**UPDATED**

I am still having trouble with this motor :/

Anyways, whenever my engine is cold from a fresh start acceleration is rough and i feel major power loss at the pedal. Like if I try to rev it while idling cold the motor will studder then rpm's willl drop then catch itself, also during this backfiring from the intake occurs. Once the temperature gauge reaches the 2nd bar before the normal operating temperature the car starts to gain most of it's throttle reponse and power. At normal operating temperatures the car runs pretty good, great response and power except for 1 out of 3 times i try to go past around 3.5-4k. the car feels like it is holding back and i would have to give it more gas to accelerate.

Things I replaced
- Spark plugs (Around 1000 miles))
- Spark plug wires (less than 500 miles)
- Distributor cap (less than 1000 miles)
- Distributor rotor (less than 500 miles)
- ECT (less than 150 miles)
- Fuel filter (Less than 150 miles)
- O2 Sensor (Less then 500 miles)


Any one have any clue what the problem is? Seems like it's dealing with some type of sensor that controls the engine's function at certain operating temperatures, i thought it was the ect but still it was a no go. I have been suspcious about the wiring to my ECT (local shop did my swap) here is the wiring atm.

this is from the h22a ect connector to the 92 si engine harness

Black to Green/White
Green to Yellow/Blue
Correct?


I think it might be wired improperly so it burns ect's out quick. Also my jdm h22a did not come with an vtec oil pressure switch (it was blocked off with a bolt?) but my jdm p13 still throws a cel 22. i heard that some jdm h22a's didn't come with vtec oil pressure switches.. is this causing my problem?

 

Just installed my new sub-meter (gas/temperature gauge, old one fried on me) and this is confirmed, when the car moves onto the 2nd temperature bar it starts to idle and accelerate better then once it reaches the middle the car drives fine.

 

The backfiring sound is coming from the intake itself if that helps with any new suggestions :/

 

You may really need a valve adjustment.

 

that or new spark plugs

 

It has new spark plugs and i'll look into getting a valve adjustment pretty soon since the motor is ticking. Any other suggestions?

 

ya man since i had a lot of problems kinda like this im no stranger for this problem. fuel filter? pump? im a huge believer on the valve adjustment tho thats what fixed mine...

 

Going to replace the fuel filter later this week, might follow that DIY posted on here and see if that helps.

 

ya it takes like 15 mins its easy.

 

Since it has problems when cold, but ok when warm, let's look at how things are different.

When first started, the ECU has a 'default' program for fuel mixture and runs with only the most basic calculations based on Absolute atmospheric pressure, throttle position and rpm.

After about 120 seconds, (on 92 or newer), the Oxygen sensor is hot and starts to function.... however, the engine is still quite cold. The O2 sensor then takes over and the ECU starts trying to hit the right fuel air mixture. Part of the calculation for this considers engine coolant temperature. Since the engine is below running temp, there is still a percentage fudge factor to enrich the system... ie, choke is on.

Once up to temp, throttle position, RPM, absolute air pressure, all provide data for the final fuel amount - however, the O2 sensor is used to apply a correction factor for the optimum amount of fuel. There is a short term trim and a long term trim that uses the O2 feedback.

Since this is only a problem when partially warm, you will be looking for something that starts to be used when not cold, but is used differently when up to running temp. That would be the O2 sensor, the MAP (pressure sensor), and the throttle position sensor. Additionally, the ignition module may have an issue.

Bad acceleration can be caused by a failure to enrich the fuel mixture or timing not advancing. Timing problems a somewhat dependent upon the IGM. Mixture during acceleration comes from throttle position and mass air flow meter.

I know this is a lot of info. Hopefully, I gave you kind of a path to follow. If you can find some decent salvage parts, possibly try the shotgun approach and just start swapping parts until you find the problem. Unfortunately, I have never had that luxury, so I just worked on things one item at a time.

 

Nice, thanks for the useful information. Going to replace my ECT soon since the O2 sensor is pretty much brand new.

I have a feeling this is going to take a few parts being replaced to diagnose the exact problem.

Any suggestions on how I have my ECT wired up? I can't seem to find a diagram to tell me which one is ground and positive.

 

Tested my ECT today and it was reading up and down from 30-190ohm, the min in the helms manual was 200-400ohm so I replaced it and now it runs way smoother when the car is warm. The true test is when the car cools down and I'll see if it still sputters a bit when I try to accelerate while the temperature gauge reads 1-2 bars.

 

Bump, I am getting tired of pulling out of my drive way backfiring and studdering down the street after cold starts Embarassing lol.