QuestionQUESTION: Roland,
A couple of weeks ago I decided to change the spark plugs and spark plug wires in my 1998 2.5L V6 Cirrus. It had been having trouble starting in the rain, and I thought this might help. Immediately afterwards it started having the same trouble, and slowly became worse. The car began running rough at idle, and under heavy acceleration would not respond very well. After observing the engine running at night, I noticed some flashing coming from behind the intake manifold. I checked the wires again, and sure enough, noticed that the rear wires had been compressed under the intake manifold (my fault for not routing them like the previous ones). Around this time the check engine light came on (after flashing a few times) and my reader gave a P0305 reading. I changed all the wires just as a precaution (and routed them correctly this time), and the problem still persisted. So I switched out the distributor cap that I had on there (which was an older one anyway that came with a distributor I pulled from a junkyard) with the old, cleaned up cap. This didn’t solve the problem, and neither did tightening up the egr pipe connection to the intake manifold (which I had noticed was leaking). A few days later, with the problems of a rough idle, poor acceleration, and missing throughout all speeds still persistent, I took a look again at the running engine at night and still observed flashing behind the intake manifold. This time, the connectors to the distributor were removed, inspected for breaks in the wire, and wrapped in electrical tape. This did not solve the problem.
The car runs fine when cold, it will only show signs of not running correctly when under heavy acceleration. However, once the car comes up to normal operating temperature, the problems become worse the longer the car runs. There is an erratic shuddering at idle (which I assume is cylinder 5 missing), and under acceleration becomes much worse. It will eventually smooth out once the car gets going and the engine is not under a heavy load (like going up a hill), but still feels like it is missing occasionally.
Any suggestions? The arcing that seems to be coming from behind the intake manifold is still occurring, what other wires run back there? Could it be a byproduct of carbon tracing from the previous wires arcing? Thank you in advance for your time and help.
Aleks
ANSWER: Hi Aleks,
I haven't personally looked behind the engine, but in light of the arcing and the fault code it would be a good idea to visualize the arc if you can with a mirror, or if that is not pratical then I would remove the upper intake manifold so you can check things out, and allow you to inspect the plugs for possible replacement. Here is the procedure for doing that:
INTAKE MANIFOLD - UPPER
REMOVAL
Disconnect negative cable from auxiliary jumper terminal Auxiliary Jumper Terminal
Remove bolt holding air inlet resonator to intake manifold Air Inlet Resonator
Loosen throttle body air inlet hose clamp.
Release snaps holding air cleaner housing cover to housing.
Remove air cleaner cover and inlet hoses from engine.
Disconnect connectors from MAP and intake air temperature sensors Intake Manifold Sensors and Left Manifold Support Bolt
Remove manifold support bracket bolt located rearward of MAP sensor Intake Manifold Sensors and Left Manifold Support Bolt
Disconnect TPS and idle air control motor connectors Throttle Position Sensor and Idle Air Control Motor
Disconnect brake booster hose.
Disconnect purge hose from throttle body.
Squeeze retainer tab on throttle cable and slide cable out of bracket Throttle Cable Attachment
Slide speed control cable out of bracket, if equipped Throttle Cable Attachment
Remove EGR tube from intake manifold and discard gasket EGR Tube and Right Manifold Support Bolt
Remove manifold support bracket bolt located rearward of EGR tube EGR Tube and Right Manifold Support Bolt
Remove bolts holding upper intake manifold and remove manifold Intake Manifolds
INSTALLATION
Install new gasket and position upper intake manifold to lower manifold. Install manifold bolts and tighten to 18 N·m (13 ft. lbs.) Intake Manifolds
Install bolts at manifold support brackets. Tighten bolts to 18 N·m (13 ft. lbs.)
Install EGR tube with new gasket to plenum. Tighten EGR tube to intake manifold plenum screws to 11 N·m (95 in. lbs.)
Install throttle and speed control cables.
Connect brake booster hose.
Connect purge hose to throttle body.
Attach electrical connectors to sensors.
Install air cleaner cover and inlet hoses.
Tighten air inlet tube clamps to 3 N·m ±1 (25 in. lbs. ±5)
Install bolt holding air inlet resonator to intake manifold Air Inlet Resonator
Connect negative cable to auxiliary jumper terminal
You might want to lubricate the stem of egr valve with WD-40 and move the stem back and forth via the slot in the stem using the tip of a screwdriver. If that valve sticks ajar it can cause rought running and poor acceleration.
Roland
---------- FOLLOW-UP ----------
QUESTION: Roland,
I did not consider the EGR valve itself, as it is only about a year old. I will try that today though. Last night, my dad and I wrapped some parts near where we were noticing the flashing in aluminum foil (if it was around the right part, we could isolate and see the arcing more easily) and seem to have narrowed it down to the spark plug wire. After connecting a metal tool to the wire and isolating the wire with a rubber pad from other components, we still saw flashing and definite sparking when grounded to part of the engine. When running you can see light flashing through the wire, in time with the engine. My dad and I ended up pulling the upper intake manifold off, along with the distributor cap, plug #5, and wire #5. Resistance through wire #5 was approximately 6300 ohms (I believe the manual put this within the acceptable range, as the wire’s about a foot long), plug #5 looked fine from the outside, and there were no cracks, carbon traces, or broken points between the contact points and external ports on the distributor cap. I know the normal response would be that the wire is bad, but after changing the first set I put in (because of my careless routing) with another new set, it seems highly improbable that there’s another bad wire in the same exact place. I still haven’t ruled it out completely though. One thing that I was thinking is: could the spark plug have an internal break that is causing a voltage buildup in the wire, causing it to arc? As I said before, the problem is barely noticeable when the engine is cold, but steadily grows worse as the engine reaches normal operating temperature (and above, when moving slowly or idling). If a break in the spark plug grew worse with temperature increase, is this a possibility? I know this may not be a problem specific to Chrysler vehicles, but do you have any other suggestions? Thank you.
AnswerHi Alexs,
Thanks for the update. It appears that you do have an arcing problem rather than an egr problem based upon the observations and the egr being so new.
It is the case that the energy stored in the secondary winding of the coil is going to choose the short pathway (lowest resistance) to ground: That would be the spark plug gap if everything is right, or if the plug for some reason had a disconnect to the center electrode it might arc across the insulation of the wire (particularly if the insulation were damaged) or if a crack in its insulator it will short to the wall of the cylinder head nearby, etc. So if you have any suspicion about the wires having been overheated when not properly installed or that the plug is defective then I would change out one or both of those items.
Roland
