new to the civilian 6.5...need help

[ChevyDuty]

hey all, i'm new to the civilian 6.5, but i worked on them for years in the military...but those were all mechanical injection (good 'ol DB2) and very simplified.

while looking online i found an ad for a '98 K2500 ECSB with a 6.5 turbo diesel and 4L80E for sale or trade for a gas-powered truck of equal value. just because i could, i sent her an email offering my '91 K1500 ECSB with the TBI 350/700R4 as a trade and she wants it! we haven't actually DONE the trade yet, but it will be happening this weekend. now, i've done some searching on here and a few other sites about the problems the truck has, but i wanted to see if i could get advice/help on my specific situation...

here's the story as it was told to me. the truck was running perfect (193k) and she decided to replace the fuel filter to keep up with maintenance. the truck wasn't running bad at all, she just decided to change it. she admittedly doesn't know anything about diesels except to use the green pump. so after putting the fuel filter in, she couldn't get it to start.

thinking she had seen her brother start a diesel with ether, she used it. the engine kicked back in protest and chipped the flywheel and broke the starter. she had a Chevy dealer replace them both. after getting it started, the truck had 5 codes. replacing the PMD (and relocating) cured 3. she also had the dealer put in a new supply pump...but that didn't do anything. the two codes left are the infamous P0251 and the P0370. the dealer just wanted to throw an IP on it. now, i know that could very well be the problem, but i'm kinda thinking it might be contaminated fuel.

see, the truck runs great sometimes...such as today, she's gotten in it twice and drove it...it's ran great...but other times it has little/no throttle response. i know i need to do a lift pump test, and other things (that i'm not familiar with) but i was hoping by giving all the info i knew maybe y'all could give me some advice on it?

thanks in advance!
Josh

[bl78ljb]

It sounds like you are fairly knowledgeable about engines in general, and I would do due diligence in checking fluids. The one big thing I would check is coolant, and be sure it is not using any - even a small amount, as it could indicate bigger problems especially with the ether use. The '98 has a lot of good options on it, but the addition of the oil squirters in the block can cause cracking with overloads / abuse and heads can have cracks as well and not always obvious by oil in the coolant (I was snagged by this "it leaks a little coolant over time but I haven't found the source yet but has not been much"). Hopefully others with more knowledge will chime in as well.

[ChevyDuty]

thanks for that information! i knew the oil squirters were in a couple years, wasn't sure which ones. it was between this one and a '95. i haven't actually done the swap yet, but i haven't heard back from the guy with the '95 yet. he's out of town on business. but i am still leaning toward the '98. just really hoping it's only contaminated fuel. i know ATF will clean it out, with some 2-cycle oil to lubricate things...but how much ATF should i put in? i read somewhere i should use about a "teacup", i'm sorry, i'm not a tea drinker lol...how much is a teacup? i don't wanna pour too much in the filter housing...

[rustyk]

Use the two-cycle engine oil - it's designed to burn with minimum residue. ATF is designed for transmissions, and that's where it should go.

[ChevyDuty]

will the two-cycle clean it out? or should i just get some Diesel Kleen or something like that from the store? if it's got contamination in the fuel system i need to clean it out as best as i can...

thanks for your help!

[DmaxMaverick]

Good ol' clean fresh #2 is the best cleaner. A little fuel additive, like Diesel Kleen (or FPPF, Stanadyne, Howes, STP, MMO, etc, at double max label dose once, then as directed, any "injector cleaner" that doesn't contain alcohol), is also a good idea. Burning ATF is old school. It can help to clean up the inside of the fuel system, but can also cause new issues with the combustion chamber.

That said, it doesn't sound like contaminated fuel is the problem.

Two cycle oil will help to replace the lubricity lost in late production fuels. It does contain detergents, and may help with cleaning, but I have no proof of that. I use 2 cycle oil and Power Service with every fill up. Increased mileage and piece of mind offsets the cost.

[ChevyDuty]

what are you thinking it is? i know these codes also point to a bad IP, but i just have a lot of trouble believing the pump went like that. i mean, all it was was a FILTER CHANGE. it was running great before that. it simply sucked some air in and had to be reprimed...

i'm not saying that's impossible...i'm just asking...what do ya think it could be...? where do i begin on this thing? i'm probably going to have it in a few days...

[ercaduceus]

Did she bleed the air out of the system when she changed the filter. ? air in the pump.

[ChevyDuty]

that is a great possibility. all they did was get it started...so it could still have some air in the system...

[rustyk]

DmaxMaverick: Good ol' clean fresh #2 is the best cleaner.

Amen, Bro'. To digress a bit, the use of ATF was sanctioned years ago when cars were carbureted and gasoline was leaded. Any model of engine would accumulate deposits (mostly lead and some phosphorous compounds) which would contribute to "knock" (by taking up room in the combustion chamber, increasing the compression ratio, and causing "pinging"). Engines were tested to determine the point at which engines' deposits stabilized, and then increased octane gaso was tried until the octane number caused the pinging to stop, and the difference between the octane number starting the test and that at the end was "octane Requirement Icrease", or ORI. For obvious reasons, while we at the oil companies knew, auto companies never divulged the figure to the public (I wonder why?). Note that increasing the octane of the fuel did not significantly reduce deposits.

A second cause of "pinging" is preignition, also caused by deposits, but in this case they would retain the heat between combustion cycles, and ignite the gasoline too early. Pinging was the audio symptom. Increasing octane number had little effect.

However, by changing the combustion parameters in the engine either of the above deposits could be reduced, and that's what ATF did. Considering the lead and lead-scavenging additives in the gaso, ATF's additives were relatively benign, but the base stock was effective in doing what was wanted.

As an aside, the third cause of "pinging" is detonation, an explosive kind of combustion caused by a too-lean mixture, not related to knock or preignition, but in many cases, mirroring the symptoms casued by the other two.

Anyway, use of ATF in a modern car engine (with ported or direct FI, and in most caes with TBI, running on unleaded) is generally discouraged, as the injectors are set for a certain viscosity, and ATF or 2-cycle messes with that. Injectors can get dirty, but occasional use of a reputable additive like Seafoam or Techron (which is what I prefer) can, in many case cure the problem. Unleaded fuel has eliminated the usual build up of deposits, except for those caused by incomplete combustion - caused by dirty or defective injectors.

Diesels, however, have different issues. Where the injectors on a gaso engine operate at fairly low pressure (the injectors' function is to atomize the fuel into the air flow, and to do so more efficiently than a carb), hence cleaner, more efficient combustion. But, with the exception of some proposed direct injection systems, the atomized gaso-air mixture is drawn into the cylinder by suction.

In the diesel, air is drawn in, and then the fuel is introduced. Because the intake valve is closed on a gaso engine when ignition occurs, the injector is isolated from the combustion process. Diesels' injectors have to endure the combustion process.

To make a short story intolerably long, this is why I discourage continual use of any lubricant except diesel fuel additives specifically designed for such use, biofuel (properly prepared, and in small doses), or 2-cycle oil; none has additives that can lead to deposits. The object is to lube a mechanical pump, and nothing else. So the chosen additive should do nothing else. In a pinch, ATF is better than nothing, but only then, and only by a small margin. Because they are designed and calibrated to operate in the combustion process, diesel FIs tend to be robust, but they do wear out. Occasionally one will develop sticking, but diesel fuel is a pretty good solvent (Jeez, that's what we used instead of Goop in the Olde Days-but then we had to clean up, so's we could put the gas in peoples' cars, clean the windshield, inspect the air filter, fill the windshield washer tank, and check the oil, etc. :D), and running the engine usually clears up temporary issues.