99 Ram engine issues
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99 Ram engine issues
Hi guys, i need some help. I dont know where to start, ill just lay it all out. I have a 99 dodge ram that I bought new in Nov, 1998. Im not a car guy, ...But I want to be 
Its a 5.2L 318 quad cab 2wd
About 6 years ago, i developed a leak in the radiator and overheated the truck. When I did I lost first and second gear. I replaced the radiator, the governor solenoid and pressure switch in the tranny. Now I had 3rd gear but not 1 and 2. I tried several iterations of swapping the old/new solenoid and pressure switch out, but got no joy, so the truck sat in my driveway for years.
About 6 months ago i decided to try and get the truck going because i was tearing up my Avalon getting to the river to paddleboard. Truck wouldn't start but it was obvious that the fuel pump was out. So I ordered a new tranny valve body and a fuel pump. I installed the fuel pump ( my second one in this truck), the filter part on the bottom of the old fuel pump had disintegrated to nothing in the tank, but I cleaned all of that up. Anyway I cleared all of the engine./tranny codes got the truck running, and to my surprise No tranny issues. YAY! I don't have to try and figure out the valve body job. I'm perfectly content to leave that thing in the box. I drove it like this occasionally for months.
AC compressor front seal was out, so I replaced the compressor and the suction line and got the AC working again. I do know that there is a vacuum leak under the dash somewhere because the air constantly flips back and forth from dash supply to window defrost. Ill deal with that eventually, but not ready yet.
The truck was getting really bad gas mileage, maybe 11 mpg( and even though I just replaced the fuel pump, the fuel level sensor is already not working! UGH!) I decided to go ahead and do a full tune up so I could better estimate the fuel remaining from mileage. Wires, plugs, distributor, rotor. At first I had the firing order wrong , but afterwards the truck was running like it was brand new. On the first trip I went about 30 miles, going up to 85 mph. It drove awesome. On the way home, all the sudden it started performing really badly. As if the engine doesn't want any load on it. If I ease it up, I can still get it up to speed, but If I punch it, it struggles, and will even backfire if I hit it hard enough and hold it. IT hates accelerating up a hill. I'm not an expert. I think it might be a timing advance issue, but I admit it could definitely be anything. Like I said, I'm not a car guy. All of that is computer controlled so I don't know where to go from here. I am getting a P505 code ( Idle air control system) but based on the freeze frame, it looks like that code pops before the engine even starts. I could take it to a shop, but I don't want to.
While the truck sat a rat ate some insulation off some of the wires, but I have repaired all of that. Was the MAP sensor, injector 4, IAC, and TPS. All of which, the wires were intact, so I de-pinned the connectors and heat shrinked the wires to keep them from shorting out, the put the pins back in the connectors.
I pulled the injectors rigged up 12 volts to them and sprayed carb cleaner through them all. They look fine. I thoroughly cleaned the fuel rails. I bought another set of plugs (the original champions this time) and changed those. No change. I don't want to just throw parts at this. Can someone help troubleshoot?
Its a 5.2L 318 quad cab 2wd
About 6 years ago, i developed a leak in the radiator and overheated the truck. When I did I lost first and second gear. I replaced the radiator, the governor solenoid and pressure switch in the tranny. Now I had 3rd gear but not 1 and 2. I tried several iterations of swapping the old/new solenoid and pressure switch out, but got no joy, so the truck sat in my driveway for years.
About 6 months ago i decided to try and get the truck going because i was tearing up my Avalon getting to the river to paddleboard. Truck wouldn't start but it was obvious that the fuel pump was out. So I ordered a new tranny valve body and a fuel pump. I installed the fuel pump ( my second one in this truck), the filter part on the bottom of the old fuel pump had disintegrated to nothing in the tank, but I cleaned all of that up. Anyway I cleared all of the engine./tranny codes got the truck running, and to my surprise No tranny issues. YAY! I don't have to try and figure out the valve body job. I'm perfectly content to leave that thing in the box. I drove it like this occasionally for months.
AC compressor front seal was out, so I replaced the compressor and the suction line and got the AC working again. I do know that there is a vacuum leak under the dash somewhere because the air constantly flips back and forth from dash supply to window defrost. Ill deal with that eventually, but not ready yet.
The truck was getting really bad gas mileage, maybe 11 mpg( and even though I just replaced the fuel pump, the fuel level sensor is already not working! UGH!) I decided to go ahead and do a full tune up so I could better estimate the fuel remaining from mileage. Wires, plugs, distributor, rotor. At first I had the firing order wrong , but afterwards the truck was running like it was brand new. On the first trip I went about 30 miles, going up to 85 mph. It drove awesome. On the way home, all the sudden it started performing really badly. As if the engine doesn't want any load on it. If I ease it up, I can still get it up to speed, but If I punch it, it struggles, and will even backfire if I hit it hard enough and hold it. IT hates accelerating up a hill. I'm not an expert. I think it might be a timing advance issue, but I admit it could definitely be anything. Like I said, I'm not a car guy. All of that is computer controlled so I don't know where to go from here. I am getting a P505 code ( Idle air control system) but based on the freeze frame, it looks like that code pops before the engine even starts. I could take it to a shop, but I don't want to.
While the truck sat a rat ate some insulation off some of the wires, but I have repaired all of that. Was the MAP sensor, injector 4, IAC, and TPS. All of which, the wires were intact, so I de-pinned the connectors and heat shrinked the wires to keep them from shorting out, the put the pins back in the connectors.
I pulled the injectors rigged up 12 volts to them and sprayed carb cleaner through them all. They look fine. I thoroughly cleaned the fuel rails. I bought another set of plugs (the original champions this time) and changed those. No change. I don't want to just throw parts at this. Can someone help troubleshoot?
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From: Clayton MI
The IAC code is telling you the computer doesn't think it can control the IAC..... probably one of the wires that didn't look broke, actually is..... If you know how to use a meter, verify continuity of all four wires. They only go from IAC to PCM, so, pretty easy. Download the factory service manual from here, wiring diagrams are in section 8W.
As for the performance problem, is it always like that now? Or only after the engine warms up?
As for the performance problem, is it always like that now? Or only after the engine warms up?
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Ill check out the wiring again. I honestly think that's not the performance issue and I think that code started happening after I pulled the fuel rails and injectors to try and fix the performance issue. Maybe I didn't seat that connector very well.
As for the performance problem, it does not matter if its cold or warmed up. In park it performs fine, I can rev it up, and notice NO problems at all up to 4000 rpm. It only loads up and bogs down when there is load on the engine. Seems to really hate the area between 2800 and 3000 rpm when driving and accelerating.
As for the performance problem, it does not matter if its cold or warmed up. In park it performs fine, I can rev it up, and notice NO problems at all up to 4000 rpm. It only loads up and bogs down when there is load on the engine. Seems to really hate the area between 2800 and 3000 rpm when driving and accelerating.
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I checked continuity on the TPS, MAP sensor and IAC. Everything was fine.
So I replaced the IAC valve and the camshaft position sensor.
and now it has the same issues, but also idles really high rpm( this happened on the IAC change out.) I idle at 30 mph now.
So I replaced the IAC valve and the camshaft position sensor.
and now it has the same issues, but also idles really high rpm( this happened on the IAC change out.) I idle at 30 mph now.
Last edited by mcgraw; Jun 19, 2023 at 11:03 PM.
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I disconnected the battery for 10 minutes. No Changes.
I bought a new crank sensor too, I guess that is next, I just have to find it. I think i know where it is ,
I read its just above the bellhousing on the back of the engine, just not sure the best way to get to it.
Seems like The biggest problem is that it just isn't advancing the timing when you load it up. Friends are saying its got to be the computer, but I'm not ruling out sensors yet. The problem is randomly better or worse which seems like an input issue rather than a computing issue. I guess i need to know what other sensors could be causing that IAC code that its throwing.
I bought a new crank sensor too, I guess that is next, I just have to find it. I think i know where it is ,
I read its just above the bellhousing on the back of the engine, just not sure the best way to get to it.
Seems like The biggest problem is that it just isn't advancing the timing when you load it up. Friends are saying its got to be the computer, but I'm not ruling out sensors yet. The problem is randomly better or worse which seems like an input issue rather than a computing issue. I guess i need to know what other sensors could be causing that IAC code that its throwing.
Last edited by mcgraw; Jun 19, 2023 at 10:59 PM.
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From: Clayton MI
What IAC code are you getting?
Ignition timing is purely computer controlled, if the crank sensor is wonky, timing will be as well. Sensor is behind the passenger side head. Yep, it's a pain to get to, even more so if you have an auto trans.... Theoretically, the bolts also have an alan head, which is what I used to pull mine. I got 'em from up top. Not easy. Some folks say going from underneath is easier... I didn't find it so.
Ignition timing is purely computer controlled, if the crank sensor is wonky, timing will be as well. Sensor is behind the passenger side head. Yep, it's a pain to get to, even more so if you have an auto trans.... Theoretically, the bolts also have an alan head, which is what I used to pull mine. I got 'em from up top. Not easy. Some folks say going from underneath is easier... I didn't find it so.
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P0505D2 Generic Idle air control. Freeze frame data shows 0 RPM when the code was stored.
But its crazy because I can reset codes and it goes away. It comes on just by switching the engine to the on position without ever cranking it. I think that means it is sensor related.
But its crazy because I can reset codes and it goes away. It comes on just by switching the engine to the on position without ever cranking it. I think that means it is sensor related.