Car hessitating and laggy..Help.

[SrSLeePeR]

Well...My car is hessitating for some reason.

I changed my fuel pump, fuel filter, and spark plugs and it still hessiates..Example:

Ill start off and if I give it gas, the car will not move, and a second later it'll start working normally if I step on it harder, as if there was lag at the throttle. When RPM's are high it's fine. When I floor it, it's fine. But when I'm driving normal, there's hessitation and lag.

Also, when I'm at idle, RPM's seem to rise and fall continuously from 400-1300 back and fourth every couple seconds.

All coils are fine but it seems as if when driving "normal", the motor doesn't get enough fuel and/or spark but all cylinders are firing and fuel pressure is perfect.

Does anyone have any idea what might be wrong? Can you guys/girls give me some suggestions, opinions, experiences?

-ThankS

[ItzGenX]

hmm if your coils are alright its either the spark gap or the air meaning the mafs.

[iceburgslim]

Check your O2 sensor, it may be bad or the pins may have backed out of the plug. Use a volt meter to test the 02.

[SRJesse]

Check for leaks around the InterCooler Piping, the smallest leak can cause alot of hesitation.

[SrSLeePeR]

It's not leaks...But that was some good advice. Uhm...MAYBE it's the MAF, I'm not sure. Any other suggetions?

-ThankS

[Gladimor]

Eh I can already feel the heat but here it goes.

I had the same problem with my golf, in addition to the symptoms you mentioned it would give a kick when I pressed or released the accelerator, past a certain point. My spark plugs were carbonized, so I put in some irridium plugs and closed the gap a bit to about .28, will be different for a 240. Also I put a half a can of seafoam in the gas and the rest in the engine. In addition I used some slick55 fuel line cleaner. Within two weeks my car was running normal again.

I also have a bigger problem with the engine which caused the carbonation in that I have blow by in one of my pistons, causing oil to get in my intake via a suction vent in my valve cover. All the seafoam did was to put a temporary seal on that piston, which means no more trips to the autocross:mad: !

Hope this helped somewhat.

[SrSLeePeR]

Well...Here is a plug that I messed around with before the car started doing what it does now.

Courtesy of SpeedRacer



I unplugged that, and thats when the hesitation began. I plugged it back in, but the hesitation didn't stop. It's still like that...People said that if that plug was unplugged it was okay and it would only effect cars with Auto trannies.

[Gladimor]

If everthing is ok mechanically something might have happened to the ecu when that plug got unplugged and didn't reset, just a thought.

[1991240xs]

try the thermostat..

[that180guy]

if so, try resetin the ecu?

[pampadori]

hey chief, those plugs are for the idle control valve. if your hessitation started when you unplugged these, it set a ecu code too. did you alter anything else when you unplugged them? try reseting the ecu by either the directions on 240sx.org faq or by disconnecting the batter for 20 hours. why did you unplug these while the car was on?shaun

[SrSLeePeR]

I unplugged them while the car was off. I've been told that plug is only for auto trannies. So I went ahead and unplugged it so my idle can drop since it idles at 1300 all the time....but now...oh man how I regret it.

[SpeedRacer1]

The plug affects the auto transmission ecu somehow causing it to raise the idle about 1500 rpms. Im not sure what effect it has on manual ECU's.

Try reseting the ECU, it shouldnt take that long.

[Daunttless]

:withstup

I already had him reset his ECU like a week ago, but its not like it would hurt it again.

[SpeedRacer1]

Cant they just build an ECU that will throw codes but not have adverse effects. Well im sure in Japan there are 50 tuner companies that do this but none of there ECU's make it over hear. And while were on the subject, why dont you reset your ECU again:P What error code was it throwing again, I dont think you got the right one.

[Daunttless]

It wasn't throwing any code, thats the problem. : (

[SpeedRacer1]

He told me he was picking up a code 55 which i couldnt find an error for.

[implict]

u sure it isnt his cams?

[SrSLeePeR]

I reseted the ECU. Same thing.

I checked the code, which was 55.

It was a...blink blink blink blink.....fast blink fast blink fast blink fast blink fast blink .....

55 Means there's either NO problem, or some other thing I forgot....

I'm really confused here. It only hesitates now from about 1500-3000 RPM's on a light pedal. If I floor it, it hesitates but the power kicks in a bit after....

I'm gonna try some carb cleaner today and see what the outcome is....Does anyone else know what may be wrong?

[SrSLeePeR]

My bad...Code 55 means "other falfunction. CONSULT terminal required"..What does that mean?

[Gladimor]

Ah man no carb cleaner, that stuff really screwed up my golf. Whatever you do don't use it while the motor is running just take out what needs to be cleaned and spray it down and wipe off. Spraying it into a running engine will make your mixture too rich causing carbon deposits galore, trust me I spent an entire day ripping apart my head cleaning valves and my intake manifold of carbon deposits, not to mention new spark plugs. But then again I did use a lot of carb cleaner. :pface

You said that your car was running ok till you unplugged that plug so it has to be something electrical that maybe was reset or blown. I would check the electrical systems that might have been affected by unpluging that plug in a Haynes manual or something.

[SpeedRacer1]

Personnaly it really does sound like the BOV so try to find someone in your area and hook up their stock recirc valve.

[SrSLeePeR]

UPDATE: Thanks to Dauntless and SpeedRacer1 for helping me through my hell problems. They've suggested it from the beginnign but I didn't think it was it since it was working fine before everything started happening.

IT WAS THE P.O.S. GReddy BOV. The head of the BOV was stripped bare so the adjustment Bolt/screw was really out causing the valve to stay open. I dont know what I'm going to do yet, but I used a regular FAT A$$ screw and screwed it in TIGHT. There's still some LITTLE air getting out but at least it doesn't hesitate AS BAD. It's good enough to drive as long as I dont drive hard.

Anyways, I want to keep the BOV because I really like Type-S's. But the head is messed up so the only solution is to take it to machine shop and have it rethreaded somehow. Anyone have any suggestions? If not, I think I'm gonna go with TurboXS H-RFL.

-Thanks again to Dauntless and SpeedRacer1 for the help and support!