car is running really funny...help please

[lxkid90]

ok...i got the break in miles on the clutch...so i go to get on the car in 4th gear....the car has no balls now....it almost like vibrates the car. it only does this when the thermostat opens at 160 degrees...it feels like its cutting out on random cyl's...its hard to describe...help please...i know its not a good description of whats happening but i hope this has happend to one of you guys before!

[Italian LX]

Give us some background on the car. What motor, what mods, etc....

[EHardy1971]

Give us some background on the car. What motor, what mods, etc....
:agree: ,need gear ratio,speed you are shifting at,etc,also,who installed the clutch.Give us a play by play breakdown here!

[lxkid90]

i dont think it has anything to do with the gear ratio, clutch....but any way it has 3.73's installed by the best guy around here for rear ends(dennis and b&l used auto) the clutch was installed by myself, its a spec stage 2 with a spec flywheel. the motor is a 5.0 mass air motor. its got long tubes, a/c and smog delete, orhp, msd 6a box.

[Italian LX]

It sounds like an ignition problem.

Bypass that MSD box and see if it still does it.

[lxkid90]

It sounds like an ignition problem.

Bypass that MSD box and see if it still does it.

ill try it

[lxkid90]

bybassed it...just as i thought....still does it...it has something to do with the thermostat opening up and the computer sending something messed up to either the dist. or the fuel injectors it seems...

[EHardy1971]

so I take it you have a 160 T-stat?,if you do,you need a 180,or some of your sensors will act freaky,causing the ECU to go back and forth between open loop,and closed loop

[lxkid90]

so I take it you have a 160 T-stat?,if you do,you need a 180,or some of your sensors will act freaky,causing the ECU to go back and forth between open loop,and closed loop

maybe thats what it is, but was running fine with the 160 stat for 6 months no problem at all...

[EHardy1971]

hmmm,try a 180*,and see what it does.they come from the factory with 198* units,I had a 160* in mine,and it ran rich

[QWKSNKE]

Have you adjusted the timing recently?

[03slobra]

I'm with lee it sounds like a timing or ignition problem.Does it do it only in 4th or when its under a load like maybe a plug or wire breaking down?

[Italian LX]

....or when its under a load like maybe a plug or wire breaking down?
Yeah, that would've been my next suggestion.

[coupe]

I doubt the thermostat is the problem...but it might have to do with the temperature of the car.

I've personally never had them go "out," but alot of folks have had TFI modules go bad and they are very heat-specific problems. That's the little box on the side of the distributor that plugs into the harness. That'd be my first guess.

Also, check your cap & rotor and make sure there is no water/moisture in there. Things go crazy if there's moisture in the cap.

The thing that strikes me as odd is the fact you said "teh car almost like vibrates" when it's acting up. Is it misfiring/sputtering sound out the exhaust? This can cause vibration/shaking.
Describe this a little more indepth please. ;)

[QWKSNKE]

You could check the tfi but usually I think the car just shuts off when the tfi gets hot if its bad.

[lxkid90]

its like a random cyl misfire...the car makes no power and hangs at rpms...it will stay at 2000rpms for a full second when its punched and just linger up...im trying the coolant temp sensor and the air intake temp sensor tommorow as well as the thermostat...the wires are good, plugs are good, cap and rotor are good. thanks for the help...oh it does it in almost every gear, 2nd, 3rd, 4th...doesnt matter but it pulls hard when its not up to temp and runs perfect...im leaning toward the coolant temp sensor...they can make a car do really funny things...(i work at an autopart store and no not a chain store, and actual one owner old school auto parts store)

[EHardy1971]

have you checked your TPS voltage?,and is it running rich?,it's starting to sound like a sig return voltage problem,or possibly a bad MAP/BAP sensor!

[Italian LX]

...the wires are good, plugs are good, cap and rotor are good. thanks for the help...
Just want to be clear how you know your wires are "good." Have you changed them already or at least swapped them out with a known good set?

[Craig K.]

Could it be an O2 sensor?
Last time I did my clutch when removing the exhaust I had hit one of the sensors, this had cracked the sensor elimate, and the car ran very rough, and would not pull at all (when warm) when cool it ran fairly close to normal.

Does the 88-93 computers allow you to do a KOEO test? What about a engine run test when you jump the engine compartment plug?
This is how I was able to get the actual codes and determine it was the O2 sensor.

[lxkid90]

Just want to be clear how you know your wires are "good." Have you changed them already or at least swapped them out with a known good set?

they have been changed...

[lxkid90]

i did the coolant temp sensor, did nothing...next is air temp...then ill do 02 sensors(both are fairly new tho)

[lxkid90]

i did the air temp and the ignition module...still doing the same thing...next is the 02 sensors, and if that doesnt do it i dont know what will

[EHardy1971]

when you put the clutch in,was there a ground strap that one of the bellhousing bolts went through?

[QWKSNKE]

i did the air temp and the ignition module...still doing the same thing...next is the 02 sensors, and if that doesnt do it i dont know what will

before spending the money on sensors you need to have the computer scanned for codes.

[Italian LX]

Are you still running the stock MAF? If not, which one are you using?

[97cobrasvt]

before spending the money on sensors you need to have the computer scanned for codes.

The best thing to do is like Lee said and scan the computer first. It will be alot cheaper if you diagnos it instead of swapping parts, that will get expensive. Looks like a multi meter is going to be you best friend for awhile to find the culprit.

[EHardy1971]

The best thing to do is like Lee said and scan the computer first. It will be alot cheaper if you diagnos it instead of swapping parts, that will get expensive. Looks like a multi meter is going to be you best friend for awhile to find the culprit.
yep!,I've BTDT!,that's why I asked if he checked his voltage @ the TPS and all,I went through that,threw ALOT of money at my car,and it was a non-grounded TPS that took me 5 minutes to fix!

[97cobrasvt]

yep!,I've BTDT!,that's why I asked if he checked his voltage @ the TPS and all,I went through that,threw ALOT of money at my car,and it was a non-grounded TPS that took me 5 minutes to fix!

Thats what I'm talking about. I have learned not to guess and take my time and check everything if I have too to find the culprit. Thats the type of stuff that would grip my butt is when I would guess and keep getting it wrong and it be something that simple as not being grounded.

[EHardy1971]

roger that!,first investment to make when dealing with any of these cars,IMHO,is a digital voltmeter!

[Blown89]

I've had a bad mass air sensor cause about what your describing . Car would run fine when cold or driving it easy but give it any throttle and it would miss and shake car badly . Code reader wouldn't read that it was bad.

[lxkid90]

i checked the mass air yesterday(pulled the two tamper proof bolts out and pulled the wires out) they were very clean. what should the voltages be for everything?

[EHardy1971]

i checked the mass air yesterday(pulled the two tamper proof bolts out and pulled the wires out) they were very clean. what should the voltages be for everything?
on TPS,with key on,engine off,it should be right around .98v on the green wire

[lxkid90]

fixed it...i had my brother put my wires back on when i was finishing up underneath the car(hes really handy) but he crossed up the wires real bad causing them to cross fire...and he left one boot really close to the header...starting to melt it...new wires on....properly installed by me...no more problem...thanks guys!