dongfeng tractor with y385t wont start help

[Bob Rooks]

My F-350 has a turbo boost gauge, two temperature gauges, and a fuel gauge, plus tach & speedometer. Guess they think I don't need to know anything else. When I upgraded the instruments on my dozer I installed Murphy Switchgages and connected them to a strobe light. I now have high temp. and low oil pressure alarms. A good thing.

20P7-100: Lockout Pressure Swichgage®

20T-250-4-1/2: Temperature Swichgage®

On your fluctuating meter; is that an ammeter or a voltmeter? It sounds like it's just your voltage regulator cutting in and out, but I would check all your battery cable connections to be sure.

 

[reelnative]

I like those gauges bob thats a great idea, me im kind of like a pilot, i scan my gauges about every 20 to 30 sec hahaha old hab from operating boats out at sea with nothing better to do, im a lic USCG captain and on the smaller boats I ran i didnt get to have a eng like yourself looking at all that stuff, I had to do it myself, hahahhah, hey bob is there a pressure switch in the oil system of these tractors and that is why my pressure drops from say 65 to 50 when the rpms are up or could I have an oil pump cavatating, I thought a pressure switch cause it allways did it at the same rpm and pressure ? and on that meter yea i thought it was the reg comming on and going off it just looks strange, my new gauge ill just hook up to the batt or keyed power

 

[quicksandfarmer]

is there a pressure switch in the oil system of these tractors and that is why my pressure drops from say 65 to 50 when the rpms are up or could I have an oil pump cavatating, I thought a pressure switch cause it allways did it at the same rpm and pressure ?

There is a bypass on the filter that opens when pressure gets too high. I don't know if that's what you're seeing.

 

[reelnative]

cold start up it is dead on 60psi and when at 80c and 1000rpm its at 42psi, so to me that sounds about as normal as can be, there was one weard thing tho and maby you guys can tell me what is going on I think i have an idea but when i add throttle the pressure goes up until it hits about 65psi at 1800rpm then when i hit 2000rpm the pressure drops to about 50psi, im thinking that there is some sort of bypass

 

[Bob Rooks]

cold start up it is dead on 60psi and when at 80c and 1000rpm its at 42psi, so to me that sounds about as normal as can be, there was one weard thing tho and maby you guys can tell me what is going on I think i have an idea but when i add throttle the pressure goes up until it hits about 65psi at 1800rpm then when i hit 2000rpm the pressure drops to about 50psi, im thinking that there is some sort of bypass

I'm thinking you have the terms "bypass" and "relief" confused, and no, I'm not playing semantics.
The symptom you describe where the pressure drops 15 psig at 2,000 r/m sounds like the oil pump relief valve dumping excess volume - a lot of it. Enough to hold it open until it re-seats itself. Is this repeatable?
Quicksand also makes a viable point about the oil filter bypass. However, that takes place around 15 psid, and that most likely happens at around 30 psig, so you may not even notice it happening.
So the question arises; Why is the relief valve popping?

 

[reelnative]

I'm thinking you have the terms "bypass" and "relief" confused, and no, I'm not playing semantics.
The symptom you describe where the pressure drops 15 psig at 2,000 r/m sounds like the oil pump relief valve dumping excess volume - a lot of it. Enough to hold it open until it re-seats itself. Is this repeatable?
Quicksand also makes a viable point about the oil filter bypass. However, that takes place around 15 psid, and that most likely happens at around 30 psig, so you may not even notice it happening.
So the question arises; Why is the relief valve popping?

yes bob it is repeatable, when i hit 2000 to 2100 it does it and the pressure is at 65psi when it drops back down to 50 it doesnt do it like a dump it goes down as you increase rpm just as it climbs when you add rpm, at 1800 its at 65 then as you add rpm it dropps till it hits 50, so say if i was at 1900 it would be somthing like 55 or so, could my oil pump be cavatating, and why would it be popping if it is at 65psi thats not a real hi psi, is there an adjustment that can be made

 

[Bob Rooks]

yes bob it is repeatable, when i hit 2000 to 2100 it does it and the pressure is at 65psi when it drops back down to 50 it doesnt do it like a dump it goes down as you increase rpm just as it climbs when you add rpm, at 1800 its at 65 then as you add rpm it dropps till it hits 50, so say if i was at 1900 it would be somthing like 55 or so, could my oil pump be cavatating, and why would it be popping if it is at 65psi thats not a real hi psi, is there an adjustment that can be made

Okay, my bad. Bad choice of words. By "dump" I meant to open. The relief valve is spring loaded so the regression of pressure would be linear with the increase in engine speed. You haven't checked those bearing inserts yet, have you. No problem - for me anyway.

 

[reelnative]

no I didnt Bob , well not yet any way hahahha, i wanted to ck out the oil pressure with a real gauge before i dug in, does my pressure look high for this eng even tho the bearings and rings are new ? and if that pump is opening at 65psi isnt that kind of low I saw a post were quicksandfarmer was running up to 100 psi on his 385 ?

 

[greg_g]

I wouldn't be so quick to conclude there's an engine oil bypass on that machine. I seem to recall discussions that recommended making sure that any replacement filter purchased has its own internal bypass, since the OE filter housing does not. Or perhaps just some OE filter housings did not, I don't recall the specifics anymore. That said, the drop to 50 psi @ 2000 rpm does suggest a relief valve somewhere.

That said, your pressure figures seem a bit high compared to the 4 Chinese tractors I've owned. Cold pressure among them averaged perhaps 50 psi, hot idle between 7 and 10, working temp at PTO speed around 35-40. When working them hard on a hot summer day it was not out of the ordinary to see 25-30.

Does your filter housing have a pressure adjust feature? It might look like a screwdriver adjust locked down by a hex nut. If so, you could lower the pressure so that it hits 50 max.

//greg//

 

[Diamondpilot]

I wouldn't be so quick to conclude there's an engine oil bypass on that machine. I seem to recall discussions that recommended making sure that any replacement filter purchased has its own internal bypass, since the OE filter housing does not. Or perhaps just some OE filter housings did not, I don't recall the specifics anymore. That said, the drop to 50 psi @ 2000 rpm does suggest a relief valve somewhere.

That said, your pressure figures seem a bit high compared to the 4 Chinese tractors I've owned. Cold pressure among them averaged perhaps 50 psi, hot idle between 7 and 10, working temp at PTO speed around 35-40. When working them hard on a hot summer day it was not out of the ordinary to see 25-30.

Does your filter housing have a pressure adjust feature? It might look like a screwdriver adjust locked down by a hex nut. If so, you could lower the pressure so that it hits 50 max.

//greg//

On my tractor my pressure is right in line with Gregs.

Its a 2004 Jinma 284 with a 385 engine.

Chris

 

[Rich Waugh]

Yep, that's where the pressures run on my 304 Jinma with the TY395 engine.

 

[reelnative]

I wouldn't be so quick to conclude there's an engine oil bypass on that machine. I seem to recall discussions that recommended making sure that any replacement filter purchased has its own internal bypass, since the OE filter housing does not. Or perhaps just some OE filter housings did not, I don't recall the specifics anymore. That said, the drop to 50 psi @ 2000 rpm does suggest a relief valve somewhere.

That said, your pressure figures seem a bit high compared to the 4 Chinese tractors I've owned. Cold pressure among them averaged perhaps 50 psi, hot idle between 7 and 10, working temp at PTO speed around 35-40. When working them hard on a hot summer day it was not out of the ordinary to see 25-30.

Does your filter housing have a pressure adjust feature? It might look like a screwdriver adjust locked down by a hex nut. If so, you could lower the pressure so that it hits 50 max.

//greg//

mine isnt much off from that at cold start its 60psi warm at 1000rpms, at 80c amd 1000 rpms its 40 and at 2200 its 50psi and warm 80c at 800rpms its at about 35, i hate to say it but if your running 7 to 10psi at ldle warm that sucks no matter what kind of eng it is, anything below 20 is bad in any eng at any rpm, dont you get scared when you see your oil gauge almost pegging zero,, hahahha mine just goes from 40psi up to 65psi then back down to 50 on the way from 1000rpm to 2200 rpm

 

[Rich Waugh]

Mine runs around 9-10 psig at idle when up to full operating temp and I understand this is pretty normal for these engines and not something to be concerned about. As long as the oil is circulating through all the places it should, I can't see how it matters if it is doing it at 10 psig or 30 psig - the engine is getting lubricated. After all, many engines get along just fine with only "splash" lubrication and no oil pump at all. Some of these are industrial diesel engines too, not just lawnmower engines.

I'd be much more concerned about excessively high oil pressure, which could indicate a restricted flow in a critical area.

 

[reelnative]

Mine runs around 9-10 psig at idle when up to full operating temp and I understand this is pretty normal for these engines and not something to be concerned about. As long as the oil is circulating through all the places it should, I can't see how it matters if it is doing it at 10 psig or 30 psig - the engine is getting lubricated. After all, many engines get along just fine with only "splash" lubrication and no oil pump at all. Some of these are industrial diesel engines too, not just lawnmower engines.






I'd be much more concerned about excessively high oil pressure, which could indicate a restricted flow in a critical area.

yea it might be ok for these engs but that doesnt mean i have to like it hahaha, i would feel a whole lot better if an eng holds atleast 20psi when warmed up, I was worried when i thought mine was hitting 80psi but nowing now that 60 to 65 is were its topping out at, that doesnt bother me much, exp that the rings and bearings are all new, im sure it will drop when the eng gets broke in

 

[SPIKER]

Mine had a good gauge (China one) but I had 4 tractors (20' container full self import) and one of the others that I sold had a bad gauge so I swapped my China Gauge into that 284. I put a mechanical on mine that first week in May 2002 and it's oil pressure with the china shipping goo was 80PSI at start up 1000 rpm and stayed there till warmed up and drops back into the mid 60's on good oil. now after almost 600 hrs and well used up oil cold it sets at 1000rpm its 80 PSI cold and 50psi warm with idle and HOT it drops back in the teens.

Mark

 

[greg_g]

t if your running 7 to 10psi at ldle warm that sucks no matter what kind of eng it is, anything below 20 is bad in any eng at any rpm, dont you get scared when you see your oil gauge almost pegging zero,,

Nope. I was assured by a Chinese tractor dealer that I know and trust that there are no oil pressure concerns until hot idle is consistently below 6 psi. Owning/operating/maintaining four Chinese tractors over 10 years seems to have proved that 7-10 is indeed normal and safe. If in fact that your drop from 65 to 50 is being produced by a relief valve, the tractor is trying to tell you that the oil pressure is too high - a measure that protects gaskets and seals. Again, I point you toward the pressure/flow adjustment on the oil filter housing.

FWIW, my $36,000 John Deere 3720 doesn't even have an oil pressure gauge.

//greg//

 

[reelnative]

hi greg I looked
at my filter and on the side of the filter mount there is a larger bolt and a cap nut on top of it, is that the adjustment, the po might of messed with it before I got the tractor, but on the post above yours SPIKER says that his tractor runs up to 80psi on start up, and QUICKSANDFARMER has a eng that runs at 100psi on start up, could i have a very touchy valve that wants to dump early, if that bolt is the adjustment i will mark were it is now and adjust it to see what it does, but to me even 65psi is not a lot, with new bearings, pistons and rings the motor should have a higher pressure, to me it seems like my pump is cavatating at higher rpms and that is why it is dropping, I also will ck my oil level today, thanks everyone for the help,

 

[Rich Waugh]

Have you looked at the manual for that engine to determine if it has an oil pressure relief valve on the oil pump? Nearly every engine I've ever worked on had a ball check relief valve either on the oil pump or on the primary oil gallery.

 

[Bob Rooks]

...with new bearings, pistons and rings the motor should have a higher pressure, to me it seems like my pump is cavatating at higher rpms and that is why it is dropping.

There is no correlation between pistons and rings and oil pressure. I doubt your oil pump is cavitating.

 

[Rich Waugh]

I doubt a cavitating oil pump, too. I believe these tractors use a gear pump for the oil and they're not know for having cavitation issues. I think you'd have to spin one p to near supersonic speeds before it experienced any cavitation.