GritzNGravy

What's up guys? After combing some threads and google for a while I couldn't really find what I was looking for so I decided to make a thread and see if I could get some help.

First, some background: I recently installed a new head gasket into my 04 EX. While I did that I also replaced the driver side engine mount (completely snapped in half) and cleaned the throttle body, EGR ports, IAC valve and VTEC solenoid. Put it all back together, started it up and drove it for a few weeks. Car started and ran fine but was rough around the edges. A few weeks in and I noticed the car was leaking fuel from the injectors and my issues seemed to be fuel related so I figured this would fix all my woes. Well, after 3 sets of injector o-rings and a new fuel rail, turns out I never reinstalled the spacers for the fuel rail because I had no idea wtf they were. Got those back in and after 300 miles I'm not noticing any leaks or smelling gas.

That brings me to now. The car doesn't seem to be leaking fuel anymore but the issues I had originally thought it was causing are still there. If I'm driving the car and depress the clutch, my rpms will drop down to 400-500 and the motor stutters for a second before coming back up to normal idling RPM's and staying steady. I've also noticed that the car will do this same drop if I do anything that puts even the slightest strain on the electrical system. Turning the lights on, turning the steering wheel, even just increasing the A/C speed up a couple notches will make the rpms drop and the engine stutter for a brief second. All of this causes the car to not drive very smoothly because the idle seems to want to drop off every time you let off the gas.

The car also vibrates a **** ton while it's idling. it's not as bad when the A/C is off, but when you flip it on and have water in the cup holder it looks like you are going through a damn earthquake. I expected it to have more vibration due to having better compression after the HG but not so much, especially after replacing a completely failed motor mount.

I'm still thinking this could be a fuel issue but I don't know where to start on figuring out the problem.

bsmiley

Search this forum or download the repair manual and do the idle learn.

ezone

Idle learn.

This is why aftermarket mounts are not recommended (by me, anyway).
If you want a soft mount like original, get the original.


Better compression? No.
Fixing a head gasket cannot do that.
All it can do is restore compression to the designed ratio, if it had lost any at all...and these usually do not lose compression at all when the head gasket blows.
Even if the head was machined, any compression increase is minimal and inconsequential unless it was machined far beyond max limit.

GritzNGravy

I'll try the idle learn procedure again. Maybe I didn't give it enough time but I disconnected the battery for a minute and then allowed it to idle for 12+ mins. I am using the shop manual for these repairs by the way.

I'm not sure what you're getting at on the mount? It was the stock mount that snapped in half.

The last part I should have said restore. I originally did a compression test and the 4th cylinder was reading very low which is what led me to replacing the head gasket.

ezone

Try like several minutes disconnected, then when you let it idle the engine temp needs to be at operating temp before it starts the learn. If the computer has to wait for it to warm up, don't include that time in the 10 minutes of learn time. Same if the fans run, don't include that time in the learn time.
Aftermarket rubber mounts tend to be much harder than stock, thus more vibration transmitted into the body of the car. If you only changed a cast bracket that shouldn't make a difference

UNLESS you got it (or they gave it to you) for the wrong car ----coupe and sedan could use different mounts but they may look almost the same


Have you rechecked the compression now that you did the head gasket? If you still have low compression that will cause you problems.

GritzNGravy

I gave the idle learn another few tries at operating temp and I'm still getting the same results. But...

I've been noticing a gas smell occasionally when getting out of the car and it seems to be coming from the exhaust. No leaks that I can see and I don't smell anything in the engine bay. Only when the car is running and I'm standing behind it. I'm also getting worse gas mileage than before replacing the HG (6mpg less).

I'm not sure if this relates to my original problem but the only thing I can think of is the O2 sensor, though the car isn't throwing any codes atm. I'm hesitant to drop $250+ for the sensor on just a hunch.

ezone

Have you rechecked the compression now that you did the head gasket? If you still have low compression that will cause you problems.

Valve adjustment?

Got fuel leaks in the rear of the car?

GritzNGravy

I checked compression on the 4th cylinder which was reading low before and it was within range of the rest.

I did the valve lash to spec in the shop manual after I received the head back from the machine shop.

And I haven't noticed any leaks and I've been checking pretty frequently. The smell doesn't ever linger and seems to only be there when you are down wind from the exhaust.

ezone

Check all 4?


You could do a battery disconnect or PCM reset to clear adaptives, then unplug the front O2 sensor and drive it to see how it runs. Disconnecting it should put the computer in open loop without feedback, if a bad sensor were causing fuel trims to be whacked this might at least let you decide if there is improvement before replacement.

GritzNGravy

I'll test compression on all 4 tomorrow and come back with the read outs.

Is it bad to do an extended amount of driving without the O2 sensor? The problem is intermittent so it would probably take more than a few trips around the block to really notice a difference.

ezone

Kinda depends on how it runs. If it runs perfect there probably won't be adverse effects as the computer will use its basic fuel map without trim corrections.

If it runs crappy enough to make you say 'damn', then don't drive it...There's something else making it run bad.

mac25

It may not be fuel related exactly, you may be running rich, which would smell like gas, but it wouldn't be leaking it would be un-burnt.

Re-check all the electrical sensors you disconnected I would completely remove them then plug them back in, once I had a coil pack that looked pluged in and it took me 2 hours to discover it was not, because I kept missing it by only thinking it was pluged in fully.

Especially since you cleaned the throttle body and egr valve, check the MAF and temp sensors, the throttle position sensor and the wires from the egr.


Good luck.