Dodge D-50

1988 Dodge D-50 Engine  When accelerating When warm 

I have a 88 Dodge Ram50 with 132K miles. The engine would lose power if slowed down after driving for about a hour on the freeway in warm weather. It'd restart and idle just fine but couldn't accelerate until I let it "rest" for 30 minutes and everything will be fine again for a while. Engine did not over heat, replaced a fuel filter, spark plugs & wires, distributor cap and rotor. Worked fine for 3 months after a fuel pump replacement but same thing happeded again. Please help!

Still pulling for you. I pray your headaches are over.

Roger

Hello, Have you considered replacing the filter inside the fuel tank that the fuel pick-up line draws fuel through first? This "sock shaped" filter is a fine nylon screen and when it gets dirty the fuel pump can suck it flat causing a serious reduction in fuel flowing to the pump.

If this filter goes completely flat it can block fuel flow completely and the engine will die. After the pump stops, the filter can reopen to it's original shape and the engine will start again 'til the pump sucks it flat again.

Another possibility is your catalytic converter may be stopping up and restricting exhaust flow.

Roger

I have changed the fuel filter already but it wasn't inside the tank, it was outside of it. Is there another one inside? I didn't see that in the repair manual. As for cat converter, what would be a good way to check it? Thanks!

Yes, there is a filter inside the fuel tank on the fuel line pick-up tube. Looks like a test tube in shape (or a hot dog) and is often referred to as a "sock filter" where I am.

A cat converter that is stopping up causes a hissing sound out the exhaust tailpipe. I've had cars that had no power on acceleration and when I disconnected the exhaust header pipe from the manifold the power was immediately restored and loud as could be! I replaced the converter and that was that.

Roger

Very interesting suggestions. But, I am still puzzled as to why it'd lose power only when I slowed down from a long freeway drive and wouldn't do so if I kept on going at high speed. I can see it causing the engine not to accelerate after I stopped and lost power, but can't understand why it'd lose power only when I slowed down. Is it a big job to replace the internal fuel filter? or do I need a new tank?

No, you don't need a new fuel tank. And rethinking about the symtoms I would want to test fuel pressure when the condition is present before dropping the fuel tank to replace the pick-up filter.

Let me think about this and see where else we should find possibilities.

Roger

Thanks for the reply. I usually get stuck off the freeway ramp somewhere 11pm at night so it's kinda hard to put a pressure gauge on at that time. I usually just wait 30 minutes and drive again for another hour to get home.

Would it be safe if I install the fuel pressure gauge on the engine and drive until I see the symptom? It usually takes about 1.5 hours highway driving and slowing down at a stop light for the problem to appear.

Yes, so long as the gauge has a leak free connection and precautions are made to avoid a vibration or heat hazard, you should do fine.

What size engine do you have? Is it a Mitsubishi engine?

Roger

It is a Mitsubishi 4 cyl/2.0. I am gonna buy a pressure gauge this weekend to try it out. Please standby for my result. Thanks.

If you don't want to own a gauge, I wonder if you could rent or borrow one?

Of course I'll wait for your test results. Does the check engine light ever come on when the condition is present?

Roger

No, no engine light warnings. I brought it to 2 ASE certified repair shops already in the last 4 months and they all gave up on it because no mechanics wanted to take the car out and spend 2 hours on the freeway at a time. They just let it idle and rev high for a long time in the shop but nothing ever happens when they do that. Very frustrating!

Do you have a FAX number I may send info to you? I'd like to send you a few pages on the emission system for the Ram 50.

Roger

Thanks, Really appreciate it. It's [redacted] .

I'll get it FAXed this evening.

Roger

FAX completed. Please advise.

Roger

Did your FAX arrive? It is helpful? What's next?

Roger

Hi, Sorry for the long silence, got sent on a business trip. I did however find a vacuum leak last weekend and have replaced the hose going to the egr. I haven't had the chance to do the "100 miles" test drive yet. Probably will do that this weekend. Please stay tuned! Thanks.

Thank you, I'm pulling for you!

Roger

Hi Roger,
I took a long drive yesteday and got it to sputter again after 95 miles and I found out what happened to my truck after playing with the air cleaning system. Actually, there were really two problems combined (just to mess up my life). First, it's the thermostatic air cleaner temperature sensor that seemed to pull the vacuum motor to draw hot air during idle even when it's hot off the freeway; Second, the hot air duct from the exhaust to the air cleaner was blocked because a section of its internel lining got melted and deformed allowing only about 1/2" opening for the engine to breath. If you like, send me your e-mail address and I'll send you the picture I took of it. Right now, I just temporarily disable the vacuum motor so it's always drawing cold air until I get the replacement duct and temperature sensor.

Man, Isn't it great to finally get to the bottom of a problem? Who could possibly guess to tell someone their heat duct has melted internally?

All-Parts policies are to not disclose personal e-mail addresses for privacy protocol. I share in your excitement with genuine interest. I've never professed to know it all and I learn from good people like you and share with others in need.

Where do we go from here?

Roger

I'll stop by the dealer this week to get a new duct and temp sensor. Boy, if I didn't take off the duct, I would never have seen the inside of the duct.

I'm looking forward to the report that all is well with the repair.

Respectfully,

Roger

Well, definitely got the problem licked. Test drove the truck with a new air cleaner assembly in 90+ weather in So Cal on Wednesday, didn't feel any hiccups at all. I think this is it but I will feel more comfortable if it stays good for a few more trips since I had such a bad expeience so many times. Thanks for your help.