power/speed issues
power/speed issues
I have a 84 720 2.4l with a weber carb conversion, im having an issue at speeds around 35 mph. it feels like the fuel filter is plugged, which I have changed. if I slowly ease on the accelerator, speed will slowly increase. I set my carb 1 1/2turns out on both set screws. Could I have put the vacuum hoses in the wrong places, or timing not set properly? I have tried everything in the Chilton book that I could think would help but no solutions. so if anyone has any ideas please let me know!! thanks!
Re: power/speed issues
What exactly is your problem? All I see is "If I slowly ease on the accelerator, speed will slowly increase", which sounds like what is supposed to happen. What is happening that is unexpected?
Re: power/speed issues
At speeds around 35 it Boggs down and starts to spouders.
Re: power/speed issues
Is it an automatic or a manual? Are you always seeing problems right around 35mph, regardless of what gear you're in, or does it seem to map to a particular RPM, or does it only happen in a particular gear (or a particular couple of gears)?
That said, a few things come to mind: if the float isn't set properly, that could cause fuel starvation. Also, if there's crud in the fuel lines, then that could restrict your fuel flow even with a new fuel filter. From what I've read, the fuel pumps tend to last pretty long on these trucks, but a bad or worn fuel pump could also result in lower-than-normal max fuel flow.
That said, a few things come to mind: if the float isn't set properly, that could cause fuel starvation. Also, if there's crud in the fuel lines, then that could restrict your fuel flow even with a new fuel filter. From what I've read, the fuel pumps tend to last pretty long on these trucks, but a bad or worn fuel pump could also result in lower-than-normal max fuel flow.
Re: power/speed issues
It's manual trans. The fuel pump is fairly new. I'm always seeing the problems around 35 whether in 2nd and 3rd gear. It's like there's no top end power. My first thought was a fuel problem either filter or pump. So I changed the filter did not help at all, so maybe the pump, not getting enough flow?
Re: power/speed issues
Well, I know on the stock carb (for z24, not z24i, clearly), there's a secondary fuel filter that sits right where the fuel filter enters the carburetor (it's essentially a banjo bolt). Any idea if the Weber might have something like that?
The second thing that comes to mind is that maybe the advance on your distributor isn't working correctly? I don't know too much about the Weber carbs, or about the z24i ignition setup, unfortunately. But if you've got a timing light, I would rev the engine and make sure that the timing advances through the rev range.
The second thing that comes to mind is that maybe the advance on your distributor isn't working correctly? I don't know too much about the Weber carbs, or about the z24i ignition setup, unfortunately. But if you've got a timing light, I would rev the engine and make sure that the timing advances through the rev range.
Re: power/speed issues
I dont think the weber has a filter like that. I think it's pretty straight forward. But I did in fact pull the dist. Cap and pulled a vacuum on the advance and made sure it did advance. I did also over the weekend installed a new fuel pump, spark plug wires, dist cap, rotor bug. Also pull the carb cleaned every little orfice I could find on it, and checked the float. That seemed to help with adjusting the idle but not with speed at 35 or 2nd gear at 3000 rpm.
I found something else I wasent sure about too. The evap can has the dist vc, purge, gas tank connections on the top. What does the elbow fitting on the bottom of the can connect to? Some sort of filter? I can post a pic. On the old engine it had a can with a charcoal filter on the bottom.
I found something else I wasent sure about too. The evap can has the dist vc, purge, gas tank connections on the top. What does the elbow fitting on the bottom of the can connect to? Some sort of filter? I can post a pic. On the old engine it had a can with a charcoal filter on the bottom.
Re: power/speed issues
Elbow on the bottom? Never heard of anything like that, but of course, I'm still new here in the grand scheme of things.
Maybe try disabling the EGR? EGR has two pieces: the actual EGR valve, and the BPT (backpressure transducer), which is used to open the EGR proportionally to the amount of exhaust pressure. If you disconnect the signal line from the BPT to the EGR, that will disable the EGR.
One thing datzenmike (google him) mentioned is that sometimes there will be an exhaust leak in the pipe that runs around the back of the block from the exhaust manifold to the EGR valve. If so, then extra oxygenated air (rather than oxygen-depleted exhaust) can make it into the intake manifold, which could cause the truck to run lean when the EGR is open. If you disable the EGR and your issue goes away, I would start by making sure that the tube from the exhaust manifold is sound and doesn't have any corrosion or holes.
Maybe try disabling the EGR? EGR has two pieces: the actual EGR valve, and the BPT (backpressure transducer), which is used to open the EGR proportionally to the amount of exhaust pressure. If you disconnect the signal line from the BPT to the EGR, that will disable the EGR.
One thing datzenmike (google him) mentioned is that sometimes there will be an exhaust leak in the pipe that runs around the back of the block from the exhaust manifold to the EGR valve. If so, then extra oxygenated air (rather than oxygen-depleted exhaust) can make it into the intake manifold, which could cause the truck to run lean when the EGR is open. If you disable the EGR and your issue goes away, I would start by making sure that the tube from the exhaust manifold is sound and doesn't have any corrosion or holes.