XpL0d3r

Specs:

97 Civic, converted from auto to manual
JDM B18B, still running auto y7 harness
Harness was modifed for a y7 to y8 mini-me, as well has CKF sensor bypass due to JDM engine with USDM ECU
450cc DSM "Blue Tops", cleaned and flow tested, running to resistor box
Walbro 255lph fuel pump
4 bar OMNIpower MAP sensor
Garrett T3.T4 60 trim .48 a/r
3" downpipe & exhaust, cat-less.
Tuned on NEPTUNE, o2 sensor is disabled (running open loop)
Wideband A/F Gauge, with its own o2 sensor right in the downpipe


Here's the problem:

Car will idle fine from cold start, and drive fine. Once it gets warmed up, it idles at MAX RICH (10.0AFR). When I step on the gas, it goes LEAN (mid 16's to low 17's). When I'm driving this way, car bogs down and makes it VERY tough to drive. Letting off the gas (but coasting in gear), AFR goes down to a 10.0 rather than the 20.0 it should be going to. BUT, when I turn off the car then back on, it runs fine again most of the time.

I noticed this problem would even occur when engine was warm, when I turned on my HID's. I removed the HID's, and was fine with halogens. It ALSO happened when my sub would hit, so I removed the sub to fix that.

However, when the car warms up, it still has this rich idle/lean on gas issue. I've had the tuners re-check the tune, make sure battery offsets were fine, as well as check the injector wiring and resistor box, and all is good.

I now keep blowing fuse 15A under dash, alternator/speed sensor. I checked for wiring short (I know about the Service Bulletin), but cannot find a short. Using a 10A fuse rather than 15A works, though is dangerous, and still doesn't solve the rich/lean issue.

The tuner tells me to replace the engine harness. Just got a hold of a nice uncut one (for a y7, 5 speed) and will be replacing that as well. Unsure of this as I never had a problem with the harness at all before the boost install, but it does make sense a short somewhere could be causing everything..

I do NOT have a CEL on, though when I jump the connector I have code 20 (ELD). It is rare that ELD's go bad, but I just got a new fuse box with ELD and will put that one in. This is another reason it leads me to believe alternator because the ELD controls voltage from the alternator. When it needs more power (aka turning HID's on), it gets it from alternator. However, the subwoofer is wired to battery, so it does NOT go though the ELD. Since both issues caused the same problem, I can assume the ELD is good, though both of those (HID's and Subwoofer) use the alternator.

Also, I have cleaned and checked grounds, they are good. However I noticed my bottom radiator hose is cold, suggesting bad T-stat. Would coolant temp sensor affect any of this either?

If anyone has any insight to this PLEASE help me out.

Thanks for reading.

EDIT: Due to.. certain people, and yes I know who you are.. running off and telling my tuner that me posting this stuff online means I am second guessing their work.. I AM NOT. I am simply looking for suggestions on other ideas in case the stuff they recommend does not fix the issue. Thanks.

XpL0d3r

Update: Alternator tested fine on bench test.

00si2

I have these very same problems that i have been trying to figure out. The afr at idle and the car bogging when the sub hits.

I just noticed the thing with the sub the other day. If i played something with a lot of bass the engine would jerk with the music.

I was thinking either a alternator or grounding problem but haven't had a chance to look into anything yet.

XpL0d3r

Could this be two unrelated issues? The bogging/rich/lean issue has happened since the boost install, the alternator fuse issue is new.

Bump for ideas!

XpL0d3r

UPDATE: Replaced alternator, t-stat, and cleaned t-stat ground, as well as unplugged o2 sensor (since it's open loop)... car will NOT start. Turns out the 80A fuse under the hood was completely shot.

Would putting the 10A fuse where a 7.5A one should be for the speed sensor/alternator fuse cause this? That's what I have in there now because for some reason it kept blowing (looking for wire shorts, not finding anything), but I'm guessing that 10A fuse can cause the alternator to basically overcharge and blow that fuse?

XpL0d3r

Replaced 80A fuse, and put a 7.5A back in for alternator. Fuse is now fine, however.. still having this rich/lean issue

92cxturbo

sounds like a tuning issue

XpL0d3r

Try telling that to the tuner. I've brought that up before and they think I'm "second guessing" them. No, I'm not - but everyone makes mistakes so it doesn't help to recheck EVERYTHING. They say it's my engine harness, and it very well may be... but the car had NO issues before the turbo / tune, soo.... very inconvenient time for the harness to.. go bad, per say.

Myself I always thought car should be tuned in open-loop then made closed afterwards.. not ALWAYS in open-loop like it is now... Since it's always open loop, sounds like they may have made a mistake on the fuel tables somewhere, idk.

And figures, they answer all my questions, but I go to ask for the calibration from Neptune, and do I get a reply there? Not a chance.

XpL0d3r

Bump..

XpL0d3r