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Can't believe it the truck was running great even on the freeway yesterday with the air on. Left my moms house this morning and on the freeway going 65/70 it started loosing power and backfiring and the temp went to 204 with nothing on. The water is full but to dark to start checking I hope it's the fuel filter but with the carb. rebuild it should be new and i can tell if it's been replaced if not what a jerk who did the work. Hope I can find it quick. It idles fine. Any ideas what to check?:dontknow: I will start looking after work I'm leaving Thurs. for Pismo I hope.
Robert
 

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Check to see if your distributor hold down came loose and allowed your distributor to rotate, retarding the timing.
 

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Initial Engine Break-In Procedure The following form is the GM recommended crate engine start-up procedure with some minor changes made to it by Chevy Performance . You can use this form for keeping track of your engine’s break-in.GM’S RECOMMENDED CRATE ENGINE START-UP PROCEDURE
Print this page out and check off boxes below (in the printed copy) when each step is completed.StepBox1) Safety first! If the car is on the ground, be sure the emergency brake is set, the wheels are chocked, and the transmission cannot fall into gear. Next verify that all hoses are tight and that both the radiator and radiator over flow jar/tank are full and have been filled with the proper anti-freeze and water mix. 2) Before starting your engine for the first time, add one pint of engine oil supplement ( EOS¹) to the crankcase oil and then check the oil level. Once this has been done, prime the oil system with an oil pump primer tool. Make sure number 1 cylinder is on TDC compression stroke, and install the distributor. 3) Adjust the distributor timing roughly by hand for a quick start up and smoothest idle possible. 4) When the engine first starts, verify that the engine rpm is at a safe level and that the timing is set near or at 30° before top dead center (BTDC). Run the engine speed between 1,500 and 2,500 RPM’s, varying the engine speed up and down with-in this range, to prevent overheating of the exhaust valves and the exhaust system. This should be done with no-load on the engine and for the first 30 minutes of operation. 5) After the first 30 minutes of the engine running, set the ignition timing according to the timing specifications. Now would be a good time to check thoroughly for leaks. 6) Adjust the carburetor settings, if necessary. 7) Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle or high RPM. 8) Run five or six medium-throttle accelerations to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH. 9) Run a couple hard-throttle accelerations up to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH. 10) Change the oil and filter with recommended oil (10w30SG in most cases) and filter. 11) Drive the next 500 miles normally, without high RPM’s (below 3,800 RPM), hard use, or extended periods of high loading. 12) Change oil and filter again. 13) Your engine is now ready for many happy cruising miles! Note¹: EOS P/N 1052367 can be used any time during the life of the engine.
Technical Note: This procedure has been corrected and improved from the original GMPP procedure by Chevy Performance .Warning: Your engine will not be fully broke in until after at least 2,000 miles of driving have been put on it with normal organic oil.
 

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You need to go easy on the engine until it's properly broken in.
 
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Has the oil pressure dropped? Also when you said backfiring,it sounds like the distributor has retarded itself. Are you sure you're not one tooth off with the dizzy? Are you keeping the rpms under 2500 with this rolling break in? More info please!
 

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ZERO MPG
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Discussion Starter #6
Initial Engine Break-In Procedure The following form is the GM recommended crate engine start-up procedure with some minor changes made to it by Chevy Performance . You can use this form for keeping track of your engine’s break-in.GM’S RECOMMENDED CRATE ENGINE START-UP PROCEDURE
Print this page out and check off boxes below (in the printed copy) when each step is completed.StepBox1) Safety first! If the car is on the ground, be sure the emergency brake is set, the wheels are chocked, and the transmission cannot fall into gear. Next verify that all hoses are tight and that both the radiator and radiator over flow jar/tank are full and have been filled with the proper anti-freeze and water mix. 2) Before starting your engine for the first time, add one pint of engine oil supplement ( EOS¹) to the crankcase oil and then check the oil level. Once this has been done, prime the oil system with an oil pump primer tool. Make sure number 1 cylinder is on TDC compression stroke, and install the distributor. 3) Adjust the distributor timing roughly by hand for a quick start up and smoothest idle possible. 4) When the engine first starts, verify that the engine rpm is at a safe level and that the timing is set near or at 30° before top dead center (BTDC). Run the engine speed between 1,500 and 2,500 RPM’s, varying the engine speed up and down with-in this range, to prevent overheating of the exhaust valves and the exhaust system. This should be done with no-load on the engine and for the first 30 minutes of operation. 5) After the first 30 minutes of the engine running, set the ignition timing according to the timing specifications. Now would be a good time to check thoroughly for leaks. 6) Adjust the carburetor settings, if necessary. 7) Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle or high RPM. 8) Run five or six medium-throttle accelerations to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH. 9) Run a couple hard-throttle accelerations up to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH. 10) Change the oil and filter with recommended oil (10w30SG in most cases) and filter. 11) Drive the next 500 miles normally, without high RPM’s (below 3,800 RPM), hard use, or extended periods of high loading. 12) Change oil and filter again. 13) Your engine is now ready for many happy cruising miles! Note¹: EOS P/N 1052367 can be used any time during the life of the engine.
Technical Note: This procedure has been corrected and improved from the original GMPP procedure by Chevy Performance .Warning: Your engine will not be fully broke in until after at least 2,000 miles of driving have been put on it with normal organic oil.

I'm good here I'm not racing it at all. Once I got it right in the alley I put on the gas but nothing special but you could feel the power.We also did all the steps above to the T it looks like. It's for daily driving only I haven't got the need for speed yet.:poke:
Thanks
robert



I will check the dist. and all connections. I did tie rap some wires under the dash but that was the other day.
 

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ZERO MPG
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Discussion Starter #7 (Edited)
Has the oil pressure dropped? Also when you said backfiring,it sounds like the distributor has retarded itself. Are you sure you're not one tooth off with the dizzy? Are you keeping the rpms under 2500 with this rolling break in? More info please!
Oil pressure is fine and the rpm's are 1980 at 65 mph in overdrive could it be the lock up on the trans? TH2004R It's been running great on the freeway till today is the first time it happened otherwise it's good in town and idles fine at 980 rpm in park.

I don't know if you would call it backfiring it felt like it may not be getting the fuel I didn't here it back fire sorry but it gave that gulp kind of feeling and it made a sound but not a big back fire and wasn't getting full power out of the motor while pushing the gas then it would come back then do it again like when you get the motor way to hot and it starts jerking.? new fuel pump was installed
 
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Oil pressure is fine and the rpm's are 1980 at 65 mph in overdrive could it be the lock up on the trans? TH2004R It's been running great on the freeway till today is the first time it happened otherwise it's good in town and idles fine at 980 rpm in park.

I don't know if you would call it backfiring it felt like it may not be getting the fuel I didn't here it back fire sorry but it gave that gulp kind of feeling and it made a sound but not a big back fire and wasn't getting full power out of the motor while pushing the gas then it would come back then do it again like when you get the motor way to hot and it starts jerking.? new fuel pump was installed
So you're saying it sputtered and the power kicked back in? If that's the case,it may be fuel related. When you installed the engine,did you put a bottle of fuel treatment in the tank? Also,has the filter in the carb been changed? Are you smelling fuel anywhere in the engine bay?
 

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What you're describing sounds like a backfire through the carberator. That's ususally ignition related, wires, cap, rotor, module, timing, etc. Could be the accelerator pump on the carb too. Maybe even fuel pressure. But start with the ignition.
 

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Don't get all over the place. Start from the most recent things. Check your wires again. They were the last thing and the timing.
 

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ZERO MPG
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Discussion Starter #13
I will check it all everything has been changed to new other than a couple of sensors and their not even a year old. When the guy rebuilt the carb. i don't know if they put in a new filter and i can tell if they didn't. my fuel line runs down the front of the block through the alternator maybe it's getting hot. I can put my new steel breaded hose on and re-rough it if i still have a problem. I must have knocked something off last night when cleaning the engine? or the wiring under the dash i Ty-rapped some wires and my spedo is not working correctly so maybe a couple of wires going through the computer are grounding:dontknow: Just need to go slow and look at everything close.
Thanks
Robert
 

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Discussion Starter #14
Checked everything and the only thing i could find was the hot wire to the alternator was a little loose and a few strands of wire were broken off so I cut and reinstalled and reset the timing to 8 BTDC . Took a ride on the freeway drove fine but that's how it drove Monday so i need to take it again this morning to have it detailed and will see if it's still doing good. Hope so for the trip to Pismo tomorrow.:nanawrench:
Robert
 

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Don't think that would have anything to do with what you described. Keep looking.
 

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Discussion Starter #16
O.k. drove this morning 20mi. on the freeway 65mph perfect. This afternoon hot out on the freeway 20 mi. 65mph air on temp. 202/203 perfect in town with air bounced between 204/205 when stopped perfect. I give up and will wait till something comes up. Leaving for Pismo about 3 1/2 hrs freeway driving should tell the story. Maybe something in the fuel system was restricted? :secret::secret: or something electrical is loose and intermittent.
Thanks
Robert
 

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Discussion Starter #17
Don't think that would have anything to do with what you described. Keep looking.


One thing when replacing the motor I didn't see any fuse-:dontknow:able links only three braided grounds on the motor?
 

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Fusible links would be down close to starter on those wires. They're just thicker in appearance. Don't think that would have anything to do with it either. Usually they if they go bad they melt and break the connection.
 

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