1983 Chevrolet S-10

Engine Performance problem
1983 Chevy S-10 6 cyl Four Wheel Drive Manual 230ish miles

Hello, ive had problems with my 1983 S10 2.8 2BBL for quite some time now, mostly when going up hills and passing. When going up a hill you have to floor it to hold its speed, and sometimes it still looses its power. When passing people, it basicly just has absolutely no power. We have replaced the catalytic converter, coil, spark plugs and wires, head gaskets( the pistons and the cylinder walls looked fine), fuel pump, vacuum hoses, carburetor and the parts inside the distributer. It has about 230k miles on it, I cant think of what else could be the problem other than the engine itself(heads were redone as well). I love my truck and this is really annoying me. What else could I do?
February 11, 2010.

Inspect and test all the following listed below: Oxygen sensor
Catalytic converter
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)
Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Cap and rotor

Note: If it doesn't apply disregard.

Feb 11, 2010.
Thanks for your reply Razmataz, unfortunately I have already replaced and checked everything you put down : /. Thank you for your quick response though : )

EDIT: I have yet to check the EGR Valve, how would I go about testing it?

Feb 12, 2010.
Use a vacuum pump on the EGR valve, apply vacuum on it -this will cause the EGR valve to open and make the engine stall or run rough if its doing its job-or press on the diagphram to open it

Feb 12, 2010.
Ok I did the vacuum test on the valve, and the engine ran rough and almost stalled.

Feb 12, 2010.
Im still having issues with the performance : / Is there anything else I can do?

Feb 19, 2010.
Did you check and test everything I've mentioned on my 1st post if you haven't do so-there's a lot that can reduce engine performance

Feb 19, 2010.
Yes I have tested everything, But there was one thing not on the list that i'm having issues testing witch is the HEI(ECM) unit inside the Distributer.

There is 2 wires coming from the distributer going to the coil, looks like a negative and a positive wire, I turned the ignition on put the ground of the volt meter to the engines ground, then tested both wires and got around 12.43 volts in both.

I also used the meter to test the - and + wires coming from the unit itself, the voltage dropped down to 8 volts, then right back up to 12 while cranking, and it stayed at 12 for the duration instead of pulsing.

I think that was the correct way to test it or am I doing something wrong?

Oxygen sensor - does not apply
Catalytic converter - replaced
Dirty fuel injectors - does not apply
Bad MAP sensor - does not apply
Bad TPS sensor - does not apply
Bad or dirty MAF - does not apply
Low fuel pressure - new fuel pump & filter
Vacuum leaks - all hoses replaced
Bad gasoline - clean
spark plugs - replaced
Bad plug wires - replaced
Weak ignition coil - replaced
Cap and rotor - replaced

Feb 26, 2010.
If there's a problem with the distributor pick coil and the ECM inside you won't be going up hill-you'll have a no start condition-You sure its not transmission problem

Feb 27, 2010.
I'm positive, its a manual transmission with fresh oil, shifts nicely too.

Well it does have a problem starting but thats a choke issue that I cant figure out, if I go under the hood and manually set the choke it starts right up.

EDIT: Had the HEI Unit tested. It passed.

I did however find out if I hold the choke half open(as in wired it half open) It runs just fine, just that the secondary wont open. But when I press the pedal it actually wants to go.

Also the Choke light on the dash will no go off, but there is voltage coming through the wire, until the engine warms up.

This has me really confused. Because now it has me thinking that it was getting to much air and not enough gas. But its a brand new fuel pump (mechanical) and filter.

Feb 27, 2010.
I had the same thing happen 2 my 1983 s10 1st thing the carburetor needed a new one 2nd I had a leek on the bottom of the carburetor that was giving me bad fuel air mix after all that it worked fine let me know if that worked email me at pimp946312@yahoo. Com if any? K

Mar 1, 2010.
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