Spark Plug Blues

[Deep_Blue]

Hey all!

This is part me talking for no reason and part me asking for opinions. So, I changed my spark plugs today, going from some old NGK V-power copper plugs to some new autolite copper plugs. I've run the car for a test and it seems to be burbling a bit. using my stethomascope I listened to each of the cylinders firing and could tell no difference. So, I've come to three possible conclusions: #1 My gap is off. #2 My ancient spark wires need replacing. #3 I'm imagining things. So, my question for you guys: What gap do you run in your MKIII? My Toyota manual says start at .31 and throw the plugs out at .39. My plugs coming out were at roughly .34, but they were carboned and oily. I set the new ones to .31. While you're posting, what plugs do you run? And furthermore, what do think is wrong with my situation of the three options I have given?

Have at 'er!

Cheers,

Tim S.

[Supra_devil]

i would change the wires if they are ancient, lol.

could have damaged the fragile, worn out, inards of one of the wires.

i'd start with that myself.

i've always had good expericances with NGK wires, but my old toyota wires were good too.

[Trowa]

did u have a problem before you changed plugs? cause if u didn't then most likely that you screwed something up...maybe one of the ignitor or coil connectors doesn't have good contact or something....check everything you touched when u were changing plugs...my 2 cents =P lol

Andriy

[Deep_Blue]

Update:

Okay, so I took the car for a test drive, and she's pulling like an absolute beast. I didn't detect a misfire once, the whole powerband was smooth, and I was beginning to believe my overprotective (of my car) mind had imagined it, but upon bringing her to a halt and letting her cool down, I noticed that the idle is really lumpy. So, I believe the problem may have something to do with the ISC system. Andriy, I am also still concerned about wiring, particularly the ground for the coilpack. I may replace that b/c it looked brutal when I was taking everything apart. Thanks for the suggestion. As for the idle, my car went from a beautifully tuned 800rpm to a lumpy 1000rpm-1100rpm.

See, thats the thing, now it's bouncing around a bit. I might check out the CPS too. Anyhow, that's where things are at. and they need to be fixed soon with me leaving town on Saturday for the rest of the summer (I'll still come back for the meets). I'm going to try and troubleshoot the problem with my Toyota manual, but feel free to offer your advice and experience.

Cheers,

Tim

Edit: I just checked the toyota manual, and the idle is supposed to be 650rpm. Not even 800rpm was good. Oh shitballs :eek: !

[GOT_BOOST]

Hey Tim,

Good too hear this is working out for you. In addition as to what has been suggested already check your ignition timing. Is is possable that you adjusted it by mistake? Also check your throttle cables ontop of the valve covers. It may be possable that one of the plastic sleves is out, or has become stuck keeping the throttle slightly open at idle.

Mike Nikolai

[Deep_Blue]

Good call on the Throttle cables Mike! I hadn't even thought of thought of that! I was starting to wonder about the TPS maybe, I'll check it out after I'm done eating lunch, and maybe we'll have the culprit! I'm still interested in lowering my idle down to the ideal 650rpm, but my engine has 312000km on it and I highly doubt I'll be able to get that done, but given how strong my engine is for its mileage, I guess it's a possibility.

I'll let you know if it's the throttle cable!

Cheers,

Tim

[Supra_devil]

i would try for 800 or so, at night time your alt can't handle every thing at 650 and if you drive in winter the car will be warmer, faster.

[dogstar]

i like my idle between 800 and 1000, but ive got idle issues.
sometimes at night, itll drop to 600ish, sometimes it stays at 950
other times it will roll up and down the range (600-1000) while at a red light.

definitely something needs checking, but its not a major issue, so im not real worried.

[James Earl]

Mine is 850~960 cold and 760~850 warm. As long as it does not stall who cares..it's not like we spen hours idling the cars.

[Supra_devil]

holy crap url, you got like 60 more posts than me, what a post hoar.

[James Earl]

I have no other life...oooppps another one!

[Deep_Blue]

Another Update:

I still don't know what the problem is.

I'm going to be gone for the next couple months (still going to be at DTP!) and not driving my car very often, but after that, I'm goiong to replace the spark wires, pull the plugs and see how they're doing, and replace the ground for my coilpack (If anyone has a spare one let me know, Toyota doesn't sell them).

The idle is still lumpy, but it's inconsistent. Today I was driving and braked from about 4000rpm to a halt in neutral, and the rpm dropped so much the car just about lost it. It almost happened agai, but those are the only two times... might try the old plugs and see if the problem goes away, but I don't think it's the plugs. So, that's what's new!

Cheers,

Tim

[dogstar]

im saying vacuum leak somewhere.
these cars are kind of susceptible to vacuum issues ive noticed, and i was mentioning it to a friend of mine with a corolla GTS and that was the first thing he suggested.

might be a good idea to start playing with vacuum lines...unfortunately the only "easy" solution is to replace them all, checking vacuum lines is a pain in the ass.

[Deep_Blue]

Dogstar,

I thought the same thing, and I just might replace all my vacuum lines, and throw out the unnecessary ones.

Cheers,

Tim

[dogstar]

its a long job, but not very hard... on the mkII at least, most of them are quite easy to get to.
just pull one off, measure, cut, replace and repeat.

it solved a few minor issues on mine, but ive still got a few hoses to replace... maybe in a couple weeks ill break down and do it

[CanuckDave]

changing hoses made a big difference for me, I had no cruise until I did them, and the engine idled and generally ran smoother when I did them all. definitely worth doing IMO, even if it doesn't solve your specific problem (hope it does though...)