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| Need a little help again https://www.slantsix.org/forum/viewtopic.php?t=4991 |
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| Author: | wolfears [ Tue Feb 11, 2003 2:16 am ] |
| Post subject: | Need a little help again |
Ok, this time it is my 87 sl/6 van. It takes forever to warm it-up and until it does, it likes to stall every time i make either right or left hand turn. I have learned to compensate in turns by double tapping the gas pedal really quick, so it keeps running, but it seems to be getting progressively worst. I have tried to solve the long warm-up problem by changing the thermostat, but it didn't help and when i tested the old one in boiling water, it worked just fine. It also seems to be unable to produce hotter air out of the vents, as even when warmed-up it dosen't feel very hot. It is pretty cold and snowy up here right now, but no other vehicles i have ever owned have taken so long to warm-up. As for the stalling in turns issue(also likes to stall on straight acceleration momentarily, but comes back to life), i realize that the shift in momentum when making a turn dosen't sit well with certain parts, i just don't know what they are. The carb was re-built about 2 months ago(altough it has the original jet, since the kit didn't include a new one). I don't think it is connected to the carb re-build, since it has always done that, just not as much so i didn't really pay much attention. It started getting really bad for only past few days, but when warmed-up it runs fine. Any ideas as for what it could be? Thank you in advance for any suggestions or tips. |
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| Author: | 64 Convert [ Tue Feb 11, 2003 5:43 am ] |
| Post subject: | |
If it runs badly when cold and fine when warm, it's likely a choke problem. If your thermostat isn't staying closed long enough, or not closing completely, that will contribute to the problem. |
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| Author: | Doc [ Tue Feb 11, 2003 8:44 am ] |
| Post subject: | |
I do not know the late 80's system all that well but there may be a temp sensor in the system. If that goes bad then the "computer" will not enrich for cold conditions. Do you have a manual? This could also be a problem with the idle circuit but my bet is that there is no way for you to adjust idle mixture. (set by the factory and capped-off) DD |
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| Author: | wolfears [ Tue Feb 11, 2003 10:12 am ] |
| Post subject: | |
Doc, where would i find the temp sensor and how does it look like? |
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| Author: | Super6 [ Tue Feb 11, 2003 10:20 am ] |
| Post subject: | |
Does your van have the lean-burn ignition? 1bbl carb or 2 bbl? My truck in its stock form (lean-burn, 1 bbl) had similar problems, my main problem among a few other things was vacuum leaks. Old hoses, worn carb gasket, and though im not positive i believe i had a manifold vacuum leak as well. Id snug everything up (manny to head bolts, carb hold down bolts) and replace suspect vacuum lines. If you dont have to worry about emmisions id ditch the lean-burn ignition (if you have it) for a simpler more reliable std electronic ignition. -Aaron |
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| Author: | wolfears [ Tue Feb 11, 2003 3:17 pm ] |
| Post subject: | |
It is a one barrel, not sure about the ignition, but i think someone has tampered with it(possible conversion), if it is a lean burn ignition, it dosen't live up to it's name. Lucky to get 10mpg city driving, light footed and no load. |
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| Author: | rustycowl [ Wed Feb 12, 2003 8:11 am ] |
| Post subject: | lean-burn and more |
I get 16mpg out of my '86 D250 w/318 2bbl(ESA). Have you tried to see if the heat-riser flap in the exhaust manifold is free and operating correctly? |
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| Author: | wolfears [ Wed Feb 12, 2003 11:31 am ] |
| Post subject: | |
Ok, this is going to sound really stupid, but what is a heat riser flap? If it is inside the exhaust manifold, do i have to take off the manifold to see it? Sorry, i'm not very mechanically inclined, but if you give me few hints i can figure out most of it. |
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| Author: | GTS225 [ Wed Feb 12, 2003 3:00 pm ] |
| Post subject: | |
Wolfears.....a heat riser flap is actually on the inside of the exhaust manifold, but you won't need to take the exhaust off at this time, maybe later. On each side of the manifold, positioned between the header pipe flange and the "union" of exhaust to intake, you'll see the shaft, counterweight and spring that controls the flap. Reach down, (suggested while cold), and see if you can turn that counterweight and spring by hand. It only turna about 90*, so don't get crazy with it. You should not have to apply a great deal of force. If it's real stiff, or locked due to heat & rust get some Mopar brand heat riser solvent from your local Mopar dealer, (or other well-known brand), and spray both ends of the shaft on each side of the manifold and let it soak awhile. It may take a few doses to free it up, but try to be patient before you decide it's terminal. Roger |
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| Author: | wolfears [ Wed Feb 12, 2003 7:49 pm ] |
| Post subject: | |
I have located the heat riser, the shaft moves freely, about 90 degrees as suggested. The other end of the shaft is attached to a little spring, which dosen't seem to have any purpose, because it is just resting on the shaft. My guess would be vibration control of some sort. Assuming that the heat riser is ok, what else could be causing the long warm-ups and poor fuel economy? The choke dosen't stick, it opens all the way when warm. |
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| Author: | 64 Convert [ Thu Feb 13, 2003 5:24 am ] |
| Post subject: | |
The spring is an anti-rattle spring. When I lived in cold country, I sometimes put a piece of cardboard over the lower half of the radiator. Some vehicles just have a lot more cooling capacity than others and in cold weather, it's a problem. Your poor mileage might be because of the winter fuel blends used in your area. They can make your mileage drop 10-20% compared to summer blends. Also remember that normal winter driving conditions affect mileage even without the fuel changes. |
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| Author: | rustycowl [ Thu Feb 13, 2003 8:03 am ] |
| Post subject: | I've found my special purpose |
The purpose of the heat riser is to speed warm-up and improve cold-engine driveability. When the engine is cold it will direct hot exhaust gases up to a chamber just below the plenum in the intake manifold, this helps to warmup the intake charge and better atomize the fuel and keep it in suspension in the air bound for the intake valve and later combustion. You need to make sure it is directing the exhaust up when cold, and down into the head pipe when fully warmed up. There may also be a sheet metal 'stove' on the exhaust which connects to the air cleaner snorkle via a flex hose to preheat the air before the carburetor, again, for improved cold engine driveability. |
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| Author: | wolfears [ Thu Feb 13, 2003 4:40 pm ] |
| Post subject: | |
Thanx again for all the reply's, good point about mpg and the cold weather, hopefully it improves once it gets warmer. |
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| Author: | 77VolareSW [ Wed Feb 19, 2003 8:03 pm ] |
| Post subject: | |
sry i am going to ask some dummy questions....is your Radiator fluid full?, have you tried to flush your system?, Check to see if your Choke is working fine?, Is it timed right?, does your EGR valve work properly? and another thing might be a clogging Fuel Filter. |
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| Author: | wolfears [ Fri Feb 21, 2003 12:42 am ] |
| Post subject: | |
Radiator is full, has been flushed 4 mts ago, egr valve is brand new, choke is working fine and the fuel filter looks fairly recent, but it probably wouldn't hurt to change it just to be sure. |
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