Rough Idle

[91CivicLX123]

Hey all. 91 Civic LX here. Had it for years and just about to give her up and get the 05 special edition before the 06 comes out (Hate the new 06 from the spycam shots)...But gonna be passing her on to my dad to commute to the train.

As I'm trying to fix small little things for him - I came across a TSB service bulletin about replacing the grounding harness to stop rough idle and problems shifting out of park (which I have whenever I stop at a light - no matter what electronics I have on - and have problems with park for years).

Just trying to find out if anyone has done this? Heard of this? etc. The part itself through honda is only $12.99 - But the TSB itself doesn;t give enough info (tech directions) for me to change it myself - Is it worth getting this done? Will it finally fix these problems as I finally give up my Civic?

Also, if you have done this/had it done....any ideas on what ground wire I'm actually replacing. Can I do it myself? Or do I have to rip out tons of stuff to get to it?

Would be interested in knowing...

Thx

Also - might be selling the integ console out of it - keep an eye...

[turtlecrxsi]

There a few grounds. The ecu ground (most important and most overlooked) is the one connected to the thermostat housing (where lower radiator hose meets the block). There are a few more... valve cover ground to radiator support, negative terminal of battery to chassis ground...

someone else can point out the others I'm forgetting... They are all pretty easy to get to and replace...

[91CivicLX123]

The "directions" that the TSB provides:

1. Disconnect the three-pin conductor from the throttle sensor.
2. Remove the Grn/Wht wire from the three-pin connector [with tool number]
3. Cut off the Grn/Wht wire as close as possible to the gray tape wrapping the wire harness. Discard the cut off piece (because you might actually save it in a memory book or something)
4. Install the terminal end of the new ground harness into the three-pin connector. Gently pull on the wire...blah blah blah..make sure in
5. Route new wire under existing harness. Use electrical tape - etc - blah blah blah
6. Remove the bolt holding the harness bracket to the intake manifold. Install the eyelet on the new harness between the bracket and the manifold and reinstall the bolt
7. reconnect three-pin cennector
8 Test drive


SO basically - I guess I'm just going to the intake manifold....following th ground wire that's connected to it - unplugging that connector and doing surgery on it?? WOuld that make sense?

Again - is this worth my time and sweating in 98 degree weather on a dirty parking lot in my apt complex?

[turtlecrxsi]

Sounds like it's replacing or improving the ground to the TPS. I wouldn't worry about it... If you wanted to splice in a better ground, it would probably cost you about $2 for an electrical connector pack at any auto parts store and maybe take about 10 minutes of your time (20 min. cuz it's so damn hot)...

[91CivicLX123]

LOL...not worried....just trying to see if I can do this so I don;t have to tell dad to put it in neutral at every light (damn automatics)...to keep from a rough idle

[turtlecrxsi]

Check for cracks in the hoses going to the intake manifold... could cause rough idle. Also, you can adjust your idle screw a bit. It won't hurt anything to raise the idle to 1000. Mine sits at 1200 unless it's terribly hot out then it drops a bit, but I have a cam and other mods... GL

[91CivicLX123]

I just finished checking the hoses - they seem solid - also used a soapy water solution to check for craks or leaks (old school bar-b-q- style) and nothing....they're good.

I have raised the idle before, but find that the car doesn;t like going into gear at the higher idle (instead of my normal bump into gear with my old honda kick tranny, it was rather big...also shifting ratios seemed to be affected...so i put it back)...

I think I may just buy this new grounding kit and try it. I can;t get any more sweaty than I am right now....

still if anyone has tried this....please let me know...otherwise...i'll report back in about a week...

[Smoghog]

Originally Posted by 91CivicLX123

I just finished checking the hoses - they seem solid - also used a soapy water solution to check for craks or leaks (old school bar-b-q- style) and nothing....they're good.

I have raised the idle before, but find that the car doesn;t like going into gear at the higher idle (instead of my normal bump into gear with my old honda kick tranny, it was rather big...also shifting ratios seemed to be affected...so i put it back)...

I think I may just buy this new grounding kit and try it. I can;t get any more sweaty than I am right now....

still if anyone has tried this....please let me know...otherwise...i'll report back in about a week...

Have you checked the IAC? The computer uses the IAC to adjust the idle when there is a load. (air cond./lights) How does it idle when you first start it up cold? >1500rrrs is good. Sometimes when you pull up to a light does the idle seem high, then go down? Sticky IAC.

My 88si idled rough and I raised the idle with the adjustment screw it lasted for two minutes then rough again. Cleaned out the IAC with carb cleaner and smooth as a babies rear.

Also, beware of modifications to any sensors. Instant FAIL for a smog check!