Wrong forum
- Thread starter congo714
- Start date
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DadOSix
Full Access Member
Congo -
you need to break this down a bit.
trying to read into your story - you changed plugs and coils. Truck did or did not run before ? not specified but Now, definitely no start.
since the engine cranks, spray a bit of brake clean into the throat of the throttle body and crank again - Fire up but dies down? No fuel. Crank, but no change, no spark.
If crank, no spark, did something happen to set the security module into theft mode? If is sets, no spark, no fuel.
Signal wires would be +12v, +5v PCM, PCM ground, Ground. A light is not going to tell all.
I'd plug the PCM back in until you can help us with enough detail to follow what led to all this and where we are now.
you need to break this down a bit.
trying to read into your story - you changed plugs and coils. Truck did or did not run before ? not specified but Now, definitely no start.
since the engine cranks, spray a bit of brake clean into the throat of the throttle body and crank again - Fire up but dies down? No fuel. Crank, but no change, no spark.
If crank, no spark, did something happen to set the security module into theft mode? If is sets, no spark, no fuel.
Signal wires would be +12v, +5v PCM, PCM ground, Ground. A light is not going to tell all.
I'd plug the PCM back in until you can help us with enough detail to follow what led to all this and where we are now.
Thank you for replyin Dad0Six.
Yes. It did run before. Not very well, but it ran. Went and bought a code reader. It threw out like seventeen codes. Wrote them all down, defined all of em. Tried my best ta fix as many as i could.
Replaced the cam, crank, TPS, idle air, intake air temp, MAP and the engine coolant temp. sensors. Cleared seventeen of em.
Started, still ran like crap.
But it ran. Still roughest idle ever. Wouldn't rev above 2200 rpm. Had so little power it wouldn't even pull up my driveway.
Idle, rpm's and no power is really what started ALL of this. So next i replaced plugs,(NGK ZFR6F's) They came pre gapped but i checked the gap ta make sure. Six new coils. Thats when the no start came about.
It always fired right up. I could just reach in and bump the switch.
So i downloaded the '05 service manual. Found the voltage specifications for the connectors and the ohm spects for the injectors and coils
The ohms readins were all good. Had control voltage ( 12 V. )on all, but no signal voltage on any. The three i have left are P0113, intake air high input. P0107, MAP low input. P0123, TPS high input.
I'm pretty sure my liberty doesnt have a security system. My key only has lock, unlock and back glass. I couldn't find anything in the owners manual about it.
Tried startin fluid ( didn't know bout break cleaner) and yes it tried ta start but no dice.
When checkin voltage from the PCM wire do i need ta ground it to the PCM grnd. or can i grnd. it to a block grnd.? Checked PCM grnd. and on the connectors that have a grnd. and i had continuity.
I noticed in the service manual that all the previously mentioned sensors are on the same block of pins that the coils and injectors are on. It's not givin me any codes pertainin ta the coils or injectors or the PCM.
Ok, I believe that's bout it. Sorry bout first post. Not very articulant. Thank yall for stayin with me. Open for questions. Ill try ta help as much as i can. Contact may be sparce ( at work) i'll read when i can. Thank yall again
DadOSix
Full Access Member
Much better now!
I admit to being a bit stumped at this point. Q: on the coil packs you used - what brand?
You will find on these jeeps, that they are very picky about sensors and the like. For coils, OEM or Standard Motor Products are preferred. Any chance you still have the old coil packs to swap back in and see if you can get a running jeep?
Cam, Crank, TPS, all would be preferred Mopar, except in case of emergency to get home.
Thinking about your coils tho - What is the chance that you displaced a pin or 6 when putting the connectors back on? Another thought - on these 3.7, there are ground straps from a single point on the firewall to each head. Braided aluminum corrodes, but looks good. A favorite old trick is to run a jumper cable from Batt Neg to a point on the block or head. Try to start - Yes ? You got a bad ground somewhere.
Re the theft mess - there is a red light on the dash. Just a little red ball. If it is on, the jeep is in theft mode. Isn’t going to run until it is solved. Most of these had some theft deterrent from 04 up. My 06 has a tombstone head key, the 04 has a black key and a grey key.
The starting fluid tells you that the ignition side is working and points to a fuel problem.
When you go key on, do you hear the fuel pump run a few seconds? Do you have access to a fuel pressure gage to put on the fitting on the rail?
Again - very odd that the coil packs killed it. GOtta be something simple, but you changed so much at one point, it is not clear where we are broken down. BTW - new parts can be bad out of the box.
Let’s keep digging at this!
I admit to being a bit stumped at this point. Q: on the coil packs you used - what brand?
You will find on these jeeps, that they are very picky about sensors and the like. For coils, OEM or Standard Motor Products are preferred. Any chance you still have the old coil packs to swap back in and see if you can get a running jeep?
Cam, Crank, TPS, all would be preferred Mopar, except in case of emergency to get home.
Thinking about your coils tho - What is the chance that you displaced a pin or 6 when putting the connectors back on? Another thought - on these 3.7, there are ground straps from a single point on the firewall to each head. Braided aluminum corrodes, but looks good. A favorite old trick is to run a jumper cable from Batt Neg to a point on the block or head. Try to start - Yes ? You got a bad ground somewhere.
Re the theft mess - there is a red light on the dash. Just a little red ball. If it is on, the jeep is in theft mode. Isn’t going to run until it is solved. Most of these had some theft deterrent from 04 up. My 06 has a tombstone head key, the 04 has a black key and a grey key.
The starting fluid tells you that the ignition side is working and points to a fuel problem.
When you go key on, do you hear the fuel pump run a few seconds? Do you have access to a fuel pressure gage to put on the fitting on the rail?
Again - very odd that the coil packs killed it. GOtta be something simple, but you changed so much at one point, it is not clear where we are broken down. BTW - new parts can be bad out of the box.
Let’s keep digging at this!
Duralast. ( what i could afford)
I didn't know bout their pickyness. Yes i still have the old ones. Didn't think bout reswappin them.
Unplugged all the connectors ta check the pins and they were all nice and straight. Checked braided on drivers side but not passangers. Will do when I swap coils.
In all of my years in this jeep, i've never seen a red light on the dash. Like i said i couldn't find anything on theft deturant in my manual. I will definitely go thru the entire index in the back though. Or maybe even the service manual i downloaded ( there's like 6000 pages in that thing). Sorry, thinkin out loud.
I have a guage with the hose, but i don't have the fittin to connect it to the rail. ( Like a big valve stem. As you know ). Advance, autozone even harbour freight, no one seemt ta know what i'm talkin bout either by tellin em what it is ta even tryin ta describe it to them. The only way i can describe it is like a big fat valve stem.
And yes sir i'm totally aware of " new products outta the box".
Im down withdiggin at it. As soon as I get home this afternoon i'll do the coil swap, jumper from battry to da block and check braided ground on passenger side.
Thank you man, i really do appreciate it. I get done with swap and stuff will post results.
Thanx
