looking for some shoforum insight

[inverse1216]

ok heres the low down, recently my cars ce light came on within maybe a day of the light coming on the car has had the following symptoms:

in any gear and at any speed it will randomly drop in rpms at first it would be about 50 to 100 in drop but now its up to 500 in drop causing the car to surge

if i let go of the gas pedal while its surging the rpm drop goes away only to come back within a few minutes. under accelaration the rpm is not present only when keeping at a constant speed does it drop

sometimes the surging will not show itself upon start up if the car sits till the motor is cold and until second start up does it show up, but then sometimes on the first start up after the motor is cold itll show up bout an hour into driving, very random.

after reading some of the other threads ive come to the conclusion that its either

a) the crankshaft position sensor or
b) camshaft position sensor

am i on the right track here or can it be something else?

any advice is much appreciated the car is a daily driver so i need it up and running asap.

also if it matters its a 93 mtx with 73000 miles

thanks again

andy

 

[ckinart]

Check your codes.

Andy,

If your CEL was/is on, it's trying to tell you something. Have a look here for instructions on how to check your codes (very simple). Let us know what you find.

 

[inverse1216]

ok ckinart,

thanks for the link for the codes it helped me out a lot cause i lost me eec tester so i couldnt run codes, i wasnt aware that u could run codes that way.

well here is what i came out with i believe i read them right, im goign to run codes again when i get off work.

KOEO

111- ok

117- ect sensor is/was grounded
(possibly a code in memory)

217- primary circut failure in ignition coil 3
(also may be a memory code) i want to say this may be my problem?

618- shift failure from 2nd to 3rd
(memory, also i think i may have read this one wrong considering i have mtx and havent had any problems with shifting)

KOER

412- idle speed system not controlling idle properly (believe this may be causing my problem?)

225- knock sensor not tested (ignore if not pinging)
as far as i know its not pinging would the ping be something very audible?

167- no throttle position sensor change in "goose" test
(if im correct this means i didnt push the gas pedal down far enough?)

well thats what i came out with im going to run codes again see if i get the same stuff.

any advice, insight is much appreciated i would really like to get this car running smooth again.

thanks

andy

 

[inverse1216]

anybody have any idea what the problem may be?

 

[Rob94]

If the ECT sensor is bad, the computer will not know if the engine is warm or cold. That alone will cause numeruos driveability issues. As it's a $20 part, I'd start there. As far as the 217 code, if there were a current problem with ANY of the coil packs, I'd think you'd know it for sure. I'd start with the ECT sensor, then clear the codes and see what happens.

 

[inverse1216]

thanks rob ill go pick one up tomorrow and change it out, ill let u guys know what happens.

andy

 

[93SHO'nOFF]

--------------------------------------------------------------------------------

If you want to test the ECT sensor use a DVOM to measure resistance and anything that measures coolant temp.Take readings through the sensor pins.

ECT SENSOR VALUES
-------------------------------
Temp. *F ---------------- RESISTANCE (K ohm)
_______________ ________________
248 *F ---------------------- 1.18 K
230 *F ---------------------- 1.55 K
212 *F-----------------------2.07 K
194 *F-----------------------2.80 K
176 *F---------------------- 3.84 K
158 *F---------------------- 5.37 K
140 *F----------------------- 7.70 K
122 *F-----------------------10.97 K
104 *F-----------------------16.15 K
86 *F----------------------- 24.27 K
68*F----------------------- 37.30 K
50 *F----------------------- 58.75 K


Later,
Mike.............
__________________

 

[inverse1216]

hey mike,

i saw that diagram somewhere i think it was on here maybe posted by u but i dont understand how to go bout that is there a write up somewhere for it? also whats a DVOM? thanks for the info.

andy

P.S its 4 in the morning here so i havent gottent the sensor yet so look for a post later today.

 

[SHO_Driver]

Also try driving with the MAF unplugged. See if the rpm drop goes away. Does sound like its ignition related, like a bad coil.

 

[inverse1216]

ok well i went to auto zone today and got the ECT heres a pic of it...

now i cant find where this is supposed to go i didnt find anything in my chiltons manaul where this is located so can someone point that out for me? also is this the right part? i was looking at the engine bay and is it part of the tb? cause the guy at auto zone said its on the driver side intake manifold.

SHO_Driver,

ill disconnect it in the morning and see what happens if its goes away does that mean that i have a bad maf? also im thinking its a bad coil also cause thats one of the codes that came up #3 to be exact, im goign to erase the codes in the morning also and see if that one still comes up.

in short can any one tell me where the ect goes and if i got the right one? thanks again everyone ur help is very much appreciated.

andy

 

[projectSHO89]

That ECT look correct from the given angle.

The ECT mounts to the water outlet assembly. Follow the upper radiator hose back under the throttle body to the thermostat housing. Look about 8 inches rearward (toward the firewall) and you will see the two wire sensor screwed into the water outlet.

Use a 1" deep socket to remove. Be advised that if the sensor is plastic, it may break as you attempt to remove it. In this case, you are screwed until you can figure out how to remove the pieces.

Steve

 

[inverse1216]

ok well i drove with the maf disconnected and still had the surge so guess thats not it. i also put in the new ect sensor and the surge is still there.

so any other ideas guys cause im at a loss here, the only thing next that could be it is the coil pack, it gave me the code that #3 was bad whats involved into replacing that? ive never had a coil pack always distributors so this is new territory for me.

any insight much appreciated. thanks

andy

 

[inverse1216]

anybody have any info on the coil packs? if thats the problem? i really need to get her going again. thanks

andy

 

[SHO_Driver]

There is a way to test the coil pack with a volt meter, I think you could dig it up in a search. Also check to see if its physically cracked.

 

[inverse1216]

i took it to a diagnostic place and had them run a full car diagnostic and its the crank sensor so im goign to replace it and hope that does it. thanks for all the advice and input guys its much appreciated.

andy

 

[inverse1216]

ok guys bad news new CPS is in and no change what so ever. still getting the drop in rpm's. anyone have any clue what else it could be?

i understand that the cam shaft sensor wont show up when i run codes? should i assume that would be the place to start?

would a loose or cracked vacuum line be causing these symptoms?
im going to replace the fuel filter (long shot) and see if that fixes my problem.

ill keep updating the progress.

looking for any advice here thanks

andy

 

[Rockledge]

Surging is not necessarily limited to ignition problems, so you might consider your Idle Air Control valve, it's even related to one of the codes you pulled:

http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=79

Also, have you checked the fuel pressure? When is the last time the fuel filter was changed?

Are you still getting the same codes?

 

[inverse1216]

ok thanks for the link. i read up on the IAB cleaning goign to get some cleaner and give it a shot. the filter isnt to old from my understanding it was changed not to long before i bought the car but im goign to change it anyway.

yeah i cleared the codes and the only codes that came back b4 i changed the CPS was bad connection with CPS and something bout grounding in the fuel pump but from my understanding its nothing to worry bout? those were the only codes that came up and since the change of the CPS no CE light has come on. so its just trial and error from hear on out i guess.