rough idle after warmup on 93 6.5 - Chevy and GMC Duramax Diesel Forum
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 01-06-2009, 08:49 PM Thread Starter
Join Date: Dec 2008
Location: Watertown, TN farm
Posts: 3
rough idle after warmup on 93 6.5

I have a 93 chevy with 6.5 TD. Mechanical injector pump so there is no PMD to overheat. I've replaced a lot of stuff and got it so that it starts up fine and runs fine until it warms up.

I read an article about the mechanical pump that said there is a High Pressure Cold Advance solinoid in the injector pump that advances the timing about 6 degrees until the engine reaches a certain temp which is detected by the coolant temp switch.

If my engine runs fine with timing advanced by the solinoid, does my normal timing need to be advanced? If so how would you do that? Does something need to be adjusted? Is my injection pump bad or could it be something else like leaking air.

I would think that if it runs fine until it warms up, the IP would be OK but maybe I'm wrong. I don't want to spend the $ on a new pump and find out I have the same problem.

Thanks to all!

holmesgap68 is offline  
Sponsored Links
post #2 of 5 (permalink) Old 01-06-2009, 09:15 PM
daddysLBZ's Avatar
Join Date: Mar 2008
Posts: 7,336
may be the oil pressure switch,idk if the 6.5's had a kill switch on them...

2006 GMC 4x4 CC/SB/sle1/LBZ**312,000 miles!!** PPE HOT+2 225 TUNE beeeyotch:-)AutoMeter egt/boost Suncoast 5 trans w/1056TC!tsktsk,billet in/out shafts/MagHytec pan!!,M/A built T-Case,4 in.str8piped,5%tint all around......
2007 Chevrolet 4x4 cc\sb,lbz.......SOLD to blunova
Also, I speed and don't come to complete stops at stop signs.

''don't sweat the petty things,pet the sweaty things''
Click below/pictures of my junk!!
daddysLBZ is offline  
post #3 of 5 (permalink) Old 01-06-2009, 09:55 PM Thread Starter
Join Date: Dec 2008
Location: Watertown, TN farm
Posts: 3
Already replaced the oil pressure switch, fuel pump relay, lift pump, glow plugs, glow plug controller, injectors, and CDR valve. Put new connectors on the glow plug wires.

Before I did all that, you could hardly get it started.

It runs great when I first start it, then after it warms up, it acts like its about to die. The engine starts rocking side to side making the whole truck shake.

I want to drive it down the road a little and see if it smooths out but it was leaking coolant and I had to get a heater hose connector. I haven't put the connector on yet because its been raining two days straight. I will once it stops raining.

You can drive it like it is, but something ain't right.
holmesgap68 is offline  
post #4 of 5 (permalink) Old 01-06-2009, 10:30 PM
Oh...... Squirrel!
Tow Master's Avatar
Join Date: Oct 2006
Location: Irwin PA
Posts: 24,083
Man thats strange. I know about the newer 6.5's with the pmd but not the older ones. Even with that I cant think of what could cause the truck to do that.

The only thing I could think of is if the fuel pump isnt timed right. But I, not even sure how you'd time it

2006 Silverado 2500HD LBZ CC SB
Exterior: Escalade Handles, Front windows tinted to match the rear, painted bumpers & mirrors, billet grille, 305/50/20 Cooper Zeons on BMF Novakanes Death Metal, Cognito Braces, Stainless Sleeves, Train Horns
Interior: 4 Kicker 10in Subs in 2 custom box's, Autometer Ultra lite II Pyro and Boost gauges, Aeroforce Interceptor Gauge, LED Lows & Fogs, Painted accents
Performance: EFI Live Tuned by Blackout Performance, Custom Blackout Performance S475 over stock twins, 45 over stock injectors, MBRP Turbo Back Stainless Exhaust (Straight piped), Raptor Lift Pump, AFE Filter, GMAX6 kit with Suncoast 1057 converter installed by Blackout Performance
1999 Ford F-550 PowerStroke ''Wrecker'' **Jerrdan bed, S&B Intake
Tow Master is offline  
post #5 of 5 (permalink) Old 01-16-2009, 05:17 PM
DMax2004's Avatar
Join Date: Dec 2008
Posts: 4
The 92, 93 6.5 were mechanicaly controlled, so no pmd. From the sounds of it you injection pump needs to be retimed. I've heard of this happening, but never understood why. Since your truck runs fine when in advanced timing/high idle. To time the injection pump you need a special tool.
DMax2004 is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Chevy and GMC Duramax Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome