Ok, so I'm trying to fix a messy engine swap. The car is a '92 CivicVX, engine is from a '00 GSR, with a OBD1 P28 ecu that has a mystery chip (old fashioned, soldered directly to board). Engine harness is a pretty hacked up GSR one, while the chassis harness is VX. Fuel injectors are OBD1, pretty much everything else is from the GSR they came from except for the '99 CivicSI radiator. The only current modifications to the engine are a Skunk2 intake manifold, short ram intake, test pipe instead of cat, and some kind of aftermarket muffler because the gsr one was too big to fit.

Original problem: The car was running really rich (strong fumes from unburned fuel I'm guessing and low mpg) and problems with cold starts; dumping fuel into engine and bogging down. Also a lack of torque/becoming less responsive around 4k rpms and a rougher idle than I believe is normal. Also, no cel codes.

Fixes tried: Bought a supposedly untouched P72 OBD1 ecu to go with the engine hoping it would solve some of the problems caused by the mystery chip in the ecu. Oh, also replaced fuel injectors and fuel pressure regulator (was an adjustable one, now stock), neither was the problem.

New problem: After installing the ecu, the car had no power in the low end (barely wants to go unless you hold the clutch and floor the gas), until about 2k rpms after which it is very peppy and responsive and requires very little throttle.

Fixes tried: Checked the cel codes, got 41 and 23. Checked the wiring, knock sensor was wired up to the wrong shock tower, lol. Checked again, now only code 41. After checking wiring for O2 sensor, found that the signal and ground wires were wired backwards. After sorting that out, I still got 41. Tried replacing the O2 sensor with a used one I had laying around, original was very dark from running rich, this one was white (not sure what that means). Might still not be wired 100% correctly.

Outcome: Still got code 41 and no power until 2k rpms, but the car starts up and idles perfect and no longer seems to be running rich; no strong fumes. Still works the same as before if I put in the P28.

So, any suggestions for how to fix the low end power problems? I'm wondering if the Skunk2 intake manifold is messing things up with the stock ecu (maybe too much air? Really don't know). I can replace it tomorrow with the original one, but I don't want to waste time if that isn't the problem. Or is the ecu even the correct one I should be using? Would the O2 sensor alone be causing such problems? I'll be checking timing tomorrow to make sure it isn't off (very likely that it is) and trying to go through more of the wires, although I'm not getting anymore codes, so yea...help would be very appreciated since I can't find my Helm's manual and I've spent too many hours searching the internets trying to come up with a solution.

Sorry for the super long first post! Please move the post if it is in the wrong place by the way.

 

vx has different engine harness so i would assume the chasis harness is also different

check the pinouts for vx and regular civic.

i did a d15z1 swap into civic and vx engine harness wouldnt work

civic VX has a wideband O2 sensor and i belive some other sensors are wired differently.

 

Yes, the chassis harness is different, but the car runs without giving any other code than 41 with the obd1 P72 ecu and no codes with the mystery chipped P28 (guessing the O2 sensor is turned off). Yesterday I checked the knock and O2 sensor pinouts, which are now correct, but I will be checking the rest of the pinouts today.

Both O2 sensors tried were from GSRs, so they matched engine & engine harness, and now they are wired correctly at the ecu as well.

 

So first thing this morning, I checked the timing, it was way off, so off that I could not correct it with adjusting the distributor.

So, good news, more power in the low rpms; bad news, have to take off the timing belt. Any suggestions on how to best get it set properly?

 

is the distributor remanufactured aftermarket or is it OEM?
aftermarket dizzy doesnt line up as well.

you checked to make sure the T belt is on correctly and not skipping a tooth?
or the head has been milled and now tdc on the head doesnt allign with tdc on the block

check the valve lash
and stick to gsr ecu if the engine is stock internally
check the idle speed to make shure its adjusted properly.

once that is set (i think gsr is 750rpm idle)
follow the service manual to set the idle. you have to set timing when the car is at correct idle and warmed up to normal temps.

 

Here is a pretty good step by step....
http://www.team-integra.net/forum/bl...nt-g3-teg.html 94

 

Thanks fcm and raverx3m, fixed now! My dad found the Helm's manual this morning, was buried somewhere in the garage.

The problem was that the timing was about 8 degrees off, so impossible to set with the dizzy. The cam gears and crank were not lined up properly the last time my dad took the engine apart to fix a bent rod, he's a good mechanic, but not always into the details. And last time I wasn't able to help him check everything either since I was busy with classes.

Fix: Aligned the crank and cam gears all correctly. Sure are a pain to get them all lined up correctly with the tiny marks you need to use.

Outcome: Timing was spot on first try. Car rockets off like it used to when the engine was in my GSR race car. Good power throughout the rpms, likes to rev, and very responsive again.

Oh, and raverx3m, almost everything including the dizzy on this is oem, stock, and fairly new (other than what I listed in my first post) since I bought the GSR with about 15 miles on it as a theft recovered car, with no previous owners, to make it into a race car.

Now I just need to finish checking the wiring to make sure that is all correct (still getting code 41). If anyone could help me with how the O2 sensor is supposed to be connected to an OBD1 GSR, I would really appreciate it!

 

a trick to getting those lined up is to use a needle pick or a thin screw driverput it on top of the gear tooth all the way to the mark that way you can tell exactly where it is.

 

if i remember correctly the 5 wire harness grounds were not wired in same as normal honda so i gave up on that.
i did find a pinout somewhere on interwebs for both z1 and z6 engine plugs

google it i cant remember the name

heres the vx ecu pinout




best way is to download the 92-95 civic service manual that includes the d15z1 electrical diagram and download the 94-95 integra manual that includes gsr wiring

http://www.hondahookup.com/manuals/