What year? If it's a first gen I'd bet it's your ECU in need of a rebuild.

 

91 Stealth R/T NA.
I got a new ECU a month ago or so because whatever controled the IAC motor was burnt and it wasent shifting points. The replacement I got has new capasitors and nothing else appears to be burnt on it. I had the same sputtering problem with the old ECU and this new one.

 

I replaced...spark plugs with Bosch platniums that are pregapped.

There is part of your problem. Those plugs suck. Take it from me. I used them for about 500 miles before I switched back to my NGK plats.

I would suggest taking those out and putting in some NGK coppers instead.

How fouled were your original plugs? Perhaps the reason it's still running the same is because those Bosch plugs are performing just like your old fouled ones

EDIT: also, those plugs are not properly pregapped. When I got mine they were off by about .008

 

Harrasser, I'm still with you on this one. Exact sysmptoms and have done the same things except replace my IAC. The sputtering/hesitation is getting worse and I'm running new copper plugs and new accell wires. Shit, I've replaced almost all the sensors I could think of EXCEPT the VICS. But from what I understand the VICS stuff doesn't kick in until WOT. Not sure. Getting friggin' annoying.
I'll sure be watching this post though.

 

Harrasser, I'm still with you on this one. Exact sysmptoms and have done the same things except replace my IAC. The sputtering/hesitation is getting worse and I'm running new copper plugs and new accell wires. Shit, I've replaced almost all the sensors I could think of EXCEPT the VICS. But from what I understand the VICS stuff doesn't kick in until WOT. Not sure. Getting friggin' annoying.
I'll sure be watching this post though.

VICS kicks in past 3000rpm, not necessarily at WOT.

 

Took the intake plenum off today and took it all apart cleaned it up. stripped all the old paint off it and gave it another coat, just waiting for it to dry so i can put it back together and try it out.
I noticed when I was pulling off my VIC motor that it piviots on the 3 screws. Anyone know how to adjust it properly? Maybe it was outta wack...

Guess i can go buy some new NGK COPPER plugs and try those. If it fixes the problem i'll be very amazed tho...I wonder if maybe one of my coils is bad and giving a weak spark, anyone heard of that? I guess i can put a spark tester on the coil and check how far of a gap it'll jump. but it doesnt miss at idle or WOT so it would probably show alright.

 

Well the plenum is all cleaned up and painted. No change in the hesitation. altho it does seem to run alittle better I think. No one knows where to possition your VIC motor? It must piviot for a reason.

 

yeah, I don't know much about the VICS but I never really messed with it since my problems/hesitation occurs at 2K - 3K and the VICS (thanks bigtyla) don't kick in till after that. As a matter of fact RIGHT past 3K RPM is when she pulls hard. Makes me believe we're not getting enough air. (hence the reason your car runs a little better after cleaning the plenum -- more/smoother air flow) I was leaning towards my IAC since it seems like it's the only sensor (other than my CAS) that I haven't replaced and which controls minor air intake, but I doubt that's my problem.

I did want to mention that Jeff Lucious checked out my datalog and believes that I have a short somewhere in the harness. I have no clue where to begin on that one. Anyone know of common harness shorts??

 

I am also having hesitation problems and an unsteady idle.

It comes and goes but it's has gotten real bad.
First the car idles at a high 2k or 2.5k rpm, then starts to fluctuate from 2k to 2.5k at about 1 second interval.
My mechanic is checking the car right now and thinks is the VIC Servo. Perhaps out on timing or positioning.
I have the service manual but I don't see a lot of info on how to re-position the servo. It tells you to check for continuity and apply low 6V DC to make the control valve shaft turn. Other than that there is an adjustment on the opposite side clockwise to open counter to close. I will keep you posted.

Thanks

 

Sweet Stealthnight, let us know Btw, do you own a 91 N/A??

 

I have a 95 Civic EX that was having the exact symptoms your describing with the hesitation that turned into high idles and 1sec interval rev surging that goes away once you rev it. It ended up being my ALTERNATOR. I got it replaced and it went completely away.

Also, check to see if your interior and exterior lights are surging as well. It'll probably be real subtle but that will be a tell-tale sign that its your alternator.

Hope it works out for ya.

- synth0id

 

How many miles are on the car? Check the fuel injectors, that cleared up my hesitation problem.

 

check out the post below yours (Blinking ECS/engine bucking). Its easy to try and best of all, its free.

 

I have a 91 N/A DOHC. The battery is fairly new. After checking the car today everything points out to the Air Flow Meter.

Will keep you posted

 

I had almost the same problem and was told to replace the fuel filter and the fuel pump . did a pressure check and sure enough it was low, I replaced both parts and now it runs perfect. ~ Dont know what you think but try a fuel pressure test. ~good luck~

 

synthoid - I've always been concerned with the alternator since I've heard they go bad around 80 - 90K miles but I haven't seen any signs of surging lights and my engine has had revving intervals YET.

GT711 - I have 83K miles. I've also had the injectors professionally cleaned and pattern tested.

rxod - I probably read the same thread about disconnecting the ECS computer. Tried that and it didn't work.

stealthknight - Replacing the Mass Airflow Sensor was one of the first things I tried and it didn't work for me. Let me know because all the sensor's I've been using as replacements have been used. So you never know...

Showbiztonight - I've replaced the fuel filter and Fuel Pressure Regulator but haven't messed with the pump. From what I understand, our pumps are pretty tough and we usually don't have any problems with them... ??? I guess I figured I'd have many more problems if the pump was going bad. ??

 

Just to add to this post, i'm also having the same exact problem. Identical. I'm Running NGK Iridiums, Just took the valve covers and intake plenum off to put new gaskets on, cleaned, painted, and it continued to run the same. It did run a LOT better after changing the gaskets as far as the low RPM Hesitation, tho it still does it to a MUCH lesser extent and still continues to sputter.

 

Hey Monster -- Is this a 91 N/A also? How many miles? Replaced any sensors yet? I assume you did the ol' Capacitor replacement on your ECU?

One thing I have noticed and was wondering for all who's having the identical problem is that everytime I turn on the A/C for 10 - 15 minutes then back off the hesitation seems less. It's still there, but there's no .5 second pause....(which gets worse or longer every month) only a slight hesitation.

 

I guess it could be my alt. I havent had any real problems with charging tho. Just when i put my signal on the battery volt gauge jumps up and down with the blinking of the signal. I dunno if this is normal or not. I unplugged my ECS and it didn't help. I heard that the tour light would flash when there was a problem with the system tho, mine just doesnt come on at all. What could I check if when I was idling and switched modes and didnt hear any sounds comming from the struts. Cause I dont feel any difference at all. OR at least didnt before when the light use to come on. Even around hard corners..

 

I guess it could be my alt. I havent had any real problems with charging tho. Just when i put my signal on the battery volt gauge jumps up and down with the blinking of the signal. I dunno if this is normal or not. I unplugged my ECS and it didn't help. I heard that the tour light would flash when there was a problem with the system tho, mine just doesnt come on at all. What could I check if when I was idling and switched modes and didnt hear any sounds comming from the struts. Cause I dont feel any difference at all. OR at least didnt before when the light use to come on. Even around hard corners..

It's not your alternator. A bad alternator wouldn't cause the hesitation; the battery would just drain and die.

The voltmeter going up and down with the turn signal is normal.

 

Does the hesitation only happen when you start the car and goes away after the car is in operating temp?

 

GTO_VR4 - The hesitation USED to go away (or maybe not noticable) when the engine was at operating temp. Now it just lessens a LITTLE when at operating temp. It's almost like I have a short in a sensor/harness wire that has better contact after heat is applied....??

 

Ya mine is the same way. Once it warms up its not as bad, but its getting worse and time goes on. If its a short then why does it go away when u step on it. It's gotta be either lack of fuel or lack of spark...I wonder if the timing advance is somehow screwing and putting it outta wack.

 

Just letting you all know, I have 2 ECU's for a TT for sale. Excellent Condition, one used in my 92 TT , opened up and confirmed good and cleap caps, the other bought new from Mitsu dealership..

have pictures if anyone is interested. can negotiate. let me know

 

I have an NA and JUST got a new ECU for it. I heard tho if ur doing an NA to TT converstion if u swap the ECU u get like 40 hp or something. Cause it has different fuel curves. What if u put a TT ecu in an NA?