91 Civic Hatch 1.5 Rough idle/throttle

soulsproxy

New Member
For the past couple of months since I purchased this car I've been dealing with some minor problems, but now a new one has cropped up, and I'm not sure what it could be at this point. Yesterday morning, the car was working just fine. I had just installed a new dizzy rotor, the night before, as the old one had been having trouble staying put. After leaving work, about 5 hours later I noticed that the car was having trouble climbing the hill to get on to the freeway, and then once I got on level ground it had trouble shifting into 3rd gear/going above 60. The closer I got to home the worse the problem got until it seemed as if every time I brought the car to a complete stop it was going to die, but it never did.

After getting home I checked the dizzy cap/rotor (I had a problem in the past where water got into the cap, and caused a similar condition), but there was no play in the rotor. I did notice that the cap looked a little warn, and that there were stress marks around some of the metal nodes. I ended up replacing the cap, but the problem persisted.

The next morning, with the help of my uncle, we did some more diagnostics. We checked to see if any of the vacuum tubes had a crack, they didn't. We checked to see that each of the sparks were firing correctly, which they were, and then we checked to see if we had a constant pressure among the cylinders, which we did (around 185-190). We did noticed that one of the seals had failed causing one of the spark plugs to be covered in a fair bit of oil, but my uncle ruled out that it would cause this big of a problem. He also noted that the spark plugs seemed to be burning normally.

After all of this we still did not find any real problem, and now are turning to the web to get some other opinions. I have also recorded a video of what we are experiencing.

 

Tj_Civic

New Member
Hello

It could be a number of things causing this run condition, ill try to help as I had a similar issue and worked through a lot of things before working it out with my mechanic.

I had oil in all of my spark plug wells also. If you have oil there, that is the first thing you need to fix before moving on to anything else. There is the valve cover gasket and the 4 grommets (these seal the top of the plug wells, under the valve cover.) On my engine (d15b2) there are 4 more o-rings under the rocker arm assembly which can go bad and cause oil to seep into the plugs. Youtuber EricTheCarGuy has a great video on a honda doing this job.


I found that the hesitation in my car was less after wiping the oil from the plugs and wells so I knew it had something to do with that. Over months I cleaned, replaced, and tried to troubleshoot.

I eventually noticed a tiny crack in one of the spark plug wires, along the shaft that connects to the boot. the heat and the oil combined to damage the newer NGK wires. They were probably damaged first from the inside before a crack on the outside of the plastic formed.

In summary, I worked for months trying to troubleshoot symptoms when the source of the issues came from having oil where it shouldn't be. Replacing the wires fixed my run-condition.
 


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MotorMo

Respected
Howdy- sounds like your running on three cylinders. If your compression is good across the board then I would look into your spark side of the engine. Your engine has two injectors for four cylinders, so it having a "dead hole" like it does guides me away from an injector/fuel issue ( altho those dual injector set ups are also known for being problematic). With my ear, it sounds like you have no speark in one cylinder. I would perform a cylinder kill test to isolate which cylinder is not contributing ( by pulling one plug wire off the spark plugs at a time and listening to the rpms- google it ). At that point you can swap plugs into other cylinders to see if the misfire moves, or if its in the wire/cap/rotor. Good luck. Better to fix this sooner than later so you dont wash out your cylinder walls and dump lots of raw fuel into your oil/crankcase.
 

Szady

D-Series Master
Registered VIP
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5+ Year Member
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Um...did you two look at the original post date...? I'm guessing NOT, as it's from November... 2015!

@Tj_Civic @MotorMo




@XpL0d3r
 


David Valentine

New Member
I don't care how old this is....my car recently started doing this. At 1500 rpm every time the engine hesitates and stutters. I have checked everything but the tps which mine is a 1999 but its not the adjustable TPS. Any suggesitons?
 


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