Early Ford V-8 Club Forum

EFV-8 Club Forum / General Ford Discussion / loss of power/missing at higher RPM

Reply to Discussion | New Discussion << previous || next >>

Posted By Discussion Topic: loss of power/missing at higher RPM -- page: 1 2 3     tubetype 09-30-2015 @ 11:44 AM reply profile send p.m. Member Posts: 41 Joined: Apr 2013 starts and idles good. starts missing at 35 in 2nd gear. Plugs and plug wires good. Carb rebuilt since this problem developed. Vacuume steady at 18. cylinder pressures - 1,2,3,4, 90psi. 5,6,7,8, 60PSI. does this sound like a blown head gasket or crack in block or head?? Comments please. BUD MG 09-30-2015 @ 12:15 PM reply profile send p.m. Senior Posts: 1262 Joined: Nov 2009 @Tube - Next time this happens, pull over to the side of the road and check to see if your carburetor is overflowing.... ken ct. 09-30-2015 @ 1:16 PM reply profile send p.m. Senior Posts: 1513 Joined: Jan 2010 Compression kinda low on drivers side. ormally you would not get all cyl on either side to read all the same ? all 90 and all 60.Dont think your carb is at fault. Got to be something else.Did you take compression test the correct way??? ken ct. len47merc 09-30-2015 @ 2:36 PM reply profile send p.m. Senior Posts: 1165 Joined: Oct 2013 Side-to-side compression variance and consistency across each respective side does seem odd. Assume no water in the oil. Suggest checking the torque of all head nuts to spec to eliminate or validate one of the obvious potential issues for starters. Steve This message was edited by len47merc on 9-30-15 @ 2:37 PM carcrazy 09-30-2015 @ 2:39 PM reply profile send p.m. Senior Posts: 1691 Joined: Oct 2009 Look for a problem in the fuel supply system. Missing at higher speeds and/or loads can indicate a weak or marginal fuel pump. You may have a partially plugged fuel line or plugged fuel tank vent. ken ct. 09-30-2015 @ 3:55 PM reply profile send p.m. Senior Posts: 1513 Joined: Jan 2010 A fuel supply problem would not cause low compression on 1 side of the engine which is not very good could be valves ?? ken ct. len47merc 09-30-2015 @ 4:35 PM reply profile send p.m. Senior Posts: 1165 Joined: Oct 2013 To ken's point, even if some vermin built a nest or a rag was dropped in one side of the carb/manifold and created a partial blockage it would only affect 2 of the 4 cylinders on each side of the motor. While the engine missing @ rpm is agreed to be a potential air/fuel delivery mix concern carcrazy (&/or an electrical coil/dist/wire(s) breaking down) why all driver's side cylinders are low on compression would be my first concern and order of business. During pursuit of that problem the root cause of the missing-at-rpm may be revealed. If not, at least one serious issue can be addressed and then a standard review of plugs, spark, fuel delivery, etc., can be undertaken. Perhaps I am missing something more obvious but 60 psi across one full side is so far from spec and standard that the motor must be out of balance. Have personally never seen or heard of such a variance. I'm curious here and am all ears nonetheless - someone give us the smoking gun... Steve This message was edited by len47merc on 9-30-15 @ 4:36 PM tubetype 09-30-2015 @ 6:39 PM reply profile send p.m. Member Posts: 41 Joined: Apr 2013 forgot to say that I have 5 lbs fuel pump pressure. have blown down all fuel lines. fuel tank vent working OK. 5/6 lbs pressure varies on left and right bank. At idle and slight above idle engine is rock steady, vacuume reading also very steady at 18 inches. will check torque of heads later. Thanks you all for you comments. ?? would a leak in intake manifold cause one side to give less cyl pressure.?? BUD carcrazy 09-30-2015 @ 7:35 PM reply profile send p.m. Senior Posts: 1691 Joined: Oct 2009 What is the history of the engine? Was it recently rebuilt or assembled? Does it have comparable cylinder heads on both banks? Is the left hand exhaust manifold and/or crossover pipe clear of debris? The difference in compression from side to side could be caused by one of these conditions. cliftford 09-30-2015 @ 8:46 PM reply profile send p.m. Senior Posts: 845 Joined: Jan 2014 With the high steady vacuum reading at idle, I too would question the accuracy of your compression test. Is your guage in good condition? Did the engine crank over at about the same speed for all cylinders? As stated it is highly unlikely that you would get the same reading on all 4 cylinders in one bank.

<< previous || next >>

PAGE: 1 2 3

NOTE: YOU MUST BE A REGISTERED USER AND BE LOGGED IN TO POST (and reply to) messages in this forum. If you are a first time user, please click the CREATE A NEW ACCOUNT in the masthead above to register and Log In. After that, all you do is LOG IN to enjoy using this site.

DISCLAIMER: The V-8 Club does no independent testing of any of the opinions, thoughts or suggestions presented in the website on the Forum, in the Tech Tips section, or any section. A reader should consider the website to be a forum wherein differing solutions to a particular set of circumstances may be discussed. Ultimately, the selection of an item for an individual's vehicle must be based upon the independent study of the vehicle owner in consultation with people in the hobby and restoration experts.

EFV-8 Club Forum Home | Back to Home Page | Contact the Webmaster

Copyright © 2009 - EFV-8.org
Powered by < CF FORUM > v.2.1