95 CHEVY 6.5 TURBO DIESEL PROBLEMS

THE 6.5 THAT HAD A CRACKED PISTON.WELL WE INSTALLED A 94 6.5 IN THE TRUCK BUT WE CAN'T GET IT TO RUN RIGHT.WE INSTALLED NEW MARINE INJECTORS BEFORE WE PUT IT IN.THE TRUCK WILL NOT IDLE RIGHT & HAS A MISS IN IT.WE PUT THE PUMP FROM THE 95 MOTOR BUT IT DID NOT HELP.THANKS KINGPIN

Reply to
KINGPIN2
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Greetings,

First thing is you need to check the timing of the fuel injection pump, as well as the function of the fuel solenoid driver. These are common issues with these motors. I think the FI pump timing is going to be the most logical reason, but unless you've done other modifications as well (at least a chip and higher number calibration resistor for the FSD), then just intalling marine injectors by thenselves present their own set of issues with getting the motor to run properly.

Below I am recopying a reply I sent to a person on this group earlier with some basics about marine fuel injectors, but I'd plan on doing a timing and calibration of your FI pump first (especially since it's from a different motor than the one it's on now).

Here's the earlier post...

Yes, injectors will help get you extra HP, but you should realize a few things first.

First, the reason why marine injectors give improved performance is that they let you use that much more fuel and are not regulated for federal highway emissions standards. You could get a whole lot of extra power but that doesn't mean your mileage will be all that great or you will pass a smog test. Remember, the claim of +40hp is probably not from installing the injectors alone, but is seen with a host of other modifications as well (or at least a few others).

Second, in order to take advantage of marine injectors, you need a way to improve your fuel flow and engine management - which translates into spending money on something like a chip. In fact, since it's your fuel solenoid driver (FSD) that controls the fuel output of your fuel injection pump, you will need a higher numbered calibration resistor for it to get you more fuel. Your truck came from the factory with a #4, 5 or 6 chip (9 is the highest for on-highway vehicles) but you will need a resistor from a marine FSD of around #15 or more to get you the fuel delivery you need. Good news and bad news - the good news is a new calibration resistor only runs about $20.00. The bad news is if your FSD is still mounted to your fuel injection pump then it's incredibly difficult to remove the old resistor (which lives inside the wiring harness connector to the FSD) and replace it with a new one. There is still some debate as to when the ECM looks at the resistor value, so you may have to perform a calibration on your fuel injection pump in order to take advantage of a new resistor and increase fuel flow.

Third, if you want to increase your power you will also need to install an intercooler. An intercooler takes the compressed air from the turbocharger and cools it down, which increases the density before it enters the cylinders. The more air you can pack into the cylinders, the more efficient you will burn your fuel and the more power you will get. Unfortunately, an intercooler is NOT cheap, but if you're adding more fuel with marine injectors you will want more air in the cylinders as well to be able to burn it, and while possible it's not simply a matter of increasing the PSI from your turbo.

Fourth, adding power means generating more heat. Pre-'97 motors had problems with burning through head gaskets in the rear-most cylinders from too much heat, so you should also consider installing the post-'97 high flow water pump with dual thermostats and crossover. This water pump increased coolant flow through the motor and helped solved the burn-through problem with the gaskets.

Fifth, more power means more stress on your tranny, especially if you have an automatic. If you do, the 4L80E is a great tranny but increasing the input power will stress it and you will need to consider beefing it up as well.

And lastly, I recommend going to

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as it's a great resource for info about light-duty GM diesels. Much of the info I've gotten over the years keeping my former '95 Chevy in top shape came from them.

Cheers - Jonathan

Reply to
Jonathan

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