I need some OBD1 help. Fuel is EXTREMELY rich

Ok folks, I need a little advice on the codes my 92 5.2 is throwing.

Its flashing the 27 code twice. I've never seen this happen before.

I have been chasing a code 27 issue for a while, and up until today it has only flashed 27 once in the series.

First question is why is it flashing the same code twice?

Now on to what lead up to the code reading today.

Today I believe that I had an injector or two stick open. It was running extremely rich, enough so that it was hazing out the tailpipe and would burn your eyes, and didn't want to idle.

Of course it happened 25 miles from home, so I limped it home running like crap and praying it didn't strand me in the 103° heat out in the middle of nowhere.

Previously (about a year ago) I had found a couple bad injector connectors (the previous code 27 issue I had) and have those fixed. Its not the ECU my spare ECU throws the same code when on this truck. The NOID lights say the injectors are all getting the signal to fire. I checked that today after I made it home.

Perhaps there's some crap stuck in an injector or two? Or maybe just worn out?

I came across an older post on a Dakota forum on the internet, and others with the same symptoms had been able to fix it with an injector change. This was usually after several other parts, TPS, IAC, MAF etc had been swapped. I did change the TPS, and IAC a couple years ago for a different issue with the idle surging when the engine was cold.

I am trying to decide if it's time to delete the MPFI on this 5.2, or do I spend a couple hundred on new injectors?

I will say up front I am a novice when it comes to dealing with fuel injection. So I honestly don't know what to look for to check an injector for proper functionality.

If putting a set of injectors into it is the correct option, is there a better injector than symtock? I run a Mopar Performance ECU is there a performance injector that would compliment the ECU?

I think you need to try to figure out which cylinders are rich. You might pull all the plugs are see what they look like. Is this a stock engine ?

It's a TBI engine so looking at plugs might tell it's rich but it won't be cylinder dependent.

Pull the air cleaner, look down the throttle body and have someone turn the key on, but don't start. a leaky injector will be obvious.

92 should be magnum, i think.

Its a 5.2 magnum. Not TBI

I had it in my head 93, but that's when the 5.9 went magnum. ah well, crs huts

I talked to my son, who's a master diagnostic tech. He said most of the time when a fuel injected motor is way rich, look at MAF sensor, o2 sensor, or fuel pressure regulator. Still could be injectors though. Tell us what you find.

I will do some checking.

Can the MAF sensor be checked?

I have a fuel pressure tester, so checking pressure at the rail shouldn't be an issue.

The O2 sensor will usually trigger its own CEL, but I can try to get someone to help me get to it.

When reading the codes on the dash display, the codes are very generic and most of them cover multiple, more detailed codes. For example, you might have an O2 code, but it could be the heater circuit or the sensor itself (out of range, rich or lean). That is likely why you are seeing the code twice. You really need to hook it up to a scan tool.

And, my personal opinion is that would NEVER take injection off an engine to go carb, even if I took my 5.9 Magnum and put it in an older car that didn't need a smog check.

It doesn't have a MAF, it's a speed density system. A couple things on these, the fuel purge hose can get soft and deteriorate at the throttle body as well as the vacuum hose elbow for the MAP sensor creating vacuum leaks. I have also seen where the coolant temp sensor wires insulation down by the thermostat housing will also deteriorate and crumble off. This shorts the wires together and the computer thinks it's -40° causing a very rich condition.

The Actron Scantool with the Chrysler cartridge does a reasonably good job of letting you watch OBD-I operation in real time.

After using it for some time I cannot imagine troubleshooting without it on my 1995 OBD-I Magnum 5.9 V8.

This one on ebay only has the GM cartridge

https://www.ebay.com/itm/284384762128?hash=item4236a71910:g:ETkAAOSw6jdg~Zcx

Now days the official Chrysler dealership scan tools show up on ebay from time to time.

There are two coolant temperature sensors on the OBD-I so the one your dash gauge is reading can be different than what your PCM computer thinks the coolant temp is.

The maze of vacuum plastic miniature hoses at the back of the engine definitely gets brittle with age and can create weird problems with the EGR.
If your EGR valve is original it is near certain that the valve seat has corroded away letting exhaust flow all the time causing rough running or miss fires at idle.

On a 1995 the wire insulation and even the fuel line plastic covering is “tasty” to rodents and squirrels, do not ask me how I know......

27 is a generic injector fault code, You need to the "P0" code that will tell you witch cylinder has the injector issue. Take it to one of the parts stores that will read codes for free. Also you can pull the plugs and see what they look like that may give you a clue.

speaking of the coolant temperature sensors, the bulb in the coolant can get "green" deposits on the brass, effectively insulating it, making it think it's "-40" as has been mentioned.
cleaning it up to a nice brass finish like it was when new, will often times make it work like it should.
just sharing my experience playing with this stuff over the many years.

There will be no "PO" codes on an OBD I vehicle

Yeah, Your right. If it was a OBD2 then you could get individual injector codes.

If one of the cylinder fuel injectors were to stop spraying for any reason,
I believe the OBD-I system with its single Oxygen Sensor, would falsely calculate “too lean air/fuel”
and lengthen the “on time” of injector pulses,
which would eventually have the other cylinders become rich.

Could be bad wire in harness to injector,
bad injector coil,
plugged up catch screen at top of injector,
etc

There have been multiple reports by past Ram owners that the inner liner of the fuel hose starts breaking up into pieces that then plug injector catch screens.

On OBD-II Rams the PCM can compare the pre-catalytic Oxygen Sensor to the post-cat Oxygen sensor and give a more informed trouble code

The OBD1 magnum computer is a pretty good system, although diagnostics will mostly be swapping parts. Code 27 has to do with injector driver circuit open or shorted. The code will set if the ECU does not see 12v or 0v when it cycles the injector on/off. Basically on an EFI system the computer tells the injectors to do a thing, then it monitors the electronic signal to try to confirm the injectors are doing that thing. If you're getting the code twice I would suspect you have two problematic injector locations. You could try ohming out your injectors or swapping out your injectors with ones from the junkyard however I would start first by ohming out the harness from the ECU to the injector connectors. There's possibly a couple broken, corroded or chaffed wires somewhere.

If the injector itself was physically plugged it would not be setting this code. This code relates to the electronic portion not responding so if it's not an ECU issue which you've confirmed by swapping out a spare, and if it's not a harness issue you can confirm my ohming out the injector feeds and grounds then it's one or more injectors in which the electronic solenoid has failed internally.