1990 W150
318 engine
46RH transmission
Dual gas and propane fuel system

Codes: 12, 33, 21, 51, 21, 55.

Symptoms: Starts great. Stalls coming to a stop. Struggles to start again after stalling, will jump rpms once started like its full of gas (am pumping the throttle while cranking)

Work we've done: regular-simple maintenance (oils, filters, diff fluids), water pump replacement, and passenger valve cover gasket

I really don't want to sell the truck, i want to know if i can afford to fix it instead. I've seen both the MAP sensor and O2 sensor cause similar issues on this forum and that is what codes 51 and 21 indicate and they seem cheapish to fix.

 

What I am seeing is most of those codes are O2 sensor related. This one is TBI, isn't it?

 

Yep, i was told its the first year for dodge TBIs so the last guy struggled to find someone to work on it

 

Yeah, not many of the new kids now what to do with an OBDI system..... and I am not sure the shops around here even have a scanner that will talk to them.....

But, the 33 is shorted EGR solenoid, isn't it? That will make it run funny. The O2 sensor will make it just run inefficiently....... though it is likely a contributor to the problem as well. I would be tempted to disable the EGR valve, to make sure it STAYS close, and unplug the O2 sensor, see if it runs any better.

 

everywhere I've checked says 33 is a A/C relay which I've been ignoring because i have no A/C period (total base model). But i can definitely try both of those this Thursday. If it's just the o2 sensor i might cry lmao

 

First off, you have an early fuel injection engine and pumping the throttle doesn't really do anything. Codes 12 and 55 are normal. 12 means the battery was disconnected within the last 50 to 100 starts. (It varies by year.) and code 55 means end of test session. At least you don't have to use a scanner. I think the one code is for an EGR valve. I'd look at that puppy to see if it's your problem child.

 

Ooops. Yep. 33 is a/c something or other.

 

Ok sweet, this is finally a direction the last direction we had was a trans rebuild due to a code 37. Any ideas where to check for a replacement if it is an issue? Rockauto is out and I'm not sure if any of my local salvage yards would have one (car-part.com had 1 too far away)

 

Real possibility you won't find one...... I would be more tempted to just bypass the system entirely, and call it a day.

 

To make sure i don't further break something, is there a recommended way to go about testing and/or bypassing it?