Terrible Truck Engine Noises

[LewZor]

So, New Weber, I made sure all the fuel lines were hooked up correctly, and the fuel pump is doing 4psi at pump and between 2.5 and 3psi at the carb.

 

Truck will idle like a kitten...until you put it in gear! 

 

You'll hear it run rough, then I will shift into N, then R, then D. Then video stops.

 

[LewZor]

Part Two...

 

[datzenmike]

That's just the exhaust or muffler rubbing. Engine torque in drive will force the engine to turn counter clockwise very slightly and as the exhaust is mounted to the moving engine it will move also. This torque effect rubbin is increased by having such a high idle speed. Should be about 750 in gear.

 

When the pipes are cold, safely climb under and grab the exhaust and tug on it. up down side to side. work your way back looking for where it's hitting. The pipes/muffler/cat or resonator may have been installed improperly or an engine or transmission mount may be bad, and allowing too much movement.

[datzenmike]

The second vid is about the same. The idle is too high and to the truck, it's like you stepping on the gas while holding the brake on... it's working too hard. Is that a small back fire I hear???

 

 

This would indicate the ignition is poor and this can be many things.

 

First thing, get the valves set properly with the engine hot. A tight intake valve will leak intake vacuum and cause a poor idle that needs turning up to run. Tight valves over all cause a poor idle. Check and set them first.

 

Now get the timing set. Engine hot. 3 degrees BTDC +- 2 degrees.

 

Check clean the plugs. NGK BPR6ES for the intake side and BPR5ES for the hotter exhaust side plugs. Wires/cap/rotor in good shape???

 

With this done now, and now only, should you attempt to adjust the carb.

 

Adjust the idle speed down as low as possible.

Adjust the idle mixture for the fastest smooth speed

Turn idle back down and repeat as many times untill you can't improve the idle quality and it idle smoothly at abut 700-800 RPMs.

 

 

This is a new weber? or a junker that was someone else's problem?? Float set? Not flooding?

 

http://www.classicinlines.com/WeberTune.asp

 

Set up... best lean idle adjustment.... http://www.carburetion.com/Weber/adjust.htm

 

Weber trouble shooting guide........... http://www.webercarbsdirect.com/v/vspfiles/images/Weber%20Trouble%20Shooting%20Guide.pdf

 

 

 

Your temp gauge is also a bit low. Warm up should take about 15 min roughly and be just under half on the gauge. Rather than waste time testing the thermostat and as you have to take it out anyway to test ansd it's likely the original just save as a spare and get a new 180F. Spend $10 don't cheap out and get the WallMart $2.30 one.

 

Your Z24 was designed to run at about 185-190F for best power and economy.

[LewZor]

I went through all the exhaust before I recorded. It goes from about 1000 rpm idle to 550 in gear. When it's in gear the exhaust "pops" loudly every once in a while. I guess I have to figure out a way to record the sound better.

[LewZor]

New coils, plugs (proper ex and int), wires, cap, rotor, fuel relay, battery, exhaust (cat back), timing set to 3 btdc. Everyone saying that a brand new Weber straight out of the box..."just slap it on and set the idle speed..." Does it cost anything to advertise it in the classifieds? haha

[LewZor]

Oooo! How about this one! I barely made it up the hill! Sorry about the picture...

 

[datzenmike]

I went through all the exhaust before I recorded. It goes from about 1000 rpm idle to 550 in gear. When it's in gear the exhaust "pops" loudly every once in a while. I guess I have to figure out a way to record the sound better.

 

Typically an idle of 700-800 will only drop a 150-200 RPM placing it in gear. Dropping that much says the idle isn't as strong as it should be.

 

Set the valve lash, the timing (in that order) and any carb adjustments from the links I provided.

 

 

New ... exhaust (cat back)...

 

Well right there... is been messed with. If muffler shop, they didn't check the fit. show them, have them adjust. Watch that the don't just hammer a dent in the pipe for clearance.

[LewZor]

So here is the deal.I am goofing around with the spark plug wires thinking I might have gotten I3 and I4 mixed up during the carb replacement. Nope, But then I started looking at them and tracing them back to the cap. It's all messed up!!! Intake 2 is on Exhaust 3, Intake 4 is on Intake 1, etc. Datzenmike says something about valves and stuff. I think about the head. The head gasket was replaced about 7 years ago. I called the shade-tree that I used to replace it and he remembers that when he had it all buttoned up it wouldn't run right. He had to swap all the wires around until it did run right, etc. So when I recently replaced everything I didn't pay attention where on the labeled cap everything went I just swapped one-for-one and kept going. Now I am thinking that I will maybe purchase a timing chain kit and do it all up correctly. I should be getting the shop manual in the mail any day now. Any ideas where to get the kit and what brand to get? Thanks.

[datzenmike]

The distributor drive spindle may have been put in wrong. The distributor would then also been wrong and all the wires moved around on the cap. Nothing wrong with this as long as they are in the correct order. Just find the number one wires and make sure that the numbers 3 then 4 and last 2 follow them.

 

 

 

 

I assumed that this was correct on your engine and that it hasn't been running like this for 7 years. So if this is a recent problem then it's something that happened recently. If you changed the wires, check them.

 

 

Don't over think this. Check the wire order and continue setting the lash, timing carb.This will eliminate the easy simple things and move closer to finding the cause. Could be a blown head gasket but setting the valves is cheaper and easier. Timing chain is expensive and not likely the cause.

[LewZor]

So. Took truck to mechanic and after two weeks of off and on working on it he found that the previous mechanic messed up the timing chain and ran the spark plug wires in some kind of weird way. I replaced the cap and wires thinking I switched them out one for one but didn't work that way.I installed the Weber and must have switched and exhaust for an intake so that when a load was put on the engine the special sensor that cuts out the exhaust spark it made the truck run like poop. He figured it out and It runs like a raped ape! Man, it's brand new again. Thanks for all the suggestions everyone. Brakes and suspension are next after A/C.