Rough morning starts after spark plug change

[spinfire]

I changed out the spark plugs in my 1992 Honda Accord with identical new plugs. The plugs should have been correctly gapped per the setting under the hood, although this is the first time I've gapped plugs so they may be off. I didn't check the gap on the old ones I took out.

Since replacing the plugs the first start of the morning has always been rougher than usual. The car cranks longer before it catches, and then it stumbles for a second or two before it smooths out into fast idle. Previously the car might take a bit longer to catch but it would always start right up without any stumble. The rest of the times I start the car during the day it starts right up as I would expect.

The problem first manifested itself the morning after changing out the plugs, so I think it is most definitely related. Is this problem symptomatic of improperly gapped plugs?

 

[oily boyd]

Easy enough to recheck the gaps on your car, yes?

Are the plug wires original? Maybe the removal/replacement caused a crack(s) in the wire(s).

Make sure the wires are tight on the distributor.

Also, check for vacuum leaks, you may have disturbed a vacuum line.

 

[Terry]

cracked a plug porcelain, you tighten the plugs properly, torn or damaged wire connection as mentioned by boyd.

 

[m2200b]

Rarely the plugs but you can't touch 100k wires w/o killing them.

 

[Drew99GT]

I'd say you messed up a plug wire, OR, a wire is not seated on the plug completely. You should feel a crisp snap when you put the wires on.

 

[Quest]

agreed with what Terry and Drew said.

lemme see:

things that you may have touched on/replaced/serviced during the whole ordeal such as spark plug wires (plug boots), wire sets itself, damaged/cracked/incorrectly gapped spark plugs, etc.

Other things like distributor cap and rotor, distributor housing seal leak, distributor cap gasket, moisture trapped inside distributor cap+ rotor area, carbon tracking, etc. could have all contributed to this.

Last but not least: make absolutely sure that you have purchased/installed the proper model/type/heatrange sparkplugs. For Japanese cars, you can never go wrong with NGKs.

 

[spinfire]

The new plugs are exactly the same as the old ones, NGKs. And AFAIK the plug wires (also NGK, blue if that makes a difference) have around 30k miles and not that much time on them. They look quite new.

To add a bit of info from this morning, it was about 80 degrees when I started the car and it started right up as normal. The problem has only been a bit of a stumble on cold starts when the car has sat overnight (probably indicating block temperature below 60 degrees). Maybe I'm just expecting a bit too much from an old car

I replaced the distributor cap and rotor after replacing the plugs, and that didn't change anything, so I doubt that is the problem.

I will recheck the gaps this evening once the car cools.

 

[ThirdeYe]

Mine does the same thing sometimes, but it's usually when the car's warm that it struggles to start. Starts perfect when it's cold. Just recently replaced my plugs with OEM NGK's from the Acura dealership and some nice blue NGK OEM-style wires. Never noticed it before this, I might try putting the old wires back on and see if that changes anything, I doubt it's the plugs. I made sure to put the dielectric grease on the boots and white portion of the plug and anti-seize on the threads and torqued them all properly with a torque wrench. My distributor is brand new and it didn't make any difference whether it was my new one or my old one.

 

[onion]

I dealt with a wierd problem after doing some work on the wife's '01 Lumina. Changed the intake manifold gaskets, plugs, a few other things... thereafter the car had a distinct miss only when started cold. The miss might last 10 seconds- might last a couple minutes. After a fair amount of tinkering and cussin, I narrowed it down to the #1 cylinder. Pulled the plug- it LOOKED fine, but I could move the glass insulator very slightly in the plug. Replaced that one and the car was fine.

 

[pidster]

I would suspect either the plugs themselves or the wires. It could very well be that you got a defective plug. It is easier than you think to damage wires by removing them once they have some mileage on them.

 

[The Critic]

Could've damaged a plug by gapping it. The plugs come pre-gapped anyway so why were you even touching the gap? It isn't uncommon for someone to damage a plug inadvertently by regapping it if they are not experienced with that task.

 

[ThirdeYe]

The thing is, I didn't re-gap mine, I left the gaps as they came, they're supposed to be pre-gapped. My wires are less than 2k miles old, too.

 

[Merkava_4]

I prefer to use the type of gap gage that uses a hard wire with a 90 degree bend at the end: An 'L' shape if you will. I then gap the ground electrode to where I've got to give it a real tug to get the gage through; that to me ensures that I'm not getting the gap too wide.

 

[TheLoneRanger]

It could very well be bad 'new' plugs from the manufacturer. They're easy to check with an ohmmeter; a new one should have about 5-6K ohms measured from the electrode tip to the wire terminal. (This is the value of the internal resistor.)

If one shows up with a substantially higher reading, or even shows an open, you've found your bad plug.....

 

[eljefino]

I like the idea of a defective plug. Never know if it was dropped somewhere in the distribution chain.

 

[spinfire]

I changed the gap on the plugs because they were not set correctly when I bought them (the gap was a bit too small).

I did pull all four plugs and recheck the gaps last night -- on two cylinders the gap was a bit too big, chalk it up to being a beginner and overshooting, I guess. No evidence of cracking on the plugs themselves. I reset them to the specs on the VECI label and put them back in, being sure to torque everything down right.

This morning the car started right up (but it has also been warmer lately, so it might be that). If it starts doing the rough starts again I'll look into the other possibilities.

On the plus side, the 4-banger makes it really, really, easy to pull the spark plugs and check them again. They're right on top and no acrobatics required to reach them