Starting and rev issue...please help

[clipseclipse]

First time posting, and yes, I have read thoroughly through the threads about similar problems.

I have a 95 eclipse rs that intermittently starts, and most likely unrelated, sometimes revs up high with the slightest touch of the gas (upwards to 3k) yet at times responds the way its supposed to be (tap revs up a bit on the tach).

STARTING PROBLEM: Sometimes it will turn over instantly. At other times, regardless of weather, it will just crank but not turn over until I give it a couple more tries. I have tested the battery, alternator, and starter and all turned out fine. I have replaced the spark plugs as well.

REVVING PROBLEM: As mentioned above, sometimes a tap will cause the tach to skyrocket in rpms, with a very slow return rate of down-revving(or whatever it is called). Sometimes it will respond what seems to be correct with the slightest of throttle response, along with quick "down-revving" back to correct idle. I have cleaned the IAC (if that helps in any way). I have made sure the contacts to the battery are flush, and I am suspecting perhaps a bad ignition coil or coilpack(which from researching here may be the problem). Will the TPS affect this in any way? If so, how can I test the TPS with a standard multimeter?

Nothing in either seem to be consistent to weather/environment. No codes are being thrown as well. Considering that these two problems may be related or unrelated, what may be the cause of either/both?

Please help! Thanks in advance.

BTW, here is the ride...

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[sarge281]

As far as the idle goes, I believe there's a testing procedure for the IAC (or ISC) where you can test the resistances for each pin. Your idle speed motor's coil may be going out. As for the starter, when you had it checked, did they check the solenoid?

 

[davidaham]

check your map sensor if it goes bad it can make your car do all kinds of funny things.. when mine went out it started reving really high and then it would just die

 

[1slow97]

Is the car throwing any codes??

 

[clipseclipse]

negative, no codes. Does anyone here know how to test the coilpack, TPS, crankshaft, camshaft sensors with a multimeter? Thanks

 

[rstare]

TPS;
ECU supplies it with 5v. At idle (minimum throttle) it should be .4v and at WOT it should be 3.8v.
CAS;
The crank counterweight has notches in it. When the sensor aligns with a notchs it outputs 5v, when it's aligned with a metal portion is outputs .3v (IIRC). The ecu uses this along with a 60* timing mark to determine engine speed.
The CPS does the same thing using a magnet.

 

[Dirks99]

Too add comments about the revving problem. Have you noticed while you are driving, if so your clutch might be slipping/going out, if so there is usually a burning smell that follows. There are other threads that discuss this in further detail (search clutch slipping going out)

I'll be relpacing my clutch this weekend (for i've had the same revving problem) and will reply if it has fixed my issue

 

[clipseclipse]

Too add comments about the revving problem. Have you noticed while you are driving, if so your clutch might be slipping/going out, if so there is usually a burning smell that follows. There are other threads that discuss this in further detail (search clutch slipping going out)

I'll be relpacing my clutch this weekend (for i've had the same revving problem) and will reply if it has fixed my issue

The problem occurs regardless of whether or not i'm in gear or in neutral.

Have people had similar problems to mine vanish when changing their coilpack and plug wires?

 

[VelocitàPaola]

negative, no codes. Does anyone here know how to test the coilpack, TPS, crankshaft, camshaft sensors with a multimeter? Thanks

The TPS is basically a potentiometer. If you set the multimeter to test for resistance and place its leads on one of the outer pins and the center pin, you should see continuously increasing or decreasing values on the DMM. If there are any shorts or opens, then the TPS is probably bad.

The TPS, CPS or CAS could all be causing this problem. If they are all functioning, however, I would suspect the ECU.