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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Diesel injection pump pressure test ?
I am would like to find out the approximate pressure of my Ford 7.3 IDI
F250 injection pump . I suspect in is going bad but I want to confirm it before replacing it . Can I get a 0-3000 psi guage and plumb it up ( with the pessure appropriate fittings and metal line ) to one of the the injector pump ports and crank it for a couple of seconds ( cold, no glow plugs ) or would I be better off installing it in a Tee and connect the injector ( basically running it parallel) . As I presume that it takes about 1800 psi to run the injector , the pump should be running a minimum 2,000 psi hot or cold . =thanks |
#2
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wrote in message oups.com... I am would like to find out the approximate pressure of my Ford 7.3 IDI F250 injection pump . I suspect in is going bad but I want to confirm it before replacing it . Can I get a 0-3000 psi guage and plumb it up ( with the pessure appropriate fittings and metal line ) to one of the the injector pump ports and crank it for a couple of seconds ( cold, no glow plugs ) or would I be better off installing it in a Tee and connect the injector ( basically running it parallel) . As I presume that it takes about 1800 psi to run the injector , the pump should be running a minimum 2,000 psi hot or cold . =thanks For a good test you need the injector out of the engine, this enables you to determine if the spray pattern is OK or if any dripping is occurring. This test is normally done with a hand operated pump. Jack |
#3
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"Jack Hayes" wrote in message ... wrote in message oups.com... I am would like to find out the approximate pressure of my Ford 7.3 IDI F250 injection pump . I suspect in is going bad but I want to confirm it before replacing it . Can I get a 0-3000 psi guage and plumb it up ( with the pessure appropriate fittings and metal line ) to one of the the injector pump ports and crank it for a couple of seconds ( cold, no glow plugs ) or would I be better off installing it in a Tee and connect the injector ( basically running it parallel) . As I presume that it takes about 1800 psi to run the injector , the pump should be running a minimum 2,000 psi hot or cold . =thanks For a good test you need the injector out of the engine, this enables you to determine if the spray pattern is OK or if any dripping is occurring. This test is normally done with a hand operated pump. Jack That's for testing the injector, it sounds like he wants to test the pump itself. |
#4
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I want to test the pump pressure itself ( at least get a good idea as
to whether it is going bad ) not the injectors . |
#6
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On 29 Jan 2005 16:06:29 -0800, "
wrote: I am would like to find out the approximate pressure of my Ford 7.3 IDI F250 injection pump . I suspect in is going bad but I want to confirm it before replacing it . Can I get a 0-3000 psi guage and plumb it up ( with the pessure appropriate fittings and metal line ) to one of the the injector pump ports and crank it for a couple of seconds ( cold, no glow plugs ) or would I be better off installing it in a Tee and connect the injector ( basically running it parallel) . As I presume that it takes about 1800 psi to run the injector , the pump should be running a minimum 2,000 psi hot or cold . =thanks Having had three diesel engines, I would recommend taking it to a diesel shop (e.g., Seattle Injector, in Seattle) for testing. I really think that test you (or I) would do would be inconclusive or darnright wrong. Injection pumps don't often go bad. Air in the lines is bad. Tom |
#7
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If you have a way in, a guage that reads the pressures desired & the
specs your already there. Most of the 7.3s I see have an extension of some sort on top of one of the injectors (usually right front) that screws onto the top of the injector, then the line screws onto that. If you had one of these (from a junkyard) you could tap threads into the side of it to accomodate your guage & it would be a bolt in/ removable situation so you wouldn't have to destroy anything in the fuel system to tap in. |
#8
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In article .com,
" wrote: I am would like to find out the approximate pressure of my Ford 7.3 IDI F250 injection pump . I suspect in is going bad but I want to confirm it before replacing it . Can I get a 0-3000 psi guage and plumb it up ( with the pessure appropriate fittings and metal line ) to one of the the injector pump ports and crank it for a couple of seconds ( cold, no glow plugs ) or would I be better off installing it in a Tee and connect the injector ( basically running it parallel) . As I presume that it takes about 1800 psi to run the injector , the pump should be running a minimum 2,000 psi hot or cold . =thanks Injector pumps are positive-displacement things, so you absolutely must have a way for the diesel to get out. If you stuck the gauge directly to the end of the line you'd break something. Probably the gauge, but no guarantees it won't ruin the pump. You cannot tee-in to the fuel line either. Besides the lines being too stiff for you to make room for the tee, the volume of that line is calibrated. Changing it will throw off the pressure your fuel pump develops when injecting, so your measurements will be meaningless. If the pump cannot develop enough pressure to run the injectors due to wear you'll have hell even starting the engine. But that shouldn't ever happen unless it's been fed bad fuel. Your pressure is controlled by the injector needle, not the pump--it just builds pressure until that needle gives. Before pulling the pump what you need to do is bench-test your injectors as another poster described. Or test them in the engine: If your problem is rough running from a single bad cylinder, then with the engine running, crack each fuel line loose (one at a time) and see if diesel fuel is spilling out to make sure that cylinder is getting fuel. Crack it at the injector end, so you don't wind up letting an air bubble into the fuel line. You may even let out an air bubble in there already. Also listen to the engine, if there is no change to the engine sound/RPM when you crack it, or you start with a loud hammering sound that goes away when you crack the line, you've isolated the bad cylinder. Swap that injector with any other injector in that engine and run the test again. If your problem moved when you moved the injector, the injector is bad--replace or rebuild it. If the problem stayed in that cylinder, then you either have a problem in the pump or you have a mechanical problem, like a valve setting. Do the usual mechanical checks on the engine. If the engine's good, it's the pump. Once you narrow it down, you can decide what to do. Checking the pump's performance any further requires some hideously expensive equipment and is done off the engine. If you find a problem with the pump you might as well pull it and take it to a pump shop for a rebuild. -- B.B. --I am not a goat! thegoat4 at airmail dot net http://web2.airmail.net/thegoat4/ |
#9
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The best way is to remove the pump and attach it to a test arrange to check
for all of fuel delivery aspects. Regards, Ralf -- www.omnibusclub.de |
#10
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I have workred in a fuel pump shop for 15 years
diesel pumps realy work on volume of fuel depends on load and speed ,if your motor starts and runs / idle smooth the pump is in pretty good mechanical condition if it is hard to start hot or cold and the motor is in good condition ,compression , timing etc the pump elements are worn out through dirty fuel a simple test to check pump elements remove an injector from motor and turn it up side down replace it back on the injector pipe (dont worry about the return pipe let it flow to the floor /container ) crank the motor over and watch the spray patten (in the run position ) KEEP HANDS AND BODY AWAY FROM DIESEL SPRAY , DIESEL IN YOUR BLOOD STREAM YOU DIE QUICKLY the spray should be an atomise spray ( not like an oil can) to check for a miss undo one injector pipe at a time if you find a miss swap the injector to an other cylinder and see if the miss follows the injector the best thing to do is remove the pump and have it tested on a test bench and reset to the test data wrote in message oups.com... I want to test the pump pressure itself ( at least get a good idea as to whether it is going bad ) not the injectors . |
#11
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"Ralf Ballis" wrote in message ... The best way is to remove the pump and attach it to a test arrange to check for all of fuel delivery aspects. Yep. Bench test, calibrate and time it. FWIW the injector crack-off pressure is probably many times 3000psi. and it is more likely that your injectors need service, although mechanically controlled pumps do have an awful lot that could go wrong, especially if it has automatic cold start, temperature and altitude compensation etc. Huw |
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