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Mild Thunder

1998 E7 wont start

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Hey guys. Had the truck out today. Was a little low on fuel in the tank. Headed to the fuel station to get fuel and a coffee. I got about a mile from there, and the truck kinda started to sputter a little. Made it to the station, set the parking brake, and it was idling fine. So I shut the truck down, grabbed a coffee and fueled up. Got back in the truck, wouldnt start. Thought maybe it was air in the lines. Pulled the fuel filters, they were full. Pumped the hand pump a bunch and still nothing. Called a service truck out. He came out with fresh fuel filters, filled them with fresh fuel, nothing. He cracked open a couple injector lines thinking they were air locked, no help there. Actually no fuel coming out there either though. Gave it a couple sprays of ether and it would run on the ether for a second then stall back out. He blew the line from the tank and that was clear. He loosened the return line to the tank, and fuel was coming out while cranking.

Ended up having to get a wrecker to tow it back to my yard. Any tips on what to check for next? Fuel Solenoid? Injection pump problem? Any insight would be great.

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If its an Etech, maybe the gear spun on the fuel pump. Just remove the pump and spin the gear, if the shaft doesnt spin with the gear, the pump is bad. You could also check the pressure relief valve. Its the fuel fitting going into the block below eup 5. Remove fuel line from fitting and pump primer. If fuel shots out easy, there could be debris stuck in it, or it could just be bad. You should feel some pressure build up while pumping the primer pump if the relief valve is good.

But if its an E7 with an injection pump, none of this applies.

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Pretty sure its a basic E7 With injection pump. Do the fuel shutoff solenoids go bad on these trucks?

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Based on the pic, it is NOT an ETech but rather a conventional pump-line-nozzle injection system.

Is the transfer/supply pump providing fuel to the injection pump? If so then the problem is between the pump and nozzles. Or could be a problem with the ECM.

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Also, noticed the engine cranks over hard, like fast hard. Not like it doesnt have compression, but like I just installed 3 new mega batteries.

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clean and check all grounds you might have a low voltage issue that's causing the problem, double check eng. to frame grounds. you can install all sorts of new stuff and not fix anything if grounds are poor!

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Installed new supply pump today, no luck there. I have a feeling it's something electrical that controls the fuel shutoff valve, however I don't know where that's located to even begin checking voltages for it. So far 400 bucks for a tow, 300 for a fuel pump, and 2 days lost work. Next is probably gonna be having to get it towed to the mack dealer.

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My advice is call the dealer and see if they can get some one on it.If you cant test it and just throw parts on it the repair can get very costly and still not be repaired.It could be electric and it could be fuel related and by you saying its cranking very fast it could be mechanical related.

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No, that is the econovance (engine timing control).

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The fuel shutoff solenoid is just to the left of the circle (10 o'clock position). It is mounted on the front side of the injection pump. The fuel solenoid itself may be functional but it is controlled by the V-MAC module (ECM). There are many sensors that "feed" the ECM. It could be anyone of these sensors that is causing the ECM to shutoff the fuel.

Is the CEL (check engine light) illuminated?

As theakerstwo posted, your best bet is to get it to a Mack dealer so they can hookup a computer and diagnose the issue.

As much as I like to "do things myself", it is sometimes less expensive and time consuming to pay an "expert".

Either way good luck in resolving your issue.

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Thanks for the help! No, there is no check engine light. Engine was running great prior to this. was trying to avoid bringing it to the local mack dealer. They have been known to take a while to get to the repair, and very costly. Plus another 400-500 tow to get it there isnt sounding good!

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Check the gray round connector coming out of the back of the pump. Make sure all the pins are good and tight. A bad connection there will cause a, crank, no start problem.

Etech came out in 1998, that why I mentioned it.

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Check the gray round connector coming out of the back of the pump. Make sure all the pins are good and tight. A bad connection there will cause a, crank, no start problem.

Etech came out in 1998, that why I mentioned it.

Thanks, I did that today. Looked good in there.

Being a hobbyist, from cars, to boats, to all kinds of stuff, its always been pretty awesome to be able to go on the web and get information on how to. I gotta see if I can access a manual for this truck to start running some sort of diagnostics to be able to test things, before bringing it to the dealership. This truck has been nickel and diming me to death these past couple months, any profits i've made have went right back into the truck, and this problem may end up being the nail in the coffin if something doesnt go right for me soon. A new rig isnt in the cards, and sinking 5000 into this old truck isnt either. :blush:

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I am no mechanic but I would bet it is related to the low fuel level. If it were mine I would keep running it carefully on ether while holding the throttle to the floor to try to force air out of the lines.

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Might try checking the silenoid in the dash to make sure it is getting a full 12 volts through it when cranking the engine. We had 2 different trucks do this, and they acted as you described. Good luck

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Might try checking the silenoid in the dash to make sure it is getting a full 12 volts through it when cranking the engine. We had 2 different trucks do this, and they acted as you described. Good luck

Thanks, I will check that in the morning!

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I have a 95 CHR, vmac. Every now & then the big solenoid under the dash don't come alive with ign on, starter will work good but eng nogo. I can tell when its happened because the volt gauge stays dead. For what its worth I'd be second checking that the fuel system only has fuel in it, no air.

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I do know that when I turn the key on, my volt meter is showing voltage. Also, yesterday i checked that solenoid with a test light and got power in/out with key on. I'll check it while cranking with a voltmeter today. Wish i had a pinout of the harness that goes to the injection pump.

As far as fuel goes, the truck has 2 new fuel filters I put on, filled with fresh diesel. A new supply pump installed. I get fuel out of the supply pump while cranking. I get fuel out of the return line back to tank while cranking. I cracked open a couple injector lines, no fuel there. While cranking I get no smoke, or anything from exhaust.

I am guessing the problem is between the supply pump, and injector lines. Which leaves me with the injection pump itself, or something that controls the injection pump? ECU, fuel shutoff, wiring, etc

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Fooled with a bunch of wires all day. Finally before giving up, I found the TDC sensor wire rubbing on the engine block, where it had rubbed thru the wire insulation. Got it moved, taped the wire up, and truck started. However, its running a little rough right now. Sometimes idle smooth and rev's smooth. Then will start idling rough, and while revving it will miss/hesitate a bit. Thinking about replacing the TDC sensor, and maybe the TEM sensor, as the wires going into the TEM sensor dont look so great either.

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