it.

 

This has plagued me in my prelude as well as my CRX and two friends integras, and it ALWAYS ended up being corrosion inside the battery cables going to the fuse block/and or the ground. The corrosion was always inside the insulation too, and not visible untill we cut the rubber off the wires.

Good luck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SIred91 &raquo;</TD></TR><TR><TD CLASS="quote">This has plagued me in my prelude as well as my CRX and two friends integras, and it ALWAYS ended up being corrosion inside the battery cables going to the fuse block/and or the ground. The corrosion was always inside the insulation too, and not visible untill we cut the rubber off the wires.

Good luck.</TD></TR></TABLE>

All my ground are new as of Sept. 06 (4gauge clear wire). I guarantee you they are all in good working order.

 

Fuel pump? Injector issue? Try checking your grounds as well like SIred91 mentioned. Also maybe try running some seafoam through it, it couldn't hurt.

 

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

All my ground are new as of Sept. 06 (4gauge clear wire). I guarantee you they are all in good working order.</TD></TR></TABLE>

Ok, what about the positive wire going to the fuse block? That was the culprit on both my cars believe it or not. Just looking at it didn't show the problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SIred91 &raquo;</TD></TR><TR><TD CLASS="quote">

Ok, what about the positive wire going to the fuse block? That was the culprit on both my cars believe it or not. Just looking at it didn't show the problem.</TD></TR></TABLE>

Which positive wire are you taking about? All my wiring is correct as far as I know. MY brother looked it over and gave me the ok aswell. I ran resistance tests on my grounds and power wires when the B16 wouldn't start, that's when all the grounds got replaced. I don't think the ammount I used it since then (sat for 3 months) would of harmed anything but I won't rule anything out. I was redo it all tonight to make sure. I am not ruling ANYTHING out so throw suggestions.

I'm adjusting my valves tonight to be safe. This stupid LS has plagged me since the day I put it in.

 

On the positive terminal on the battery, one wire goes to the starter and the other goes to the fuse block on the fender, cut the insulation off of the one going to the fuse block.
Its the only way to check it. Then just replace it. I replaced mine with some kick *** 8 guage.

 

That happened to me once and it turned out to be a vacume line I knocked off the bottom of the map sensor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bejita &raquo;</TD></TR><TR><TD CLASS="quote">That happened to me once and it turned out to be a vacume line I knocked off the bottom of the map sensor.</TD></TR></TABLE>

I have a TB mounted map sensor. I am gonna replace it tomorrow and give her a boot. Also going to run some tests on my TPS.

I'm gonna try putting in my B16 ecu tomorow and seeing if it's the P06 ecu I'm using.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wiZCo &raquo;</TD></TR><TR><TD CLASS="quote">Fuel pump? Injector issue? Try checking your grounds as well like SIred91 mentioned. Also maybe try running some seafoam through it, it couldn't hurt.</TD></TR></TABLE>

Good call on the seafoam. Maybe it's build up. The engine internally is very clean, very surprised for what I paid for. I think it came from a little old ladies car cause the IM had alot of carbon in it. I'm gonna try everything to make it work.