Weberman Posted January 24, 2021 Author Share Posted January 24, 2021 Yeah I'll throw that thin one on again tomorrow or Saturday and try again. Idk why this intake has such thin sides. Looks like I have possibly got the vacuum down. I put that metal piece in and with some adjustments, I have good vacuum at idle. Now the other thing. It will idle good and the gauge will drop randomly like 5" and go back up. Very random. Could be steady for 20 seconds and then dips, could be a couple seconds between them. There's a slight metallic tap coming from the drivers side. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 24, 2021 Share Posted January 24, 2021 Looks like I have possibly got the vacuum down. I put that metal piece in and with some adjustments, I have good vacuum at idle. Now the other thing. It will idle good and the gauge will drop randomly like 5" and go back up. Very random. Could be steady for 20 seconds and then dips, could be a couple seconds between them. There's a slight metallic tap coming from the drivers side. Is the tap regular? Or does it coincide with the vacuum drop? If it is regular it is probably a lifter or it could be an exhaust leak as they sound very similar. On the vacuum, try moving vacuum hoses while the engine is running and monitor the vacuum. See if some movement causes it to drop, which could indicate a cracked hose. If not, open up the idle mix screws ~1/8 - 1/4 turn and see if the vacuum drop changes. Link to comment Share on other sites More sharing options...
Weberman Posted January 24, 2021 Author Share Posted January 24, 2021 Is the tap regular? Or does it coincide with the vacuum drop? If it is regular it is probably a lifter or it could be an exhaust leak as they sound very similar. On the vacuum, try moving vacuum hoses while the engine is running and monitor the vacuum. See if some movement causes it to drop, which could indicate a cracked hose. If not, open up the idle mix screws ~1/8 - 1/4 turn and see if the vacuum drop changes. Tap comes and goes randomly like the gauge does. Bronco has true duals before the rear tire(that's good have to change when its road worthy because whew, don't know how the previous owner did it) but its on the driver's side. I revved it up a bit and held it and it sounded shakey and then smoothed out like it should. I'm just thinking maybe valve? I know I noticed a ticking before that rocker fell off so maybe the other side? That was a bit more consistent. I should have gone through the drivers side when that happened but I'm pretty sure I only did the passenger since I had that head off. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 24, 2021 Share Posted January 24, 2021 Tap comes and goes randomly like the gauge does. Bronco has true duals before the rear tire(that's good have to change when its road worthy because whew, don't know how the previous owner did it) but its on the driver's side. I revved it up a bit and held it and it sounded shakey and then smoothed out like it should. I'm just thinking maybe valve? I know I noticed a ticking before that rocker fell off so maybe the other side? That was a bit more consistent. I should have gone through the drivers side when that happened but I'm pretty sure I only did the passenger since I had that head off. A sticky intake valve or lifter could cause fluctuations in manifold vacuum. If you have a gasket it might be worth pulling the DS valve cover and checking for pushrod slop while making two complete revolutions of the crank. Link to comment Share on other sites More sharing options...
Weberman Posted January 26, 2021 Author Share Posted January 26, 2021 Tap comes and goes randomly like the gauge does. Bronco has true duals before the rear tire(that's good have to change when its road worthy because whew, don't know how the previous owner did it) but its on the driver's side. I revved it up a bit and held it and it sounded shakey and then smoothed out like it should. I'm just thinking maybe valve? I know I noticed a ticking before that rocker fell off so maybe the other side? That was a bit more consistent. I should have gone through the drivers side when that happened but I'm pretty sure I only did the passenger since I had that head off. Just for giggles, went through them all before actually checking them. Most turned a decent bit before reaching torque. I backed them off and then did it properly. Seems to have made a difference. It sounds and revs better I think. The tapping is there still, continuous, but the vacuum dipped like it did a couple times and then never did again. Checked the oil and its little above and smells like fuel pretty good. I drove it around the yard a bit and couldn't tell too much as it was wet and I was spinning. Doesn't like going into gears. It wants to die and stumbles when given gas, but if you get it right in between it'll catch itself and then be perfect. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 26, 2021 Share Posted January 26, 2021 Just for giggles, went through them all before actually checking them. Most turned a decent bit before reaching torque. I backed them off and then did it properly. Seems to have made a difference. It sounds and revs better I think. The tapping is there still, continuous, but the vacuum dipped like it did a couple times and then never did again. Checked the oil and its little above and smells like fuel pretty good. I drove it around the yard a bit and couldn't tell too much as it was wet and I was spinning. Doesn't like going into gears. It wants to die and stumbles when given gas, but if you get it right in between it'll catch itself and then be perfect. Sounds like you need a new fuel pump. And and change of oil. Then drive it and see how the vacuum is. The gas in the oil may have thinned it enough to cause a lifter to collapse every once in a while, and good oil may cure that. Link to comment Share on other sites More sharing options...
Weberman Posted January 26, 2021 Author Share Posted January 26, 2021 Sounds like you need a new fuel pump. And and change of oil. Then drive it and see how the vacuum is. The gas in the oil may have thinned it enough to cause a lifter to collapse every once in a while, and good oil may cure that. Yeah I'm gonna grab some oil and fuel. Tank is low too at the moment so I'm gonna fill it up and see if it does anything on that part. I know the springs need to be changed out. I have too weak of ones in there for what it idles at. I'll swap those out today and see. I thought that the door panels could interchange through the years but I guess it was the outer skin that was the same. Tried to swap and it just doesn't fit right. Still have the perfect dash in it and other parts too so still a deal for the other truck Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 26, 2021 Share Posted January 26, 2021 Yeah I'm gonna grab some oil and fuel. Tank is low too at the moment so I'm gonna fill it up and see if it does anything on that part. I know the springs need to be changed out. I have too weak of ones in there for what it idles at. I'll swap those out today and see. I thought that the door panels could interchange through the years but I guess it was the outer skin that was the same. Tried to swap and it just doesn't fit right. Still have the perfect dash in it and other parts too so still a deal for the other truck The door panels swap from 980 through early 1981, and late 1981 to 1986. The 1980 and early '81 trucks had slide locks where the late '81 through '86 trucks had pin locks. Link to comment Share on other sites More sharing options...
Weberman Posted January 26, 2021 Author Share Posted January 26, 2021 The door panels swap from 980 through early 1981, and late 1981 to 1986. The 1980 and early '81 trucks had slide locks where the late '81 through '86 trucks had pin locks. Yeah someone swapped doors and bed it seems from a 87-91. The holes for the pins are slightly off and the handle is pretty well touching the panel with no room for the hand to open it. I found another truck that had a factory tach and nice gray interior but the dash was cracked so I passed it up. I'll get a tach one of these days. Link to comment Share on other sites More sharing options...
Weberman Posted January 27, 2021 Author Share Posted January 27, 2021 Yeah someone swapped doors and bed it seems from a 87-91. The holes for the pins are slightly off and the handle is pretty well touching the panel with no room for the hand to open it. I found another truck that had a factory tach and nice gray interior but the dash was cracked so I passed it up. I'll get a tach one of these days. Changed oil, good amount of fuel in there. Got it replaced and still a tap, may be a bit less. Put the different springs in and it seems better. I could actually idle in gear. Wasn't a hesitation anymore. I'll have to do some more testing to see. Was wet in the yard so I'll have to see when its dry or on the road. Link to comment Share on other sites More sharing options...
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