i know you checked but make sure #3 wires are not crossed. i did the same thing drove the car trying to sort out the problem same symthom no power and backfire,small miss at idle
| Slant Six Forum https://www.slantsix.org/forum/ |
|
| Backfiring https://www.slantsix.org/forum/viewtopic.php?t=23044 |
Page 1 of 2 |
| Author: | maxxus [ Sat May 05, 2007 10:02 am ] |
| Post subject: | Backfiring |
i have three different problems and I don't know if they're connected or not. First, the one I'm most concerned about is that my slant backfires on deceleration. As i bring up the RPMS it has a bit of a misfire but a small one. I don't have a timing mark on my timing cover so I retarded the distributer to a point before it starts to ping. I've played around with the fuel mixture screws on the carb with no luck there either. Second, there is a lot of carbon in the exhaust. I don't have the pipe on it yet and i can see huge amounts of carbon underneath the exhaust manifolds. Also I pulled the spark plugs to check the gap and they were coated in carbon. And third, it has no power. I have to bring the engine up to about 3,000 RPM to get the truck to move just a little bit forward in drive. If I try to reverse, the engine cuts out at 1,500 RPM and will die if I don't let off the gas. I hope you all can help me as I've been trying to work this out the last couple days in the rain, and it's driving me crazy! |
|
| Author: | SlantSixDan [ Sat May 05, 2007 11:02 am ] |
| Post subject: | |
Year, make, model, engine, transmission, mileage, brand and type of carburetor, location where you're running it, any recent work, any modifications, any recent parts replaced...? |
|
| Author: | maxxus [ Sat May 05, 2007 11:10 am ] |
| Post subject: | |
1979 Dodge D100 255 /6, not sure on the tranny but 8118 is molded onto the top, 0 miles brand new engine from jasper, Carter BBD 2 BBL carb, Kansas City MO, as far as work, I just dropped in the motor last weekend and spent the week putting everything else in, the only mod is i'm running a dutra dual. |
|
| Author: | Jeffc [ Sat May 05, 2007 11:06 pm ] |
| Post subject: | |
Backfire out the carb (true backfire)? or exhaust? |
|
| Author: | maxxus [ Sun May 06, 2007 9:21 am ] |
| Post subject: | |
Backfire out of the exhaust. Shoots about a foot of flame out the exhaust manifolds. |
|
| Author: | dakight [ Sun May 06, 2007 9:31 am ] |
| Post subject: | |
I would start with the cap, rotor, and plug wires. Also be careful of the way the plug wires are routed. It look cool to have them neatly tucked in looms and running straight and parallel but that isn't the best way to run them. Parallel wires can pick up a charge from an adjacent wire and fire the plug whle the intake valve is open. A misfire and/or backfire can be the result. Carbon tracks and bad contacts in the distributor cap can also cause havoc. |
|
| Author: | CrAlt [ Sun May 06, 2007 9:54 pm ] |
| Post subject: | |
Beg, barrow, or steal a timming light. You may be WAY off by doing it by ear. I'ed also take off all the plug wires and put them back one at a time. 1-5-3-6-2-4 |
|
| Author: | Slant6Ram [ Mon May 07, 2007 12:10 pm ] |
| Post subject: | Distributor installed wrong |
Sounds pretty much like you or someone else has the distributor installed 180 degrees out of time. The engine will run this way, but very badly. It's the first thing I would check and it's not hard to do. The rotor of the distributor should point to the #1 spark plug wire at very close to top dead center of the compression stroke for the #1 piston. Remember that the crankshaft turns 2 times for each time the distributor rotor turns once. If the distributor is installed correctly, the intake and exhaust valves should be closed for about half of a turn before you reach top dead center. I suspect you have a reasonable idea of where the timing mark is located on the timing chain cover so that you can estimate top dead center. If this isn't your problem, then there are lots of other good suggestions to look at, but I'd say check this one out first. It's a very common mistake. Hard to say if the transmission is related or not, but with the distributor installed wrong, the engine would have no power at all, and waste huge amounts of fuel (as indicated by flames and carbon) Good Luck |
|
| Author: | maxxus [ Mon May 07, 2007 5:10 pm ] |
| Post subject: | |
Per dakight's suggestion I checked the plugs, wires, distributor and rotor. Everything is brand new, and there wasn't any obvious damage. I pulled the plugs and cleaned the carbon off of them. I pulled the wires off and put them back on one by one in the right order. I'm pretty sure that I'm not off a tooth on the distributor because I move it too far one way or the other the engine starts to die. I have a timing light and the engine runs best when the timing mark on the balancer is lined up with far right bolt on the water pump. The distributor could be in 180 degrees off. A couple of other notes: There is a peg sticking off the timing cover to the left of the water pump, could this be the timing mark. And two, the gas in the tank is from two years ago and could potentially have a bit of water in it, could that cause the backfire? |
|
| Author: | CrAlt [ Mon May 07, 2007 6:00 pm ] |
| Post subject: | |
Quote: And two, the gas in the tank is from two years ago and could potentially have a bit of water in it, could that cause the backfire?
Yea
|
|
| Author: | Slant6Ram [ Tue May 08, 2007 7:25 am ] |
| Post subject: | Timing tab and 180 out |
Quote: There is a peg sticking off the timing cover to the left of the water pump, could this be the timing mark.
There where two types of timing marks that I have seen on slant sixes. Yes, the timing mark would be mounted to the timing chain cover to the left of the water pump. One version is a metal tab welded directly to the cover, the other has a stud in the cover that allows the timing tab to be bolted in place.If the 'peg' is actually a threaded stud, then you will want to find the timing tab that matches that type of cover. Those are pretty common, and I may have one in the parts pile. Otherwise, you may just want to get another timing cover with a tab already installed. While you may have a bad batch of gas, consider the fact that water doesn't blow out the exhaust as flames! I think you are a dead ringer for distributor installed 180 degrees out. Take a few moments to check because it is a very common mistake. |
|
| Author: | maxxus [ Tue May 08, 2007 4:46 pm ] |
| Post subject: | |
I took the distributor out and I tried to put it in at 180 degrees from what it was. I couldn't get it to set at 180. It would only sit at a tooth to the left or the right of the 180 degree mark. Either way it wouldn't fire up at all. The peg is a threaded stud, so I guess I need to find the timing tab. The engine runs best when the timing mark on the balancer lines up with the rightmost bolt on the water pump, which is about 90 degrees clockwise off of the threaded stud. So even if the distributor is 180 degrees off, why are the timing marks so jacked? Its a brand new balancer so its not worn rubber. Anyway, the motor still runs crappy, are there any other things I should check? |
|
| Author: | dakight [ Tue May 08, 2007 5:02 pm ] |
| Post subject: | |
You need to do two things to be sure your timing is right. First you need to get a timing tab. There are a couple of different ones. Some mount on the driver side and are held in by a timing cover bolt while others are on teh passenger side and I'm not sure of the mechanics of attachment. Once you get a timing tab in place you need to use a degree wheel and piston stop to locate true TDC then mark your balancer accordingly if it isn't already correct. That's the only way you get your ignition timing set correctly which will eliminate one possible source of yor problem. |
|
| Author: | Slant6Ram [ Wed May 09, 2007 2:19 pm ] |
| Post subject: | Next |
Quote: I took the distributor out and I tried to put it in at 180 degrees from what it was.
A better way to check, is to remove the valve cover and observe the valve events to be sure you are at tdc on the compression stroke.While you are at it, I would pull the #1 spark plug and make sure you are actually at top dead center. This would help rule out improperly installed timing chain. I hope I am helping and not harping, It's easy for me to run 10 tests on my car in a few minutes, but takes days to list them out one by one and wait for responses online. It always makes it into more work than it really is this way. If you've got a place close by to find a junk motor, you've got about a 50/50 chance of finding the timing tab you need. If it's not welded on, then it's gonna be the one you need in my experience. If you are really stuck, give me a pm with your address, and I'll drop on in the mail for you. |
|
| Author: | terrylittlejohn [ Wed May 09, 2007 3:44 pm ] |
| Post subject: | backfire |
i know you checked but make sure #3 wires are not crossed. i did the same thing drove the car trying to sort out the problem same symthom no power and backfire,small miss at idle
|
|
| Page 1 of 2 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|