bernie f

Late last fall my Honda after driving 5 miles and the engine warmed up started to not accelerate. I drove it very gently back home and by the time I got there all it would do is idle. When I tried to accelerate in park, the engine would try to stall. I could hear a sound coming from under the intake manifold every time I moved the throttle. My best description of the sound would be the word "clock". O.K. go ahead and laugh. I tried to locate the origin of the sound but had no luck. After the engine cooled down I couldn't start the car again.

Here is what I know. D16Z6 VTEC engine. Good spark, Compression O.K., Fuel to the injectors, Ignition timing on, Valve timing on, I get no CEL codes.

Today when I was checking the fuel injector pulses, the engine tried to start. I cranked it for ten seconds and it started. I left the engine warm up and when I tried to accelerate I got that darned "Clock"sound then short hiss sound from under the intake manifold. I couldn't find where the sound is coming from with a stethoscope but I could hear it with a hose under the intake manifold. I hope one of you guys can tell me what's going on.

joey1320

Can you raise the car and listen from the bottom or search with the stethoscope? Kind of hard to help without more info but it may be related to the pcv system.

bernie f

I lifted one side of the car up today without the engine running to try and look under the intake manifold. It's so damn close under there I just couldn't see enough. I'll raze the car tomorrow and reply. Now if it will just start again. It hasn't started all winter. What pvc stuff is under the manifold. My Haynes doesn't show that area at all.

bernie f

O.K. I got it up on ramps, removed the oil filter and behind a wiring harness I found a hose lose from what I can only assume is a blow by filter. I put the hose back on the box but still have the same problem. The car starts rough and struggles to accelerate. The noise I was hearing was the sound of the PCV valve coming out of the disconnected hose. The hose may have been off for a long time. I just might not have noticed the sound until this problem showed up. I'll check the pcv valve and hoses tomorrow. I can't find a decent drawing of the PCV/vacuum systems. One thing, the acceleration problem only shows up after the engine has warmed up.

TomCat39

Hey Bernie, welcome back. I'm sorry to hear the issues with your Honda.

These might help.

The black box is the breather box, there is a hose from the box to the bottom of the intake manifold where it connects to a grommet for your PCV valve, and the the hose from the PCV valve on the top of the intake manifold that runs to the plenum of the intake manifold.




It sounds to me like you have a clogged hose, a loose grommet and/or a clogged PCV valve.

collkid

Seriously? A clogged hose can cause this? That's nuts.

TomCat39

Well, if there is no place for the blow by to evacuate, the pressure can build up and fight the pistons from coming down on the down stroke. I would think it would blow out one of the crank seals first but who's to say.

It also may not be the issue with the power loss. But the hose was found so it would be good to get that taken care of so one knows if it is or is not part of the problem.

There is another hose under the intake too that I think connects to the coolant pipe but I will have to wait until after work to investigate a little and take some pictures for Bernie.

TomCat39

The other hose runs from the IACV to a spot either in the head or the block right behind the alternator and the timing belt area.

bernie f

Hey TomCat,
It has been a while since my last thread. Thanks for the hose information. I'll get on the problem this weekend. There is a learning curve every time I work on my grocery getter. The fact that the engine runs just fine until it gets up to operating temperature should tell me where to look first if I understood the vacuum system better.

TomCat39

Maybe these will help:

bernie f

Thanks for the drawings they were a big help. I checked all the vacuum hoses, the PCV valve works, MAP sensor voltage, signal and ground good, Throttle Position Sensor voltages correct. Ignition timing good.
I still have a long crank to start and I noticed when the engine is cold the timing advances correctly for acceleration. After warm up, the ignition timing will only advance if accelerated slowly. Quick acceleration the timing retards and engine tries to stall.

bernie f

Also no CEL codes

TomCat39

This makes me think it's an issue in the distributor or the ECU.

If the sensor in the distibutor isn't working well teh ECU can't respond. I was also thinking maybe something haywire with the ignitor (ignition control module) but it seems the Honda's only behave with a no start or a misfire if the ICM is bad/going bad.

So that would leave the TDC Crank Angle Sensor. But if there was a problem with that, there should be a CEL.

Here is some more sheets for you:

bernie f

Finaly some time to check things. Thanks for the schematics.

Ignition coil primary is supposed to be between 0.6 and 0.8 ohms. Mine is 1.1 ohms.
Secondary is within the required resistance with 13.6K ohms. This coil was installed last year when the original coil failed. This coil is an after market coil.

Igniter test showed battery voltage for test 3 & 4.
There was one test in my Haynes that says the resistance between White/Blue and Blue wires on the igniter should be 3.3K ohms. I get 69K ohms. I have no idea what that test proved.
Since the problem shows only after warm up, both these parts are suspect. I'm not one to throw parts at a problem. Can I check the pulses going into the igniter when the car is running after warm up? When the problem shows, spark to the plugs is intermittent at acceleration.

TomCat39

At this point, you show out of spec for the parts... Would that really be considered throwing parts at it?

Also on the ignitor did you do the checks at the ECU?

If you notice, if all the tests check out, they next step is just to replace the ignitor.

As for the resistance check, I don't know the actual circuit design of the ignitor but if it is utilizing a carbon/silicone based conductive component (i.e. transistor, diode etc) when the silicone material is still conducting properly it will have a certain resistance. As the layers separate the resistance will go up and also the conductive properties will diminish until it finally becomes an open in the circuit and conducts zero current.

It is quite probable that check was checking the resistance of a transistor or something of the like which will eventually give out and cause a much higher resistance reading.

bernie f

I expected a larger out of spec. reading for the coil not to work.

As to the igniter unit test I thought the test steps were for a no spark condition. I have spark and assumed the test will show that step 5 and 6 will have continuity. Therefor in a no spark situation the igniter must be bad if everything connected to the igniter is working. Since I have unstable spark the igniter might be bad. Like you said about the one resistance measurement. I might be reading a failing semiconductor. I didn't reverse the ohm meter leads to see if I was measuring across a semiconductor.

I think I'll go with the out of spec. after market ignition coil being bad first. It looked to me that there might be a faint sign of a hot spot on the side of the coil. I could be wrong. Now the question is do I get another after market coil or go with the OEM coil?

TomCat39

Not sure if you can find it, but if you don't want to go OEM, I have not had a single issue with my Accel "super" coil. It's been in my car for going on 3 years now without probs.

ACCEL brand | Part #: 11076

I'd still be curious as to why your coil is burning, as I thought you found a burnt coil last time when you were doing the timing belt and such?

bernie f

I found one on Amazon new for $46 and free shipping. While waiting for it to arrive, I will warm up the engine until the problem shows and do the resistance checks again on the coil and igniter.

bernie f

I found the coil on line new at Amazon for $46 and free shipping. While waiting for it to arrive, I will warm the engine up until the problem shows and then repeat the resistance checks on the coil and igniter. Just to see what I find.

Former User

Ohm test the ECT sensor and test whether unplugging the O2 sensor eliminates the issue that occurs after engine warms up.

bernie f

Hey Ron, nice to hear from you. I'm having a senior moment right now. I don't remember what a ECT sensor is or where to find it. I'll have to do a little research.

What I just did was heat up the engine and when the problem showed, I checked the resistance of the coil. Both went up. Primary coil is 1.2 ohms and the secondary is 15.5K ohms. I nicked the yellow green wire that delivers the pulses to the igniter and they blink steady at idle and are a solid light at acceleration. On the other hand, all of the plug wires lose spark at fast acceleration. I interpret that to mean the ECM is delivering the fast pulses to the distributor but they are not getting to the plugs. What do you guys think?

Former User

The ECT sensor has a 2 -wire connector and is located below the distributor. The two tests I suggested are pretty simple and should be done.

Are you saying that the Yel/Grn wire continues to show ground pulses when the engine loses spark? How do you know the engine loses spark?

bernie f

Yes. I clamp a timing light to any of the plug wires and when I accelerate the engine the light doesn't fire. Sometimes it fires a few times but the engine tries to stall.

bernie f

Yes

Former User

How are you monitoring the Yel/Grn wire pulses during this^ procedure?