Running Riot

I am completely out of ideas. Changed the injectors, set the timing, increased the fuel pressure, checked the intake manifold, checked the gaps on the plugs and everything but i'm completely out of ideas.

I have a B16 in my 2000 EX

When I first start the car, its drives fine. When it warms up it stumbles on partial acceleration. If I punch it, it accelerates fine.

Now after I've driven it and start it, it starts fine but stumbles on partial acceleration. If i punch it, it drives fine. If i stop at a light for a second or two, it drives completely normal.

I have a slight hunting idle and every now and then it will stall at idle. I am throwing an O2 and AIT code. I know to usually clear the codes first before yada yada, but the o2 and AIT should not cause this to happen. Does ANYONE have an idea of what the **** is going on with my car?

Any help appreciated.

BlueEM2

iTrader: (1)

Have you tried an ECU reset??? A compression test may be in order here, as well as a head gasket check.

Running Riot

i was afraid of that. I did a compress check. engine warm 241-240-241-185.

it's not over-heating or burning coolant

BlueEM2

iTrader: (1)

I know it says you checked the intake manifold but that's kind of vague. Did you spray it with throttle body cleaner to see if there is a vacuum leak somewhere? ( You seem to know what your doing and I feel pretty useless offering ideas lol )

Have you checked your distributor?

I wonder if the o2 code has anything to do with it.

By ECU reset I meant idle relearn... stupid me.

Running Riot

i put the intake mani on with the head off the car and in the right sequence and both the head and manifold were checked and planed. if there is a vacuum leak it's not coming from the manifold. I afraid it may be the headgasket. I'm going to replace the fuel filter today. It's only got 30k miles on it but you never know.

I checked the dizzy timing and it seems spot on. I thought MAYBE the o2 code had something to do with it but I've not read about anyone having the car buck at them from the o2 sensor being bad. Maybe its a bad ground at the o2? I'm at wits end

BlueEM2

iTrader: (1)

is the overflow reservoir overflowing??? if your not burning coolant or overflowing the reservoir I would assume it's not the head gasket. Do you have any other head gasket symptoms like white smoke out of the exhaust? You could have a vacuum leak from one of the intake manifold hoses that leads into a sensor, it might not be just the IM gasket.

Do a check for exhaust gases in the coolant system. But it really does not sound like head gasket is your issue.

Sorry for not being very helpful, seems like you have everything covered.

The other crappy question is, since youve obviously removed the head... Did you bend a valve?

Running Riot

thats why i removed the head to begin with i had two bent intake valves. now you said exhaust gas in my coolant, what would that look like? hoses and all are connected theres only the charcoal canister, the iac and the brake booster going to the IM, not much to cause a leak you know? The over flow reservoir is going up and down like it should, i haven't noticed any coolant loss. But what would exhaust in my coolant look like?

BlueEM2

iTrader: (1)

Here is a very informative video... You can't actually "See" exhaust gas in your coolant. You have to check for it. It's the best way to check for head gasket failure. Here is a very informative video:

http://www.youtube.com/watch?v=QA7KVQq9vKA

Hope that helps... Quick question though, if you just removed the head why are you worried about a head gasket? Did you reuse the old one? Do you know how you bent valves to begin with?

BlueEM2

iTrader: (1)

One more thing did you torque the head bolts down properly? In the proper order to the proper torque specs?? They are 14ft/lbs 36ft/lbs and then finally 49ft/lbs. In the following order:



This is for a D17, so double check for your B series but I'd imagine it's pretty close.

BlueEM2

iTrader: (1)

Though your compression test is technically a pass... #4 has a pretty large deviation from the other three cylinders........ I think anything above 140 is good but you don't really want a difference of larger than 15% on the cylinders.