3.0 engine injector
jsgold
02-19-2016, 02:20 PM
This may sound like a stupid question but you never know until you ask....Can a computer detect issues with a fuel injector and disable it or randomly send signals if the injector is damaged? I have a 2002 Sable with the 3.0 OHV motor. Same as a Taurus for the most part.. A while back I lost cylinder 5 while driving. Made a lot of pinging and misfired badly. What I saw was that the spark plug had lost the platinum tip and it was apparently banging around until I could get stopped. I replaced all plugs and wires and find it has a bad misfire at idle. Not at normal speeds though. I checked and found the injector is "clicking" half of the time. About 30 seconds or so of every minute at idle it simply does not work. Thought perhaps the injector was damaged but I hooked a noid light to the cable and the pulse is random. Seems a bit much of a coincidence that something else would be wrong so am curious if perhaps the computer may be detecting issues and sending a random pulse. of course that does not explain to me the random flashing of the noid light. Like I said, may be a stupid question but had to ask.
shorod
02-19-2016, 08:54 PM
I'm pretty confident that the computer is not intentionally sending a random injector pulse to the injector. I'd be more inclined to suspect a damaged wire or a faulty camshaft position sensor to the point where the engine doesn't quite know where the camshaft is at a given time and isn't firing the injector (or more likely, injectors) at the correct time.
-Rod
-Rod
jsgold
02-20-2016, 09:53 AM
Thanks! I now have some additional information i did not have before.... I was concentrating only on cylinder 5 as it was so far, the only one the CEL is showing with a misfire problem. However ALL front cylinders are doing the same thing. When the car first starts all injectors are firing perfectly. After about 1-2 minutes they start random on/off firing. They will fire for 15-20 sec then off for the same period. I have not checked the back 3 yet as I am unsure how hard they will be to get to. Strange how it does well at cold.
jsgold
02-20-2016, 10:06 AM
OK, more information. I now have multiple codes. I have not driven this car much as the fuel pump went out and just got that repaired so drove it to work yesterday and now I have P305, 316, 304, 306, and 1151. I know the 300 codes are misfire codes but will have to look the 1151 up. I was puzzled to also find the random misfire is occurring at high rpms also, even though the engine seems to be smooth at normal driving speed. Not what I was expecting for sure.
jsgold
02-21-2016, 02:20 PM
Since all of the injectors are shutting on and off I assume that either A-the computer is bad, B- The cam sensor is bad, or C the entire cam sync is bad... I know the cat bad a bucking problem as well so may just try replacing the entire unit and hoping the computer is OK. If anyone has a better idea let me know.
shorod
02-21-2016, 05:36 PM
The P1151 code is defined as P1151 - Lack of HO2S-21 Switch, Sensor Indicates Lean per the service manual. This makes sense if the fuel injectors are not triggering.
Camshaft position sensor / synchronizer would be logical, but before going that route I'd suggest you attempt to determine if the injectors are not firing due to a lack of battery voltage or ground signal. I suspect it will be the ground signal since if it were battery voltage all three would drop out at the same time and likely stall the engine. The only reason I suggest confirming the power though is because I came across a Duratech engine once that had a bad connector for the front bank of injectors.
-Rod
Camshaft position sensor / synchronizer would be logical, but before going that route I'd suggest you attempt to determine if the injectors are not firing due to a lack of battery voltage or ground signal. I suspect it will be the ground signal since if it were battery voltage all three would drop out at the same time and likely stall the engine. The only reason I suggest confirming the power though is because I came across a Duratech engine once that had a bad connector for the front bank of injectors.
-Rod
jsgold
02-21-2016, 09:26 PM
Will do some more checking then.....Wish I had a tester that would let me monitor all of these at one time to see what is going on when they drop out and in what order etc.. What puzzles me a lot is why none of them drop out when the engine is cold. At least not for about 2 minutes or so. Then the on/off thing starts. I will also see if I can test at least one from the other bank.
shorod
02-21-2016, 11:31 PM
The cold versus warm operation could be caused by a solder connection that needs to expand a bit before it acts up or a sensor monitored by the PCM that doesn't get accounted for until after the coolant reaches a certain temperature. Basically Open Loop versus Closed Loop operation.
-Rod
-Rod
jsgold
02-28-2016, 11:32 AM
Not sure how much this helps but here goes.... The voltage remains constant. It would seem the pulse side (ground) is what is cutting on and off. I was able to get 2 of my noids to fit and when I test cylinders 4-5-6 what is get is a constant pulse on 4. Both cylinders 5-6 cut on and off together. Wish I could test the back cylinders but not possible with what I have to work with.
shorod
02-28-2016, 09:06 PM
Interesting, that would tend to point toward the computer not triggering the injectors for cylinders 5 and 6 like it should.
My first suspect now would be the Camshaft Synchronizer.
-Rod
My first suspect now would be the Camshaft Synchronizer.
-Rod
jsgold
02-28-2016, 10:11 PM
Thanks, will try replacing it and see what happens.
jsgold
03-02-2016, 08:46 PM
Just a thought....Do you think I should try the sensor first or replace the whole assembly? I do not hear the chirping noise many describe hearing when these fail but I also have seen gears partially stripped on pics I have seen researching it....My car has 125K on the motor.
shorod
03-02-2016, 10:22 PM
Chances are good that if you only purchase the sensor, you'll need the entire synchronizer. However, if your local parts store has both in stock, you might start with just the sensor knowing you can pick up the assembly if you later determine you need it.
-Rod
-Rod
jsgold
03-06-2016, 03:04 PM
I finally just completed replacing the entire unit. Took some doing to remove it once everything was off but it finally went. A couple of tries and the new one went in fairly easy. Broke my temp sensor, lol but it still works. I have not driven it but it runs much better. No missing I can see, and the injectors are still all working as they should after 10 minutes of running. It had gotten so bad before that the injectors were dropping out even at starup....Am going to test drive it but already far better than it was. Old sensor showed some discoloration but was not as bad I as thought it might look. A LOT of slack in the main unit up and down...Side to side seemed OK and gear looked OK. Will get back later tonight and give my final word on it but so far that seems to have nailed the problem. And I learned something and that is not a bad thing. Thanks for your help!
jsgold
03-06-2016, 07:11 PM
Will be watching it for a few days...It was doing Ok and then got a flashing cel light halfway to my dads. When I got there my scan tool showed cylinder 6 was misfiring. I looked over the wiring etc and am thinking the injector wire may have been the culprit. It seemed like it was not fully connected as it and cyl 5 have been plugged and unplugged to much and in the cold....bot tabs are broken of and I found a crack in cyl 5 injector as well near the connection. Anyway it ran great on the way home so pretty sure the major issues was the cam sync. Now what i need to do is clean the throttle body, and maybe replace some of the wiring / connectors etc. No mad rush to replace the injector...hoping maybe some sealand will do there for now. It is working fine. Will advise if anything happens in regard to cam sync,
shorod
03-06-2016, 11:04 PM
Great, glad to hear it sounds like you're on the right track. I've heard of folks having to cable tie the injector plugs in place for exactly the reason you found.
-Rod
-Rod
jsgold
03-07-2016, 09:22 AM
Yep, it ran great this morning on the way to work so pretty confident the repair was a success. Best it has run in a long time. Will see about the wiring issues and clean the TB out soon. Now maybe I can work up the courage to tackle the oil leak, lol. (Timing chain cover). Thanks once again!
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