93 6.5 turbo hard to start when hot/ Turbo options

[wings04]

Hi there, I am new to the forum and new to the world of the gm 6.5 Diesel.

The problem I am having is that when warm it doesn't start well, my first bit of research showed that I must have a bad pmd or need to relocate it, now I am learning that I don't think the 93 has a pmd??? Would this just be an injection pump issue? I hope not... or could it be bad fuel? I have no idea how long the fuel has been in the truck as I bought it with a blown turbo and I am also in the process of replacing that.

Which brings me to my next question..? Can I swap a turbo in directly from any year 6.5? or do I have to stay with the 93 and why? With that how can I make a newer turbo work also what other options do I have?

Thanks everyone.

[BamaChief600]

I had the same problem with my 93. I used to carry a gallon of water with me and pour it onto the Pump head ( end of pump with fuel lines coming out). It cools down the pump long enough to start. I had to replace mine but that trick can help you determine if this is the same problem. As for the turbo Im not so sure about that. I do know it is a spring loaded wastegate so that could be a consideration.

[JohnC]

The hot start problem is probably due to a worn pump. You can try adding 1-2 quarts of 2-stroke oil to 6-5 gallons of fuel in the tank and see if the added viscosity helps at all. If it does, the pump's goin'.

Any year turbo as long as it's not off a van will work. 94 and up had a vacuum operated wastegate, so you'll have to get a turbo master or rig something up.

[wings04]

Like I said I am new to this can anyone elaborate on a turbomaster or what I rig up to make a newer turbo work??

[DaveBr]

First - why do you want to upgrade your turbo? If it is wore out then yes do the upgrade. If you are looking for more power (aren't we all) there are ways to get more boost out of your existing turbo. 93 6.5 has a mechanically acuated waste gate. You could increase spring pressure to hold the waste gate from opening so soon. If you decide to do this you need to upgrade the exhaust, pull the snorkel for the air intake(it lives between the inner and outer fender) Turn up your IP and get a set of A pillar gauges. EGT, Boost and tranny temp. Tere is no computer saftey shut downs so you need to live by these gauges. You can search exsisting threads for this info. If you can't find it P.M. me and I'll help you out.

Dave

[56pan]

I had the hard starting problem when hot on my '93 6.5 TD 2500 pickup. There's a service bulletin from GM about this. The switch contacts in the engine's oil pressure switch that feed the fuel pump deteriorate and don't supply the pump with full voltage. These contacts are bypassed through the ignition switch when cranking. My truck, when hot, would start and die. This can be checked at the ALDL connector with the engine running and is described in the service bulletin, if I remember it correctly. My pump was only getting 7 volts from the oil pressure switch contacts with the engine running. The contacts were burnt. There's a newer oil pressure switch from GM as per this service bulletin to correct the problem. Sorry, I'm at work away from home and don't have a copy. But you can look it up at www.alldatadiy.com. Of course, you'll have to buy a subscription. And no, I don't work for them. This fixed my hard start problem straightaway.

[Robyn]

The Hard HOT start is very likely a worn out pump.

As John mentioned try adding some Oil (two stroke is fine) or even a couple or more quarts of 30 wt oil to the fuel tank.

With about a half tank of fuel this will thicken the MIX and if the issue resolves some, its the IP thats going.

The head a rotors wear out and the clearance on the plungers gets a tad too much and at cranking speed, just can't make enough pressure to pop the injectors.

The turbo on your rig is likely a GM 1 or GM 2 The turbo from any of the 6.5 TD pickups will physically fit the engine.

The early rigs (92-93) had a spring pressure controled waste gate device bolted to the turbo. (Little Pod with a connecting rod to the turbo)

You can probably swap your parts to another turbo simply by unbolting your parts and exchanging them.

The Later units. GM 5,6,7 and 8 had slightly different connection points on the wategate arm.

The Turbomaster spoken of is a device sold by Heath diesel . this is a little bracket with a rod and spring assembly thats ajustable.

You can mix and match things here to get it up and running.

The Injection pump is probably a DB2 #4911
If its shot a pump from a J code 6.2 will fit and work in a pinch.

The fuel output on the 6.2 is not quite as much but can be turned up to near 6.5 values.


Keep us posted

Robyn

[wings04]

I am replacing the turbo because it is hooped, there is currently a Gm-3 in the truck, or used to be I just removed it yesterday. By they way everyone in here scared me a little bit with the removal instructions, but really it was a 30 minute job and I only have basic tools.

I now have something to run by you guys, I have another thread talking about a switch that i know nothing about, do you think this could be something to do with the pump? an isolator switch or something for more voltage on start up? remember it is only a hot start issue, so I am presuming that this is indeed an IP problem.

Now I will be replacing the orginal GM-3 with a GM-8, the only reason for this is an auto wreckers has one just down the street from me. If I am understanding everyone correctly all that I need to do to make it work is remove the vaccume actuated waste gate and replace it with eother a spring of sorts or possibly even rig the mechanical waste gate?

[DaveBr]

You should be able to take the mechanical waste gate actuator and bolt it to the GM-8. Same position that it was on the GM-3. Remove the vacuum actuated waste gate controll that comes with the GM-8 as it will not work on your rig. It needs a vacuum pump and 93's don't have them.

[DaveBr]

Thinking about my last post - The mechanical waste gate will not work without mods as the position of the waste gate arm on the GM-8 is different than the GM-3. You will need the Turbo master. Sorry about that.