P0206

I've been having no luck figuring out what's wrong with my 94' dodge dakota 3.9 sport. I bought it in the past five months and when I got it, it ran perfect. None of the symptoms I am seeing now. A few days after I purchased it all I did was have the engine oil and coolant changed at a Jiffy Lube. They (Jiff Lube) recommended that I replace the radiator because of rust, change the battery, and spark plugs but, at the time all I could afford was to replace the radiator and front shocks. The thing that I am concerned about most is the replacing of the radiator because I did not bleed the air or even check the proper level of coolant after I replaced it because soon after I started getting these syptoms: rough and low idle, white smoke from the tail pipe and a gas smell, and a misfire code for p0206. Soon after I started seeing these codes i did some research and I decided to put some fuel cleaner (seafoam) and it helped some because the truck ran smoothly with no check engine lights but, the symptoms came back not too long after so, I put some more seafoam and the symptoms still returned but, sooner and even more severe. The smoke got more aggressive and the idle became more hectic with the truck shaking so, I took it to a shop and they told me they checked the wiring and it seemed to check out so, they told me to replace the computor so I did and the issuse was gone for a few weeks although, the check engine light persisted so I took it to another shop and all they told me was that my battery was 120 amps too low of the recomend amperage of my truck , 600 instead of the 480 the place I bought it from had on it and to change the ground cable so I did. My problems were still there though. I decided to go the do it myself route and so ive researched how the three possible culprits for the miss fire code p0206 to appear from the wiring (fuel injector ohms resistance, continuity, the spark test at night with mist spray, visual inspection of the wiring harness thus far) and the others ignition and spark that i am not to confident in testing. I am running low on funds so I can't take it to anymore shops because they're all too pack and busy to see my case closely and with all the details so I am desperate to hear any tips out there. Other additions to.my case include: I replaced the spark plugs inhopes of solving the issue, noted the thermostat on my truck is recomended at 195 degrees Fahrenheit but when I swapped it out I found a 180 degrees fereinhiet one and replaced it with the 180, and I replaced the temp sensors and still the temp gueage reads very low, under a quarter even after thirty minutes driving, and I have a leak on my lower radiator hose, the radiator fan seems to always be running and the rely to the radiator fan is missing entirly, the housing to the relay and wiring ate completely missing.Thank you. Sorry for the long message.

Actually, the only thing I have found to be suspect on the fuel system thuse far is that the resistance on all of the injector are around 15.7 to 15.8 except one which is 17.something and it is a new inject the only new injector it appears. Also I replace the fuel pump after I checked to see if I could find a fuel filter some where one day and I accidentally broke the old pump by misplacing a few parts. Turns out my truck doesn't have a fuel filter, just a strainer from what I can tell.

I had to Google the code definition. For anyone else reading, P0206: injector circuit malfunction, cylinder 6.

Is the injector with high resistance on cylinder 6?
Your issue reminds of this one:

Yes, injector six is the one with high resistance 17.(something). I switched the injectors, six with four and the misfire did not move to injector slot four so I think that I may have bad wiring because the injector that was missfiring on six did not missfire on the fourth cylinder slot. Although, I am not sure if I reset the computor good. The 94´ model doesn't have the obd2 clear codes option. Thank you for the video. Much appreciated.

Okay I've reviewed the video but, I am wondering about those injectors. Since they were difficult to get to ScannerDanner had to check the injectors by hooking up those wires to the PCM and the computor scanner to check the wave form, could I just use a mood light to test the injector signal and see if there is a wiring issue? My injectors are easy to access.

Mood Light? Maybe, Noid light?

Noid light will show power, ground & control. If you switched the injector to another cylinder & the problem stayed with the original cylinder, your injector isn't the issue.

Lol. Sorry for my spelling. I'm still in school lol. So the niod light wont tell me about the wiring? I'm certain the injectors are fine. I'm just struggling with testing my wiring. I'm taking off the harness to inspect the wiring and it looks fine although there is a wet area covered in what looks to be oil near the transmission that has covered the wiring.

VJ wrote: could I just use a mood light to test the injector signal and see if there is a wiring issue? My injectors are easy to access.

Yes.

Thank you and everyone for the feedback. Ive listened and looked to many motions but, I've been doing some thinking about my current issue. When I first got the check engine light and the truck started running funky I took it to the auto parts store and had my codes checked. The code I first got was p0204, where the single new injector was replaced. Then, after I changed the computor the code p0204 switched to p0206 for some odd reason and now that I switched the injectors to different slots, the code is still on the injector six slot with the single new injector. I am wonder about that new injector and more so because the resistance on it is 17 ohms compared to 15.8 like the other old injectors. I looked online and I heard of some data that the computors use to tell the injectors specifics like pulse width and other variables and so I am wonder if the people that put the single new injector diled in the new injector to specs. Could this be my issue, finally?

The spec's on your injectors should be 14.5 ohms +/- 1.2 ohms @ 68* F

So all your injectors should be within the range of 13.3 ohms to 15.7 ohms @ 68* F

17 Ohms is a little too far out of spec's & I would be very concerned about that injector

Now you say that you switched the injector to a different cylinder & the misfire is now on that cylinder - Strike 2 for that injector

There is no adjustment for the injectors, so the people that installed the new injector had nothing to "dial in"

The noid light is a good way to test the computer driver & wiring - compare the suspected bad cylinder with a known good cylinder - The light flashes should look the same

If you are still skeptical about the new injector being bad, switch it to another cylinder & see where the misfire lands

You are contradicting your previous statement that the misfire did not move, so it's hard to help until we get some more information

Swap that injector to a different cylinder (not one of the previous cylinders) & let us know what happens

I could be way out of field here. But with the misfire staying to one cylinder or the one next to it, the white smoke, the 180 thermostat, the what sounds like straight wired fan, etc....blown head gasket? You could also see what the ect sensor reads on a scanner, can not always go by the cluster. Sounds like previous owner was trying to fix or hide a overheating issue.

I could be way out of field here. But with the misfire staying to one cylinder or the one next to it, the white smoke, the 180 thermostat, the what sounds like straight wired fan, etc....blown head gasket? You could also see what the ect sensor reads on a scanner, can not always go by the cluster. Sounds like previous owner was trying to fix or hide a overheating issue.

I agree with arbez. The noid light will let you know if the power and control are present. If not, then you need a schematic and start tracing wires. Dont panick but i have seen injector control drivers go bad in the pcm for only one injector, especially on a cadillac.

Okay so I swapped the cylinder six injector, with the new injector on it, to cylinder one injector and the misfire code is still p0206. Since the injectors now seem to be all in working order and that I've put in a new pcm and fuel pump, I've narrowed the possible problem areas to wiring I believe.

Thank you for your reply. I agree. The previous owner was trying to fix something on the truck before I got it because of all the new parts on it.

I don't think that the truck had a blown head gasket because the white smoke smells like gas and I've looked at the oil and there is no sign of white sludge. I could be wrong though because I haven't checked the temperature of the truck yet so, ill try to get to that. However, I've took apart the wiring to the ground wire connected to the pcm and visually there is no corrosion or damage to the wiring but, I have not looked at the wiring to the power side because I'm gonna have to move multiple components on the engine to get to it but I can see that there are two parts on the power side of the wire harness that are greatly exposed to the elements. Ill look there first and fix wiring issues if I see then. Also the injector connectors 2, 4, and 6 have broken connection clips on them but, the injector six is the only injector misfiring so that shouldn't be my problem.

Okay so I today was testing the injectors with the engine running. I unplugged them as the engine ran and saw the engine change it's performance when I unplugged them for injectors 2 and 4 but when I unplugged injector six I saw no change in preformance so I am certain now that the wiring has an open or short in the wiring. Whne I did a resistanve test this timw with the injector one in the injector six slot I saw that the resistance was 15.8 and that the resistance in the injector one slot which has the new injector read about 15.8 to 16.0 and wouldn't level out. I took the resistance test ans unplugged the injector connections after I drove the truck around for about half an hour.

Have you done a compression test?

Unplugging the injector, with no change just says that cylinder isn't contributing. Doesn't necessarily indicate that the injector, or wiring is the issue. If that ignition coil was bad, unplugging the injector would not make any difference. The same if that cylinder had bad compression.

Do you have a noid light, or at least a test light? Any light bulb (12v) that you can use to jump the injector terminals will work. Light should flash with engine cranking or running. Compare it to a good cylinder & let us know.

Oh, no I have not done a compression test yet but, the code I have is p0206 so the computor is showing that the injector circuit is out of spec. I got a test light and checked each injector for power and all of them are lighting up good with the engine running. Then I did a group ground test to each injector and I noticed that injector six was pulsing very dimmly compared to the rest of the wires and when I pushed the test light in for better ground the light would get brighter. As I stated before, the connector clips to the four and six injector are sort of broken so ill see if I can fix the clips for both of them and possibly change the whole connector to the injector six after I clean it and try to see of it get a a better contact to the test light.

Do a resistance test from the injector to the PCM. If the resistance test is OK, you need a PCM. Compare the spec's to a cylinder that is working good & you will have your answer.

Okay I will but I put a brand new pcm in the truck a few months ago.