I think my advance piston might be bad. Sometimes when I let the truck idle for a while, then when I get in and go is clatters like the timming is advanced, it only lasts for about 5 seconds.
This pump only has about 20,000 miles on it but it sat for about 6-7 years. It was on a parts truck that had bought last year, the owner had the paper work that showed the pump and injectors were low milage. So when my pump went bad on my truck, I put that pump on, and injectors in.
My question is, what harm will this do? Does it do this because the pump sat for so long? Is there an easy fix or should I get my pump rebuilt? Other than the advance, the engine runs good with no smoke. I put a quart of oil in the fuel tank last fill up, I think that helped.
It is not the cold advance doing this, I unhooked that wire. It seems to start the same with or without the cold advance, it just clatters more with it hooked up. Did the same with the old pump.
If your advance piston is worn, or rather if the bore is worn, the timing won't advance as rpms increase so I don't think that's your problem.
I think that you are either building up oil or diesel in your cylinders at idle that is pre-igniting when you take off. Take a look and see if there is any smoke during that clangy period. Just let idle for a while and then open the hood and rev it at the IP while watching your exhaust.
Thanks for the info. I have been meaning to clean the cdr valve, maybe that has something to do with it. I have never cleaned that, I have had the truck two years, I bet the PO didn't clean it either.
the pistion could be sticking a little, then slowly coming back to normal. try with the truck off moving the throttle lingage and see if the pistion is comin gback to center after u release the throttle.
u wull see the linkage on the driverside of pump, aluminum peice with a small wheel on it. as u open throttle, the rod will push pistion in. when released, see if rod is loose or not.
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PLAY TRUCK
1986 F250 6.9,ATS turbo, np435, BW1356, hp 60,welded up sterling 10.25.
converted from 2wd to 4x4
sittin on 36x12.5 goodyears
GETTING CONVERTED TO SHORTBED AS WE SPEAK!
the pistion could be sticking a little, then slowly coming back to normal. try with the truck off moving the throttle lingage and see if the pistion is comin gback to center after u release the throttle.
u wull see the linkage on the driverside of pump, aluminum peice with a small wheel on it. as u open throttle, the rod will push pistion in. when released, see if rod is loose or not.
That isn't actually the advance piston, it is inside the IP behind the big nut opposite of that rod.
That rod actually works in opposition to the advance piston by retarding the timing as the throttle is increased.
Also with the engine off it's hard to tell much about that rod since it is under pressure with the engine running and not with it not running.
For the CDR valve, a good one dosen't act any different than a bad one at idle, unless your air filter was extremely clogged.
I have not been consistently running fuel additive, till the last two tank fulls I put in a little power service, and the last tank I put in a quart of oil. I think it helped. It has not done the clatter noise for a few days,
My truck is a 87 6.9 (I know I am in the 7.3 section but I saw others here talking about the advance piston) The truck I took the parts from is a 87 6.9, so I should be good there. Partly why I am concerened is the parts truck has a bad motor. may have through a rod, not sure. I am hopping that the pump didn't destroy that engine.
I also have another parts truck with a 7.3 that runs good, I might use that engine someday if the 6.9 quits. I would like to first find a turbo for the 7.3, then run that engine.
Plywood is that correct that the timing is retarded when the throttle is increased, on a gas the timming advances with more rpm, throttle? (I guess that is ignition not fuel)It does make sense though, when ideling and I push in just the advance lever, it doesen't sound advanced, it chugs like it is retarded.
Plywood is that correct that the timing is retarded when the throttle is increased, on a gas the timming advances with more rpm, throttle? (I guess that is ignition not fuel)It does make sense though, when ideling and I push in just the advance lever, it doesen't sound advanced, it chugs like it is retarded.
Close, the timing on a gas engine advances with rpm such as the old distributors with the centrifical weights. But, remember the vacuum line, the purpose of that was when you hit the throttle and the vacuum dropped, it would retard the timing until the engine rpm caught up with the throttle and there was vacuum again to advance it.
On these diesels, they call that cam lever an IIRC "Light load advance", I prefer to call it a "Heavy load retard". On the DB2 as rpms increase the transfer pump pressure increases and pushes on the piston behind the big nut to advance the timing relevant to rpm. When the throttle is increased the cam lever pushes that rod which pushes on a spring that pushes back against the advance piston. I thought about it after and was going to mention that you can press on that lever but sounds like you're inquisitive like myself, but yeah, the engine will chug and spew white smoke due to retarded timing.
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