I have a 32 roadster ( too much street rod for the main board) with a 535 hp 427 sbc. In cool temps I haven't had this problem. Last week when the outdoor temp was 80 degrees it died three times. I was 30 miles from home and the engine died about 10 miles into the return trip home. The temp gauge is only reading 180 and no boil over. Almost acts like it is running out of fuel but I had over a 1/2 tank. If I let it sit for 30-45 minutes it will restart and go approx another 10 miles and dies again. Will not start immediately but as stated if I wait 30-45 minutes it will restart. In addition to this problem it died twice while turning right.????? When I try to restart after it dies it cranks but does not fire. Here are the particulars: Mallory fuel pump mounted close to tank (only few months old) MSD Ready to run Distributor with MSD Blaster coil. No ignition box Sniper EFI ( is this a no, no for the Off-Topic board?) Had same problem with Holley carb I dont think it is vapor lock but I guess it could be. I have a 3/8 SS fuel supply running across the firewall and it gets HOT under the hood top, not running side panels. I can hear the fuel pump when I try to restart after it dies. I would think if fuel pump it would not run after cool down but I plan to check it. Biggest problem for me is replicating the problem so I can check items without being on the side of the road. Im 83 and dont do well on the side of the road. Any ideas on a starting point to diagnose?
Do you have spark when the engine quits? Carry a spare plug and check it. Do you have your fuel line run close to exhaust pipe? If so, it could be boiling the fuel in your line and causing "vapor lock". Do you have a fuel return line? I am guessing no. You may have to change this. Those are the first 2 things you need to check. Sounds like fuel problem but verify the spark.
Do you have spark when the engine quits? Carry a spare plug and check it. Do you have your fuel line run close to exhaust pipe? If so, it could be boiling the fuel in your line and causing "vapor lock". Do you have a fuel return line? I am guessing no. You may have to change this. Those are the first 2 things you need to check. Sounds like fuel problem but verify the spark. I'll check the.spark. Fuels lines away from exhaust at lease 2-3" Have a return line to tank. I plan to take my temp gun and check temps on fuel lines when I encounter the next episode. Thanks Rockable!
With 50+ lbs of fuel pressure I doubt it’s vapor lock. So I’d follow the above and start with the ignition. Lots of things that quit because of heat take that long to cool off. Until they fail completely. The fact that it happened previously make me more suspicious.
Could be the ignition switch. The fact that it died when you made a turn caught my attention. If you have other keys that dangle with your ignition key...them swaying back and forth could cause connectivity issues in the ignition switch if the switch is on its way out. They can also act weird when hot..
Thanks for the reply Dueces. Is there a way to check a coil other that working or not?? I tend to agree with you miker98038, seems fuel would be moving and not prone to vapor lock. Black Panther, no key dangling but I will check it further. The turning issue really puzzles me. Thanks for the response fellas.
Since you have a return line, it is not likely vapor lock. So, check that spark. If you don't have spark, with the key in the run position, check to see if you have voltage to the + side of the coil. If not, trace down switch problem. If you do have 12 volts and no spark, replace coil. Only thing left after that is the distributor module.
The easiest way to check the ignition switch is fire it up and wiggle the key back and forth...see if it changes anything. Even if that checks out, it can still be the switch.
Some more info to add to the puzzle! Started the car and ran for 40 minutes in driveway and got up to temperature (200) and not a hiccup. Did some temp readings: At coil highest was 164. Dont know if that is ok or not but since it didnt die I didnt check any further. Guess I need to roadtest and if it dies check it then.
Do you have a pressure gauge in the fuel Line? Can you see it from the driver seat? Where is your fuel filter? Ben
I do have a pressure gauge but can't see from driver's seat, under the hood. Two filters like Holley recommends, 40-100 micron pre fuel pump and 10 micron post pump. Thanks for the reply Ben.
Does it happen with a full tank, or just when the tank level is lower? Take a water spray bottle with you and when it stalls, spray the fuel pump with cold water to cool it down. Take someone young and skinny along to make your own life easier. If it starts, the pump is overheating. https://www.motortrend.com/how-to/engine-vapor-lock/ This is really good info.
Did you check spark? That is the first and easiest thing to check. Plug an old spark plug into a wire, hold it against a head bolt and have someone try to start the engine. Until you can confirm this, you will chase your tail.
@rockable, I assume you mean check the spark after it dies which I will do when it dies again. Thanks. And Ben, I'll check that filter.
You didn't say where the fuel pump is located. Frame? In-tank? Is the Sniper the original version or the latest Sniper II ?
I was going to suggest the ignition module also, to me it sounds like something in the ignition system is getting hot then shutting down .... could also be the pickup coil in the distributor. Sometimes you can remove the cap and wiggle the pickup coil .... a worn out one will be loose .... thats total hillbilly diagnostics though. My 6 year old rockauto distributor the ignition module went out last week ... I checked and no spark. I replaced the coil just because I never replaced it in the past and unknown age, no help .... I installed a used ignition module from my old distributor and it now runs. I ordered a new one yesterday. The ignition switch makes no sense to me .... they do not get hot and need to cool down .... if it does you have bigger issues. I did have a 66 elcamino 283/4spd .... it had a bad switch and would die on me going down the road ... I had too many keys on the key ring. Same time I just turned the key back on and with a 4spd and rolling down the road it just started back up. A switch does not need to cool down in order to restart. In short I'm a terrible mechanic .... I feel like the old days we always carried a spare set of points, condenser, rotor in the glove box for a roadside repair. This is why I ordered the new ignition module. I bought the acdelco ... most expensive one they had for $60, I could have got the cheapest for $13. .... The one that is in it now works, it will make a good spare to carry in the glove box if needed .... along with the known good working coil . Just basic modern tuneup. We use to call it maintenance. With the module I also bought cap, rotor, plugs all acdelco and was over $150 I use to tune up my 1969 mustang for $20.
Im kind of leaning towards the ignition module also but need to verify the coil is good first. The distributor is an MSD pro billet ready to run # 8360 and can get a new ignition module for $161 if I need to. It needs to dye again so I can check stuff. Thanks for all the responses, I appreciate the help! And to answer @AHotRod, the pump and filters are on the frame rail near the tank. Not a Sniper II
You are describing almost the exact same problem that ALL 1970s Fords with electronic ignitions had once they got into the 1980s lol Obviously this is not a professional diagnosis without being there at the car but It sounds like the ignition control module is on its way out. I just went through this with my little Saturn wagon shitbox (with 72,000 miles on the clock) also it too had an ignition control module "heat soak" issue and it is a distributorless ignition, it's a common problem that pretty much plagues all cars with electronic ignitions... The symptoms you describe are very typical of an ignition control module, all makes all models including the aftermarket are guilty of doing almost exactly what you described. The only thing that is remotely odd is you say while making a right turn it will usually happen which means that could be a bad ground or loose connection but more than likely it was just a coincidence because once the car cools down a little it will restart which more than likely means it's not a loose connection somewhere. I am sure there is probably information somewhere of how many ohms the control module should read (for example 1,500 to 3,000 ohms or 20,000 to 90,000 ohms) and I would be willing to bet yours when the car is stalled on the side of the road is out of those parameters, the hard part is finding that information because it is an aftermarket part and because it's an intermittent problem being able to replicate it when you have the tools handy is almost impossible So here is how I would do it and be prepared to sit for a little bit if the car dies. If you have another distributor laying around or maybe someone's you can borrow I would install it take it around the block, keep it super local but make sure to get that ignition module hot, this way if you have sit on the side of the road waiting for a tow you're close to home. Anyways if changing the distributor didn't solve the problem you now know for sure it is nothing inside the distributor meaning it isn't the magnetic pickup or the ignition control module, distributor cap or rotor, So now since you're on side of the road dead I would bring 3 other items with you for a quick diagnostic work while it is dead, I would bring another ignition coil and a coil wire and just quickly replace it on the side of the road, don't worry about putting it on the bracket or any of that crap just quickly get the positive and negative hooked up along with the coil wire since it'll take about 5 minutes, theoretically the car will be hot still then try to start the car if it still doesn't start you've now ruled out the ignition coil and the coil wire, next think I would do is bring a can of starting fluid spray a good size Huff down the carb (or air intake on an injected vehicle)if the car fires up with a spray of the vroom juice then dies as soon as the spray and start runs Out that will tell you it's a fuel problem, obviously if the car doesn't even try to start that will tell you that it is definitely an ignition problem not a fuel problem but if you've replaced the distributor set up and the coil that pretty much leads you to a wiring issue and it is very rarely a broken wire it is almost always a bad plug or connector but don't rule out wires, the way you diagnose that type of stuff is you get alligator clip wire leads and you start bypassing wires, again this stuff is really hard to replicate because it is an intermittent problem and all you're trying to do is get it to happen while you are prepared for it which is really hard. Like I think I said a second ago in this long diagnostic comment my gut is telling me it's an ignition control module because every vehicle I've ever dealt with that the control module went bad it is almost always the same thing the car runs great when you first fired up in the morning it'll get you just far enough down the road that you're thinking it's not going to do it again and then it'll do it and leave you sitting on the side of the road, you call AAA you drag the vehicle home but by the time it gets home you hit the key and it starts right up again... I've always referred to it as ignition control module "heat soak" I don't know if that's a technical diagnostic term but I do know inside an ignition control module there is transistors and transistors are noted to have issues when they get either hot or too cold. Anyways keep us posted when you figure out what it is I would love to know what the actual problem was.
My history: coils get hot and shut off, fuel vapor locks in the right conditions, anything electronic can fail with heat. That being said, what kind of vent do you have on the fuel tank? The next time it does it, I would remove the fuel cap and see if there is pressure built up. Check the sniper hand held and see what it says. Turn to the screen where it shows info and see if you have cranking rpm when trying to start it, if there is no rpm, the ignition has failed. Looking through the sniper book in the trouble shooting might help to see if you have an ecu problem. One of my friends had a similar problem. turns out that the suction line for the pump was partially clogged with rust from using an old tank. When the sniper was installed, was a gauge installed somewhere to verify 58 psi?
I have done some checking of the fuel system and all seems ok. However I determined my fuel tank is smaller than I first thought and the gauge inaccurate and now believe when it reads below 1/2 tank it is actually less and when turning right it moves away from the fuel supply fitting to the pump and starves the pump. It did start right up after the turn. I plan to drive the car today and see if it stalls. I'll take test items with me and hopefully determine if the coil is a problem or not and go from there. I'll also connect the Sniper handheld as wfo guy suggested. Thanks again for all the comments and suggestions!
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