Odd hesitation on acceleration

[88hurstolds]

All I said is that I didn't think that the accerator pump was the issue since he stated that it only happened when he was going 40ish. Accelerator pump would happen at all times. He could be starving for fuel or possible air or spark as well. I think he should check his pump as I said before. I'm betting on a vaccum leak as he said he can hear a vaccum leak. The other issue I'd it may be the vaccum advance on his distributer. I was just giving him my opinion sorry if it conflicted with yours. if it's the accerator pump congrats to you you get a point.

No need to get butt hurt, this is all speculation, he needs to make an educated decision based on the resources available to him.

My experience with vacuum leaks is that they would also cause a rough idle and to run rich.
My experience with stumbling at any acceleration is the accelerator pump.

 

[88olds32]

Thanks all. Two issues were the cause for the hesitation. First, there was a vacuum line near the front of the carb (above the fuel filter inlet housing) that was cracked. It was on the bottom of the hose, so it wasn't easily seen from above. I replaced it and a few other lines. Second, someone suggested that the fuel filter check valve might be stuck or defective, and to run a fuel filter without the check valve for better flow. I don't know what the long term effects will be with running a fuel filter without a check valve (especially since the manual specifically states that a fuel filter with a check valve should always be used), but, the car doesn't hesitate as it originally did.

 

[mr evil]

Change ALL vacuum lines and properly route to the CSM or visit here:

http://www.gbodyolds.com/forum/showthread.php?297-Vacuum-and-Emissions-Diagrams

...

88, I went to that link but got a bunch of X's where the pics should be I'm assuming.....I believe that's your site so just giving a heads up.

 

[88hurstolds]

Thats because you're not logged on to the site.

 

[pencero]

I had all the exact same issues described in this thread on my 88 w/ 307 back in 2010 just before it went into storage. Next thing to expect problems from will be the fuel pump, if it went on for more than a few weeks. Fixed the same stuff and that's the next thing that broke on me. All that time starved of fuel finally caught up to it I suppose.

 

[pontiacgp]

since your idle speed is up and it's bogging I'd be looking at the choke and high idle which may be causing the secondaries to be locked

 

[88olds32]

I think it was the newly replaced fuel filter that was causing the problem. I bought a second filter without a check valve, and it solved the hesitation issue and really helped with acceleration. Changing out all the spark plugs caused the idle speed to return to around 800-900rpm. The next step is to switch out the plugs, rotor, distributor cap, and oxygen sensor. I'll switch out the fuel pump eventually, but for now, we'll see how things go.

 

[John Willis]

Time to break out the wd-40 ....spray a limited area at a time and see if the idle speed varies. Track the problem from there...Good luck