Hello everyone. I have purchased a 2002 Caravan with a 3.3 for my wife and all was well until it started to buck...The bucking started when I would ascend up a steep grade. It got so bad I didn't think I was going to make it to the top.

So I did a code check via odometer and came up with, 1684, 0135, 1391 and 1494. Did some research on the meaning of these codes and found;

1684-battery loss in the last 50 starts

0135-1/1 O2 sensor heater failure

1391-Intermittent loss of CMP or CKP

1494-Leak detection pump sw or mechanical fault

So after researching in here, I went to a friend who has the latest Actron CP9580 and he came up with 6 codes.

P0135, 1391, 1494 and 3 new codes.

0301, 0304 and 0300. So I tackled the 0135 first as there was mention that faulty O2 sensor could cause misfire. Changed sensor to no avail.

Now the 0300 codes lead me to changing out the plugs and wires to still no avail. Did another scan and now the only error coming up is NO DTC definition found. Not sure what that means. I have also read od cam and crank sensor causing all this, as well as faulty injectors and wiring to injectors and sensors.

So I scheduled a complete diagnostics today at 8a.m. at Canadian Tire. I am going to ask what this test will show as far as electrical and mechanical faults.

I continued to search dilelma and someone mentioned checking the spark at night, so off to a secluded area to check for spark and all the wires at the front plugs show spark shooting out of them at plugs only. And any wire that is touching metal also sparks at point of impact.

IS THIS NORMAL?

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So I went and got the diagnostics done...a waste of $85...they didn't tell me anything I already didn't know...The wires were crap so I returned them. there was a vaccum hose leaking which I fixed. they noticed wires resting on manifold which I checked and tied up, they suggested I replace cam and crank sensors as did another technician who had the same problem with the same type vehicle...so I'm off to buy the sensors in hopes they will fix the problem..Oh and the battery will get replaced tomorrow...

I will post back my results as soon as possible....if anyone has any other suggestions they will be greatly appreciated....

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From the initial code list I would have suggested cam/crank sensors as the first thing to look into. If it loses one or both of those I could see a severe stumble resulting. Check the wiring, and if the wiring is good replace the sensors, perhaps one at a time to try to figure out which one it was (or was not).

O2 sensors will rarely (if ever) produce any stumble or bucking, generally they cause a slightly rich/lean condition and impact fuel economy and spark plug / catalyst life.

 

No you should not see any arcing on the plug wires. You replaced them a second time correct?

Is this bucking happening ONLY when the engine is under load as in going uphill or accelerating? Does it idle ok? Does it accelerate on a flat road ok? Any maintenance done just prior to this starting?

Lots of info here: http://www.aa1car.com/index_alphabetical.htm

 

If only going up hill I recall something close to this in another vehicle, it was the fuel filter restricting gas flow.

 

Hi Guys...

zero10:

wiring seems OK...replaced the cam sensor and now it will idle but wont take any kind of load...seems worse then before i replaced it..

Cougar41;

Thanks I didn't think there shud be any archin..I replaced wires and no arcing now...replaced cam sensor and now it is running worse...cant keep her running and i need to fix her so i can drive the 36km home from afternoon shift...
The bucking was worse when i would accelerate under load...on the flat or passing or uphill...i managed to keep her around 60mph but she would still buck intermittently...
The maintenance I can remember is tranny fluid and filter and some intake cleaner..

DBLR;

I was contemplating that as well as a plugged cat...not sure how to test a cat beyond smelling for rotten egg scent from exhaust...

I wish i had a better picture of where the crank sensor is so I can replace that before midnight and hope for the best...HELLLP!!!!!!

Thanx *****

 

OK i found a diagram in the service manual of the location...well pitch dark out here so I hope I can limp her up onto ramps to access...

 

Well I shud have waitied for a professional...Now I'm dead in the water...My brute force ended up breaking sensor flush to bell housing...Looks like I am going to have to pay to get the sensor removed..That thing is in an akward place...

Well gonna need a tow to friendly mechanic...I will follow up with results as they occur...Thanx for all your help and I am praying as is my wife that this will fix the bucking as this is our only set of wheels...

 

Ever feel like you should have just stayed in bed?

Stuttering under load can point to a weak fuel pump especially if it was running ok at idle and slower speeds. Should be supplying 55psi. If it's only putting out 30-40 psi it won't handle the added demand when you press the pedal. Can be causing your P0300 since lack of fuel can cause a misfire. Other things to look at would be the mentioned plugged cat and a vacuum leak if it's not idling right. Egr valves and intake manifold gaskets are a common cause. A plugged cat will show up as slowly decreasing vacuum. Can also be tested by monitoring O2 sensor function with a scanner or checking pressures fore and aft of the cat. A P1391 can be bad sensors or worst case scenario a cracked flex plate.

 

Oh Yeah!!!!

Well the 0300 code only popped up at home...after I replaced the plugs and wires it went away and the cam/crank code came up. They did mention cat but suggested i change the sensores first. They also mentioned vacuum leaks so I fixed the one spot he pointed out..If the crank sensor doesn't fix the problem, then I have the cat and flexplate as like;ly canidates for my next operation..Man chasin' this down can and is a real nightmare...
Wifey says she is gonna buy me a $100 vehicle to work on so I can leave the family one alone...LOL... Well getting it towed this morning to her mechanic in hopes of recovering my lack of professionalism and tools...

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