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Author Topic: 76 2.3 vacuum leak  (Read 1139 times)

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Offline Greymare

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76 2.3 vacuum leak
« on: June 04, 2015, 09:38:31 AM »
Hello all!
I am in need of some help or advice. I have been working on my 76 Pinto with a 2.3 for a few weeks now. This car had been sitting for about 5 years when I pulled it home. Long story short I had to end up replacing the head and cam. I took the head to a reputable shop and had them do all the head work and clean everything up and check it out. Installed the head and place everything back into place. I rebuilt the Holley 5200, installed the new fuel pump, cleaned the tank, and installed a inline filter to catch any rust which may be left over in the tank. I will be the first to admit I am not a carburetor man and never have been but I have torn a few apart and rebuilt them and have always managed to get them close enough to have someone adjust everything so that it would run properly. I fired up the engine and managed to keep it running long enough to break in the cam with the setup I had. (I am not sure how needed a break in on the cam is with the setup but I did it all the same.) I ran into one of my cousins that use to be a very good mechanic and asked if he would come adjust the carb for me. He said yes and came by and the before I even start the car he wants to pull it off. Well to shorten the story I end up buying a remanufactured carb and installing it.

Here is were we set today. The car will run if you choke it to death and yourself after a few minutes in the garage. I am pretty sure I have a vacuum leak but I am not sure where. I tried spraying some carb cleaner around all the intake runners, vacuum port, and vacuum lines. Never could really detect a change in RPM as the car is running rough flooding itself to death. I went a head and replaced the PCV valve and the hose running to it. Then I unplugged every line and put plugs on all the vacuum ports. The car is still the same with everything plugged off. The only thing I have not messed with in the testing is the egr. You can see it appears to be functioning with vacuum and it has a new gasket. I plan to try and build a block off plate tonight just to test and see if it changes anything. Anyone got any other ideas what might be causing my vacuum leak?

Offline Pinto5.0

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Re: 76 2.3 vacuum leak
« Reply #1 on: June 04, 2015, 02:29:08 PM »
I have been chasing a vacuum leak on my wagon for 2 years now & am planning an engine swap with brand new Weber 38 to finally try to solve it for good. Yours sounds like a stuck float in the new carb. I'd start there.
'73 Sedan (I'll get to it)
'76 Wagon driver
'80 hatch(Restoring to be my son's 1st car)~Callisto
'71 half hatch (bucket list Pinto)~Ghost
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Offline amc49

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Re: 76 2.3 vacuum leak
« Reply #2 on: June 06, 2015, 01:35:01 AM »
Compression check after motor is warm. If the headwork did not include a collapsed tappet clearance check (MANY shops do not do them), the valves could be held open and the loss of compression will quickly wet plugs to look like flooding issues. With loss of compression the burn drops way off and the plugs do not get hot enough to stay clean, they then wet out.

That mistake was commonly committed by shops here in North Texas and the major reason why many shops pronounced the engines as hard to rebuild right.

You need to know if the basic engine is solid anyway, if not all other effort is a waste of time.

If you changed cam you dang sure better have changed the followers (rockers on these) too or the cam will last maybe a month. Worn follower surfaces often tear up new cams.