Gadget

Let me just start off with "I'm not dumb".. I've worked on imports and domestics, carburated and fuel injected for years... This one seems to puzzle me..

I have a 95 Civic 2 dr DX coupe.. Started life as a D15B7/auto trans combo.. it ran REALLY good.. Er as well as a DX could possibly run.. Anyhow.. it always had a hesitation if you just started it and drove it after a cold start.. Sometimes if you started it and just let it idle it would miss/sputter and almost stall but never would.. other times it'll start up and idle perfectly normal til you try driving it.. It would only do it during the first minute or 2 tops while driving the car after an initial startup, then it'd "clear out" and run perfect.. I only say "initial startup" because it would mainly do it when cold, however I've driven to the store and purchased something and while the car's still hot, start it up and it'll still sputter/miss for a minute or 2 then clear out... Further in detail, if you atarted out in drive and tried accelerating it would only maintain speed of 5-10 mph and maybe decelerate a little as you press the pedal to WOT.. just as you approach WOT the car would "clear out" and run as hard as it could according to the particular throttle position at the time of it's random "clearing out"...


Now, pissed off because it's missing/sputtering as it is and it's enormous lack of HP I swapped it.. Basically a "By the book" Swap.. Unbolt a GSR from a 95 integ, and bolt it into a 95 civic.. using the harness and ALL swap parts from the integ that ran perfect before being rear ended and totalled (Bless that car) including the harness, all emission components, and ECU.. The only thing other than the basic swap I did was remove the A/T shifter spot weld a shifter boot plate inside the floor and close the circuit for the neutral switch for the starter, and install the clutch pedal assy from a Y2K integ..

The car STILL operates the same as it did BEFORE the swap.. spurratic missing/sputtering when you start the car for the first minute or 2.. it don't happen EVERY time you start it.. It only happens maybe 2-3 out of 10 times you start it..

The GSR runs HARD and PERFECT aside from this little problem..

I've heard of other EG's having the same problem.. Do we know what causes this? Keep in mind, everything under the hood has been swapped and it's running a different ECU now, and STILL has the same problem..

Any help would be greatly appreciated..

Gadget

Bump

loyalty4eva

no clue i owned another car that did the same thing. But if you swaped everything then it wouldnt be the motor or ecu/tranny.

suspendedHatch

I will take some shots in the dark here. Fuel filter? Fuel pump? Clogged cat? Grounds?

Gadget

I thought the same thing.. Sorry to say, if it was the fuel filter or pump, it wouldn't run correctly at the point of highest demand.. Wide Open Throttle..

it runs like a CHAMP at WOT.. And fuel pressure does not drop after the car sits for a while..

I have 3 grounds.. one directly from the trans mount to the battery, one from the trans to passenger frame rail, and one from the driver radiator support to the valve cover stud, but not the valve cover itself since it's completely insulated by rubber gaskets..

The cat would be an impossibility.. if it were plugged, the car would have no power at high RPM and would be getting REALLY hot.. it's fine.. becides, it did it with a test pipe too..

Remember, this is completely spurratic and only happens for a short time after inital startup, then goes away and the car runs fine afterward..

I was running a P06 that I built to run my GSR.. I added the SK5150 hi-side switch and the other hardware to operate the IAB's and chipped it with a P72 program.. it runs good.. However I just tried a P72 ECU that's completely stock and it still does it.. =/ I knew it wasn't the ECU, but I wanted to try it anyhow..

suspendedHatch

Well I have an EG, two different motors, never had that problem. I've had other problems that spanned across two motors. One was due to a bad fpr. That's right, both motors had bad fprs. They both had barely functioning injectors. In my experience, not all problems can be "logicked out". Try everything anyway, short of just throwing parts at the problem of course. Your problem "feels" kind of like an ignition problem though it doesn't make sense so it wasn't my first guess. If it's not something on the chassis not affected by a motor swap, then that leaves something on the motor.

You swapped the complete harness from ECU to sensors? Did you keep any sensors? O2? MAP?

Ok I'm not really helping so good luck.

Gadget

Yes.. Everything from the engine to the ECU was replaced except the chassis harness.. as far as the engine, I removed it from a perfectly running GSR and dropped it in the EG.. I didn't reuse anything.. I think I'm going to throw a main relay at it.. we'll see if it catches..

92civichatch1

i have the same problem with my eg. i have a b18b swap. heres my conclusion on the situation...

If its cold (overnite) and i wake up late and gotta get to work and i get on it it hesitates for a sec or 2 then goes. I think its because the oil isnt thin enough yet to flow fast so the car has a "limp mode" to protect it.

Well heres how i came to my solution...
1. whenever i allow the car 5-10min in the mornin to warm up and then drive and get on it shes fine.
2. whenever i dont do that it hesitates

Thats my story and im stickin to it

Gadget

Haha.. I wish it was "limp mode".. I think it's the main relay.. if the ECU don't have a good +12v signal, it'll get facked up readings from the +5v refrence voltage comming from map/tps etc..

I'll let you know one way or another when I swap the Main relay... that's about the ONLY break in the circuitry from battery to the ECU aside from the IGN switch which I replaced after the 3rd time my car was stolen...


Good to know I'm not alone..

Gadget

bump

Sketch_hs

sounds like the car is having issues getting good open loop performance.

has the O2 sensor been changed?

Gadget

I've tried 2 different O2's.. I have a narrow band AFR guage and the O2's NOT lazy, it's very responsive in fact.. Upon initial startup the ECU don't use an O2 sensor unless the car is already warmed up.. This typically happens only when the car is cold on initial startup and hasn't run within a day or sometimes even a few hours..

Idle is perfect.. However in BAD instances of it, the car will studder and almost idle like it has rediculously large cams in it but only for the first minute or 2 then it snaps out of it and runs fine until the next time I let it sit over night or for a few hours to cool off..

it's wierd.. I've heard of a couple other people having this problem too.. I was basically just posting to see if anyone has had this prob and has remedy'd it..

743power

I've never heard of this problem on an eg or dc, ek sure. I would try the main relay. Also, make sure all the connections on the chassis side of the ecu harness are good. I had a sputtering problem at part throttle randomly and one of my ecu pins had some wire exposed and it must have been shorting out, so i fixed it and now everything is fine.

Gadget

You know.. I know better than to ovrlook crap like that too.. you wouldn't happen to know the ECU Chassis ground points in a EG would you?? I have a factory service manual in PDF format.. It looks like I'll have to dust it off in a sec.. =D

turboxsi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Gadget &raquo;</TD></TR><TR><TD CLASS="quote">You know.. I know better than to ovrlook crap like that too.. you wouldn't happen to know the ECU Chassis ground points in a EG would you?? I have a factory service manual in PDF format.. It looks like I'll have to dust it off in a sec.. =D</TD></TR></TABLE>

I have the same issue and have not been able to resolve it yet and have replaced all the obivious like you. And it still does it!!!

I pretty sure the ecu grounds are all ran to the thermostat housing...

Bump for help figuring out this problem!