5.2 problems

[Cvec92]

I have searched and could not find the same problem. My 98 has almost 400,000 mi all Original tune up was done around 250 mi ago timing chain about 10,000. Out of the blue I had an extreme loss of power check engine started flashing. I limped to the parts house and scanned it. P0300 p0301 p0303 p0304 p0307 are the codes that came up. There is also a very loud sucking noise coming from the engine bay that I cannot locate I have checked all vacuum lines. All are good. Money is very tight due to the pandemic. Does anyone have a good guess at what it is? I'm thinking intake gasket, Catalytic converter, or fuel injectors. But I don't have the money to throw at it. If anybody has had the same problem or has insight please help. I need my truck for work

 

[RandomRam]

I have not worked on a Magnum V8 nor do I own one. I have worked on a lot of older V8’s from that era. Those codes you posted are generic misfire codes. The sound you’re describing could also be the engine being out of time. Based on all of the above I would suspect it’s an ignition or timing issue or both.

My suggestion is start simple. Check your distributor and make sure it is tight. If the hold down clamp is not tight enough it could have rotated and thrown it out of time. Make sure the cap is tight and all the plug wires are on correctly and not corroded. Make sure the plug wires are connected to the spark plugs and not corroded on that end. I wouldn’t pull the plugs right now as that’s not your problem. Make sure your coil is good and not arcing or grounding. On Chevys aftermarket coils will cause all sorts of problems with computer controlled ignition, suspect Mopars are no different.

Finally look up out to index your distributor. Computer controls ignition timing but if the distributor is not index corrected (like it has rotated) the truck won’t run correctly. I found this video that may be helpful -
Hopefully this helps you where to start.

 

[crazykid1994]

Check your spark plugs to make sure they’re all snug. Have you ever checked the intake plenum gasket? Maybe try taking silicone spray around the intake manifold gasket to see if the sucking sound goes down. Are you sure it’s not a blown head gasket either? There’s a small chance that it’s a fuel injector o ring. You could spray silicone spray around the base of the injector port to check as well

 

[Okiespaniel]

Do NOT, repeat DO NOT move your distributor unless you have a tool to set the fuel sync!!!!!

This is not the problem.

Was the truck running fine after the tune up and then stop running correctly... or immediately right after the tune up? Did the air noise start out of the blue?

If you hear air noises that is start of your problem. You likely have a large vacuum leak. It will cause a lean fuel mixture and set misfire codes.

Buy a can of cheap carb cleaner and carefully spray around your hose connections, brake booster, intake manifold, and check your vacuum connections on the passenger side that run your hvac unit. Also the hose(s) from your purge solenoid to your charcoal canister. If the engine runs rough when you spray an area that be your problem. Spray around the base of the fuel injectors on the affected cylinders to check for a bad o ring

Or...it could be your gasket from the air cleaner to your throttle body is missing. This will generate a lot of hissing.

Misfires can also be caused by low fuel pressure. But you need to find where the air noise is coming from.

If the truck ran bad right after the tune up there may be other issues. There's a TSB on plug wire routing for instance.

You can check your plenum gasket two ways. One , with the truck engine off, crack the the throttle body wide open and look into the intake. If there are pools of liquid oil you have a plenum leak.
The other is a vacuum gauge test. http://dodgeram.info/tsb/2000/09-05-00.htm

 

[Cvec92]

Do NOT, repeat DO NOT move your distributor unless you have a tool to set the fuel sync!!!!!

This is not the problem.

Was the truck running fine after the tune up and then stop running correctly... or immediately right after the tune up? Did the air noise start out of the blue?

If you hear air noises that is start of your problem. You likely have a large vacuum leak. It will cause a lean fuel mixture and set misfire codes.

Buy a can of cheap carb cleaner and carefully spray around your hose connections, brake booster, intake manifold, and check your vacuum connections on the passenger side that run your hvac unit. Also the hose(s) from your purge solenoid to your charcoal canister. If the engine runs rough when you spray an area that be your problem. Spray around the base of the fuel injectors on the affected cylinders to check for a bad o ring

Or...it could be your gasket from the air cleaner to your throttle body is missing. This will generate a lot of hissing.

Misfires can also be caused by low fuel pressure. But you need to find where the air noise is coming from.

If the truck ran bad right after the tune up there may be other issues. There's a TSB on plug wire routing for instance.

You can check your plenum gasket two ways. One , with the truck engine off, crack the the throttle body wide open and look into the intake. If there are pools of liquid oil you have a plenum leak.
The other is a vacuum gauge test. http://dodgeram.info/tsb/2000/09-05-00.htm

It all happened out of the blue. My truck was running great I have checked all vacuum lines and they are all good. This thing just has me stumped

 

[Cvec92]

Could a plugged Catalytic converter cause these issues

 

[crazykid1994]

Could a plugged Catalytic converter cause these issues

Most likely no. The sucking noise is an issue. A catalytic converters would rattle or make bubbling noise from the exhaust.

 

[Okiespaniel]

Could be a brake booster or check valve. Forgot about those.

You need to do some checks. Spray carb cleaner (or brake clean) Check your plenum. Find your HVAC connector and check it. You have an air leak. You'll need to find it.

A 98 can get a clogged converter. But you usually have a HUGE power loss and overheating issues.

 

[Sasquatchtdg]

As stated before, use some carb cleaner or starting fluid, spray around all the vacuum connections and listen for a difference in the idle speed. No chance of a video?

 

[Cvec92]

Could be a brake booster or check valve. Forgot about those.

You need to do some checks. Spray carb cleaner (or brake clean) Check your plenum. Find your HVAC connector and check it. You have an air leak. You'll need to find it.

A 98 can get a clogged converter. But you usually have a HUGE power loss and overheating issues.

I do have a huge power loss. The down side is I have already started to tear it apart so now it is inspecting. I'm in the process of taking the intake off to replace the plenum gasket and change the injectors

As stated before, use some carb cleaner or starting fluid, spray around all the vacuum connections and listen for a difference in the idle speed. No chance of a video?

If that doesn't fix it I will post a video if that will give some insight

 

[crazykid1994]

Plenum gasket will cause a huge power loss. Order an aluminum plenum pan to replace the stock steel pan. And get a good gasket. Not sure if Hughes engines still sells their plenum kit or not. I doubt it’s still available on eBay. Came with new bolts and a decent gasket.
Edit: here you go. http://www.hughesengines.com/Index/...U21hbGwgQmxvY2sgRG9kZ2UgTWFnbnVt&partid=30712

 

[Cvec92]

I was able to test my fuel pressure before I tore it apart it ran 60 psi on the dotat idle and under a load

 

[EvilSpirit]

Plenum gasket will cause a huge power loss. Order an aluminum plenum pan to replace the stock steel pan. And get a good gasket. Not sure if Hughes engines still sells their plenum kit or not. I doubt it’s still available on eBay. Came with new bolts and a decent gasket.
Edit: here you go. http://www.hughesengines.com/Index/...U21hbGwgQmxvY2sgRG9kZ2UgTWFnbnVt&partid=30712

Since Cvec92 stated in his original post that money was tight, a $165 plate kit probably isn't spending money very wisely. Sealing the original plate using quality gaskets and sealants (I prefer the Fel-Pro intake/plenium kit), and either using slightly shorter new bolts or trimming a little off the factory ones is a proper long term fix at a greatly reduced cost. Although it is expensive, especially if you buy a tube just for this job - I use Permatex Right Stuff sealant on both sides of the gasket. You can also use weatherstrip adhesive to glue the gasket to the pan, and Right Stuff or silicon on the other side. I slightly trim the bolts to prevent them from bottoming out, and use blue Locktite on them. Never had a failure from re-sealing a factory pan.

 

[Cvec92]

I did buy fel-pro gaskets. I have always used fel-pro. I also bought new bolts for the plenum as well as new intake bolts which is a good thing. All 4 corner bolts broke off in the heads so that's where I'm at now. I have them soaking in pb blaster. I'm going to start working them out at daylight. I will post pictures tomorrow. I am very surprised at how clean the engine is with almost 400,000 miles and has never had any major work done to it. I have seen a whole lot worse on vehicles with 120,000 miles. I have a new problem tho. my donor truck is an 01 model it has different style connectors for the fuel injectors than my 98. Will the new style injectors work if I take the time to remove the pins from the old connector and replace with the new style? I don't really want to ****** my wire harness if I don't he have to. Thats why I will use a pin removal tool if it will work. Does anybody know if this is Doable? if so please give me some insight

 

[Cvec92]

How do I add pictures?

 

[Cvec92]

This is the new injectors
https://www.speedyracer.com/1set-8-...-1500-Van-00-03-RAM-2500-Van-5-2L-V8--1006822

And this is the old
https://www.amazon.com/Re-Manufactured-Genuine-Injectors-1996-2000-53030778/dp/B07ND4X9MV

If it will help to know if this will work

 

[pacofortacos]

Do the pins look the same?
Why not just use the old injectors?

On your new bolts for the plenum. BEFORE you install the gasket, run the bolts in the holes - what you are looking for is if they go the whole way in or stop short from going the entire way in.
The original plenum bolts were ok, but some of the plenum holes were a bit shallow.

 

[98dodgeramnc]

Check your spark plugs to make sure they’re all snug. Have you ever checked the intake plenum gasket? Maybe try taking silicone spray around the intake manifold gasket to see if the sucking sound goes down. Are you sure it’s not a blown head gasket either? There’s a small chance that it’s a fuel injector o ring. You could spray silicone spray around the base of the injector port to check as well

I think I'm having the same problems mine except mine is throwing codes for injector 7 and 8 and runs like crap. I replaced them and didn't help much..I do know its missing most of the air cleaner