I have a 1990 Dodge RAM B150. When I check the engine codes I get 35. I am not sure what this really means and what to do about it. One of the other postings says that in the B150 it is actually an A/C relay switch. Still not sure where that is located and if that is what I should replace.

Problems that are occurring:
Engine starts fine, but once I tried to accelerate even in neutral it starts to actually sound/feel like it is missing.It sputters a little and then revs higher for a minute and repeats.

Prior to this I was driving it one night and then it would not start. It appeared that the battery had run all the way down and it was not being charged. Almost like the alternator was not charging it. Since then I check to make sure the battery is still good by testing it at Advance Auto overnight. FUlly charged I installed it back in the van. Started fine, but now has the problem described in previous paragraph.

I get a 12.2V reading on the battery when it is running. WHen I turn the A/C on it engages and drops the volts to 11.9. I then add various lights, and radio and it drops make to 11.7. Accelerating does not increase the volts on the meter.

Any thoughts as to what to troubleshoot next?

Rob

 

It should be up around 13.5 volts. If you have an external voltage regulator replace it, if you don't then replace your alternator.

 

13.5 should be the minimum voltage you see. The voltage regulator is internal to the engine computer, but before blaming that check all the connections at the back of the alternator, especially the 6 awg cable ground to block.

There is also a fusible link stuffed behind the brake booster. The 20 year old fusible links on the charging circuit are known to fail not as fusible links are designed to. Basically they can still pass some current, but only a fraction of what the battery and engine needs.

They should stretch out and have burnt looking insulation when they fail, but at 21 years old, that is not always a given. Carefully Pull out all the fusible links from behind the brake booster, and find the one on the alternator to battery cable and closely inspect it.

If you cannot detect any issues on the charging circuit, then blame the alternator, but have it tested at an AP store before replacing it.

The VR inside the engine computer has been known to fail. An external VR can be added, but it might illluminate the check engine light, which might make you fail a smog or inspection test.

http://www.alternatorparts.com/Dodge...tor_wiring.htm

Also know that most places who test batteries do so incorrectly. If your battery is over 5 years old, just replace it. Trying to get the last little bit of life from a starting battery becomes a frustrating lesson in futility.

If you battery has been run dead over 5 times consider it's lifespan and capacity to be cut by 40 to 70%. This alone can overwhelm a vehicle charging system and lead to the issues you are now experiencing.

Thing of an aging battery as a gas tank that keeps getting smaller. when new it might have held 35 gallons. You can still fill it up, but it might only take 8 gallons to do so now.

 

THanks guys! Both of these posts were helpful. SO basically here is what I have narrowed it down to in the wiring department. If I look at the 6 guage wire coming from the ALternator to the B+ post, I have found a break in the connection where the black 6 guage wire connects into all of the (Hypalon Wire) Fusible Links/ and 6guage wire leading to the battery. On both ends of this 6 guage wire it has quick disconnects.

THe issue is that it looks as though someone did a rewire job at some point. THe 6 guage wire from the ALternator is crimped onto 2 16 Guage wires which were then all crimped together back at the junction point of the B+ 6 guage and Fusible links. My thought is to remove the 2 16 guage wires and crimp the 6 guage back together.

Now I have to ask a question regarding the Voltage off of both ends of the 6 guage wire. I get a reading of 29 Volts coming from the 6 guage wire coming off the alternator when the engine is running. Separate from this 6 guage wire is the battery wire that is measuring 12.7 Volts. Is this right?

WHat I have been reading is that the regulator in the alternator could be bad and not regulating the correct output voltage. WHen I did connect the two wires briefly it did fix the engine miss that was happening upon applying more RPM's. I quikly turned it back off and disconnected the wires because I did not wan to cause any other damage. THe 6 guage wire and the 16 guage wires were very hot to the touch after the 15 seconds of being connected to the 12.9V battery side of the 6 guage cable.


SOrry for such a confusing description..........THanks for your help in advance.