I replaced the knock sensor in my '94 SE VE30 a few days ago. I lot of the hesitation is gone, but the car is still considerably slower when warm - what else could be the problem?

 

Supposedly the coolant temperature sensor (connector or sensor itself) can also get corroded and contribute to heat soak. Might want to check that out.

 

Mizeree
Also how are your coils looking?

 

coils look okay, but would worn coils affect the performance of the car only when warmed up? It seems like the coils are coils, whether the motor is hot or cold. There might be something to the temperature sensor theory, because I damaged the sensor that sends info to the gauge during the operation. The one that talks to the computer seems okay though.

 

I'm not completely sure, but I think as long as the coils arent cracked you really dont have to worry about them wearing out. I've got a set of 165k mile coils with no cracks and they run perfectly fine.

I'd just double check the temp sender stuff like Mizeree said. Maybe just clean up the terminals abit, never hurts.

 

does the vg ever have any kind of heat soak problems coz since it has gone colder i feel it more now. i know the vg doesnt have any problems with the knock sensor and vtc's and it also doesnt have coil problems like the ve. ive had my thermostat replaced an my radiator flushed. im starting to think it could be my exhaust system and im aboutto have that replaced. does anyone have any other ideas or do you think that i could be right with the exhaust.

 

I had a '91 SE, which has the VG motor, and it really began to run like crap when the exhaust system went, so you might be onto something there. Can't prove that theory because I sold the car without fixing the exhaust. Could be temperature sensor maybe? One thing about the VG in that car, after the exhaust went it was always slow, hot or cold motor.

 

The coils will break down easier when hot. I just replaced the three rights (I had to order the lefts) and almost ALL of my heat related hesitation is now gone. I got the three Borg Warner e581 rights from O'Reilly Auto parts (http://www.oreillyauto.com) for $50/each. They had them in stock just a block from where I work. The lefts I ordered from Courtesy Nissan for $65/each.

Basically, ANYTHING electronic will lose performance as heat increases.

 

shoult

Unless you have a CAI, you will be pulling warm air from your engine bay, too. All of these things may be contributing to your sluggish performance.

If you think it might be something to do with your knock sensor, maybe you should check your timing.

As for exhaust, recently I replaced my y-pipe. My old one was fine, but the o-ring gaskets had totally worn flat and it was very loud and leaky at the rear header flange. During the process, the guy helping me wiped off the o2 sensor. Now, my car idles smoother, seems to have considerably more power (Cattman y contributes some of that ) and it hasn't hesitated since. It was either the exhaust getting through the leaky gaskets were screwing things up or my o2 sensor was really dirty. Either way, my car runs a lot better. I don't know what happened and I still plan on replacing my cracked coil (it's taped right now -- thanks Mr Gone...)

 

3rd gens are cool

Davebond is affraid of me now :evil:

 

I had corroded terminals on one of my VTC solenoids.

 

I didnt read all the responses so if this was mentioned sorry but...

Do you have a pop charger (cone filter under the hood)? If you do I would suggest you get a CAI. when it heats up under the hood you are taking in that hot air which in turn can make it feel more sluggish.

if you have the stock air intake then this theory is pointless though LOL.

Just something to think about.

 

Did you test the KS harness when you replaced the KS? My KS tested OK (we still replaced it), but the harness was crap.

Just a thought.

 

How did you know the harness was poopy?

 

We did a voodo dance and it showed up having bad mo-jo.

 

Well Lordrandall and friends can do voodoo dances because there just that good, but the rest of us probably have to break out the Ohm-meter

 

......

 

Yeah, I replaced teh knock sensor and harness. The harness terminal was fuzzy and green with corrosion, and the casing of the KS itself was cracked. My KS symptoms are gone, but the car is still sluggish, the longer you run it and the warmer it gets. It doesn't help that I broke the plastic nipple (huh huh) off the power valve solenoid actuator when attempting to change vacuum hoses in 8 degree weather, so now I effectively have no power valve. I can still tell there's a heat-related problem though