Strange problem

[mobilevet]

Anyone have any ideas about this:

Starts fine, runs for a minute or two then dies. No codes. Turns over fine (nice and strong - not like there is a weak battery) but doesn't start for a few minutes. Then starts up and runs fine. The only thing I've notices is that once it cranks back up the voltage meter is down around 10 volts and then gradually comes back up to normal (about 13 - 13.5). ?? Maybe due to having to try and start it multiple times??? This doesn't happen every time, nor very often (as of now). Checked voltage at batteries with truck running and got 13.5v at both. I'm going to try and pay attention better and see what the voltage is at start up normally. At this point the next step will be to have the batteries checked for dead cells (even though they are only 1 year old) and also double check the alternator.... maybe also check the electrical connections to the remote PMD.

Other thoughts?

[More Power]

Starts fine, runs for a minute or two then dies. No codes. Turns over fine (nice and strong - not like there is a weak battery) but doesn't start for a few minutes. Then starts up and runs fine.

Sounds like there might be air in the fuel injection system. A fuel tank cap that is not venting correctly can produce excessive vacuum in the tank, which will pull in air somewhere in the fuel system as the vehicle sits (like overnight). Cooling fuel (like going from 80 degrees during the day to 40 at night) contracts, which produces vacuum.

Jim

[mobilevet]

Thanks Jim.... you may be right.. I just figured out that my OPS is out.. maybe since the IP was doing all the pumping (sucking) it got some air from somewhere?? Whatever the case a new OPS is on the way.

I just replaced the OPS last year and at that time was going to wire in the relay that you featured in an old TDP article (Oil Pressure Switch & LIft Pump Fix for the 6.5L Turbodiesel), however after visiting Radio Shack for the parts I wasn't sure if I had the right relay. They only had one that seemed close enough but I wasn't sure if it would work. The article only had two references to what kind of relay. One was in the diagram and said "5 amp (min) normally open 12 V DC relay" and the other in the text said "relay [with] a coil rated at 100ma (.100 amps)". Based on this the relay at Radio Shack was a 40A 12VDC Automotive Relay - there was no info on a "coil rating". Also it has 4 contacts. From the diagram it looks like one set it to a "switch", and the other just shows a line from contact to contact with a rectangular box in the middle of the line???

Any idea if this relay will work?

I assume that I use the switched set of contacts?

[JohnC]

You can get a generic 20 amp (or thereabouts) automotive relay from any auto parts store. The two contacts illustrated with a switch are the ones to control the load and the two connected to the box are the coil. Automotive relays often have a standard numbering system. 30 is the switched input. 87 is the normally open output. 87a is the normally closed output. 85 and 86 are the coil. the position of the contacts is standardized as well.

[mobilevet]

Thanks John... so how do I know the coil rating? Which leads do I used to protect the OPS - I can't really tell from the diagram in the article.

Have you done this mod?

[JohnC]

Don't worry about the coil rating.

Yes, I have done it twice. Never had a failure after that. See PM for more details...

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