Thread: Push it off a CLIFF..... Engine Problems?

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Ok I have a strange one here. This had happened a few times in the past, but with no regularity. Engine hot, opperation temp, 185 to 195. Engine dies. I thought a first it was a carb problem, kinda acted like it was flooded. If you held throttle open it would fire and then die like no gas. Not vapor locked, fuel in carbs. Now it will only run about 5 mins. Long enough to get to opperating temp then dies like you just turned off key. Hold throttle open and refires, then dies. Sometimes you can hold throttle open and get it to run at about 2000 rpm, drop near idle, dies.
Here is what I have done.
At first appeared to have no or very weak spark, so I changed coil. It is an accel unit, I Know POS. But the guy at auto parts store pulled a fast one and warrentied it for me. Ran 15 mins, same problem.
Spark may be weak, not sure, but has spark, enough to nail me.LOL
Ran compression check right after died and wouldn't restart normally.
All cyl's above 130#.
Pulled dummy blower and carbs and tried holly of my 66, (which runs fine), same problem.
Checked valves to make sure they weren't too tight. It's hot now and I changed oil and used Valvoline vr 50. Valve lash looks ok.
Changed plugs ac R45TS, same problem.
Fuel pressure between 2.5 and 4 P.S.I.
Gonna stop by wrecking yard and pick up a coil, just to make sure it's not the Made in china pos accell coil. But I am lost. It has to do with temp. Let engine cool down and will refire normally and idle at normal rpm. It has got progressivly worse over the last couple of weeks till saturday, when I drove it 3 miles and died, let cool for 10 mins and off we go. Just barely made it back to the house. Died in drive.
I am ready to Push, (I can't drive it) off a friggen cliff.
Any and all help appreciated. This thing is driving me crazy

What type of distributor/ignition module are you running to trigger spark? Sounds to me like that is where your problem is - electronic module gets hot, weak spark; cools off, starts OK but only until the module gets hot again.

Originally Posted by rspears

What type of distributor/ignition module are you running to trigger spark? Sounds to me like that is where your problem is - electronic module gets hot, weak spark; cools off, starts OK but only until the module gets hot again.

Not sure of brand. Small body and cap like point type. External gm type module, mounted under cover on outside of dist. Thought this might be an issue. But in my mind, module and dist triggers spark and delivers via plug wire. It seams to me, now correct me if my thinking is wrong, this would result in a no spark senario. I did check rotor button, and cleaned rotor tip and brass contacts in cap. Spark travels from coil thru coil wire to rotor button thru brass to rotor tip to corisponding term on dist cap thru plug wire to plug. The dist does trigger spark. So am I thinking correct?

Originally Posted by dlotraf33

Not sure of brand. Small body and cap like point type. External gm type module, mounted under cover on outside of dist. Thought this might be an issue. But in my mind, module and dist triggers spark and delivers via plug wire. It seams to me, now correct me if my thinking is wrong, this would result in a no spark senario. I did check rotor button, and cleaned rotor tip and brass contacts in cap. Spark travels from coil thru coil wire to rotor button thru brass to rotor tip to corisponding term on dist cap thru plug wire to plug. The dist does trigger spark. So am I thinking correct?

Yeah, you're thinking right. The module is the trigger, and they either work or not but weak is not generally a symptom. Seems strange that a new coil would have the same problem, but then there have been some really bad experiences posted about Accel parts recently.

It seems to me that some component is not working when it gets hot.....could be electrical or fuel. I'd drop another distributor in there and see what happens. The modules will do that sometimes.

Don

Yeah, I thought about this morning, and even though it's gonna be a pain I am going to pull hei dist out of my 66 this afternoon and drop it in. This will either eliminate electrical system or narrow it down to either dist, or coil. I would have rather not had another accel coil but they warrentied it. As soon as I can afford it, assumeing it's not another bad coil, I will try to get somthing else. So if you guys have any good or bad luck with a particular coil, round package type, let me know. I'll let you know the update later today. Good news dist is under warrenty, bad news, gotta come from tenn. Thanks for the help so far.

Check the fuel psi.

Ignition problems can do this 'come and go' stuff.

Just to get this out of the way..
Do you think the coil is over heating?
Is there a ballast in the system?

Our old ford would do this exact same thing, and it was a brand new rebuilt 460, it turned out to be the ignition module.

Originally Posted by 1wild&crazyguy

Check the fuel psi.

Ignition problems can do this 'come and go' stuff.

Just to get this out of the way..
Do you think the coil is over heating?
Is there a ballast in the system?

Our old ford would do this exact same thing, and it was a brand new rebuilt 460, it turned out to be the ignition module.

Fuel psi between 2.5 and 4 at the time of MECO (Main Engine Cut Off),sorry just came to me and had to throw that in. It does have spark after it shuts off, might be weak, hard to tell, I don't see so great at that distance. But it knocked the shit out of me yesterday so I felt (haha) that it was stong enough. And I have also pulled carb top after it shut off, without any additional cranking and fuel level in bowl appears to be correct. Gonna swap dist this afternoon so we shall see. And you assume that you put a new part on, (coil) and so it can't be that, but then some of this china stuff, well you never can tell. Bought a chevy solonoid once, the plunger has been the same size, well these were just a tick too small, everyone that was in stock at advance, paid 3 times that ammount at another parts house and still made in china, however it worked. Whata ya gonna do?

I had a 77 Ford F150 that had an intermittent problem similar to that.Some times when it got hot it would go dead, start and run for a minute and go dead,and sometimes you could hold it wide open and it would only run about 1000 rpm.Seemed just like a fuel starvation problem.Turned out to be the ignition module.

msd blaster 2 coil .. never had one fail in 20 years

Originally Posted by dlotraf33

Fuel psi between 2.5 and 4 at the time of MECO (Main Engine Cut Off),sorry just came to me and had to throw that in. It does have spark after it shuts off, might be weak, hard to tell, I don't see so great at that distance. But it knocked the shit out of me yesterday so I felt (haha) that it was stong enough. And I have also pulled carb top after it shut off, without any additional cranking and fuel level in bowl appears to be correct. Gonna swap dist this afternoon so we shall see. Whata ya gonna do?

Do you have a vacuum gauge? Reason I ask is you should measure vacuum from a cold engine untils it dies. If you're losing vacuum when it get to operating temp. that''ll eliminate the ignition and fuel systems. I've had a couple cars with dual wall pipe that had the inner wall "swell" and block off the exhaust system. They would run good cold then slowly lose rpm \ power. We could only diagnose this with a vacuum gauge. I've seen a car do it with a blocked cat. converter too. Act like a bad fuel filter or weak coil but the darn thing just couldn't breathe! It's easy to check too!

Originally Posted by 34_40

Do you have a vacuum gauge? Reason I ask is you should measure vacuum from a cold engine untils it dies. If you're losing vacuum when it get to operating temp. that''ll eliminate the ignition and fuel systems. I've had a couple cars with dual wall pipe that had the inner wall "swell" and block off the exhaust system. They would run good cold then slowly lose rpm \ power. We could only diagnose this with a vacuum gauge. I've seen a car do it with a blocked cat. converter too. Act like a bad fuel filter or weak coil but the darn thing just couldn't breathe! It's easy to check too!

Yes that thought did occur to me, such as manifold possibly heating up and opening a gap in the sealing surface as to induce a major vacum leak. I guess I could pull gauge off my vac brake bleader. I was going to try dist from my 66 but was too hot this afternoon and I just didnt feel like sitting on that hot engine. It does seam sometimes I end up with somthing like that, it cant be the simple fix, has to be the bizzare one. Just my luck. But I thank you, never thought to check the vac. For another reason I was going to install a direct mount vac gauge, just havent gotten around to ordering one yet. But I may do that before I jerk out that other dist.

Originally Posted by dlotraf33

Yes that thought did occur to me, such as manifold possibly heating up and opening a gap in the sealing surface as to induce a major vacum leak. I guess I could pull gauge off my vac brake bleader. I was going to try dist from my 66 but was too hot this afternoon and I just didnt feel like sitting on that hot engine. It does seam sometimes I end up with somthing like that, it cant be the simple fix, has to be the bizzare one. Just my luck. But I thank you, never thought to check the vac. For another reason I was going to install a direct mount vac gauge, just havent gotten around to ordering one yet. But I may do that before I jerk out that other dist.

10-4 on the hot day / hot engine! And that's another reason I always hook up a vacuum gauge! Can tell you so much with so little effort!

I had a Camaro that did something like that. Mine turned out to be the pickup coil in the dist. Would get hot, resistance would go infinite, run like crap and die, then cool off and run fine... till it got hot again.

maybe its time to go back to the basics the first thing to check as in any electrical problem is powers and grounds the coil needs full bat. voltage in about 13volts the wire from the coil to the dist. goes to the module that is just a switching transistor it turns off and on the ground when it is on it allows power to flow through the coil to charge it then the pick up tells the module to open the magnetic field collapses and you have spark then the pick pu tells the module to close and the process is repeated so if you have full bat. voltage at the coil it is time to look at the ground make sure the dist. is grounded to the eng. and the eng has a good ground back to the battery remember a good dvom is your friend.......ted p.s. there is no magic