engine knock after top end rebuild | Page 6 | Ford Explorer Forums - Serious Explorations

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engine knock after top end rebuild

Have you had the battery disconnected at all when all this work has been done? That will reset the ecm.cps is camshaft position sensor, if you didnt know what it was doubt you have one.I would start with vacuum lines, may have missed one or cracked one.the tb line that goes to the purge is brittle and likes to crack or break.or even a bad iac could cause it drop to low in rpms when engaged in gear
 



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when i let the motor site for awhile then start it back up, theres that same hollow bang from someplace. could it be the last or the 87 gas getting pushed out in front of the 93 or something?
 






yeah i had the battery disconnected. while i was working on it. when i started it up i could hear some whisteling coming from the vaciim tree but after i re seated the lines and used a zip tie on one, i believe the vacuum lines are good.

when i was retorqueing the head, i smashed a hole in the ac box to get the wrench back there. do i need to close that up with tape or anything? my car has been with out it for over ten years and ive been running the ac delete belt. i figured it wouldnt matter bc it a wasnt hooked up. i suppose i could replace the iac. i cleaned it about a year ago just because and it didnt notice any change in performance. before i started i didnt have any problems with it.

could any of this be fuel system related? i replaced the vapor purge valve, fuel pressure regulator, and fuel filter. shoulf i replace the pump or relays?
 






so im on the way to the junkyard today to get a pcm, see if there are any loose lifters, or as i like to call, junkyard pocket change, maf, iac, egr, and any and all loose sensors and engine stuff. ill be there for the next few hours so if anybody can think of anything helpful to take let me know. its about an hour drive from my house so the less trips the better
 






Update: the explorer moved today for the first time in two months!
 






Well........???
 






I cleaned the maf, put in a fuel relay fuse from the jy and a jy pcm. After initially running well, in reverse and drive it pops and pings rythmically.

It did move though. Wereas before in r or d it would stall now it runs rough.still no cel. Not sure where to go from here
 






Im outa ideas. Hopefully someone else will chime in
 






Worst case I'll call a tow truck to take it to a garage to get it looked at
 












Are you sure your valve and ignition timings are correct?
 






i did replace the timing chain and gear but before i took the gear off i aligned the marks on the crank and cam gear. then when i took it off i realized its impossible to put the timing gear on wrong because theres a tab on the end of the cam and will only allow the gear on one way. i kept the crank from turning by putting the bolt back in and bracing it on the frame with a breaker bar. that said, im not sure how to check for mis- timed engine symptoms.

it runs fine, if a little rough, in park and neutral. sometimes when it goes into drive or reverse when the rpms drop it pops and pings. i did make triple sure the spark plug wires on in the correct pattern.
 






How low do they drop before they jump back up? Or do they jump back up? To me it still sounds like a vac leak or iac.or tps or idle screw adjusted wrong..
 






i start up and it idles at around 800, then settles down to 600 steady, in park. i sounds nice and smooth, but when i sit in the car i can tell there's a bit of a lope. when i shift into reverse, it drops to 500 and sounds super rough. it wont die, and sometimes it even smooths itself out, but when i actually step on the pedal to go backwards it starts popping and making weird noises, same with drive.

i switched out the iac from one with the junkyard and theres no change. i unplugged the iac while the engine was running and it died immediately, so i know its working. i think the thing i did that made a difference was switching the fuel relay fuse. it ran better but its not quite there.

yeah i have no idea what is making it so rough.
 






is there a way to replace the vacuum lines to rule that out for certain? like some stock tubing?
 






I'm willing to put money on it not being a vacuum leak, but you can buy rubber hose for real cheap at napa or go the expensive route and replace it all with silicone. They sell kits to. Lots of different colors and anodized quick disconnect connectors, real fancy stuff haha

You can also make a homemade smoker, check for vac leaks that way. But you need an air compressor
 






Unplugging the iac shouldnt kill the motor...thats how you set the idles screw.unplug iac and set idle to spec then plug the iac back in.

Spray them with carb or break cleaner wile running(coldish block), same with injectors or any joint.if rpms change you got a leak.
 






Ooo also check the uose that goes to the trans.make sure it hasnt come loose or has melted from the pipes
 






hose to transmission.... ill check that. yeah the engine died right away without the iac. ill clean it- it does look pretty black on the inside.
 



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