hard start when cold

[pete315]

I just got done cleaning nostrils on car and got rid of codes on moms 93 ATX. it's hard starting when it sits overnight and is cold. it cranks and starts then dies right away. after a couple attempts, then we get it running. when warm, it starts right up. I'm leaving car at my house tonight and will see what happens in morning. I'll check for new codes. what would cause hard starting when engine is cold? is there a sensor acting up?

 

[NotSoSlowSHO]

If you press the gas pedal a bit while cranking, does it fire right up?

 

[pete315]

I'm not sure. Mom says she has to crank her a couple of times before she gets it started. I just did a code check onit. I got while off- 124 and 212. while running, I got- 412,167, and 225. any ideas?

 

[NotSoSlowSHO]

Here is a break-down of those codes:

124 - Throttle position voltage was higher than expected

167 - 167 No Throttle Position sensor change in "goose" test (must get at least 25% rotation)

212 - Ignition TACH signal was erratic (module/wiring) or SPOUT circuit fault

225 - Knock sensor not tested (ignore if not pinging)

412 - Idle speed system not controlling idle properly (generally idle too low)

Seems to me that the car could use a new TPS sensor.

And as I suspected earlier, the idle air bypass valve may be failing.

A failing idle air bypass valve commonly sticks closed when cold, and works okay when warm. This causes cold start problems as you described. Holding the throttle open just a touch when cranking allows enough air in the motor to fire.

A failing TPS can also cause similar problems. Motor will fire, but cannot sustain idle.


I would replace the TPS (throttle position sensor) and clean or replace the idle air bypass valve. Both are inexpensive items, and easy to swap out.

 

[pete315]

the car starts up if I hold pedal slightly down. if I let go of pedal,the car will stall. the car ran for about a minute or 2 and now will idle fine. I remove idle air bypass valve. I sprayed cleaner in it, reinstalled- same problem. I went to my parts store and they have to order it, will not be in until 4 pm. cost $70. TPS cost about $25. I read another post that said while the car is running at an idle and you disconnect the idle air bypass valve( is this also called IAC?), the car should stall. I unplugged mine at idle and the car continued to idle fine. I even unplugged the TPS and the car idle did not change. do you think I should change both sensors? I don't have a volt meter so I'm not sure about adjusting the TPS. is there a procedure to follow if I install both sensors so the computer will relearn the idle. thanks for the help. Mom thanks you also.

 

[NotSoSlowSHO]

If it continued to idle even with the idle air bypass valve unplugged, then the IAB valve is due for replacement. At this point, I would replace both the TPS and the IAB valve.

There is no real "adjustment" for the TPS. Just install it.

 

[pete315]

changed the TPS and idle air bypass valve. took 10 minutes to change. $98. problem gone. starts up right away when cold. nice smooth idle.

 

[NotSoSlowSHO]

Great!

Glad things are smoothed out!