Code 27, How do i fix it?

[Matthewh]

Working on a 92 Dodge W250 318 auto. Swapped ECM's due to a bad voltage regulator, bought a reman'd unit from Carquest, computer numbers match, 56027141, high altitude emissions.
Everything fit back together good, started truck and after a minute or so of running, check engine lit. Checked the codes and got 27. Never had this code with the last ECM. Truck still runs good, though I haven't driven it due to not knowing what's up with code 27. I understand it has something to do with the injector driver in the ECM, so wondering if I didn't get a bad reman'd unit.

Back-story on the truck. Was given it for free, from my brother in law. It ran and drove, just needed some love and maintenance. It ran like crap once warmed up.
Turns out the bushing in the block was bad, as well as a worn distributor. Ended up replacing all the plugs, the tps sensor, new kickdown/tv cable. New melling oil drive, brand new distributor, fixed the battery cables with soldered lugs, and a new battery. Wires were new, as the previous owner had just replaced them

Have been chasing a miss while driving, noticed while plowing my driveway under acceleration either forward or reverse it'd miss like a fuel issue after you were moving. Checked fuel pressure, have 32 lbs while idling, with the vacuum hose still hooked to the regulator. Thought maybe it had the pressure, but was lacking volume, so threw on a new filter.

That was today, installed my new ECM, and the filter, now I'm getting code 27. Not sure where to go from this point. Not much info online or in the FSM about the injector driver circuit, just that its in the ECM.

Any ideas? Was gonna hit the local junkyard later today to see if I could find another ECM and swap them just for the heck of it, as a replacement ECM is 3 days out

[Tom Petroff]

From another Site.
Googled Mopar code 27 and got a lot of hits.
Not sure if there of any help but I thought this one might point you
In the right direction.

My thoughts are that with a replacement ECM you might have to have
A Dodge dealer flash your serial number in it so it can read the circuits Parameters?
TGP

Code 27 in my 97 Service manual points toward a fuel injector driver not responding properly to the control signal. It could be one of 8 or one of 6 depending upon if you have a V-8 or V-6.

It more than likely means the PCM is not seeing a fuel injector, or in electrical terms, the computer sees the fuel injector (s) as an "open circuit." I strongly think you have an intermittent connection to one or more of your fuel injectors because of the comment you made that it only does it when it is cold, and sounds like it is not running on all cylinders.

I would recommend looking for the following:

1. Find out if the fuel injector wiring harness, especially the part that goes to the injectors, has a "block connector" and see if that is either loosely connected, greasy, etc. If you find it dirty, greasy, etc. , unhook it and then clean it with "electrical parts" cleaner (Radio Shack). I used brake degreaser on my 93 Dodge Shadow that had a poor connection at a block that fed the 6 fuel injectors on it.....If it is clean, unhook it and re-connect it a couple of times to ensure good connection; look at the contacts to see if they are sound, not bent, corroded, etc.

2. Look for corrosion on said injector wiring harness and any other connector blocks on the injector harness that are corroded.

3. Try to get the PXXXX code (s) which will tell you what injector(s) is (are) having the problem. If you isolate it to a single injector, look at the wiring carefully for that injector. You could have a bad injector wire or injector plug connector.

4. Look for a small water leak (heater hose?) that might be spraying a connector and getting it wet (corrosion). Same thing for an oil leak...

5. Look for a loose ground strap that is part of the fuel injection circuits. Grounding problems can give you fits all around! It could be corrosion on a grounding point as well.

6. As something gets cold or hot, it might contract or expand just enough to cause an intermittent circuit. See if there is an injector connector block close to something that gets it hot, etc. I found the one on the 93 shadow partially melted! That may be why when it gets warm, it makes a good connection and as you describe it, "poof" your problem goes away.

7. Start it up and as soon as it does it, start wiggling the connectors gently on each injector and see if it goes away all of a sudden. If that doesn't work, gently wiggle the injector wires at the injector connectors to see if it goes away (bad wire theory).

BE CAREFUL doing the above while it is running and watch out for fan blades, moving pulleys, etc....safety first!

8. Last thought...PCM has a problem. I had a 90 Dodge Spirit that never threw a code, but all of a sudden it started running real rough at startup and missing like mad! Pulling a plug out after it did this reavealed it was soaked with gas! Dealer said nothing was wrong. Well, using a set of resistors that matched certain temperature ranges and attaching them to the coolant temperature sensor, I was able to duplicate the problem and it would only happen between 50 and 75 degrees F! That was usually the temperature the car cooled down to over night! I showed my data to the dealer and told him to let the car sit overnight and get cold and see what happens...he called me the next day and said they ordered a new computer and had never saw one do that! He said I was right on the money regarding the temp range.....

However, I really suspect an intermittent connection as your problem....

__________________

[Matthewh]

Thank you. I had Google'd dodge engine code 27, but came up short.
Google'd mopar code 27 and came up with alot of good information.
Sure sounds like I've got a bad injector, or something in the wiring. I'll be spending the day probing injectors and checking over wiring.
I haven't condemned the ECM yet, though alot of what I've found says its the death code of the ECM