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Car starts and then just barely idles

K

KTM300

New member
I just bought a 2006 3.8 NA model a few weeks ago. Car ran great until a couple days it wouldn't start. It cranked over good but wouldn't start. After messing with it I found if I pump the gas petal a little bit it will normally start. Once it starts though it goes into a really low, rough idle and won't rev up at all no matter what you do with the gas petal. While it is trying to run the DIC says "service ABS system" and "service traction system." It isn't throwing any codes. We already replaced the fuel pump, but that didn't help at all. Any ideas?
 


Re: Car starts and then just barely idls.

Another thing is, the car only responds to the key and actually tries to start about 10-20% of the time you turn it. The rest of the time it doesn't even try to crank.
 
could be as simple as a dirty throttle body.


how many miles? if near or past 100,000 its due for a tune up.

check the ground cables too, (on the bell housing bolt rad side of engine) theres a few extra grounds there other then the neg battery cable, one of them maybe falling off its eyelet.

the abs lights has nothing to do with how its running.
 
Re: Car starts and then just barely idls.

KTM300 said:
Another thing is, the car only responds to the key and actually tries to start about 10-20% of the time you turn it. The rest of the time it doesn't even try to crank.
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with this info now, check the battery cables to the battery. they maybe dirty or loose.
 
Thanks for the quick reply. The car has 192,000 miles. I read about grounds being a problem, so we already took the negative battery cable loose from the body and cleaned and reattached it. I'll check the ones that you mentioned.
 
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Re: Car starts and then just barely idls.

ScottyDoggs said:
with this info now, check the battery cables to the battery. they maybe dirty or loose.
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Already done. The negative cable was loose and wouldn't tighten up, so we put a new end on it. The previous owner cut off the factory ends and put on the kind that just clamp on the wires. I know that they aren't the best and wish it had the factory clamps. Everything seems good, clean, and tight now.
 


ScottyDoggs said:
so your back up and running now?


you 04 up guys got a goofy ground set up, the battery clamp is crap.
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No, it is still won't do anything but barely idle. I found the four ground wires running to bolt on the bell housing. I pulled on them and they all seem to still be attached good. I pulled the throttle body off, but have to get the cleaner to clean it.
 
is the back side of the TB caked with carbon? if it is and its cranking with every try now that should fix you up.

unless its just really over due for a tune up. that will make it run like crap too.

worst case would be a clogged up cat. some times you feel the car loosing power over time, then one day its a gutless pig.
 
ScottyDoggs said:
is the back side of the TB caked with carbon? if it is and its cranking with every try now that should fix you up.

unless its just really over due for a tune up. that will make it run like crap too.

worst case would be a clogged up cat. some times you feel the car loosing power over time, then one day its a gutless pig.
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The car still doesn't crank everytime I hit the key. It took like 6 turns of the key to get it to even try to start this time. When it doesn't crank it makes a clicking noise from the area of the interior fuse box.

The backside of the TB was caked with carbon. I left the battery disconnected while I cleaned it to see if that would reset anything. Put it all back together and it didn't help at all. Couldn't even get it to stay running this time. It would fire and try to run for a split second, but die.

The previous owner was having alternator problems and took it to the local shop. Since he was selling the car they did the cheap fix of running a hot wire from the interior fuse box to the alternator to excite it. I have included a pic.

He had one of the AutoChipsDirect Powerbox chips on the car. It was connected with scotchloks to the MAF sensor wires. I disconnected it and wrapped up the wires with electrical tape. He also jerry-rigged a Spectre air filter onto the car.

All of this was done when I bought the car and it ran fine, so I assume it is unrelated, but thought that I would throw it out there.




 
lets try hitting the starter next time it wont crank. no crank, hit it with a hammer in the fat body of the starter. then see if it will crank.

or have someone hold the key to start while you hit the starter.

you can also test for power on the small wire on the starter when the key is to crank, if it powers up when the key is turned the starter is bad for sure.
 


Did you try unplugging the mas airflow sensor? I had similar issues in my 01, it would start, idle REALLY rough, then die. Happened out of no where in the middle of winter. Car didn't have any issues until it just wouldn't start, unplug the sensor and see if it will start and run. Did the trick for me.
 
I just had this issue where I walked out and the car started, but it loped like it had a huge cam, it was a vacuull T at the MAP sensor that cracked. Check the vacuul line where it exits the LIM and T's back to the MAP and then where it runs around front to the bypass valve and the actuator.

Get rid of that crap around the alternator. The previous owner probably thought he had a problem but the voltage on 04+ will fluctuate between 12.5 and 15.1 and it is normal. Make sure that the current sensor is still around the negative ground cables that go to the battery.


Jeff
 
did the 04+ have the ignition switch issues that the 97-03 had? where all the high current is routed thru the switch? BackInBlack made up a diagram for bypassing the high current to a relay to save the switch contacts.
 
I don't think so it's an automated start like a push button. If you blip the start position the starter will continue to start the car. Just like a remote start would start the car. There is a starter relay on the relay box next to the battery I have noticed some of the relays have brown spots on them and just changed them and kept as spares for now, Didn't even pay attention to if it was from the coil or the contacts. But if Scotty's checks are looked at it will tell us a lot more.

Jeff
 


^^^DBW issues lol my 03 gmc did the same thing, flick the key to crank and it keeps cranking till it fires up, theres no stopping it, like say if the battery's dying, it will engage till its dead.
 
Tested the starter by hitting it...it took three tries of turning the key and hitting the starter before the car tried to start. I then tested it with a multimeter and the starter is not getting juice when the car doesn't crank.

I have already tried unplugging the MAF sensor. After about ten tries today the car finally started and again would barely idle. While the car was running I unplugged the MAF sensor and it didn't make any difference. Should it throw a code with the MAF disconnected?

Is the MAP sensor the one on the end of intake manifold? If so, I couldn't find any vacuum lines running to it. I did try spraying starting fluid around it while it was running to see if I had vacuum leak around it, but there was no change.

While the car is chugging along, barely idling the gas pedal seems to have no affect. Pumping the pedal doesn't do anything and holding it wide open doesn't do anything.
 
Unless it displayed what I have previously stated then no. Look at the relay/fuse block under the hood next to the battery there is a relay in there for the starter. Switch it with one of the others of the same size for I believe the AC relay is the same size. It's one of the larger ISO size relays.

Jeff
 
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