hesitation under acceleration and rough idle - HELP PLEASE
07-01-2002, 10:01 PM
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hesitation under acceleration and rough idle - HELP PLEASE
Ok, here's the deal. I have a 94 Civic DX coupe with a 99' b18c1. I have an RSR header, thermal cat-back and a stock 99 GSR cat (2 O2 sensors). The car was converted over to OBDII and a chipped OBDII p72 was put in. Don't ask me why it was done this way, the story is Yoshio (?, not sure of the spelling) of Japanese automotive (out of Toronto I think) did the swap. Pretty much a hack job, the wiring by the ECU is a mess. The motor is REALLY strong and was running perfect when I got it, no problems at all so I didn't want to touch it.
So, it had the stock GSR cat and I was able to get a universal carsound for free and had a friend put it in. The wires for the secondary O2 were just plugged into the the connector on the ecu side, there was no connector on the O2 side, just the wires with the pin plugs stuck into the connector. Well they pulled out when we swapped the cat and I didn't have a book so I tried what I thought was right and it threw a code so I didn't want to guess anymore so I just left it unplugged. Only left it that way for 2 days and drove very little.
So it was running in default mode and was running a little rough which I expected. The one annoying thing was under part throttle acceleration at around 3-4K rpms if I pressed the gas the engine would bog for about 5-10 seconds and then power would come back abruptly and usually you would be pressing the gas down a little more to try and get it to accelerate and then it would "catch" at that throttle point and snap you back a little. The rpm's would barely fall, but it felt like there was less fuel getting to the engine or something. So I got a book and connected the 02 sensor the right way, reset the ECU and no CEL.
But, it's still having this hesitation/bogging problem. You can hear it when it's sitting there idling too, it'll idle nice and smooth at about 8-900 rpm and then it'll drop a little and it won't sound like a nice smooth idle because they've dropped a little low and then about 10 seconds later it'll correct itself, but it'll keep doing it. It never did this before. You can hear the engine as it's about to do this and if you let off the gas and go back to half throttle it's ok. At WOT throttle the car is fine, although like I said the engine just doesn't sound as smooth as it did. I don't know, maybe that's in my head. It is so annoying.
Here's what I've tried:
*tried another secondary 02 sensor, that didn't work (i knew it wouldn't but I had to be sure)
*replaced distributor cap and rotor
*tested the resistance on the plug wires, still way below spec for resistance
*thought maybe I fouled the plugs, replaced with bosch platinums (old ones looked clean, no deposits or carbon)
*cleaned out the throttle body today. I thought this was going to be it. I opened the butterflies and stuck my finger in there and it's was like a sticky black grease all over the inside. So I bought Throttle body cleaner and sprayed about half the bottle in there and it seemed to do a pretty good job, lots of black junk was coming out of the throttle body and I wiped in there as much as I could. So I took it out for a spin and it was running PERFECT (that nice smooth idle) for about 20 minutes and then it started again. DAMMMIIIT!!!
*put a voltmeter on the 02 sensor for the hell of it and it seemed normal. I can't find info on the secondary O2 but I think it has a little wider voltage range than the primary, the voltage would fluctuate between .1 and 1.00 volts. I think the range for the primary O2 sensor is like .4 - .9 volts. Not sure though.
*ran 2 bottles of regane thru and I only use mobil 93 octane.
I have a fuel filter that I need to put in and I'm getting new plug wires anyway.
So now I'm confused. It's probably been this way now for about 1000 miles. It does it on the highway and driving around town. I have a haynes manual and I'm trying to getting around to testing the sensors and the wires (the IAT works fine). I fear it's an electrical problem and I'll be pissed because the wiring on this thing is a mess. Like I said it does it a lot less now which is kind of annoying, if it's not gonna run right I would rather it be all the time (easier to troubleshoot). It was doing it a real lot and then I decided to clean out the distributor cap and it seemed a lot better so I just replaced it but it still didn't cure the problem, just made it less frequent.
What could it be? Someone else was saying replace the main fuse, read someone else's about a bogging problem and it went away after they replaced the main fuse. Could be some validity here because I could have shorted something somewhere when I plugged the O2 sensor in wrong. I'm gonna try this one. I've heard TPS, distributor, fuel pump, map, injectors. Not sure though. Remember the engine is only a '99 with about 40,000 miles. Not that old. Sorry for the long post but I wanted to give you all the info. TIA
s
[Modified by stevel, 2:13 AM 7/2/2002]
So, it had the stock GSR cat and I was able to get a universal carsound for free and had a friend put it in. The wires for the secondary O2 were just plugged into the the connector on the ecu side, there was no connector on the O2 side, just the wires with the pin plugs stuck into the connector. Well they pulled out when we swapped the cat and I didn't have a book so I tried what I thought was right and it threw a code so I didn't want to guess anymore so I just left it unplugged. Only left it that way for 2 days and drove very little.
So it was running in default mode and was running a little rough which I expected. The one annoying thing was under part throttle acceleration at around 3-4K rpms if I pressed the gas the engine would bog for about 5-10 seconds and then power would come back abruptly and usually you would be pressing the gas down a little more to try and get it to accelerate and then it would "catch" at that throttle point and snap you back a little. The rpm's would barely fall, but it felt like there was less fuel getting to the engine or something. So I got a book and connected the 02 sensor the right way, reset the ECU and no CEL.
But, it's still having this hesitation/bogging problem. You can hear it when it's sitting there idling too, it'll idle nice and smooth at about 8-900 rpm and then it'll drop a little and it won't sound like a nice smooth idle because they've dropped a little low and then about 10 seconds later it'll correct itself, but it'll keep doing it. It never did this before. You can hear the engine as it's about to do this and if you let off the gas and go back to half throttle it's ok. At WOT throttle the car is fine, although like I said the engine just doesn't sound as smooth as it did. I don't know, maybe that's in my head. It is so annoying.
Here's what I've tried:
*tried another secondary 02 sensor, that didn't work (i knew it wouldn't but I had to be sure)
*replaced distributor cap and rotor
*tested the resistance on the plug wires, still way below spec for resistance
*thought maybe I fouled the plugs, replaced with bosch platinums (old ones looked clean, no deposits or carbon)
*cleaned out the throttle body today. I thought this was going to be it. I opened the butterflies and stuck my finger in there and it's was like a sticky black grease all over the inside. So I bought Throttle body cleaner and sprayed about half the bottle in there and it seemed to do a pretty good job, lots of black junk was coming out of the throttle body and I wiped in there as much as I could. So I took it out for a spin and it was running PERFECT (that nice smooth idle) for about 20 minutes and then it started again. DAMMMIIIT!!!
*put a voltmeter on the 02 sensor for the hell of it and it seemed normal. I can't find info on the secondary O2 but I think it has a little wider voltage range than the primary, the voltage would fluctuate between .1 and 1.00 volts. I think the range for the primary O2 sensor is like .4 - .9 volts. Not sure though.
*ran 2 bottles of regane thru and I only use mobil 93 octane.
I have a fuel filter that I need to put in and I'm getting new plug wires anyway.
So now I'm confused. It's probably been this way now for about 1000 miles. It does it on the highway and driving around town. I have a haynes manual and I'm trying to getting around to testing the sensors and the wires (the IAT works fine). I fear it's an electrical problem and I'll be pissed because the wiring on this thing is a mess. Like I said it does it a lot less now which is kind of annoying, if it's not gonna run right I would rather it be all the time (easier to troubleshoot). It was doing it a real lot and then I decided to clean out the distributor cap and it seemed a lot better so I just replaced it but it still didn't cure the problem, just made it less frequent.
What could it be? Someone else was saying replace the main fuse, read someone else's about a bogging problem and it went away after they replaced the main fuse. Could be some validity here because I could have shorted something somewhere when I plugged the O2 sensor in wrong. I'm gonna try this one. I've heard TPS, distributor, fuel pump, map, injectors. Not sure though. Remember the engine is only a '99 with about 40,000 miles. Not that old. Sorry for the long post but I wanted to give you all the info. TIA
s
[Modified by stevel, 2:13 AM 7/2/2002]
07-01-2002, 10:47 PM
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Location: Barrie, ON, Canada
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Re: hesitation under acceleration and rough idle - HELP PLEASE (stevel)
The problem with a problem like that is it could be so many things. I would suggest taking it to a shop with a dyno and wideband. You can do a run with a tester for your ignition and get air/fuel readings too. You will be able to narrow it down this way. Also, when you do the run hook up a fuel pressure guage. I guess it will be harder for you because it doesn't do it all the time. Is it more frequent when the car is hot? Weather dependant?
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