93 6.5

[farmerson]

hey havent been on here in a long time because i switched over to cummins motors. Well im glad i kept my account when i sold the chevy, because both my cummins are broke down right now and well guess what, the mighty old 6.5 has came to the rescue. 3 days ago i bought a 93 with a 5 speed, had to time it and do some clutch work on it but for 1800 bucks i couldnt pass it up. Anyway on to my question, when your drivin down the road it has a tendancy to want to lunge or lope so to speak when you let off the throttle, only way to get it so stop is push in the clutch or hit the throttle. I was wondering if this could be the timing chain (from what iv heard they have one). Also its like it dont have any power between 2500rpm-3000 sometimes and then its like the charger lights and it takes off and has some real good power for a 6.5. and sometimes when you mash the throttle its like it defuels until you let out of the throttle. I dont know much about them but im learning. thanks!

[JeepSJ]

First step, change fuel filter. You don't know when it was done last and it matches the symptoms and it is a cheap first step.

[JohnC]

Yup, filter first. And, try a heavy dose of a good fuel conditioner, too. the injection pump innerds could be hanging up.

[DaveBr]

Sounds like you could have wastegate issues. You have a mechanical wastegate so check the rod for pressure and free operation.

[Robyn]

YUP YUP sure sounds like it could have a clogged filter.

The bucking/stumbling may be related.

May have an air leak into the fuel system too.
This said, a plugged filter can result in the IP literally sucking a "Hole" in the fuel so to speak, causing an air gap to form that results in the missing stumbiling/bucking.

A stick shift rig will manifest itself slightly more aggresively than in an auto tranny rig.

As Mentioned, filter first, then see what happens.

A non functional Waste gate (stuck open) will show as low power and tons of smoke when you mash it.

OH Makes sure the transfer pump is working properly, as this can cause issues.



Good luck and keep us posted.

[farmerson]

i changed the fuel filter on it and made a whole different truck out of it. wastegate was weak so i wired it closed just because it dont build much boost... and the lift pump was not running, think my ops is bad so i just put it on a switch. made 100x difference right there. and my fuel leak turned out to be the fuel filter housing had water in it at one point and cracked. replaced it and stopped the fuel leak. runs like a dream now. just dont smoke as much as i figured being it has 40hp injectors. oh well i know a buddy good with 6.5s so im gonna have him turn up my pump. also my timing was advanced really far so we turned the pump all the way to the left and it straightened right up. I was also told if i advance the timing a little it will help it on power.

[JohnC]

You need to get the wastegate fixed first. Wiring it closed is like crimping the exhaust pipe shut.

Also, I'd fix the OPS issue. The fuel pump must stop automatically if the engine stalls, otherwise you run the risk if dying in a fire fueled by your lift pump...

[DaveBr]

Don't turn up your injector pump unless you upgrade the exhaust , pull the snorkle on the intake, get a turbo master for your wastegate and install egt and boost guages. You will fry your engine if you don't.

[farmerson]

How is it like crimping the exhaust shut? on a cummins the tighter the wastegate is closed the better it runs because its putting the most boost possible to it. iv always known the more air, the more fuel the better it runs. put a cold air intake on it also. cant hear the turbo at all, where when i had my 99 it screamed whats wrong here? im not that worried about frying the motor, if i do it will probably get parked and parted out or get a cummins swap. my nv4500 parts for my dodge will be here in early january so as long as it lasts til then ill be happy. i dont run it hard anyway.

The exhaust is upgraded on it already.

[JohnC]

The turbine housing on the stock turbo is sized for low speed response, not high flow. With all that air coming in and the wastegate closed, there isn't enough flow capacity on the exhaust side. Plus, you're forcing the blower to operate outside its design range and it becomes very inefficient. You get high input air temps, high exhaust temps and severe back pressure in the exhaust.

[farmerson]

I'll just Solve the whole problem and put my hx35 on it hahaha. A good buddy of mine has a 95 with an hx on it and he loves it.

[DaveBr]

There is a process that needs to be followed to sucessfully get more power and long life out of your 6.5. What you propose sounds pretty agricultural. You may even find that well done modifications can change your mind about a cummings conversion.