Help with loss of power in my Dump Truck

[RoyJackson]

I'd sure go with draining the fuel system and putting fresh fuel in there as the first thing. Gasoline doesn't have much of a shelf life...

 

[escavader]

EDDIE,
I had the same thing happen to my 73 360 ford.iT DID THE EXACT SAME THING.Come to find out when i was replacing the rotor,there was a little tab arm down there that i forgot to hook up.The first time i hit a snowbank it threw the timing off,so bad i thought i blew a head gasket.was able to turn the didtributer enough after i finally figured out it was the timing.It kept doing it til i finally went back in and saw what i had done.I know yours is alot newer with electronic ignition,but did it have thig arm in the distributer.Id loosen the distributer and turn it with it running to see if it helps,then you will know if its a timing problem.
ALAN

 

[PBinWA]

My vote is either a clogged fuel line/filter or bad fuel.

 

[midlf]

I vote with PBinWA. Backfire is often an indication of lean. Lean conditions can be caused by too much air (check the hoses, and that plate) or too little (good) fuel. I'd change the fuel filter, it is cheap and usually easy to do. Bad gas could also varnish up the carb jets/passages. Try carb cleaner with a lot of carb cleaner into the bowl vent. These things are easier and cheaper to do than the cam chain so probably should be tried first.

 

[EddieWalker]

Thanks for all the advice and ideas!!!!! /forums/images/graemlins/smile.gif

The fuel could be bad, but it's not very old since it was almost empty while I stored it. Then I added 20 gallons of new stuff last week, which I burned throught that first day. Then I just put in another 20 gallons of med. grade fuel. I was hoping a little more octane might help. It didn't.

The main fuel filter is a cartrridge type on the bottom of the fuel pump. Not like your normal passenger stuff, but more like what you'd find on a diesel engine. Anyway, I put a new one on when I first started messing with it a few weeks ago. I also put in a new cartridge filter thingy in the carberator where the fuel line goes into it.

I'll pull both and take another look to see if they are fouled. If so, I'll dump the tank, flush it and start over with fresh fuel.

The plate on the base of the carberator is something I don't know about. I'll take some starting fluid and start spraying everything to see if I can find a vacume leak. The engine idles fine and doesn't surge, so I didn't check for a vacume leak.

Bird really described the symptems well and it's what I keep thinking is wrong as well. Problem is that I'd like to test that somehow. Any suggestions on how to check for a bad timing chain?

The cap, rotor, wires and plugs are brand new. If I had a problem with the cap or rotor, wouldn't that be from the begininig when I put it on? As for a tab, I'm not familiar with one, but I have checked the distributor several times to make sure it's tight and not moving around. Again, it feels like the timing chain, but I'm still confused.

Thank you everyone for all your help,
Eddie

 

[JerryG]

<font color="blue"> I'll take some starting fluid and start spraying everything to see if I can find a vacume leak. </font>
WD-40 works also and is a little safer, but I have used both.

 

[rdln]

the timing chain test is turning the distrubitor about an hour one way, try to start it, the an hour the other way, try to start then two hours each way, if any these show an improvement verify by taking off timing chaing cover and look for misaligned marks (service manual comes in handy right about now) if gears are aligned then measure slop (service manual) if chain moves beyond spec, replace and you would be farther ahead down the road.

 

[HGM]

Eddie,
First off, I'm with Gerry about the starting fluid. Its not very safe... I like a little, off the shelf, carb cleaner or WD-40.

Realy sounds like fuel to me... After you check your filters, checking flow would be a good idea too. Just run the carb side fuel line into a bucket and crank on it to make sure you have good flow.

Another thing, I dont remember if this thing has cat's or not, but it could be a clogged exhaust. You could drop the exhaust from the manifold and try it.... Check your manifold vaccuum and that may help give you an idea.

As for the timing chain, take the dist cap off and turn then crank by hand(ratchet) in the clockwise dirrection untill you line up the timing marks to 0*TDC. Then rotate the crank counter clockwise untill the rotor moves. This will let you know how much play is there. Sholdnt be more than a couple of degrees. If you have a jumped chain, it should show 10-15deg...

Keep it simple, concentrate on the easy stuff first. It could be the chain, but it would really suck to change it and find it was just a clogged fuel pick-up /forums/images/graemlins/blush.gif...

 

[RobertN]

Ya, todays gas is terrible. Out here in Ca it is the worst!

My old '41 Farmall-A is hand crank to start. If it is on fresh gas, it fires up on only a couple of cranks. After it sits for a few weeks though, it is hard to start. Dump the gas, drain the carb, fill with fresh, and it starts easily again.

Of other note, the old tank on that Farmall sometimes has gunk flake off. It will plug the fuel outlet on the tank, blocking flow even before it gets to the filter...

 

[RobertN]

The Cat... Had that happen on a '89 F250 a few years ago. Was on vacation up in the mountians. Ran fine on the highway going through the valley(I5 through N.Calif). Got to the hill though, and noticed power loss. Over the weekend it got worse.

I opened the hood, and check stuff. Sitting in the driveway, it would rev up no problem. Filters were good, fuel fresh.

Finally, we were going to meet friends for 4th of July in Weaverville; lots of hills getting there. We made Weaverville, but we were going 2mph on the shoulder of the road. We pulled it the rest of the way to our friends house; it just wouldn't make the last 1/2 mile.

I checked everything again. Plugs were ok, had compression if you put your thumb over the hole. Filters were good. Electrical looked good. My Dad has worked in shops since the early 60's. I called him and he said check the exhaust. I didn't have enough tools, and stores were closed for the 4th...

Finally got tools, and unbolted the Cat. That truck fired up and ran great! It was loud, but I took it around the block. Ran good as ever, albeit loud.

It was still a holiday weekend, and all the shops were closed. We wound up driving it home open header'd. 4 hours on the road with an open header /forums/images/graemlins/shocked.gif Actually, it wasn't too bad unless accelerating. Just cruising was loud, but not too bad.

Put a new Cat on it after we got home. Worked like new(well, as new as it could for 220k miles on the truck and motor /forums/images/graemlins/wink.gif