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Discussion Starter · #22 · (Edited)
Well, I'm miffed ... last 2 days have been the hottest days of the year and the van ran pretty smooth, been running sort of rough the last several weeks, guess that eliminates any heat related issue. If I ever get this transmission project finished I think I might replace that fuel pump, could be some bubbles in the fuel line.
 

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Going to try and make this as short as possible

1998 Dodge B1500
V6
150,000 miles

Around 3 months ago, before I got my rear snow tires, got stuck in the snow, normally because the transmission is still bad I have to baby the van and drive low RPM, at least when starting, so the engine (without having a tachometer and knowing for sure) probably never sees above 3,000 RPM, or so, however, because I was stuck I was revving the engine pretty high, guessing around 4,550 or so + RPM, forward reverse, forward reverse, to get unstuck ... got unstuck, then noticed a very rough engine idle. Van was previously running pretty smooth, unplugged spark plug wires and identified the miss in cylinder #2, swapped out the fuel injector with one I had lying around, same miss, swapped out the fuel injector with cylinder #6 fuel injector, same miss, installed new spark plug, same miss, thinking maybe I blew out a cylinder.

Flushed the engine with an engine flush(oil), (changed oil 3x to make sure the flush was completely removed), engine ran smoothly briefly, then the miss re-appeared, for lack of better words going to describe the miss as 1/4 miss sometimes, 1/2 miss sometimes, 3/4 miss sometimes, this miss went on and off, but mostly on, for about 3 weeks then all of a sudden the miss stopped, back to running as smooth as it was running before this happened. Was running smooth up until a few days ago when I took an 80 mile trip on the highway, going around 70 MPH (guessing, speedometer still broke) most of the way, then afterwards the miss re-appeared (going to say 1/4 miss), not sure what cylinder was missing, didn't check, but assuming it was the same miss as before, after the next day the van started to smooth itself out again and is running smooth now.

Was talking to my "go to parts guy " several weeks back and he told me back in the day when his buddies were racing cars that when they were racing and the engine high RPM that sometimes the engine would run rough afterwards then eventually smooth itself out, he called it a " floated valve ", I this is what I think I am dealing with here, was wondering if anybody heard of this before ? The only think I can think of is that the lifter is getting hung up and not riding on the cam completely. Do not hear a " ticking " sound so not thinking the lifter is collapsing. Thinking that the engine may have previously been overheated before purchasing and possibly causing some kind of issue, which is why I baby her and run a 180 degree thermostat.

95% positive this is a mechanical issue opposed to a faulty fuel injector, spark plug / cap / rotor / wire, or a vacuum leak.

Any thoughts ? So long as she is running smooth I am not going to worry about it at the present time, other things to fix, just wondering what may be causing this ?
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Discussion Starter · #24 · (Edited)
Odd thing is, engine is running about as smooth as it has run since I got the van, I don't understand this at all, been running pretty smooth the last 3 weeks or so. If it was heat related I would expect the engine to be running rougher in the hotter weather, it is actually starting to run smoother ... still think it is something internal to the engine, lifter or valve, or something.

Not running perfectly smooth, but for a '98 with 150,000 miles it is running smooth enough for me.
 

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No more misfire codes?
 

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Discussion Starter · #26 ·
Mechanical or valve issues tend to be 'all the time' or at least 'repeatable', not like intermittents that come & go.
Has it set a P0302?
I have seen this a couple of times on the 3.9L. If the fuel pump begins to send air bubbles into the fuel line, they tend to 'pocket' at the front of the right fuel rail. This can cause a #2 lean misfire if this is what is happening.

When the misfire is present, detach the fuel hose at the rail, jump the fuel pump relay and run a sample into a clear soda bottle. Use due care and precautions in the presence of gasoline and fumes.
Look for bubbles in the fuel stream. Replacing the fuel pump has fixed this.
Finally got around to replacing the fuel pump / sending unit yesterday, can't say for sure quite yet, only drove it about 100 or so miles, but the engine does seem to be running noticeably smoother, but then the engine has had bouts of running pretty smooth, just not running pretty smooth for periods of time.
 

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Discussion Starter · #27 ·
Mechanical or valve issues tend to be 'all the time' or at least 'repeatable', not like intermittents that come & go.
Has it set a P0302?
I have seen this a couple of times on the 3.9L. If the fuel pump begins to send air bubbles into the fuel line, they tend to 'pocket' at the front of the right fuel rail. This can cause a #2 lean misfire if this is what is happening.

When the misfire is present, detach the fuel hose at the rail, jump the fuel pump relay and run a sample into a clear soda bottle. Use due care and precautions in the presence of gasoline and fumes.
Look for bubbles in the fuel stream. Replacing the fuel pump has fixed this.
IDK, drove her up to Flint and back (that could turn out to be an interesting thread) ..... seems to be smoothing out even more, think the computer may be self-adjusting .... should get a better idea the next day or two .... not promoting the consumption of alcohol, but if you were to drink a beer, or whatever, what would you drink ?
 

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not promoting the consumption of alcohol, but if you were to drink a beer, or whatever, what would you drink ?
Yuengling (Oldest Brewery in the US - in PA) or lately, a beer from a local micro-brewery - Six Beards and A Goat - 6 navy guys and a coastie started this brewery, hence the name. This time of year, I also like Octoberfest by Sam Adams. Octoberfest is seasonal and only available from August until November or December.

I prefer the lagers over pilsners. I don't care for Budweiser, Bud Light, Miller or Miller Lite. Might have a Dos XX or Heineken.

Occasionally, I'll take in a good British ale. There is a restaurant in town, Park Lane, that has European fare, and their beer menu is longer than the food menu. In addition to American brews, they have British and German beers/ales. The British ales are served warmer than American brews. Many people mistakenly believe British ales are served "warm", but they are stored and served about 10 degrees warmer than American brews - it actually brings out the taste - especially the creamier ales. We don't go to Park Lane often - it is pricier than most restaurants. Easily average $100 for just my wife and I.
 

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Discussion Starter · #29 · (Edited)
Yuengling (Oldest Brewery in the US - in PA) or lately, a beer from a local micro-brewery - Six Beards and A Goat - 6 navy guys and a coastie started this brewery, hence the name. This time of year, I also like Octoberfest by Sam Adams. Octoberfest is seasonal and only available from August until November or December.

I prefer the lagers over pilsners. I don't care for Budweiser, Bud Light, Miller or Miller Lite. Might have a Dos XX or Heineken.

Occasionally, I'll take in a good British ale. There is a restaurant in town, Park Lane, that has European fare, and their beer menu is longer than the food menu. In addition to American brews, they have British and German beers/ales. The British ales are served warmer than American brews. Many people mistakenly believe British ales are served "warm", but they are stored and served about 10 degrees warmer than American brews - it actually brings out the taste - especially the creamier ales. We don't go to Park Lane often - it is pricier than most restaurants. Easily average $100 for just my wife and I.
Nice to know, but I was referring to the genius, no offense, who solved my engine problem, because that was the problem, fuel pump must have been sucking in air and creating an air pocket in the fuel rail, go figure, running pretty smooth !

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More than happy to help. I'm glad that made a difference.🍺
 
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Discussion Starter · #31 · (Edited)
More than happy to help. I'm glad that made a difference.🍺
Yeah, I would have been racking my brain these last several months trying to figure this out, but left open the possibility of an air pocket being the problem, so I wasn't that pressed, figured I would get around to installing the fuel pump I purchased several months back eventually.

Although the morning I replaced the fuel pump I did put a deposit down on the 47,000 mile engine that went along with the 47,000 mile transmission I got a few months back ..... not sure if I would have got the engine had it been running smoother, but figured for $500 probably not a bad idea to snag the engine while I could (and they say this thing runs good) ... I missed out on the 47,000 mile rear axle by about 4 days (although one Mopar mans loss is another Mopar mans gain the way I see it). Now to figure out the best way to store this engine until needed, I will be keeping it outside and under a tarp exposed to the elements, not sure the best way to seal / preserve it.

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Discussion Starter · #32 · (Edited)
.... just when you thought it was safe to go back into the water again, same thing .... engine was running ridiculously smooth the last 3 weeks, then drove her up to Flint the other day, and when I got off the highway coming back, boom, same thing ... rough idle, disconnect number 2 spark plug wire and no noticeable difference in engine performance, check engine icon was also on, so I should be able to pull a code, but after a few days the engine smoothed out somewhat and the check engine icon went off, but still not running as smooth as she was. I am inclined to agree this might have something to do with the fuel pump sucking air, but this is a brand new fuel pump, or at least never installed but I had it laying around for over a year. I do believe the fuel pump is defective in as much as the fuel gauge drops out occasionally, below E, but this is seldom and intermittently, and this was not happening prior to installing new sending unit (sort of an ominous feeling when you are sitting at a red light and you look down and see the fuel gauge below E), I checked all 3 connectors for the fuel gauge wiring and they seem intact, so I believe at minimum I got a bogus sending unit, but this should not be related to the fuel pump operation itself I would think. So is the fuel pump itself bogus as well ? I went ahead and ordered a Mopar fuel pump off Rock Auto, should have it tomorrow.



Hopefully this one will be easier to install than the last one when there was roughly 20 gallons of gas in the fuel tank (good thing I eliminated sugar from my diet and am taking high quality vitamin supplements, was able to manhandle it pretty well), this time I should be able to run the tank pretty much dry.

The fuel pump I just installed was a Delphi, junk, isn't Delphi GM ?


My question is, why does this only happen to 3.9's ? If it does only happening to 3.9's .... seems odd.
 

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Delphi is not a junk parts vendor. They've been pretty decent the times I've used them.
Unless it is an electrical problem that affects both, the reading on the fuel level does not affect the ability of the pump to deliver fuel.
I wonder if injector 2 is plugging up or there's an electrical reason it might not be firing.
 
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Discussion Starter · #34 · (Edited)
Delphi is junk in my book ... this is the bogus Delphi idler arm(s) I made the mistake of purchasing awhile back because Rock Auto was out of Moog, had to install washers to place between the idler arm the nut so the cotter pin hole would line up with the slots in the nut ... can't say I ever had to do that before ...

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I have no idea exactly what's wrong, but that fuel injector has been replaced multiple times, could it not be getting electricity ? ...... possible, but I am going to go with the fuel pump sucking air, engine ran the smoothest it has since I owned the van after I replaced the fuel pump several weeks back, hard to think that is just a coincidence, but maybe ... looking at the design of the sending unit, possible it could suck in air .... or maybe I am getting a vapor lock somehow ? .. but then, why would it run that smooth the last several weeks ?

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.... I guess I will be finding out because regardless pretty sure the sending unit for the gauge part is bogus so she is getting replaced, shouldn't go wrong installing a Mopar unit, IMO.
 

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Carter is the OEM supplier for most Chrysler fuel pumps.
Delphi & Valeo are to be avoided.
 
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Discussion Starter · #36 ·
QUESTION :

Anybody know the best way to store / preserve the spare engine I picked up ? It is going to be stored outdoors underneath a tarp.

Do I need to spray the inside of the cylinders with anything ? Seal the intake or exhaust ? Hopefully will not need to, or plan to, replace the engine until next springish ...
 

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Maybe a couple of tablespoons of oil in the cylinders and roll it over a couple of turns.
Stuff oily rags into the throttle body & exhaust ports. Close off any crankcase openings.
 
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Don’t forget moisture comes from below as well. Probably need a tarp below and over as well.
 
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Discussion Starter · #39 · (Edited)
Carter is the OEM supplier for most Chrysler fuel pumps.
Delphi & Valeo are to be avoided.
I think we may be on to something here .... it appears the recently installed Delphi sending unit went limp on me (pictured right) ...
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... not sure if that matters as far as function ability, but it no longer has a bounce to it.

Too early to say for sure, but she does appear to be running smoother again, but not quite where she was the other day, should get a better idea over the next day or two as the computer self-adjusts. Fuel gauge seems to be working properly so far as well, has not dropped out, yet, but again, too early to tell.

... but, as usual, ran into another snag, plastic connector broke where the fuel line connects to the sending unit ...
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... had to cut and use the connector that was on the short piece of hose that came with the new fuel pump then connect it to the existing fuel line, temporarily ... I know I may be pushing my luck here, but does anybody have any idea about how to start tracking down the fuel line coming off the fuel tank, OR, a more permanent way this can be connected ?

BTW, possible I bought a Carter sending unit but paid $115 more for the Mopar name ?
 

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The rear lines were sold as a 'bundle'. I don't know about NOS availability, but you can try to search for any of the past Mopar part numbers listed also.
Auto parts stores have nylon fuel line quick-connect end repair kits.

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