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Please help with a stalling issue?
https://www.slantsix.org/forum/viewtopic.php?t=32505		 Page 1 of 2
Author:  87slant6 [ Sat Nov 29, 2008 2:10 pm ]
Post subject:  Please help with a stalling issue?
Hi, newbie here....
And I need help with my 1987 Dodge Ram 150 with a 225 and automatic transmission with 185000 km on the truck. So far as I can tell, it's all original. It starts cold (although setting the choke with a push of the throttle to the floor no longer works) and seems to run acceptably enough when cold. The problem occurs once the engine begins to warm up. I'll be driving along just fine at 30 or so mph and all of a sudden the engine falters, then surges ahead a bit, then falters again, surge, falter etc. until it stalls completely. Once I'm stopped at the side of the road with the rest of the traffic whizzing by me I can't smell gasoline, so I don't think it's going fat here. If I immediately try to restart the engine, it simply won't. If I wait two or three minutes it will immediately start up and I can take off normally. It will run fine for about three minutes then the whole show starts over again. I have discovered that if I quickly shut off the engine once the engine first shows signs of stalling that the wait time till I can restart the engine is greatly reduced. Not exactly the fix I was looking for. I have put on a new fuel filter. No effect in the symptoms. I have tried running without the air filter. No change. I sprayed some carb cleaner into the carb with the engine running. I was able to easily stall it with carb cleaner. Once I restarted the engine, it seemed to run a bit smoother, but the problem is still there. Any ideas?
Author:  steponmebbbboom [ Sat Nov 29, 2008 2:13 pm ]
Post subject: 
sounds like the ignition module or the distributor pickup. please check for spark next time it fails and does not start.
Author:  SlantSixDan [ Sat Nov 29, 2008 3:48 pm ]
Post subject: 
Welcome on the board! This problem could be fuel- or ignition-related, but Steponmebbbboom has got a good suggestion to check for spark the next time it won't start. Your choke problem can be fixed with a new electric choke kit, and you should definitely go and get these three books.
Author:  Ed Mullen [ Sat Nov 29, 2008 3:51 pm ]
Post subject: 
Have you checked for vacuum leaks (especially on the other side of stuff that opens when the engine is warm: EGR, purge canister, etc)?
Author:  87slant6 [ Sat Nov 29, 2008 4:46 pm ]
Post subject: 
re. spark--pretty sure it's got spark. It tries to start--I can hear it fire--just seems like there isn't enough fuel-air mixture to get it going. Once I wait the two or three minutes, there seems to be enough fuel-air mixture once again available to support running.
Author:  makapipi [ Sat Nov 29, 2008 4:59 pm ]
Post subject: 
could it be the float inside carb?
Author:  steponmebbbboom [ Sat Nov 29, 2008 5:14 pm ]
Post subject: 
it could be an intermittent spark problem. not ruling out carburetion, but spark testers are availabe cheap from most auto parts and tool stores. my personal favourite is very similar to this one and can be had for less than $5:

Image

what this will allow you to do is check not only for presence of spark, but the strength of that spark. mine has a 15" lead with an alligator clip. you plug it into the plug end of the wire, clamp the lead to a good ground, and adjust the anode outward to correspond with the kV value of your ignition system.

with this tool i have been able to diagnose several ignition system failures over the years that had other technicians stumped. my latest one was a couple weeks ago, on a forklift with electronic ignition and a shorted coil that would occasionally ground to the stamped steel core. since the ambient air gap requires less breakover voltage than compressed air in the cylinder, a normal spark plug will not reveal a weak secondary circuit. when the truck stalls, plug this unit into one of the plug wires, adjust the gap and try to fire it. there should be a blue spark jumping the gap on EVERY revolution.
Author:  SlantSixDan [ Sat Nov 29, 2008 5:55 pm ]
Post subject:  Quick reminder
It's great to have such a fast collection of responses. Let's each remember that the goal is to help the original poster get his truck running reliably again. A goose chase after this or that specific part will make the job harder, not easier, so anyone who has a clear, logical idea of why the problem is occurring, by all means please post it — not just the part you think might be faulty, but why and how you think it might be causing the problem. An engine needs fuel and air in the right proportion, spark and compression at the right times to run. At this, the initial stage of diagnosis, we need to figure out which of those fundamentals goes away to cause the engine to stall and refuse to restart. Once we've nailed that down, then will be the right time to try to figure out if it's a vacuum leak or a particular part creating the problem.
Author:  Doctor Dodge [ Sun Nov 30, 2008 9:43 am ]
Post subject: 
When the truck stalls, give the engine a squirt of fuel, right down the airhorn of the carb and try to restart it. (I have a little plastic squirt bottle I fill with gas) If the engine restarts with the addition of fuel, it's time to check the fuel delivery system for problems. (a can of starting fluid also works for this test)
If there is no change to the no start condition after adding extra fuel, I would move to the spark check as listed above.
DD
Author:  SlantSixDan [ Sun Nov 30, 2008 10:03 am ]
Post subject: 
A shot of spray carb cleaner also works for Doc's good test.
Author:  Aggressive Ted [ Sun Nov 30, 2008 11:43 am ]
Post subject:  Stalling
Around this time of the year with all the rain, etc. you can get condensation and water collecting in the tank and the bottom of the carb float bowl. When the choke is on your drawing extra fuel but when you push it back in your going to lean it out and if there is any water floating around in the bowl of the carb it could cause you to stall out like your not getting enough fuel. Doc's idea of squirting some fuel in from a bottle is a good test, and or pull the air cleaner lid off and see if when you step on the gas pedal any gas squirts down the throat of the carb.
I usually stock up on some HEET (in the yellow plactic bottle) as preventive maintenance. You can buy them in a six pack at Wall Mart. It will help to remove the water over time.

Some other thoughts........
If not much gas squirts out when you pump it, the float could be sticking or the fuel pump could be clogged and starting to fail.
Author:  SlantSixDan [ Sun Nov 30, 2008 1:07 pm ]
Post subject: 
The symptoms don't seem to accord with a water-in-fuel problem. Keep in mind that "HEET" (just plain old ethyl or isopropyl alcohol in a brightly-coloured bottle, marked way up in price) is largely unnecessary these days, because in many regions the gasoline already contains 5% to 10% alcohol in winter if not year round.

Again: Let's figure out what's missing — spark or fuel — and then speculate on why.
Author:  87slant6 [ Tue Dec 02, 2008 3:42 pm ]
Post subject:  stalling update
Ok, here's a bit more info....
The stalling situation is getting worse. And as far as I'm concerned, that's a good thing. It now stalls out before it even has a chance to warm up. Because it is getting progressively worse, and quickly getting worse, I'm now thinking that it isn't the carb at all, I kinda think it's the fuel pump going south. I'll see if I can disconnect the output side of the fuel pump, crank it, and see how much volume comes out. I should also mention that when I changed the fuel filter on the weekend that the fuel line on the "bottom" of the three legged fuel filter had plenty of fresh fuel available, so I'm thinking it isn't likely a fuel pickup/sending unit issue. And I could easily blow through the old fuel filter. Tastes great, less filling. But I put the new filter on anyway.
Can anyone chime in with their opinions on what happens when a Dodge slant six fuel pump starts to go dodgey? (pun intended)
Author:  Michael [ Tue Dec 02, 2008 5:14 pm ]
Post subject: 
I really get the feeling that it is the ignition module as step suggested earlier. These units can fail progressively. I used to think that the module would simply burn out like a light bulb - sometimes they do! But if they die a slower death they make you crazy by mimicking all of the afore mentioned symptoms. I don't advocate throwing parts at a problem, but its good to have a spare module and it only takes two minutes to swap. Keep the faith!
Author:  Charrlie_S [ Tue Dec 02, 2008 5:30 pm ]
Post subject: 
What is the air temperature? Is there a lot of humidity? Do you have a warm air duct to the air cleaner? I am wondering if the carb might be iceing up. It can in air temps below about 45 F degrees, and high humidity, without a heated air inlet. As soon as the engine quits, the ice will start to melt, and will allow a restart, within a few minutes.
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