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Weird starting issue

tk1218

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Nov 23, 2008
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I have a 302 that I'm having trouble getting to run. What I have

Professional Rebuilt edelbrock 600
HEI distributor new
Electric fuel pump new with regulator

It will start, runs super rough with idle surging and have to keep feathering gas to keep running

Can't check timing due to the rough running and gas feathering

It's a standard with no power brakes so only vacuum line not plugged on the carb is the front right that goes to the dizzy

Vacuum port on intake manifold is plugged

Fresh gaskets on carb and intake

I'm thinking vacuum leak but can't seem to find it

Any thoughts would be appreciated
 

DirtDonk

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Is the choke closing when it's cold? And is it closing all the way, meaning too far? If it's not closing at all it could make for a hard cold starting, but the same holds true if it closes all the way and chokes off too much air.

You can still check your timing even with the rough running. Have the light hooked up and just see if it's even close. You may not get a full idle reading, but you could see if it's in the ballpark.
 

DirtDonk

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It's also harder to check for vacuum leaks in these conditions, but not impossible perhaps.
 
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tk1218

tk1218

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Thanks

I will check the choke.

Right now the timing looks to be around 2 btdc, but it's hard to tell for sure

I usually run them around 10 btdc
 

B RON CO

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Hi, if the timing is only 2* BTDC it is way to much retarded. I would loosen the distributor hold down and advance the timing a little bit. Then start the engine and keep advancing the timing to see how it runs. I think you should be good with @12* base timing, with the vacuum hose off and plugged.
Get the ignition system tuned up 100% and then adjust the carb.
Did the problem crop up after you got the new distributor?
Triple check the firing order.
Of you can get it running better you can get a vacuum gauge reading.
Good luck
 

DirtDonk

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Agree with B RON CO completely. Even if it's not precise, get more advance into the timing. You're not going to hurt anything even over adjusting it while you're just idling and trying to get it running. Only time too much timing advance hurts is under load.

A few more thoughts:

Professional Rebuilt edelbrock 600

This is what got me on the choke line of thinking, but there is nothing in the books that says even a brand new carb can't run like crap now and then. Even more likely on a rebuilt unfortunately, but you just have to deal with it, track down the gremlins wherever they are, and get rid of them one by one.

HEI distributor new

While they've been mostly good in recent years, the HEI's can suffer from bad modules like any other electronic device. Used to be a big issue with them, but not so much lately. Still, the possibility can't be ignored...

And absolutely check the firing order. Was the engine rebuilt by any chance? A new camshaft by any chance? You know Ford firing orders come in two flavors, right?

Electric fuel pump new with regulator

Not likely to be the cause of your current running issue, so you're likely good there. But future issues that are hard to trace can definitely be failing fuel pumps AND failing regulators.
How many pounds is it set for? Did you take a gauge reading too?

It will start, runs super rough with idle surging and have to keep feathering gas to keep running

Back to a previous question, did you rebuild the engine? If so, new cam? If so, did you do the absolutely critical cam break-in procedure? Sounds like that would have been a problem due to how it's running, but if you did not and are fighting an idle/running issue, you are very likely going to be buggering up the camshaft and lifters.
Not to be Dire-News Dan, but it's a fact of life and a problem with new engines unless you're aware of all the ins-and-outs. If you are, great. But if not, that's why we bring it up here fairly often.

Vacuum port on intake manifold is plugged

All of them? And all of them on the carb, including both of the large ones front and rear?

Fresh gaskets on carb and intake
I'm thinking vacuum leak but can't seem to find it

Was wondering about this too. I don't think this is as big an issue on Edelbrock/Carter carbs as it is on Ford carbs, but did you compare gaskets to their mating surfaces just to be sure they're matching? A mis-matched carburetor base gasket is probably the single most common cause of the larger vacuum leaks.
Again though, usually on Ford carb setups.

Good luck. Hang in there!

Paul
 

Rustytruck

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Pull the plugs and look at condition and if you have even burning on all the plugs. if they are running rich it will show it. while running check the heat at all the exhaust ports use a temperature gun or a sprits of water from a spray bottle. see if the water sizzles off the same at each port. a spritz not a squirt from a hose or something excessive. edelbrocks are sensitive to fuel pressure and fuel float levels float too high will allow to much fuel in too early.
 
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tk1218

tk1218

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Well quick update.

It's sort of running, only 2 cylinders for sure. 3 and 7 are firing for sure.

The engine is a 78 Mexican block. I'm wondering if it might have an rv cam

The reason I'm thinking this is that the timing marker is on the opposite side as normal. Just assumed it was set up for a car and put a bronco timing chain cover on. Water pump is reversed also

See picture

An rv cam would have a different firing order
 

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DirtDonk

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I'm wondering if it might have an rv cam
An rv cam would have a different firing order

Nothing to do with it being an RV cam actually. The identifier "RV" is just a made up generic name and is often over used in the cam buying world. And it used to mean something slightly different in the '70's as it does now.
Any type of cam can be had with the different firing order. Even stock cams, because it's in fact a stock firing order.

So no matter what engine you're working on, if you don't know what cam is in it you need to verify the firing order manually to be sure. If you can't put the cam in your hand, or don't want to pull a valve cover to watch the rocker arms, you can find out which firing order by pulling a few spark plugs and using your finger over the hole as the engine is rotating (by hand of course).

Once the compression builds on cylinder #1 you then move your finger over to either #5 or #3 cylinder and see which one builds compression next, within the next quarter turn of the crankshaft.

The reason I'm thinking this is that the timing marker is on the opposite side as normal.
Just assumed it was set up for a car and put a bronco timing chain cover on. Water pump is reversed also

Firing order and timing don't have anything to do with which cover or which harmonic damper you are using. But both components can have a huge effect on how you can verify and set the ignition timing.
Using a damper that has markings for a different pointer location and you'll never get the timing right by using a light and can only do it by feel/ear. If that ends up being the case, then buy some timing-tape and find TDC on the compression stroke of #1 cylinder and then use the timing tape to line up with your pointer. From then on you can use a timing light to set your timing.

But for now just verify which style of cam you have. A 154 cam, or a 137 cam.

Paul
 

SHX669

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As previously mentioned - check your new HEI distributor . Last summer A Bronco friend bought a Blueprint " 306 Bronco motor " he fought issues for months and finally took it to a " shop " - bad brand new distributor wasn't firing consistently .
 

Broncobowsher

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There are 2 different firing orders used in small block fords. Get it wrong and you are only running on 4 cylinders. Could be a problem.

What firing order do you have? That depends solely on the camshaft and nothing else. It might get to the point you take the valve covers off and note which intake valve is open in ¼ turn increments of the crankshaft.
 

m_m70

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There are 2 different firing orders used in small block fords. Get it wrong and you are only running on 4 cylinders. Could be a problem.

This is where I would start if I wasn't sure on the cam.....remember the dizzy spins counter-clockwise.
 
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tk1218

tk1218

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Verified it's 154

Timing is set correctly. Checked spark on a cylinder not firing and it's getting spark

Gonna check fuel delivery and compression today
 

DirtDonk

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Verified it's 154

Great. Good to know that at least.
And what is the history of this engine? Did you just pick it up out of a vehicle, pull it from a vehicle, or has it been running in one of yours before?

Timing is set correctly.

How do you know? Or did you mean the firing order?
If timing, I want to ask you about the parts being used. You said you put the Bronco timing cover on the engine? If so, did you put a known-good Bronco harmonic damper on it as well? Remember Ford used different timing mark locations, and many of the manufacturers and re-manufacturers of these parts didn't seem to know that and put whatever random part in the box and call it good. Might be the right size and all, but has the timing marks in different locations.

So if you have not already, by all means twist the distributor clockwise a bit to see if things change for the better.
Maybe you already did that, but I figured I might as well mention it again.

and compression today

Compression will be a good check. Hopefully it's all copacetic, but I guess we'll know soon enough.

Good luck!

paul
 
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tk1218

tk1218

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Yes it has a bronco damper

Engine came out of a ford passenger car, pick and pull

Yes, wires are right, can't keep it running to get timing right, so something* isn't right
 

Broncobowsher

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Random engine from a Pick and Pull. What did the car look like? Can you tell why the car was dropped off to be picked apart? Wrecked is generally a good sign, they were running when the came to a sudden stop. If the car looked perfect, suspect the drivetrain is what gave up and why it was dropped at the salvage yard.

Have you rocked the crank back and forth to check play in the timing chain? It may have stretched enough to have jumped a tooth.
 
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tk1218

tk1218

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No compression in 4 cylinders. Using adjustable heads so redid the tightening of the rocker process again and now have a min of 165. Must have gotten out of sequence on the first try.

It started right up and timing set at 10 degrees
 

DirtDonk

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Great! Good detective work. Glad you got it worked out.

Paul
 
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