Weird acceleration problem under 3k rpms

[j_eclipse96]

Hi, my car seems to have an accelleration problem under 3000 rpms. Say I shift out of 1st gear into second, and the rpms drop down to about 2k something rpms after letting the clutch out. I can still accelerate at this point, its just if I put more than marginal pressure on the gas pedal, the car seems to hop or shudder, almost hesistating to rise in rpms. Once I get over 3000, I can put as much pressure on the gas pedal as I want, and it doesnt stutter. I don't know if this is completely normal or not, I don't know too much yet. A friend of mine said its my spark plugs, but I don't know what to think. Thanks.

 

[NjzRedGST]

Should of done a search, for most guys new plugs/wires make the bucking go away, worked for me.

 

[Jackripper_83]

Is it a random stutter, or a does it stutter multiple times per second in perfect rythm?

 

[luv2rallye]

Try testing the throttle position sensor (TPS). Measure the resistance of the TPS (pins 1 & 3 should be 3.5k-6.5k) and make sure the resistance changes smoothly (pins 2 & 3) with the opening angle of the throttle valve.

 

[j_eclipse96]

Is it a random stutter, or a does it stutter multiple times per second in perfect rythm?

Its random.

In reply to post #4, Is the TPS the lever behind the engine block that controls revs on the engine? I'll look and try to figure out what that is. (sorry, I'm a total engine newbie) Thanks.

 

[luv2rallye]

The TPS is on the other side of that unit (the throttle body) that the lever is on. It is a sensor that detects the position of that lever and sends this info to the engine computer (ECU). (The lever controls engine revs and is connected to the gas pedal). The sensor has a 3 pin electrical connector attached. Disconnect this and measure the resistance on the sensor side connector. They often go bad from wear and then the resistance won't vary smoothly (between pins 2 & 3) with the lever position. This will mislead the ECU, which controls the engine, with wrong signals and can cause the symptoms you describe. If bad, you can pick up a used throttle body just for the sensor at a junk yard cheap (or just sensor if they let you but not too likely). Or buy a new sensor if you have to (probably will cost more though). You'll need a multimeter to measure resistance while turning the throttle very SLOWLY. Use one with a mechanical needle so you can find any areas where the needle jerks to one extreme and then returns with just a slight more turning. With a digital meter it's nearly impossible to find a bad area since they "sample" every fixed amount of time and you will go right over the bad area but not see it.

 

[Spoolin4Ever]

Of course you DID replcae the plugs, seeing as they are only about $8, and takes about 5 minutes, right?

Something that is cheap and fast like that, you need to go ahead and do it if you have not put plugs in a while. What is there to think about?

Also plug wires, although they cost almost $40, so if they look good, you might be ok without new ones. I would seriously consider replacing them, though.

 

[j_eclipse96]

Okay, I replaced the spark plugs, cleaned my throttle body, sprayed carb cleaner into the carberator, and ran some fuel treatment. She still stutters, but it runs ALOT better in general now. I am thinking it is the TPS, because the way its acting now just points to that. I'll do a resistance check after the engine cools down. Oh yeah, and DAMN was my throttle body dirty! seems like that would have been the problem, but she still idles weird. Thanks for the help guys, I'll let you know how the resistance check goes.

 

[j_eclipse96]

The multimeter we have has a blown fuse

Would cleaning the electrical contacts solve anything, or is it the actual sensor that is bad? I am quite sure it is my TPS, because now when I press on the gas harder, the car responds better (due to the above routine maintnence I think), but it will hit a certain RPM, then it surges forward much faster, then climbs slowly again after a bit. Thanks.

 

[luv2rallye]

Still sounds like TPS is bad - not uncommon. Do resistance check for smoothness over entire range to test.

 

[j_eclipse96]

Would I need a TPS from a 420a? There is an auction on ebay for a TPS that works for: eclipse, laser, and talon, galant, sonata, stealth, 3000gt all turbo and non-turbo models. Yeah, I know its ebay, so I figured I'd ask first. Still gotta do a resistance check. Thanks.

 

[Underdog378]

My 1st gen has the same problem, and once it gets to 3000rpm it's just fine, I guess I should check my TPS since my plugs and wires are new.

 

[j_eclipse96]

Ha, I was just about to reply to your old thread when I saw someone posted in this one. If your still having idle issues, try cleaning your throttle body. That helped my engine in general ALOT. Just be careful not to break the gasket on the tb though, mine was already broken. But yea, reading your other thread, sounds like your tps is bad too. But do a resistance check first.

Anyone have a reply to my last post yet?

 

[j_eclipse96]

I tested the TPS, and it seems to check out. I pulled the lever very slowly, and the resistance either went up or down, depending on the polarity, but it did not seem to jump at all. It did lag a bit towards the end when the throttle was almost open all the way, but it didn't spike or anything. I tested both pins 1&2 and then 2&3 on 10, then 1000. I'll check my plug wires I guess, I really thought it was my TPS though.

 

[Fred J]

I tested the TPS, and it seems to check out. I pulled the lever very slowly, and the resistance either went up or down, depending on the polarity, but it did not seem to jump at all. It did lag a bit towards the end when the throttle was almost open all the way, but it didn't spike or anything. I tested both pins 1&2 and then 2&3 on 10, then 1000. I'll check my plug wires I guess, I really thought it was my TPS though.

I have the same problem, my 93 non turbo talon was just added a turbo conversion, but when I finished and started it, the rpm went to 2500 - 3000 and stayed there but it runs rough and the idle surges but the rpm stays constant. When I changed the throttle body, the new TPS has a forth wire (black) that my old connector didn't have. I connected all the green wires by matching the colours. Does anyone know if the black wire is a ground or where it goes?

 

[j_eclipse96]

Okay, I checked the coil pack (used guide from 2gnt.com). I couldn't get a reading from the primary coil check, but the secondary check read about 16 ohms, about 3 ohms above normal according to the guide. I checked my wires as well, and the contacts look clean (thats the only way I could think of checking the wires). So should I replace the coil pack, or just try swapping my plug wires first?