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Engine symbol blinks during acceleration

3K views 18 replies 3 participants last post by  chuzz 
#1 ·
I mentioned this in my other thread started on behalf of our wonderful '96 GC! Anyway, I'll get it all fixed up soon.

While it's been laid up and I've been driving my wife's '02 Caravan Sport (3.3L), it developed a miss. I pulled plug wires and found #1 cylinder dead. I pulled the plug and it had something blocking the spark gap so I cleaned & re-installed. No help.

I put in a new set of plugs and checked all the wires with an ohm meter. I cleared all the codes I generated by pulling wires and went for a road test. When the engine is loaded, such as heavy acceleration or a bridge/hill, the check engine symbol blinks. While on level ground and holding your speed, it's off. I've only went about 2-3 miles with it doing this.

Have any of you had this happen before? Maybe I need to drive it farther and see if it codes up. At this point, I'm thinking an injector problem. An electrical/sensor fault should code up pretty quickly and this doesn't.
 
Discussion starter · #4 ·
Crown & Chuzz, thanks for the guidance. All plug wires looked good and while the ohm meter was attached I bent & twisted in hopes of shaking out an intermittent break. No P0301 or any other faults except for the ones I set while pulling plug wires. I cleared those and no codes have surfaced since. Maybe I need to run it til it "codes up".
 
Discussion starter · #6 ·
If it is in one cylinder (P0301 through P0306), that makes it easier to find.
When I pulled plug wires one at a time, it was #1 that didn't change anything. That's also the plug that was fouled and discolored compared to the others. It was brownish on the electrode porcelain where as all the others were pretty white & clean.
 
Discussion starter · #11 ·
Fuel fouled as in a black carbon tip? That could be too much fuel.
Try a compression test?
A compression test can show if an injector is stuck open? Cool. I got a compression gauge and I can do that.
 
Discussion starter · #13 ·
No. but a compression test will show the general mechanical condition of the valves, etc to rule that scenario out.
Fuel injector testing may be easiest by swapping with an adjacent cylinder as stated in post #2.
That makes sense of course, but if the intake has to come off to get the injectors out, I'll just replace it.
 
Discussion starter · #14 ·
Ok, new plugs and wires. While idling out of our park it coded up and stayed. P0301 (cyl #1 misfire). Is an injector the primary suspect or that ignition module thing that takes the place of a distributor cap?

A compression test indicates no valve or piston problem.
 
Discussion starter · #15 ·
I took a shot and replaced the #1 injector but miss is still there. After having bad dreams about this thing, I started to second guess if I was dealing with the proper cylinder. I went outside between rains a minute ago and began pulling plug wires again. The #1 cylinder is definitely the dead one. I noticed that when pulling the wires for #3 and #5, when I put them back onto the module, I could see the spark fly when I got the wire close. #1 terminal doesn't do that so ...... module time, right? $52.99 at AAP.
 
Discussion starter · #17 ·
The #1 spark has to be going somewhere because it is getting to the companion spark plug, maybe to ground from a leaky #1 plug wire insulation or leaky #1 coil tower insulation?
It would be good if you could prove something like this before buying a coil pack.
I already got it but haven't installed it yet. Plugs and wires are all new. What else can I do?
 
Discussion starter · #18 ·
I replaced the coil pack this morning and the miss is gone.
 
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