Former User

Try the sensor body and the transmission body.

Also measure the resistance between the 2 black wires.

AjHawk

From either black wire to sensor body, OL. Between the two black wires 13.3ohms.

Former User

Same result using the transmission as ground in the tests?

AjHawk

Same result on transmission (all over it, body, ground, bolts), even if I use the exhaust manifold or engine ground or anything else near the o2.

Former User

Hmmm...no short detected.

Now return to the unplugged wire harness side. Turn key off and remove fuse 15. Measure resistance to body ground at the Blk/Yel wire terminal using the transmission as ground. Compare the latter reading to subjecting the Grn/Blk and Blk/Wht wire terminals to the same test using the transmission as ground.

AjHawk

Pulled fuse 15. Using transmission as ground.

0.1 on black/green.
16.5 M on black.
10.4 K on black/yellow.
OL on yellow/black.

Former User

Can you double check the wire colors?

The 4 wire colors in the wire harness-side connector should be:

Wht
Grn/Blk
Blk/Yel
Blk/Wht

AjHawk

My apologies, a little grease on them. Colors fixed.

0.1 on green/black.
16.5 M on black/white.
10.4 K on black/yellow.
OL on white.

Former User

Hmmm...no apparent short to ground on either side of the sensor connector.

AjHawk

After I replaced the engine wiring harness with another "known to be good" one, I saw some improvements but not enough to say it's fixed. That was last week, today was the first time I could drive it for more than 10 mins. I have been unplugging sensors since I got this car to see what happens. Could this car run well without a knock sensor, rear o2, and/or vtec? Just realized that the knock sensor is unplugged, and leaving the rear o2 sensor unplugged helps it run better.

Former User

Having the rear O2 sensor unplugged should have no effect on how the engine runs, but having the knock sensor unplugged would.

Plug the knock sensor in and then unplug the 2 O2 sensors. How does the engine run? Any CEL codes thrown besides O2 sensor codes? Does fuse 15 blow? If there are no issues, then plug one of the O2 sensors back in and repeat test. Try to link fuse 15 blowing, the engine running poorly, or non-O2 sensor codes being thrown to having one of the O2 sensors plugged in.

AjHawk

The cam timing marks are flush with the head, does this look a tooth off to anyone else? I am shooting for the single notch to line up with the white arrow correct?
[IMG][/IMG]

Former User

The pointer on the lower timing belt cover consists of two parts, like the sight on a gun. Therefore, three points must align, the two piece pointer and the white mark. The picture doesn't allow us to verify the proper alignment, but I think the mechanical timing is probably correct based on what I see.

AjHawk

How about these TPS voltage readings.
Closed: .43v or -1%
WOT: 4.62v or 83%
*According to scan tool.

Also I noticed that my TPS doesn't have screws that I can remove, almost more like rivets.

Former User

The closed throttle voltage is just slightly off - should be closer to 0.5V but I'm not sure this difference would cause a problem.

If you wish to adjust, remove TB and use a Dremel tool to score a slot into the top of the rivets, which are actually bolts. Then you can loosen and tighten the bolts with a flathead screwdriver.

Reinstall TB with new gasket and then rotate the TPS until output voltage is 0.5V at closed throttle. Use a multimeter. Tighten bolts. Then only check the output voltage at WOT - should about 4.7 -5.0V.

AjHawk

Did that^ Thank you for the tip.

My MAP sensor reading when I had it unplugged would jump all over the place the more I moved the clip, plugged in engine off at a steady 99kpa. Turned out there was water in both sides of the connector, cleaned out with compressed air and now it doesn't jump around anymore. I wonder if that was part of my problem. It runs better now than yesterday.

Former User

Sounds like there may have been a collection of problems - short, unplugged KS, wet MAP sensor connector, etc. Are you saying that the engine now runs perfectly without blown fuses or CEL codes??

AjHawk

Only codes are for a rear o2 and vtec, because those two are unplugged right now. Besides that, no blown fuses and runs better than any other day I've had the car. But in no way do I think I'm in the clear just yet, I'm going to put some miles on it and see what happens. All new plugs, wires, distributor, alternator, fuel filter; checked all timing and did an oil change. Crossing my fingers...

Former User

What happens if you plug in the rear O2 sensor or VTEC? Why are they unplugged?

AjHawk

Ok Ron, here is the more of the long than the short. The car was originally an Auto, PO swapped it to a manual and wired in the Vtec himself. I bought the car as is, pulled the wiring harness after getting these shorts that blow fuse 15. Examined it and re - installed it, I can now drive this car for about 5 minutes or 5 miles, then it reverts back to blowing the fuse and running like crap. I just drove it very aggressively and it did amazing, up hills and full power up to 5000 (where I was shifting), then I knew the fuse blew because it just fell on its face and had nothing again. Breaking up at low rpm and just enough power to get me back in the higher rpms. Ron, if I replace the engine harness with a known good one, that's for a Manual Vtec obd2a, will the fuse 15 short go away, or is there another component that could keep blowing it as well?

Former User

Rather than hoping that replacing the wire harness will fix the problem, why not do some unplug tests? Specifically, install a new fuse 15 and redo your test drive with one or more fuse 15 components, such as the O2 sensors, unplugged to see if the fuse no longer blows? Or have you done this already?

tony_2018

Was the original harness a hack job?

AjHawk

Ron I have ran the car with both o2 sensors and the VSS unplugged and it still does it. Is there another sensor on the circuit that I'm forgetting?

Tony, yes it was. Rear o2 wires were ran with separate wires and vtec spliced into harness just before the ecu. Among other things with it.

Former User

https://honda-tech.com/forums/showpo...08&postcount=9

In addition to the VSS and the O2 sensors, these are other components on the fuse 15 circuit that should be unplugged for testing:

1. Alternator
2. ELD
3. Cluster (charging system warning light)
4. EVAP shut vent valve
5. EVAP bypass valve
6. EVAP purge valve
7. Dash fuse box

I would try unplugging the alternator first and then the ELD.

Former User

I also merged your 3 related threads on this topic.