Unstable idle, speed needle pinging, car won't start
 

Hi all,



I've been reading through the threads and found some common issues (Rough idle while driving, car dying at a slow stop) that were discussed. unfortunately, all threads seemed to have the cars starting up fine. My tib doesn't start at all. Car is a 1997 Tib, 2.0, Autotragic tranny.



these things were done prior to all the trouble:

1) replaced my grounding kit. basically took out the old one and installed a new one. Car wouldn't start after installation.

2) Wiggled wires and looked at sensors and the car started up fine.

3) Car drove for a few blocks then stalled and died while on slow stop approaching a stop light.

4) Car starts fine after a few cranks and i was able to drive it to a backyard mechanic's place.

5) Mechanic adjusts throttle cable and again wiggles and checks sensors and wires.



Car now runs better than the first run but then i encounter the symptoms below:



1) was running at around 2.5K RPM then the RPM just suddenly dips to around 1kRPM or lower. didn't kill the tib though.

2) Car stalled while braking slowly as i was approaching a stop light.

3) Car dies coz i was again braking slowly to take a turn.



After point 3, i had to be towed to a gas station coz the tib wouldn't start at all.



I then tried to turn the car on at the gas station. new wonky symptoms occur:

1) I turn the car to "on" (without turning it all the way for the car to start) and the RPM and the Speedometer needle jumps all over the place. it stops after around 3 seconds and both needles settle at 0.

2) I attempt to start the car. the car cranks but just wouldn't start.



I had to get towed back to the shop this morning to have it looked at. the symptoms above are still present minus the speedometer needle going crazy. i was thinking that something must have been shaken into position during the flatbed ride to the shop. now only the RPM needle goes crazy but the car still wouldn't start.



so all in all, it pretty sounds much like the TPS problem. Except i couldn't figure out why the car wouldn't start and why the needles go crazy prior to the car attempting to start.



I also couldn't get the car scanned coz the previous owner of the tib somehow broke the OBD port.



Any thoughts? sorry for the lengthy wall of text. i just wanted to get as much detail in as i can.



Thanks in advance!

Is the car turning over but just not firing up? After trying to start the car for like 30sec or longer go under the hood and pull a spark plug and see if it has fuel on it or smells strongly of fuel. If it does then your fuel system should be ok and you might want to check for spark going to your plugs. If they all seem to be ok then you could have a bad crankshaft position sensor. Im not sure if a bad camshaft position sensor would cause your car not to fire or not but that could cause tach issues. I doubt your problem is the TPS, but that is easy to test with an ohm meter. If all those check out ok then I would have the ECU checked especially since your obd port is jacked up.



HTH

Hi man, thanks for the reply.. i've already replaced my crankshaft position sensor last year so i doubt if there's an issue with it but it still can be a possibility.. how do you check the tps and crankshaft position sensor via an ohm meter?



One additional detail btw, 1 spark plug isn't firing. Can this be caused by a faulty cps? And does a faulty cps cause the rpm and the speed needles to dance around? How do you check an ecu without a scanner or port?

Find a junk car and replace the OBD port. It should be pretty simple. That would be the first thing to do or else you will have no clear idea.



I would go to the junk yard but stuff piling up just keeps preventing me from being able to go.

If you have a plug not firing then you probably have a faulty spark plug cable or you have a failing ignition coil.



Log into hmaservice.com and look under the Engine Electrical System section for your model car and go under the Ignition System section for instructions on how to check your coil packs and wires with an ohm meter.



Under the Fuel System section go into MFI Control System and you should see the CPS and TPS with info on how to test them.

ok so i just got off HMAService and read a bunch of stuff. thanks for the tips!



seems to me that the probable suspects would be the CPK and the TPS. i also saw the IACV documentation and was wondering if this could also be a cause. would an IACV cause the car to have the symptoms above?



I'll figure out the non-firing spark plug tomorrow.



lastly, what could cause the "pinging" odometer and RPM needle?

The cam and crank sensors are magnetic proximity sensors and will put out a pulse, You can read this pulse with a meter set on AC.

crank sensor $25 ebay link



i had same identical problem u have. occasionally my car would start but go through the symptoms again by the time i would take off. swaped the crank around with a spare and it started. i believe the cam and crank sensors are the same, just at different angles. so just try swapping them to see if it will start. i think it will start without a cam signal, but not without a crank.





Edit: note when i was driving it acted almost like it ran out of gas, but was still half full. upon inspection i had no fire

car would start without the cam sensor. i had an "accident" with the screw holding the cam sensor in place hehe.



anyway, cpk sensor is only a few months old and i doubt if it's causing the problems. i'll still keep this possibility in mind though.



anyway, now looking at igniter as sensors and ignitioin coils seems to be in good shape but i haven't tried replacing anything with a spare yet.. i'm hoping that the tib would run by the end of the week.

Iirc if your primary ignition circuit is having problems, (before the coils), that will translate into a jumpy tacho.





However, I'd definitely put your old grounding kit back in place! If it is allowing too much current to flow, or if it has a dodgy contact, that could be putting out your sensor data. You may as well change it back just to rule out the extra variable.