low compression - how much longer will it last?

[GREASE FIRE]

just one oil change ago my truck started almost instantly - even in winter just a couple seconds of cranking.
less than a 1000 miles ago it would start on the first crank, but it would need to be a good 5-10 seconds.
now it will not cold start unless the block heater was plugged in or i use starting fluid. I have checked out just about everything i can think of and still the same situation - now i just need to find someone around here with a compression tester to confirm that this is the problem.
it runs fine and does not burn any oil.

anyway, i do have a spare engine but i don't have time to put it in right now.
So, the plan is to use block heater/starting fluid as needed until it quits.

has anyone been in a similar situation before? could an engine like this (170K) run for a long time still or is this a sign that it is just about finished?

thanks,
Paul

 

[dyoung14]

just one oil change ago my truck started almost instantly - even in winter just a couple seconds of cranking.
less than a 1000 miles ago it would start on the first crank, but it would need to be a good 5-10 seconds.
now it will not cold start unless the block heater was plugged in or i use starting fluid. I have checked out just about everything i can think of and still the same situation - now i just need to find someone around here with a compression tester to confirm that this is the problem.
it runs fine and does not burn any oil.

anyway, i do have a spare engine but i don't have time to put it in right now.
So, the plan is to use block heater/starting fluid as needed until it quits.

has anyone been in a similar situation before? could an engine like this (170K) run for a long time still or is this a sign that it is just about finished?

thanks,
Paul

Test the compression before you assume that its low

 

[1992f250idi]

im assuming you have, but you tested the glow plugs right? my parts truck has like half of them burned out and its the same thing.

 

[rhkcommander]

judging off of your prior posts i would make sure the glow plugs themselves were activated (use a volt meter and see how resistant each of them is right after starting up)

I would also check for any signs of fuel leaking from the IP, injector lines, return lines, olive deals, fuel filter, and fuel lines to the filter. Cant start without fuel, these trucks dont like air in their fuel lines either.

At least check the glow plugs like i said, even if the glow plugs are still working that doesn't mean that the harness or connectors or controller are giving them full power. Try manually jumping them and see if it works easier.

 

[GREASE FIRE]

thanks for the help.
as far as the glow plugs, i tested them all for continuity and they all checked out ok (using one of those 12v testers that lights up) and i also confirmed that i am getting power to the glow plugs by putting a volt meter at the wires going to the plugs.

i have not ruled out the possibilty that perhaps the beru gp's are "working" but not heating up enough. Perhaps they are worn out but not burned out completely...i believe someone on this forum already mentioned that could be the case - but has anyone actually had this happen to them?

thanks,
Paul

 

[OLDBULL8]

You can't check those GP's with a test light, that only means your getting voltage to them. With a volt/ohms meter check the resistance of them, around 3 ohm's. See if your in truck volt meter drops to around 8 volts when the GP's are cycling, they should cycle (WTS light) for around 10-15 seconds when cold 50 degrees or so. If you get a short GP cycle (5 seconds or less) more than likely some are burnt out.

Go here for more info. Thoughts on hard starts and AIR in the fuel , in the IDI tech articles.

 

[rjjp]

Me, but they were autolights not beru.

 

[Alex S]

You can't check those GP's with a test light, that only means your getting voltage to them. With a volt/ohms meter check the resistance of them, around 3 ohm's. See if your in truck volt meter drops to around 8 volts when the GP's are cycling, they should cycle (WTS light) for around 10-15 seconds when cold 50 degrees or so. If you get a short GP cycle (5 seconds or less) more than likely some are burnt out.

yes you can, its a basic test to see if they are open or not, you put the ground of the test light on the battery + and then the tip of the test on the GP terminal, if it lights up the GP is probibly working, if no light you know for sure its burn out

 

[rjjp]

A bad plug can still pass that test, I had a few of em do it.

 

[RLDSL]

Does not sound at all like a compression problem. If compression were bad, you should be eating oil, that's pretty much a given.
Whatever you do, NEVER use starting fluid if you have even one functioning glow plug!, the results can be disasterous, if you didn't need a rebuild before, you will after that. Only use starter fluid if the GP system is disabled.

CHances are you have bum gps, or air in the fuel system or a failing injection pump or injectors, YOu need to start troubleshooting along those lines

 

[Diesel JD]

Compression problems develop over a long time either from loading up critical areas with carbon or engine damage. Generally speaking if a diesel was running and starting fine last week, unless it hydrolocked or dropped a valve, pun a bearing, something drastic it's not the compression. I went through this with my truck a few years back, very hard to start cold, but it didn't have abnormally high oil consumption and had plenty of power. Good glow plugs, one day it just sort of straightened up. Must have been bad fuel, a slight air leak I couldn't track down, something.

 

[sassyrel]

yes you can, its a basic test to see if they are open or not, you put the ground of the test light on the battery + and then the tip of the test on the GP terminal, if it lights up the GP is probibly working, if no light you know for sure its burn out

trouble is--when they have over 1.5 ohms resistance--COLD--they are going out--and yes,the test light will light--but it means --NOTHING, as the resistance is what makes them work--had the same thing--took them out---resistance was a bit high. guess what??? they were heating farther up the gp, no the tip. so they were trying to heat the block--

 

[sassyrel]

Does not sound at all like a compression problem. If compression were bad, you should be eating oil, that's pretty much a given.
Whatever you do, NEVER use starting fluid if you have even one functioning glow plug!, the results can be disasterous, if you didn't need a rebuild before, you will after that. Only use starter fluid if the GP system is disabled.

CHances are you have bum gps, or air in the fuel system or a failing injection pump or injectors, YOu need to start troubleshooting along those lines

um, ive got a 6.9 now--that has low comp,and uses no oil. apparently--the oil scraper rings are wayyyy good--

 

[dyoung14]

I dont test glow plugs with ohms means nothing to me, i pull them and watch them glow