Ford 302 engine wouldn,t idle

George/Maine

George/Maine

Well-known member
I don't know much about the engine only what i have done.It wouldn,t idle well has autotrans.I put a new timing chain no change,new carb,better but not good.other dist,wires,It sounds like it got a hot cam, running good down road.Has duals and sounds even on both sides.The vacumn is only 14 says late timing.I have moved the timing with no change.This may sound crazy but ,could the intake have problems, gasket in middle 4 cylinders with the exhaust cross over.Its not leaking on outside.Looks like a junk yard motor not very clean.
picture.php
 
'Y" is it the block? Hahahaha [312 Y-Block]
So maybe the carbs? Fuel delivery?
Not idling is that 'Lopping'? on the cam?
Too rich? Float too high? Can't burn that much fuel and quenching the fire?
Check the plugs.
You need to hook up to the old SUN machines..
Those were the days.

So really big holes in the manifold or a lot of little holes equal low vaccume pressure.
So how big are the carbs? Progressive linkage?

skip.
 
Last edited:
For a 302 to have only 14 inches of vacuum at idle, there is a question you must answer. It could be a vacuum leak at the intake manifold. It could be a really wild cam. What were the marks on the front of the cam when you replaced the chain? To rule out high float level or bad carb, read the plugs. Check the plug wires to make sure the spark is strong. Run a compression check and record the answers. Let us know, - - - -
 
I do think it may have hot cam.I just bought a new Holley carb 350 2 barrell and just took it for ride,beat on it runs well, good rpms.With the automatic the idle has to be high or it will stall.
I don't know much about the truck has headers,looks like posie 9".I think maybe needs a higher stall torque converter.The good thing with this carb its got a manual chock and can play with it in traffic.
picture.php
 
George, post some pics of your engine and focus one on the distributor.Also with the timing light how many degrees advance are you running?Also what are you running for a fuel pump?
 
George, 14 seems too low, thought 18 was the norm, 350 2 barrel is a bit small for a big cam, should still run ok but loose top end, are you running a vac advance dist? is it hooked up to the correct port on the carb? Do you have power brakes? Is the vacuum modulator on your trans. connected and in good shape? Do you have any idea what the cam specs are? I dont think its the stall rate, I suspect that you either have a vac leak, not enough advance or retard in your timing, or a defective modulator on your ****** as you are stalling when you take off, you should be able to idle with your foot on the brake in gear, she should almost climb the rpms herself as you roll out of it.
 
Other possibilities, these engines may or may not have press in rocker studs, these little piggies love to bend push rods if they are not set up right, that can really throw a freak into the timing set up, they can be sensitive to valve lashing problems, if you dont know the engines history this could be some thing to look at.
 
Take a can of Chemtool [my choice] and spray along the intake edges along the head. While the engine is idling. If the idle smooths out, there you go, intake gasket. Just replaced one on one of my 302's. Of course, you could be dumb like me and have an intake vacuum fitting and knock a rubber cap off of it and spend a lot of time looking at carb and intake seal before noticing it. Not the same one I put the intake gaskets on, but same systems. Joe
 
Is the intake cast iron? I've run across a few that were warped due to over-heating. If you do decide to go the intake gasket route, be sure to check for flatness of the mating surface while it's off- can potentially save you a lot of aggravation...

 
The destructions says LOL.
I could have a leak on the valley side, says hard to find.I had a larger Ford carb on and did say thing,changed dist,
timing chain,wires,and didn't think it work work but put a new carb on yesterday,Tested today and runs good.It will not idle down good.I don't think its a head problem,but only thing left is intake leak.Yesterday used wd40 on intake for leaks and nothing.Its a basic hookup one hose to dist,pvc,new gaskets.I once had a Isky 300 cam in a y block and that was hot cam and would at least idle.
picture.php

picture.php

picture.php
 
Those 302 Fords are notorious for bad valve and valve guides. This one looks a bit crusty, like it hasn't been apart for a long time. A compression check will help, but I think its time to pull the heads and take them to your trusted machine shop for a good three angle valve job. You may be very surprised at the outcome.
 
Can you find out what size cam you have from where ever you bought the engine or if it came with the truck . That would take a lot of guessing away .
As for the heads and valve train , instead of taking the heads off, just do a air test to each cylinder and see it there is a air leat out the carb , tailpipe or where you put oil into the engine . If no air leak then you are fine but if you have an air leak in one of those 3 places it's easy to tell what is wrong ,
* if air comes from carb then it's the intake valve
* if air comes from exhaust pipe then exhaust valve
* if air comes from where you put oil in then it's rings or piston
I think I got them correct if not someone let me know . I have done this one before and saves lots of extra work and money .
Depending on the year of the engine , I have gotten more than 180,000 miles from the Ford heads with no problems .
Also check your spark plugs to see how they are firing , that will help also .

Jim
 
Hi Frank The hose was not long enought there is a piece of tubing there.It wouldn,t so bad if it was stick shift.When i put it in gear it stalles.If i turn the idle up i'm doing 30 mph.
 
So she idles ok, she snaps to life when you give her a good throttle, burns pretty clean at the exhaust, rolls down the road fairly crisp. But when you put her into gear she drops away and stalls. shes only holding a vac of 14. I think you said she had a c4 automatic. If you could hook up a vac gauge and see how far she drops off when you put her into gear? She should idle between 650 and 800 rpm higher rpm is for later 02's as they had the pollution junk, I think its real possible that you have a bad trans modulator, check the diaphragm on it, It could be the trans fluid level or a misbehaving stock stall, or maybe some one put a big stall in it, does it hit hard if you rough it into going. If she idles clean and responds crisp and no smoke and will purr down the road once she gets going, i dont think its a valve train or carb or timing problem. What will she do if you start her out in low?
 
I had a 351w with one cam bad lobe and would idle down.I have another 302 idles fine.Took dist off that one no change,new timing chain thought it may have jumped timing,wires off other engine.New carb Holley they say tested.If there is a leak its in the middle,the ends have water, eather side of exhaust cross over.I got on it the other day pedal to medal,shift to 2nd,and to 3rd under power ok.The summers go by so fast ,for bragging rights this year, its got a racing cam. That maybe true.
It sounds like a boat maybe its a marine engine. LOL
 
My 56 ideled like it had a hot cam when I bought it. The dist. was complety out of adjustment.I ended up in a new dist. It was shot. but a dewell meter and timming light will tell what going on.Make sure the plugs and wires are in good shape also.Look closely at the points if you have them.
 
Is the vacuum line hooked up to the modulator in the transmission? It's been a while since I played with a 302/C4 combo, but I believe there ought to be a vacuum tree at the rear of the intake, and one line that goes under to the passenger side of the trans to the adjustable vacuum modulator...at least that was the case on my 68 Cougar. That puppy pops off and it can lead to all sorts of trouble.
 
You must log in or register to reply here.
Back
Top