IsuzuPup.com

"If there's ever a nuclear holocaust, the only thing left will be cockroaches and Isuzu diesels." (author unknown) This site is dedicated to the humble little Isuzu P'up.
It is currently Fri Apr 18, 2014 10:38 am

All times are UTC - 6 hours [ DST ]


Forum rules


Please click here to view the forum rules



Post new topic Reply to topic  [ 13 posts ] 
Author Message
PostPosted: Sat Feb 02, 2008 11:34 am 
Offline
Regular Member

Joined: Wed Mar 21, 2007 3:43 am
Posts: 21
Truck starts right up and idles/accelerates as it should, until it warms for about 5 minutes. After that it races at mid-range RPM. Doesn't respond to throttle, unless its to accelerate more, and then it goes back to mid range RPM's. I can release clutch, at the same time I hold the brake, and it idles well, for about two seconds. and then it's back to racing. Adjustment screws, and throttle cables don't respond for me. Any clues? Craig


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 11:42 am 
Offline
Regular Member

Joined: Sun Aug 28, 2005 8:17 am
Posts: 235
Location: NC
Something may be leaking oil into somewhere that makes into your head, so after 5 minutes it warms up? Then something may be expanding and allowing oil to pass it, weither it's the head gasket, valve stem seals, or just PFM, but i beleive your getting oil bypassing something. Does your truck puff out blue smoke when you first crank it up?

_________________
Past ride-82 Luv diesel 5spd with ram-air, larger exhaust manifold, 2" pipe with flowmaster.


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 11:53 am 
Offline
Regular Member

Joined: Wed Mar 21, 2007 3:43 am
Posts: 21
Yes, there's some blue smoke at start up, and then it goes away about the time it starts racing. Where would I look to correct oil leak problem? Thanks Craig


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 12:02 pm 
Offline
Regular Member

Joined: Sun Aug 28, 2005 8:17 am
Posts: 235
Location: NC
Try some lucus oil stablizer (maybe half the bottle) to see if it quits spitting out blue smoke at startup and doesn't race as soon. If that helps it may just be your valve stem seals, how many miles are on your truck? What sort of condition was the truck in when you got it?


OH, and try pulling the wire off the fuel cutoff solenoid to see if it shuts off or does anything.

_________________
Past ride-82 Luv diesel 5spd with ram-air, larger exhaust manifold, 2" pipe with flowmaster.


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 12:42 pm 
Offline
Regular Member

Joined: Wed Mar 21, 2007 3:43 am
Posts: 21
Finalman wrote:
Try some lucus oil stablizer (maybe half the bottle) to see if it quits spitting out blue smoke at startup and doesn't race as soon. If that helps it may just be your valve stem seals, how many miles are on your truck? What sort of condition was the truck in when you got it?


OH, and try pulling the wire off the fuel cutoff solenoid to see if it shuts off or does anything.


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 12:43 pm 
Offline
Regular Member

Joined: Wed Mar 21, 2007 3:43 am
Posts: 21
REALLY appreciate the feedback. I am hopeful. Will try all, & let you know. Craig


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 12:50 pm 
Offline
Regular Member

Joined: Wed Mar 21, 2007 3:43 am
Posts: 21
Truck has 131,000 miles. gets good MPG. Has misbehaved ever since i got it a year ago, but stopped driving it, since I didn't want to damage clutch, by braking with the clutch out to slow the engine. What is PFM? Thanks again - Craig


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 1:00 pm 
Offline
Regular Member

Joined: Sun Aug 28, 2005 8:17 am
Posts: 235
Location: NC
belizecraig wrote:
Truck has 131,000 miles. gets good MPG. Has misbehaved ever since i got it a year ago, but stopped driving it, since I didn't want to damage clutch, by braking with the clutch out to slow the engine. What is PFM? Thanks again - Craig


PFM is a nuke term we use, it's "Pure Friggin' Magic", usually when we're taught some new formula to come up with an answer, sometimes we'll ask how they come up with it, or why a number is the value it is they'll just say PFM...

_________________
Past ride-82 Luv diesel 5spd with ram-air, larger exhaust manifold, 2" pipe with flowmaster.


Top
 Profile  
 
PostPosted: Sat Feb 02, 2008 1:27 pm 
Offline
Regular Member
User avatar

Joined: Mon Dec 17, 2007 11:57 am
Posts: 155
Location: Hardy,AR
something simple you may try is disconnect the cold start mechanism,i know the unit on mine makes it run really fast,just disconnect the vacuum line that runs down to your injector pump,see what happens

_________________
Kal
    82 Luv 4x4 diesel=parts truck
    86 Pup diesel automatic=new purchase,project


Top
 Profile  
 
PostPosted: Mon Feb 04, 2008 6:56 am 
Offline
Regular Member

Joined: Mon Jan 29, 2007 12:23 pm
Posts: 1785
Location: Burke, VA
Is the engine oil over full?

_________________
81 Long bed PuP 2.2 Diesel
Using Bio-D


Top
 Profile  
 
PostPosted: Wed Feb 13, 2008 2:42 am 
Offline
Regular Member

Joined: Thu Dec 01, 2005 2:13 pm
Posts: 10
Location: Del Norte -- California
Another 2 cents. Look at the ends of your vacuum lines and see if they are cracked or on tight. If any look bad replace them. I had trouble with my idle but it was just the opposite; fast idle for two minutes then down to almost nothing. Replacing the vacuum lines has fix it. Just make sure you do them one at a time so you don't get them mixed up.

_________________
1985 Diesel Pup LB (Rusty)
1982 Diesel Pup LB


Top
 Profile  
 
PostPosted: Wed Feb 13, 2008 9:08 am 
Offline
Regular Member

Joined: Fri May 12, 2006 1:32 pm
Posts: 231
Location: Worcester, New York, US
belizecraig wrote:
Truck starts right up and idles/accelerates as it should, until it warms for about 5 minutes. After that it races at mid-range RPM. Doesn't respond to throttle, unless its to accelerate more, and then it goes back to mid range RPM's. I can release clutch, at the same time I hold the brake, and it idles well, for about two seconds. and then it's back to racing. Adjustment screws, and throttle cables don't respond for me. Any clues? Craig


You ought to check for air in the fuel before anything else. All the internal pump controls are hydraulic and go nuts if any air gets into the fuel line. Bad throttle response, inability to shut-off, wierd over-revving can all happen from air in the lines.

Try hooking a gravity-feel fuel source to the pump and see if it straightens out. Or, hook a clear-plastic fuel line somewhere in the engine compartment so if there's air - you can see it.

_________________
85 Isuzu 4WD diesel PUP, (2) 81 diesel Chevettes, (2) 91 diesel Volks Jettas,(22) Chevy 6.2 diesel Blazers/trucks/Suburbans, 85 Ford 6.9 diesel truck, 94 Ford 7.3 TD truck, 92 Dodge 5.9 TB diesel truck - over 20 diesel backhoes, tractors, dozers


Top
 Profile  
 
PostPosted: Wed Feb 13, 2008 6:11 pm 
Offline
Regular Member

Joined: Sat Dec 22, 2007 6:46 pm
Posts: 204
Location: Austin, Texas
make sure the fuel screw is not turned in to far, has anyone been trying to get more power out of it? ron


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Bing [Bot], MSNbot Media and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group