89 Ram 50 Stalling after warmed up

[ckh052404]

Ok, next issue...

We put a new Weber carburetor on the truck and have it tuned and running correctly. Now an issue that we had previously had with the Mikuni is still present. We had thought that the Mikuni may have been contributing to this problem but it looks like it might be another gremlin....

After the truck is warmed up and running it will intermittently shut off, it has to sit for about 5 minutes before it will start again and when it does it starts right up. Does this seem like it could be a fuel pump issue or am I looking in the wrong spot? Fuel filter is new and isn't clogged.

[xboxrox]

Does the 1989 truck have an ignition control module inside a distributor? If so, maybe it is becoming over heated. You could try cleanin it & reinstall with new big dab of heat sink grease. Some auto parts stores tes the part for free.

Good Luck & Patience
:thumbup:

[geezer101]

Hmm. If it 'dies' regularly after it runs for a few minutes and the fault is consistent, I'd check the ballast resistor on the coil. If it's hot (I mean hell hot - it WILL burn your fingertips) - the ballast resistor has cracked. If you suspect or straight up know the ignition coil hasn't been replaced in the last 10 years I would go ahead and replace it anyway. They break down after 10 years and cause loss of spark and engine power which will be especially noticeable from midrange rpm onwards. A quick test - next time it dies try to pull a spark plug and ground it onto the engine while someone cranks it to see what or if a spark is present. Not super realistic to pull off as it takes a few minutes to do this, unless you're already anticipating a glitch and intentionally set if off. My money is on an ignition fault on this one. Fingers crossed you get a win and solve it :)

[ckh052404]

Ok, update and question all in one. I noticed that there was a small leak of fuel around the fuel pump. We have installed a new one and here comes the question. I have hooked up all the hoses with the exception of 1, my son got a head of me and pulled all of the hoses before I could label them, D!@N Teenagers..... where does the hose in the picture need to go?
252052520525205

[ckh052404]

AND geezer, I will definitely check the ballast resistor. The fuel pressure was just under 2.4 psi, that was the reason for changing the fuel pump.

[ckh052404]

O,k, apparently one of my posts didn't go thru....

[ckh052404]

We put a new fuel pump on the truck due to low fuel pressure and here is the question from the post that didn't get thru....
Where does the hose that hooks to the port circled in the picture above go? My teenage son unhooked all the lines before I got out there

[85Ram50]

I believe that is a vent line. There is a supply from tank to pump, pump to carb and return from pump to tank. Those would be the 3 with bulbs on them to help the hose clamp on.

[geezer101]

That 'line' doesn't get connected to anything. If the pump fails, any oil or fuel from inside the housing will leak from that tube.

[SubGothius]

We put a new Weber carburetor on the truck and have it tuned and running correctly. Now an issue that we had previously had with the Mikuni is still present. We had thought that the Mikuni may have been contributing to this problem but it looks like it might be another gremlin....

After the truck is warmed up and running it will intermittently shut off, it has to sit for about 5 minutes before it will start again and when it does it starts right up. Does this seem like it could be a fuel pump issue or am I looking in the wrong spot? Fuel filter is new and isn't clogged.

I've got a similar issue, still happens even after installing the Weber and electric pump, new fuel filter and plugs/wires/cap/rotor/coil. Also just rebuilt the dizzy with fresh thermal compound under that ICM, which the PO had already recently replaced when I bought it, perhaps chasing the same issue as the old ICM was in the glovebox with a note on it saying "maybe still good?"

It doesn't just die completely all at once but, rather, just starts to kinda bog down and then drops to idle and stays there, no matter how much I goose the throttle, before finally dying. However, I also don't have to let it sit before restarting; I can usually just declutch to keep coasting along, and once the engine stops turning, I can usually just restart it right away while still coasting and continue on my way.

At this point, I'm suspecting a chunk of rust/debris in the gas tank may be getting sucked into/against the fuel pickup, starving it for fuel. Until I can remove the tank to get it cleaned out and maybe sealed, I'm gonna try affixing a strong magnet at a bottom corner of the tank to draw any rust chunks away from the fuel pickup. Got a thumb-sized neodymium one I salvaged from an old desktop hard drive that oughta do the trick.

There could also be a fault in the two-way vapor valve near the tank, allowing a vacuum to build up in the tank that could impede fuel pickup. This valve should divert positive vapor pressure to the charcoal canister underhood but allow ambient air into the tank as fuel gets consumed.

[xboxrox]

Hmm. If it 'dies' regularly after it runs for a few minutes and the fault is consistent, I'd check the ballast resistor on the coil. If it's hot (I mean hell hot - it WILL burn your fingertips) - the ballast resistor has cracked. If you suspect or straight up know the ignition coil hasn't been replaced in the last 10 years I would go ahead and replace it anyway. They break down after 10 years and cause loss of spark and engine power which will be especially noticeable from midrange rpm onwards. A quick test - next time it dies try to pull a spark plug and ground it onto the engine while someone cranks it to see what or if a spark is present. Not super realistic to pull off as it takes a few minutes to do this, unless you're already anticipating a glitch and intentionally set if off. My money is on an ignition fault on this one. Fingers crossed you get a win and solve it :)

That's a great idea geezer; I just thought, keep a spare spark plug handy or a sprak plug tester plug; no need to pull the plug just the wire... Could even have a spare wire on hand and connect it to the distributor cap (less heat & grease + easier access) I love the way you troubleshoot dude, tortron is smart too... Must be that southern hemisphere air, it clears the mind ?
:thumbup:

[xboxrox]

SubGothius, I might be going down the same rabbit hole as you IF -- rebuilding my Mikuni carburetor does not solve my no start problem... I can't believe my truck went from running fine to no start, after touching the Mikuni carburetor (to replace the accelerator diaphram)

The gremlin was (not me) a heavy hand which lead to a cracked phenolic resin throttle body portion of the carb... After a second attempt (not me) to super glue the cracked GAS leak plastic a new gremlin began (super weird rough running upon cold start/like running on two cylinders) A third attempt to stop GAS from leaking was (not me) installing another Mikuni BUT that rough cold start gremlin was still there (it must be something other than a carburetor problem (thanks to a heavy hand?)

GRrrrrr

Gott love these trucks to keep at em -- good luck all on fixing your trucks
Aloha--
George