Hesitating under strain
 

Hi Guys, Thanks in advance for any help you can come up with.

I have a Honda Civic 1.6 VTEC 2003. It was hesitating like mad when driving slowly, usually about 1600 rpm, especially if going uphill.

It shudders like its stalled for about 1 sec then carries on like nothings happened. It runs smoothly all across the rev range except at about 1600 rpm, unless im giving it the beans. It never hesitates if Im giving it full throttle. I changed the plugs, oil, oil filter and changed the stock air filter for an air cone. I noticed that one of the coil packs had come unbolted and after the changes and re-tightened the coils it ran like a dream again...

Until recently, its now started doing it again.

Ive checked the coils are all screwed in tight. any suggestions or similar experiences?

I have some (but dont go too technical) mechanical knowledge and a good mate who knows more than me, who I can rope into helping ;)

If it helps... car background.
Honda Civic 1.6 VTEC Sport SE
HONDA CIVIC VII Hatchback (EU, EP, EV)
125k miles on clock
poor service history for the last 100k miles.
All stock except for the air cone filter.

Thanks again

Try replacing the fuel filter and running some good quality fuel injector cleaner through it.

Also, when that one coil came loose, it's possible it was damaged. One way to check if the coil packs are cracked is to spray water on them (mist) with a spray bottle while the engine is running.

Let us know how it goes. Good luck. :)

Its a spark issue. My brother ZC did the same thing and it turned out the plug wires were bad. My z6 did it also but my issue was moisture build up in the distributor.

Thanks for getting in touch sio quick. Forgive the ignorance, what should i be looking for when I spray the top of the coil packs? Would a change of coils and cables help if just changed them anyway.

If one or more coils are bad/cracked, when you spray/mist the coils, the engine will start to run rough/misfire etc. You may even see and hear it arcing.

If this happens, you'll need to replace the bad coil(s). Your engine (D16W7) has a coil-on-plug setup, so no ignition wires to worry about.

Try misting the water on the coils while it's running and let us know what happens.

They have a UK 2003 civic sport SE vtec which has the D16w7 engine. It's coil-on-plug. No distributor or wires. ;)

d17's don't have wires...

misting most likely not going to solve anything, especially under a hard load situation.

Only thing you can do, is hook up a scanner, see which cylinder is misfiring, swap coils with the appr. cylinders and re-test. If the misfire jumps cylinders, bingo. You can also try it with your spark plugs (yes even BRAN new spark plugs can do bad, I see it every couple weeks).

This is the only true way of properly diagnosing the vehicle. Everything is (unless its super obvious) is not going to help you find your problem.

Goodluck, should be an issue one to figure out.

Thanks my friends, really appreciate all your help. I tried misting the top of the coils but heard no difference in the engine. Im going to take it to my mates garage and hes going to pop a scanner on it. (Hopefully when his boss is not in ;) ) It's snowing here so It'll be a bit before I get it done, but I'll keep you updated if I find anything.

The problem is now unbearable. I took it to a garage and they ran a diagnostic but could find no faults. We drove 100 yards with the machine on and when it shudders it flashes up so fast and resets the ECU, so it is not storing any error codes. I drove today at a very VERY easy pace, slow acceleration and it hardly did anything, the odd shudder.

I was wondering if it could be something to do with the VTEC. As i believe (correct me if im wrong, i probably am) it works at any rev range as long as the throttle is pushed hard.

No, VTEC only engages at a fixed rpm point, regardless of throttle position and only when the engine is up to proper operating temp.

Not sure what else to suggest. I wonder if it could be the MAP or throttle position sensor...? Strange that it's flashing the code then resetting immediately.

Chris_V2 might have some other ideas...

I took it to a garage with a bigger diagnostic machine and they seemed to spend 4 hours poking around my glove box with a torch and found nothing. They suggested I leave it with them for "a few days... maybe three " (with no idea of price or plan of action) I made my excuses about picking up my wife, paid and left.
DISPAIR....
I tried another garage, who on the phone sounded like a much better choice. I took him for a test drive, showed him the symptoms and I left my car with him for an hour with a set price of £35 for a diagnostic and a look around. I later phoned up to see the results expecting no joy....

RESULT!!!
He traced the problem to a faulty Camshaft sensor.

He's ordered me one in for Monday and it should be sorted then.
£35 an hour, £56 for the sensor and probably another £35 labour for him to fit it.

Awesome! Glad you finally found the problem. :)

^ I second that~! :smile:
It sounds like it was a tricky one to resolve.