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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Skunksmash on May 19, 2012, 01:04:53 am
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What RPM should my engine idle at? 87 TBI 5.7L/700R4. It seems to idle at about 700 RPM. Is that about right?
Also, what RPM should it shift at? Depending on how much I have the pedal depressed of course. I usually try to drive the truck like a granny would. It seems to shift at about 1600 RPM when I depress the pedal about 1/4 of the way. This seems a little low to me. Most of the engines I've had would shift at anywhere from 1900-2100 RPM. But, then again I've never had a tach in one of these old trucks.
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Do you run A/C? My 84 is has a quadrajet with A/C and 700 rpm is a little too low while its in gear with the A/C on. 850 seems to work better for me.
I just put a new tv cable in my 700R4 and did the adjustment like the experts explain. I then drove it and it shifted a little too soon and somewhat soft, alsmost felt like it was slipping into gear. I increased the pressure on the throttle valve by pushing the tv cable adjuster towards the firewall a few clicks and it shifter later and slightly firmer.
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87 TBI generally idles about 600 RPM in drive (as high as 700 in park/neutral). 87 700R4 shifts earlier than 350 or 400 for slight improvement in mileage.
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No my AC doesn't work right now so I don't run it. Just another thing on the long, long list of stuff to fix
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i think 700 is ok. i thought you couldn't adjust TBI idle?
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My throttle body unit is sealed off from adjustment,had to use my snap-on scanner to adjust the idle speed.
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Ok where should it shift at? If I'm giving it say, 1/4 throttle, it shifts at about 1600 RPM. But if I really floor it, it will shift at about 2200 RPM. The weird thing is, I couldn't get the RPM gauge to say I was doing any more than 2500 RPM, at any time. I just wanted to give it a test so I floored it for a little, and it would just barely get up to 2500 RPM for a second then go back down to about 2100 RPM. Seems kind of strange. Maybe that's just how an old TBI motor acts?
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Should go higher than that, i'd suspect a faulty tach if it actually sounds like its revving past that.
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Well it sounds like its revving way past that... but then again I've known old motors to sound like they're trying to move the world, and then be doing a relatively low RPM.
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I'll just borrow another RPM gauge from a buddy or something and hook it up real quick under the hood, and verify if mine is working right.