hard start/ no start question

[GnosticSeeker]

was wondering if any one has had a simular exeperience and or answer a question for me. I have a 1988 Ford with a 7.3L Navistar. When I bought in last july I had to do some minor work on it to get it going like changing some of the glow plugs but a problem that I had was that after sitting for about 4 hours it would not start without prolonged cranking. I know I should have done something before but as used it infrequently I just sprayed a little starter fluid in the intake and waited untill the glow plug relay stopped cliking then started right up. Then I threw another monkey wrench in by starting using biodiesel in it(B20). After the second fillup comming home one night it started making a rattling noise and was overheating a bit. stopped and checked oil level and antifreeze levels. both were a little low so topped off. Continued down the road about 9 miles to my exit off the freeway and the rattling noise continued to get worse. I then parked it at a resturant a had it towed home the next day. I then changed the fuel filter thinking that the biodiesel had clogged it up. but to no avail the truck will not run. Could the injection pump have been going out and I just put the final nail in it's coffin when I went to b20? [img]/ubbthreads/images/graemlins/shrug.gif[/img] any Ideas? thanks for your help.

[aceohearts]

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I know I should have done something before but as used it infrequently I just sprayed a little starter fluid in the intake and waited untill the glow plug relay stopped cliking then started right up.

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Your first mistake...You can use ether on these engines, but NOT with the glow plugs (GP's). I use ether on my 6.9 but the GP system on it is non-functional right now. If you use ether with hot GP's you run the risk of premature combustion, and that can cause serious internal engine problems.

How did the old GP's look when you removed them? And what brand did you replace them with?

I doubt the biodiesel would hurt your injection pump (IP). It has better lubricity than dino fuel, and also tends to clean up the fuel system. Could be that if the truck has the original IP and injectors, the bio may have deteriorated the rubber seals in the pump and injector caps. The newer engines, and most rebuilt pumps use Viton seals. They're resistant to the bio where the natural rubber is not.

[Snotzalot]

Did you bleed the air out of the filter? How do your return lines look? Any chance you took a hose to the engine to clean it while it was hot?

[cdnsarguy]

Will it now start with ether or have you tried...... Was there any smoke associated with the noise.... did the oil pressure guage indicate anything when this happened.......no engine warning light on.

Remove the return line 90* fitting from the IP, then remove the check valve......check it for black particles.....

[crossbones2]

The problem that you have had for months and the problem now are most likely the same problem.......You will save a lot of time and money doing these things first...............

First, remove the fuel tank top.........
disconnect the fuel line at the lift pump (on the tank side)........blow compressed air back through the line to the tank........replace all of the rubber parts of the fuel line with new hose and screw clamps.......remove the fuel filter (replace if not new) fill it will diesel or Diesel Kleen if you wish........it will "soak in", so keep refilling until it just will not take any more...........now find the fuel return line that connects to the fuel filter and the injector return lines, then I want you to cut the return line between the filter and the injectors in two......put a bolt or what ever with a clamps on both ends.............(as cdnsarguy suggested)....clean the check valve on the IP return.....install the fuel filter...........disconnect the hot wire to the fuel solenoid......turn the engine over a few times allowing pressure to build in the filter......open the schrader valve........repeat until a steady stream of fuel comes out....with nice pressure behind it....... connect the hot wire and start the engine.......allow a couple of minutes for the engine to "purge" itself
then report any change.......good or bad..........

Do not assume the IP is bad until the above is done and a few other test are done.............

crossbones

[cdnsarguy]

The maximum return line pressure is 5 PSI....... over that # and damage may result in the selector valve or the check valve in the tank.......

[GnosticSeeker]

thanks all for all the suggestions. to clarafy, the previous owner was already using starting fluid to start as the hard starting problem was inhereted from the previous owner. yes I should know better than to use sf however I did try to minimize any damage by letting the auto glow plug relay to stop heating and let the glow plugs cool before attempting to start. When I changed the fuel filter I filled it with diesel fuel and let sit,refilled it and then had my son crake it over and I craked the the line going to the IP till I a steady flow of diesel. I have heard that if the return lines are leaking, they can introduce air into the system and then the IP cannot develop enough presure to off seat the Injectors. I just got some Vitro o-rings for the injectors and some bio-diesel compatable hose from a local parker seal dealer and will replace both this weekend. btw, when I changed the GP's half did not work when hooked up to 12V 4 did so left those and replaced the bad ones. cdnsarguy, I did't releaze there was a check valve in the tank. will check that also. crossbones2 will also try your suggestions. thanks agan

[Snotzalot]

Suggestion, replace ALL of the GP's and use the Beru glow plugs and nothing else!

[cdnsarguy]

My mention of a check valve was so you did not destroy it or blow it off the line. No need to check it out it would not cause a problem unless the tank was empty or very low.