Acceleration hesitation

Reply

  #1  
Old 03-05-08, 11:36 AM
Member
Thread Starter
Join Date: Mar 2008
Posts: 3
Acceleration hesitation

I have a 1987 Suzuki Samurai with 225,000+ miles. Lately there has been a hesitation whenever I start off from a dead stop. The only way to keep the engine running is to press in the clutch and pump the accelerator. I recently change the air filter, cleaned the plugs, rotated the tires and changed the oil and oil filter. Any ideas?
 
Sponsored Links
  #2  
Old 03-05-08, 12:18 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
What type of carburetion is employed by your vehicle?

At idle, does it idle okay, but fall flat on it's face when you throttle it under load? Or does it also idle rough?

Any vacuum lines come off on you under the hood while recently doing any work?

Ever check the timing?
 

Last edited by ecman51; 03-05-08 at 05:08 PM. Reason: sp.
  #3  
Old 03-05-08, 04:36 PM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,515
That's probably old enough to be carbureted. If so, float level in carb, fuel filter, fuel pump, or accelerator pump in carb.
 
  #4  
Old 03-06-08, 06:30 AM
mikeTN's Avatar
Member
Join Date: Dec 2007
Location: Nashville
Posts: 635
Question

if it is carburated, the accelerator pump may be at fault. do you have to PUMP the accelerator or will a depression of the pedal do the trick? the accelerator pump gives it a shot to get the air flowing and create a vacuum to pull the fuel out of the bowl. if you are not getting enough with the pump, that may be why you are having to pump it more than once. does it accelerate at road speed with no problem? check carb. mounting bolts for tightness. may be creating vacuum leak at base!?
 
  #5  
Old 03-07-08, 04:30 AM
Member
Join Date: Feb 2008
Location: 54935, planet earth, star sol, galaxy Milky Way
Posts: 60
Check for cracks in the air ducting. Under accel. the engine moves and the cracks may open, screwing up the sensors.
 
  #6  
Old 03-10-08, 05:25 AM
Member
Thread Starter
Join Date: Mar 2008
Posts: 3
Acceleration Hesitation

Yes, it is carb'ed. It idles fine. I checked all of the hoses and they are all attached where they are supposed to be. I do have to pump the gas pedal to get the power up. I discovered over the weekend that it won't let me go facter than 50 mph with the pedal all the way to the floor. I am thinking that it may have something to do with the vacuum advance??
 
  #7  
Old 03-10-08, 03:10 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
It's not independently your accelerator pump, then.

But it could be indirectly affected if say your gas level is down in the carb for whatever reason; that your bowl is not able to charge up all the way to being full, and then under load conditions that require a lot of gas, your car cannot deliver enough gas because it is not being replenished in the bowl fast enough. Sticky needle and seat or out of adusted float or clog anywhere in fuel delivery system or plugged jet holes or worn out mechanical fuel pump come to mind

It is an easy enough test to check out mechanical fuel pump and lfuel flow from the tank forward. Disconnect gasline at carb and crank to see if gas comes out good - [of course with disconnecting coil wire and not having spark anywhere near gas coming out, nor onto a hot engine, when you have someone turn over the engine, while you observe gas you collect at carb end of fuel line into a container!].

I couldn't imagine your engine could be that out of time to cause that at 50 and not be affected severely at idle.

I'm thinking that you are getting enough gas to idle the car, but not enough when any real gas demand is put on the car.

Another cause from the days of carbs and mechanical fuel pumps is that rubber fuel hoses coming out of the fuel tank have been known to collapse closed after car runs for a bit, also. Check for that also. There may be sections of ruber hose from 4 inches to 1 foot long that go between exit of fuel tank and where it slips onto the metal fuel line.
 
  #8  
Old 03-10-08, 03:51 PM
Member
Join Date: Jan 2006
Location: Ontario, Canada
Posts: 759
Maybe simply loosening off your distributor hold down, and advancing timing a little, (after marking your original setting) will tell you something too, if you suspect timing advance, or maybe a timing chain or belt slipped a few teeth? Maybe i missed it but did this just happen all of a sudden, or gradually? Perhaps some carb cleaner, just for the sake of trying it?
 
  #9  
Old 03-10-08, 06:45 PM
mikeTN's Avatar
Member
Join Date: Dec 2007
Location: Nashville
Posts: 635
Red face

Originally Posted by chief_flea View Post
Yes, it is carb'ed. It idles fine. I checked all of the hoses and they are all attached where they are supposed to be. I do have to pump the gas pedal to get the power up. I discovered over the weekend that it won't let me go facter than 50 mph with the pedal all the way to the floor. I am thinking that it may have something to do with the vacuum advance??
if it will only go 50mph, check the exhaust for pressure. rare, but if it won't exhaust, it will not run effectively. it has to breath, in and out. a partially plugged exhaust will kill the power.(forgot this last time).
 
  #10  
Old 03-11-08, 11:23 AM
carguyinva's Avatar
Member
Join Date: Nov 2003
Location: Shenandoah Valley
Posts: 1,147
checking timing is usually quick and easy so go for it...altho, messed up timing will affect idle speed and quality. fuel filter, fuel pressure, fuel volume...in that order. then check exhaust back pressure...good luck
 
  #11  
Old 03-24-08, 11:03 AM
Member
Thread Starter
Join Date: Mar 2008
Posts: 3
After all is said and done - come to find out that since it is carbed the choke was the culprit. Somehow it wasn't opening as it should and was causing no end of trouble. A full can of carb cleaner has done the trick!!

Thank you all for your input.
 
Reply

Posting Rules
You may not post new threads
You may not 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 Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'