Engine Performance problem
1978 Dodge Truck V8 Two Wheel Drive Automatic 119400 miles
I have a 1978 Dodge Adventurer 150 Club Cab (D150). It's 2WD with a 360 & approx 119,400 miles "” please let me know if there is any more info that will be beneficial in possible diagnosis. I only drive this truck once or twice a week with putting a maximum of approx 175 miles on it each time (usually not any where near that much tho). At any rate, it now stalls when accelerating from stops or near stops (slow downs). I don't have a tach so i'm not real sure of a RPM range when this occurs, but if I had to guess it's probably somewhere in the 2nd gear range (whatever RPMs that would be with a V8 ). I'll need to drive it some more to try to determine more symptoms, but it only seems to stall out when it reaches about 20 MPH or so "” under normal or somewhat hard acceleration "” as I was driving it around our neighborhood today to see if I could replicate the symptoms & it never stalled until it got to normal operating temp & only then when I accelerated normally to or above 20 MPH or so. Just cruising at low speeds (approx 10 MPH) didn't cause any hesitation or stall to occur & it idles normally. I also revved the engine after I parked in my yard after the drive through my neighborhood to see if it would stall out just by revving it. The results were; nothing but racing the engine happened in Park & Neutral, but when in Drive with brakes engaged, it would stutter as it approached the approximate range of RPMs that it would typically stall out when driving. I also depressed the accelerator slightly harder once the stutter started to see if it would clear up & the engine did not shut off. I attempted to mimic the same way I press the foot feeder when accelerating as I typically would when driving but didn't want to press it down too hard or fast for safety & fear of messing something up reasons, so there may be some variation. Let me know if any of this is unclear or if you need more info. I'm planning on test driving it some more tomorrow to see if I can provide any more input on my end. Any advice / suggestions will be greatly appreciated. Thanks!
***UPDATE: Upon driving the truck some more, it appears to primarily only stall out when in Drive between 5 & 10MPH (basically whenever you attempt to accelerate from a stop) & seemingly only when the engine has been running for a while (I drove it about 6 miles or so before it started doing it last). I've put it in 2nd gear after it started to stall out on acceleration & it accelerates normally with the exception of it stalling out once or twice, but there is definitely a difference as it ONLY stalled the 1 or 2 times & NOT any more than that. Also, I have not given this truck a major tune-up yet (changed plugs, wires, fuel filter, etc.) But am planning to do that at 120,000 miles "” what with this stalling situation tho, I may go ahead & do it just to rule all that out. I'll continue to update as I come into more symptoms / info on the subject. Thanks!
***UPDATE UPDATE: Just gave the Adventurer a major tune-up & it still stalls out on me. Upon driving it a little more, I've about come to the conclusion that it seems to only stall out and/or hesitate when I try to accelerate somewhat hard or under somewhat of a load (going up an incline) & it doesn't seem to matter how fast I'm going at the time of pressing the gas pedal swiftly. Basically, when I press the pedal down a little more quickly than typical - kind of like I'm needing to give it some gas to get on down the road, but not necessarily 'punching it' - it wants to stall out. Most of the time it does, sometimes, if I press it down just a little harder, it will get a sudden surge & go. It almost seems like the fuel pump is being 'caught off guard' & not able to feed the carb fast enough when I tap the gas suddenly. So it either chokes out from lack of fuel or, if I'm able to press the gas fast enough before it stalls out, it gets a sudden excessive amount of fuel & takes off like I 'punched it' or something. Once again, any advice is greatly appreciated.
Reading your post was an adventure lol. From everything you described it seems you need to do some carb work. Like an overhaul. Today's fuel has a lot more alcohol in it then in 78. The accelerator pump in your truck should be viton so it can take the abuse. Also if your float in then carb is plastic, ther eis a good chance that it isn't working correctly. Alcohol will eat the center of the float out and it won't float any longer.