Mudderoy
01-25-2012, 08:24 PM
I received a text message this afternoon from my recently started driving daughter. She said the Jeep wouldn't start and Mom was taking her to work.
I asked her several questions and here are the symptoms.
1. Won't start but seems to want to.
2. Started and ran fine this morning (going to school)
3. Started and ran fine this afternoon (coming home from school)
4. A few hours later when she was going to work, wouldn't start.
My wife not knowing that you aren't supposed to mess with the throttle when starting a fuel injected vehicle tried the old school method of pumping the gas while starting. She said it seemed to want to start more when she did that but still wouldn't start.
From work I spoke with her and told her how you are supposed to let the computer handle all that and maybe she flooded it when she was pumping the throttle before. I asked if she wanted to go try starting it. She agreed.
Now with her foot off the gas pedal she started the engine, and moved it up the driveway a bit.
She turned it off, tried starting it again, and it wouldn't start!
After I got home from work I tried starting it, started fine. I ran it for a few seconds and killed it. I tried starting it again. It wouldn't start.
Battery was strong, everything appeared to be fine, just wouldn't start. You could her it try every so often, but not enough that would even give you the slightest hope. ;)
This was really strange.
I started checking connections, first visually then by taking them off and putting them back on the sensors.
CKS, CPS, TPS, IAC, MAT. I tried starting with the CKS off and it wouldn't even try, as expected. The reconnected it and disconnect the CPS, and again, wouldn't even try to start. So it seemed that signals were getting from these two position sensors to the ECM.
I checked a few other things, like fuel pressure, fine, the throttle body butterfly was opening and closing with the throttle.
So then I wondered if the ECM was moving the butterfly via the TPS during start. Hard to check when you are the one starting so I thought I could act as a TPS and press on the gas pedal a little during start, vrooom it started.
I let off the gas and it died. I tried again, it started...
Hmmm bad TPS? I've never had one fail like this before. I took the throttle body off, CLEANED IT THE HELL UP! Boy was it dirty inside. Then grabbed an after market TPS that I had on my 1998 until recently when I replaced it with a real Chrysler part.
Put the throttle body back on, hooked up all the sensors, and started it. Started fine and runs smooth.
I know I should disconnect the batter to clear the computer, but this is eating into my nap time.
My youngest daughter and I started and stopped about 10 times, worked each and every time.
Dunno, but my oldest daughter certainly got lucky that it worked fine until she got home and parked in the driveway! lol
I asked her several questions and here are the symptoms.
1. Won't start but seems to want to.
2. Started and ran fine this morning (going to school)
3. Started and ran fine this afternoon (coming home from school)
4. A few hours later when she was going to work, wouldn't start.
My wife not knowing that you aren't supposed to mess with the throttle when starting a fuel injected vehicle tried the old school method of pumping the gas while starting. She said it seemed to want to start more when she did that but still wouldn't start.
From work I spoke with her and told her how you are supposed to let the computer handle all that and maybe she flooded it when she was pumping the throttle before. I asked if she wanted to go try starting it. She agreed.
Now with her foot off the gas pedal she started the engine, and moved it up the driveway a bit.
She turned it off, tried starting it again, and it wouldn't start!
After I got home from work I tried starting it, started fine. I ran it for a few seconds and killed it. I tried starting it again. It wouldn't start.
Battery was strong, everything appeared to be fine, just wouldn't start. You could her it try every so often, but not enough that would even give you the slightest hope. ;)
This was really strange.
I started checking connections, first visually then by taking them off and putting them back on the sensors.
CKS, CPS, TPS, IAC, MAT. I tried starting with the CKS off and it wouldn't even try, as expected. The reconnected it and disconnect the CPS, and again, wouldn't even try to start. So it seemed that signals were getting from these two position sensors to the ECM.
I checked a few other things, like fuel pressure, fine, the throttle body butterfly was opening and closing with the throttle.
So then I wondered if the ECM was moving the butterfly via the TPS during start. Hard to check when you are the one starting so I thought I could act as a TPS and press on the gas pedal a little during start, vrooom it started.
I let off the gas and it died. I tried again, it started...
Hmmm bad TPS? I've never had one fail like this before. I took the throttle body off, CLEANED IT THE HELL UP! Boy was it dirty inside. Then grabbed an after market TPS that I had on my 1998 until recently when I replaced it with a real Chrysler part.
Put the throttle body back on, hooked up all the sensors, and started it. Started fine and runs smooth.
I know I should disconnect the batter to clear the computer, but this is eating into my nap time.
My youngest daughter and I started and stopped about 10 times, worked each and every time.
Dunno, but my oldest daughter certainly got lucky that it worked fine until she got home and parked in the driveway! lol