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Brew Master
 
cabmandone's Avatar
 
Join Date: Jul 2013
Location: Delphos OH
Posts: 32,141
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How long does it take to bleed air out of Injection system?

I just finished getting my 3.2L engine back in after an extended job of replacing head studs. FWIW I double and triple checked valve timing and set according to Wayne's rebuild book. Both cams with dot up and number 1 at TDC. Set both sides to 1.25 (IIRC from the book) Checked that 1 and 4 intake valves were opening when they should. Adjusted all valves and double checked before putting covers on. Had engine on #1 TDC verified with Z1 on crank pully, Distributor mark, could wiggle both rockers. So I'm fairly confident all is well there.

After priming the oil pump by removing the DME relay, I plugged the DME back in and turned it over. It struggled to fire but did after about 3 tries. The only thing I couldn't find was a procedure for bleeding the air from the fuel system. I had my injectors rebuilt (cleaned and flow balanced) My problem is, it starts but it won't idle properly. I ran it for less than 1 minute probably closer to a half minute and then shut it off when it didn't idle properly. I'm going to go back over all of my vacuum hoses to make sure I didn't cross the tube that goes to the 90 on the throttle body and the one that goes to the crankcase breather on the top of the engine. I'm curious if my rough idle isn't due to air in the fuel system? I removed my fuel rails to take some yellow paint off that the PO had put on them so my rails and the feed lines were bone dry when things went back in.

Any thoughts?


Last edited by cabmandone; 06-17-2015 at 07:45 PM..
Old 06-17-2015, 07:39 PM
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Hey! Nice Rack! "Celette"
 
rich's Avatar
 
Join Date: Jan 1999
Location: Superior WI USA
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I'm no expert on that system but there is a return line to the tank I would assume. Once the fuel makes the loop the air should be purged. Maybe you have the lines connected in reverse or a pinched line?
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Old 06-17-2015, 08:11 PM
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Brew Master
 
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Join Date: Jul 2013
Location: Delphos OH
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FWIW, it was air... but not in the fuel lines. I had one vacuum line on the back of the 90 that goes to the left side of the car that wasn't attached. It struck me this morning when I woke up that I didn't recall tightening the clamp for that line. I went out and sure enough it wasn't connected. Hooked it up and fired it, it stumbled the first time and stalled but I think that was air in the lines yet. The second time it fired and idled like a champ.
Old 06-18-2015, 03:33 AM
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Join Date: Oct 2008
Location: Nash County, NC.
Posts: 8,503
Vacuum line to the left is the brake booster..glad you got it.
Bruce

Old 06-18-2015, 03:49 AM
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