Coil specs

[RCJP]

Hi to all

My jeep is 98 GC Laredo 4x4 L6 4.0 motor.

recently it has been turning off when ever it wants to and I get the P0351 error code (Low curent in Coil primary circuit ) I checked the wiring for coil to ASD relay and to the PCM and both are OK,

yesterday i checked the primary resistance and a value of 1.8Ohms saw the spec and the max is 1.2Ohm to me 0.6Ohms difference is very little but the sheets does say to replace it?

so ineed sujestions shoul I spend money on a new coil?. if not what else can I check.
Thank you

see pics of the meas that I took.

 

[SteelHeadz]

Since the coil circuit high side driver is controlled by the PCM and the low side is switched by the ASD to the PDC, and the diagnostic test you performed indicates a faulty coil unit, i would replace the coil rather than assume that it's the PCM. Re- check the harness from the PCM to the coil for chafing. The primary resistance at 70-80*F is 0.71-0.88 ohms.
Edit: Your resistance values are out of the specified limits.

 

[RCJP]

Hi I changed the coil but I still have the same problem.

Every time the gas gage was at 1/2 full it started acting up i filled up and the problem goes a away. so i tought it was the level sending unit so i went to fill it up and was full the point that when i parked gas started spilling out untill the level got down a little the spilling stoped.
any way today i have more than 3/4 of fuel. and it happedn again it stalled while i was driving.

does this mean i need anew fuel pump??

 

[Bounty__Hunter]

Every time the gas gage was at 1/2 full it started acting up i filled up and the problem goes a away.

I had a similar problem and it was a hole in the rubber line INSIDE the fuel tank between the fuel pump and the top of the sending unit.

 

[RCJP]

thank you B_Hunter I will check on that before i spend the 121dlls for the reapair kit.

 

[RCJP]

Hi

yesterday i took a part the fuel pump, did not find any significant damage on it my does not have a ruber line from the pump to the sending unit is a metal tube and the sendi unit has hard plastic one that goen into the one from the pump.

I connected the 12V to the pump worked as normal.

and this morning on my way to work, i got in to traffic so i was going a little slow and at low RMP 1500 aprox. and then the RPMs went to zero
so i put it in neutral and step onthe gas and ws able to keep it from turning off, it happend 2 times,
HELP!!

 

[RCJP]

Today my drive belt started it screaching, and the car would not stay running for more tha a couple of seconds, I spent aobut 30 min until the car kept running drove it to work no problems on the way here.

but i did check for the codes and i got a new one P0320, i found to different descriptions

NO CRANK REFERENCE
&
Ignition/Distributor Engine Speed Input Circuit Malfunction

wich one is correct??
:???:

 

[SteelHeadz]

P0320 is no crank reference to the PCM. Check your pulleys for failed bearings first. If any of the pulleys seizes up while the engine is operating at its normal output then the CKP will detect a wide difference on the actual RPM before and after and will throw that DTC.

 

[RCJP]

OK problems continue.

:x:x

I cleared the error code, the car turns off. I can still hear the fuel pump buzzing after for a little while, checked fuel line fuel is present. after a while of cracnking and nothing. i start it rocking the car very violently, that mede it wok... well turn on. so i could get to where i was going. did not bother me againd the rest of the day.

Today had the same problem and I did the same thing, and it worked again.

the pattern that i'm starting to see is that if the car is off for a long while, i will have this problem and for what ever reason making the car roc from side to side for a lttle while makes it work and not bother me for the rest of the day ....

Also took apart the fuel pump... again. found this (sse pic

i'm begingi to give up I have also taking it to a couple of shops and they can find anything or it never acts up. HELP!!

 

[SteelHeadz]

Could it be possible that the problem could be in the electrical system?.. Rocking the vehicle does very little on a mechanical issue (in my opinion) but a minute vibration on a car can make a world of a difference on a bad connection within an electrical sytem. This is just a thoery. You can verify this by checking for spark when the no start occurs. My guess would be in the wiring on the CKP or possibly the wiring on the O2 sensor. Look for chafing or a short to ground.

 

[RCJP]

Hi just saw your repli will check for that after work.. had to ride the bus today,
so ithink its oficial that it will not work in the morning and after a couple of re-re-retries,

So my question what sensor would need to be warmed up ?

also I keep getting the p0351 error code

 

[pelican]

it could be an ignition module problem or similar computer contol iggnition circuit

this would be a problem when cold and again when hot

 

[SteelHeadz]

Hi just saw your repli will check for that after work.. had to ride the bus today,
so ithink its oficial that it will not work in the morning and after a couple of re-re-retries,

So my question what sensor would need to be warmed up ?

also I keep getting the p0351 error code

So back to square one, P0351-Ignition coil #1 primary circuit..As a rule, if a diagnostic trouble code is present, proceed with the repairs on the dtc prior to repairing other problems. At this point, i'm thinking on this DTC, is a wiring issue..

 

[RCJP]

Hi
thanks for the replys

So i think i'm going to take apart the PDC to check for the wires that go to the ASD,. ...still ridding the bus:-|...

any other places i should take a look at?
... also have checked the CKP conections look ok I actually pluged a SCOPE in to the harnes that goes the PCM and was able to see the 3 sets of 4pulses from the CKP.

 

[RCJP]

Hi
yesterday i checked for more wiring issues could not find any thing yet i turned it on and it ran fine all day. so today i deciede to drive in to work.

and it shut off on me on the way about 3 times. but now i got another code.

P1282 Fuel Pump Relay Control Circuit.

and also P0351 still present.

in the discription i get "An open or shorted condition detected".

the electrical diagrams say that the relay is directly connected to PCM.
so I. guessing a wiring issue also
correct?

 

[SteelHeadz]

Yes, i would check that first.. Also the wirings to the PDC area.

 

[RCJP]

Yes, i would check that first.. Also the wirings to the PDC area.

Hi Headz,

checked all the wiring. probed from sensors to the PCM connectors. found no fault.

took apart the PDC also nothing today I pluged a SCOPE to see if got a CAM CRANKSHAFT signals and yes they are present(5V pulses). also shecked the signal that goes to the COIL i saw a 12V pulse. checked the fuel its present.
ohms values of the coolant and intake air temperature sensors. both were about
9kOhm in the afternoon (car had not been on for a week.)

also checked the TPS got a meas of 5.2kOhm and it does very when the throttle was moved.

MAP sensor with the SW in the ON position got 5V output and the one time that the car turned on i got 1.2V output. i was not able to make the car start any more.

P.S. i think we need a new name for this tread
thank you for the help.

 

[RCJP]

Hi again

So today was a good day, called a friend that knows more about cars then me.
he found that a couple of points on the distributor cap had so much sut that there was actually no continuity to the upper part were the wire is connected. so i got out my old cap, cleaned it up, and put it on and we were able to make it run with the first try. and another thing we found was that it a certain throttle position very close to fully closed (less the 1k rpm) the car will turn off or the rpm will very low close to the 0 mark on the gage,

well tomorrow i will continue to verify the changes on the road.