the stock in tank fuel pump pressure is 14 pounds for this engine. So I believe I have the right size fuel pump. and its the same one we just did on a different engine. I will have to check the return line to see how much is flowing. The most fuel I got out was a few drips on a few tries. I agree at this point it may be some kind of plug within the throttle body. I just installed the rebuild kit, maybe did something wrong.. I don't know. I will tear it back apart tomorrow. Thanks Jim
also, gonna use some noid light testers on the injectors tomorrow to veryify they are getting pulse from ECM at start up. I am pretty sure they are at this point but thats just one more thing Im gonna check too.
There should be lots of gas flowing in the return line by using a 140gph pump and there should be lots of fuel out of the injectors if your put power to them while the pump is running. You have some kind of fuel supply problem. Are you sure the pump didn't fail?
Excellent news.! The 72 c10 lives again gentlmen. My buddy came over and we threw down on the truck and disassembled the throttlebody and discovered a plug in one of the gas ports. Cleaned that shit out, noid tested the injectors just for certainty and slammed it back together and started it up. Thanks to the forum for all of the suggestions and ideas.. Got me some TBI in my 72'
So back at work on my truck. I am having trouble with the idle when I hook up the map sensor, it makes my engine idle up and down like its gonna die and then bursts back and stays running. I am pretty sure my map sensor is ok because I tested it with vacuum using a separate power supply on a bench. If I disconnect map it idles fine.-Wierd! I think it might be my ground wire on map. I am curious if it is ok to directly ground the map to the chasis and not through the ecm at pin D2 as it says in the schematic. Does this make a difference? I am just curious. The tbi conversion outline on page: http://www.gearhead-efi.com/gm-ecm-p...on-wiring.html says to ground this pin to the chasis which is in contrast to the schematic that grounds through the ecm.?
Last edited by Tyree; 06-25-2014 at 07:19 AM.
Do not tie the sensor ground wires to the engine block or to chassis ground anywhere.
yeah I didn't think so, I was just didnt know for sure on that one. So I am still stuck with this rough idle situation only when I hook up my map sensor. It was running shitty, I disconnected the plug and it went back to running fine. Anybody have any ideas on that? I have another map sensor coming in the mail, but as far as it looks when I test this map sensor it seems fine.
Frequently a hunting idle is a vacuum leak. Get a propane torch and use it (unlit of course) to check for vacuum leaks.
Square body stepsides forever!!!
It's likely going lean. It must default back to a %TPS operating mode when the MAP is missing and that likely adds more fuel.
Did you get it warmed up so it went into closed loop? If yes, what did the BLM do?
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