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Testing the fuel pump when the problem is occurring is a smart diagnostic procedure. How about testing ignition system output (spark) at the spark plugs when the problem is occurring.
I don't want to sound insulting or condescending. I get the impression you may not have the diagnostic skills to tackle this. Perhaps I can help by giving some up front skills so you fix your issues.
Your problem is going to be either fuel delivery into the engine or a component in the ignition system that gets hot and stops working then cools down and everything is fine again. Carry an HEI spark tester with you and test for spark at one of the spark plug wires when you are experiencing the power lose/no start. No spark?- the troubles with the ignition system not the fuel system.This will not isolate which component (ignition coil, control module, or pick up coil/trigger wheel) is the problem but you can eliminate the fuel system as the problem. If in fact the ignition system is the problem consult with the ignition system manufactuer for diagnostic procedures to narrow down the individual component that is giving you the problem. Do you have the original distributor for the car? You may want to consider re-installing it for test purposes. I know it is a CCC distributor w/o vacuum or mechanical advance but it will rum well enough for you to verify your diagnosis. It may be worth you while and sanity to purchase a an old school HEI that uses readily available GM/AC Delco parts.
Dieseling is usually caused by too high an idle speed. I sense you are getting frustrated with your drivability issues but they are really not too hard (at least to me) to solve. I saw your car at the spring LI Olds show. If you want additional help with this PM me.
FWIW vapor lock was eliminated years ago with reformulation of fuel. It is not your problem or the problem of the dozens of others who post here. I cringe when I hear the words.
HEI Spark tester, $14 at Amazon, $15 at Jeggs;
Last edited by Dynoking; Jun 20, 2022 at 10:28 AM.
I am continually performing R&D with this swap. Friday I broke down twice, second time on a bridge. Both ways exactly the same. 90 degree day. I am driving at 65-70, I feel like if I try to give it more than 1/4 throttle it starts acting like there's no fuel so I back off pedal and reapply 1/8. It slowly goes lower until the car loses speed then entire engine cuts off. I pull over to the side. I try to start and it just cranks. Battery good. Alternator is getting power. I disconnect fuel line to the carb, fuel comes out when cranking.
The first time I walked a mile to an auto store thinking it was an ignition coil. By the time I got back, I decided to try it one more time for the hell of it and it started right up with belt squeal which faded. Second time, I waited 15 minutes on hold with AAA then it fired up squealing and I got it moving to a parking lot, let it 'rest, then took the street the rest of the way home.
I initially thought the pump was bad but then fuel shouldn't have come out of the line. If spark or ignition was bad, why does it work later after it seemingly cools or not on the prior 40-60 minute drive. The MSD 'ready to run' distributor should be designed to deal with the heat so close to the engine.
It'll be inspected Wednesday but my guess is the fuel is boiling in the carburetor and its a form of vaporlock. Symptoms match. I didn't want to flood the carb so I never gave it heavy pedals, but if I applied some while cranking it felt like it got it going. Read now that depressing the pedal first then cranking clears it, which further ties the diagnosis. And this occurs after 40 to 60 minutes of driving on parkways / standstill traffic.
The temp gauge doesn't pass 195 but engine is still generating heat; I still shut the car down in drive. I've read a thermo gasket under the carb and a fuel filter with gas vent can solve the issues.
Been interesting dealing with issues that predate many 80s tech (dieseling/vaporlock).That being said, seriously considering the move to EFI earlier than I thought.
Breaking down or having issues with your car is no fun for sure. I think many of us have been there. I know I have been there with several of my carbureted cars here in CO and finally decided to abandon carbs and am loving the Holley SNIPER systems. Both of my hot rods have them installed and I have installed quite a few of them on other's cars. They perform well cold or hot and are very consistent. I tried all the old school and current tips and tricks to keep my cars from vapor locking and none of them worked. For me, carbs just don't seem to work as well here in CO at high altitude as they did when I was younger and working on them at sea level. I was tired of the hassle and constant tweaking and frustration.
I would definitely rule out spark and ignition issues by testing with the spark tester as noted by Dynoking. To answer your question....yes, ignition components can do weird things when they get hot. In just a few minutes of cooler temps, they can work again for some period of time. The best course of action is to test them during the time they are failing to be sure. What you are describing is classic vapor lock though so I would not dismiss that potential. My Chevelle would do this exact same thing after I drove it for 30 mins or longer in the hot summer. When I would return to my car from a quick trip into a store for like 15 mins....the engine would be flooded and I would have to hold the throttle wide open and wait for it to start and clear out the raw fuel before I could drive it again. Super frustrating and embarrassing for a nice looking restored and fast car. These fuel problems can manifest themselves similarly or differently in each vehicle.
Hopefully you will figure out your issues soon. I've gone to EFI years ago and won't even consider carbs any longer on my old cars--both current and the ones I still intend to build in the future. There are several types of EFI systems that work well for the street/strip cars. The good news is that MSD Ready-to-Run distributor will work great with the Holley SNIPER if you decide to go that route. I've installed several of them and they work great!
I forgot about my dashcam. So here is me breaking down in all its glory. You can hear the power intermittently cutting out. Then it miraculously starts later.
Testing the fuel pump when the problem is occurring is a smart diagnostic procedure. How about testing ignition system output (spark) at the spark plugs when the problem is occurring.
I don't want to sound insulting or condescending. I get the impression you may not have the diagnostic skills to tackle this. Perhaps I can help by giving some up front skills so you fix your issues.
It's not condescending at all. I didn't grow up with this so I know I am a total newbie. I actually broke down next to a Jiffy Lube the first time. The manager's dad came to help me, and after doing the fuel test he borrowed a spark plug to put in the leads to see if spark occurs while cranking. Only did the left side of the engine (facing forward), and he did it by putting the spark plug in the lead and putting it close to metal to see if it'd jump. First had spark, second didn't, third had spark, fourth didn't, but this was not exactly a reliable test vs a proper tool.
Breaking down or having issues with your car is no fun for sure. I think many of us have been there. I know I have been there with several of my carbureted cars here in CO and finally decided to abandon carbs and am loving the Holley SNIPER systems. Both of my hot rods have them installed and I have installed quite a few of them on other's cars.
EFI was always on the radar. The idea of a fuel injected Oldsmobile 455 is a mix of antiquated and modern that I like, especially since this was originally a computer controlled carb. Seeing all the work that cutlassefi does, I really wanted to but I couldn't swing an extra $5K+ to incorporate any version of fuel injection at the time of the build. Kind of a blessing after correcting things after the swap was performed. Good news is I can swing it much easier than a few years ago.
EFI was always on the radar. The idea of a fuel injected Oldsmobile 455 is a mix of antiquated and modern that I like, especially since this was originally a computer controlled carb. Seeing all the work that cutlassefi does, I really wanted to but I couldn't swing an extra $5K+ to incorporate any version of fuel injection at the time of the build. Kind of a blessing after correcting things after the swap was performed. Good news is I can swing it much easier than a few years ago.
Well the good news is that you can do a Holley SNIPER 4150 unit and a new EFI tank with internal pump for less than $2K. It's very affordable and the results are amazing.
Installing EFI on a vehicle hoping to correct an existing problem is where many EFI installations go wrong. I suggest we work through your issues and get the vehicle to run as it should. Then you can consider an EFI installation.
I’m a factory trained Holley dealer. And like many of them, I won’t sell another Sniper. They’re junk, very high failure rates. You’re an exception if yours doesn’t have some issue at some time.
Although I’ve never regarded ANY TBI system to be “fuel injection”, the Terminator X is a far better system and worth the extra $$$.
I’m a factory trained Holley dealer. And like many of them, I won’t sell another Sniper. They’re junk, very high failure rates. You’re an exception if yours doesn’t have some issue at some time.
Although I’ve never regarded ANY TBI system to be “fuel injection”, the Terminator X is a far better system and worth the extra $$$.
Well I find it hard to believe that most people out there (who are really knowledgeable) think the SNIPERs are junk. I have installed several dozen of these units on all different engines without issue. Those are in addition to the ones that I run on my own cars. I also talk with lots of people that attend car events in CO and they are pleased with their units as well. We set up a Super SNIPER for my friend with a 56 Belair which has a 900 HP BBC in it. He has several thousand miles of driving on it from race to race as well as allot of track runs. It’s no slacker I can assure you! He, by the way, also races in the Street Outlaws circuit and has two other very fast cars….the fastest is over 5000 HP. That car does have the higher-end EFI system in it for the precise cylinder-to-cylinder performance and tuning that’s necessary to win races but the cost for all that is off the charts!
Currently I have a 68 Camaro in my shop now that I’m doing allot of work to. It’s got a 525 HP 383 stroker in it with the Tremec 6 speed and it’s a runner I have to say. It has the SNIPER 4150 and the Hyperspark setup just like my 442. Out of all the units I have personally touched and the ones I have talked to others about---I hardy think it’s luck or that we are the only ones with the “good” units. My current 4150 on the 442 was a “used” unit that I purchased from a friend. It was two years old and had thousands of miles on it before I bought it from him. Now I have over a thousand miles on that unit for my car.
User reviews are all over the map nowadays. I pride myself in researching and studying things before I invest or buy them but it’s important to remember that many of the good reviews are never reported. Most have no trouble in reporting issues but many will never take the time to report a good experience with a product.
As far as the TBI fuel injection systems…I won’t debate that there are other higher-end units like the Terminator but most classic car owners and weekend warriors don’t need those extra features and capabilities so why spend the extra money? Relocating the ECU into the passenger compartment is one of the best perks for choosing the Terminator over the SNIPER but it’s not necessary if the installer is knowledgeable and competent to install the components correctly! Most of the reasons that these EFI units are criticized or returned as JUNK as you noted are for the following reasons:
1. Installation issues- users don’t follow the installation instructions and therefore create themselves more problems along the way.
2. People attempt to correct other mechanical and engine deficiencies with EFI. That never works as we all know. EFI can even highlight deficiencies and other problems that we didn’t know existed.
3. Existing or created RFI within the engine bay that must be mitigated or resolved. This will affect many of the EFI systems if left unresolved.
4. Owners and installers select the wrong product or combination of products for their particular application. This can lead to many undesirable effects and unresolved frustration in how their car performs.
5. Lastly, installers don’t know how to adjust and tune the EFI for their particular car. They start it up and believe that the unit is smart enough to run optimally over time. In some cases and for some people…that may work. For those like myself and my racing friends that want every HP out of our engines…..you must tweak and tune them to get it!
The TBI EFI units fill a void that exists for those who want something better than an old style carburetor that vapor locks, can’t adapt to altitude and weather changes, and in many cases won’t provide consistent performance hot and cold throughout the year. Is port fuel injection better than TBI—of course but not always necessary. I would recommend---talk to a knowledgeable installer who’s good and competent at installing AND tuning EFI….discuss your desires and the budget and then go from there. I have several friends that run tuning shops with chassis dynos and they highly recommend the SNIPER as one of the best EFI units on the market as compared to the other competitors. I also have a couple highly recommended Holley resellers that I go to for purchasing SNIPER units and they have no intention of discontinuing to sell them.
Stuck injector right out of the box. Turned on the key, pump came on and flooded the engine.
Replacement never even fired.
Third one ran, then got worse and worse, ran less and less before shutting off. Diagnosed as bad ignition driver and suspect ECU. Upgraded me to a Super Sniper for free cuz they were out of replacement units. So far it’s still running🤞.
The Terminator is better mainly because of two reasons, better O2 strategy and far less susceptible to RFI/EMI. The added features are secondary to me.
And a further note, rumor has it that there will be a Sniper II soon. It will address the issues at hand. I’ll say it again, the current ones are junk. At best they’re entry level EFI.
Last edited by cutlassefi; Jun 22, 2022 at 05:27 AM.
Stuck injector right out of the box. Turned on the key, pump came on and flooded the engine.
Replacement never even fired.
Third one ran, then got worse and worse, ran less and less before shutting off. Diagnosed as bad ignition driver and suspect ECU. Upgraded me to a Super Sniper for free cuz they were out of replacement units. So far it’s still running🤞.
The Terminator is better mainly because of two reasons, better O2 strategy and far less susceptible to RFI/EMI. The added features are secondary to me.
And a further note, rumor has it that there will be a Sniper II soon. It will address the issues at hand. I’ll say it again, the current ones are junk. At best they’re entry level EFI.
So I'm guessing that when you are done showing Edelbrock " the way", you will be engineering the new units for Holley.
Dave is correct !
A majority of failed units is user install error.
I never said there wasn’t installer error. My point is they have a higher than expected failure rate, right out of the box. Just go on the Sniper FB page and see for yourself. There are guys on there that openly admit they have a spare unit in the trunk, really?!
Let me tell you a little story dude.
Went to this last PRI carrying an SD card loaded with datalogs. I was having O2 issues with a particular unit. Long story short, the HOLLEY employee in the booth said the following, and I quote, “Mark, c’mon what do you expect for a $1000.00”. Kinda sums it up for me.
And I’m not even going to quality the other question with an answer.
Last edited by cutlassefi; Jun 22, 2022 at 09:50 AM.
As usual, there is a **** storm🙄. There are way too many failures and ones that run like garbage with FI Tech, Fleming442 is a good example. The Sniper also don't seem to be trouble free but not quite as bad. Plus who wants a EFI with a slow and inaccurate reading O2 sensor? Is SEFI cheap, nope. The intake conversion with injectors is nearly $1500 alone.
Last edited by olds 307 and 403; Feb 19, 2023 at 04:06 AM.
Breakdown #4:
The 455 cut out again, but more information than last time. I assumed it was vaporlock the last three times, so a carb spacer was added and braided fuel line from fuel pump to carb. When the throttle bogged after throttling from a red light, I pulled over just before engine cut off. I cranked and it started for 2 seconds then died. Tried again and it lasted 1 second then died. I tried the "hold pedal down while starting" trick but that didn't work. However, I could smell fuel. Fairly certain its not fuel related issue, especially since even an hour later the car wouldn't start when the engine had cooled. The temp gauge never crossed 180, but the last time I drove in stop start traffic it stayed at 165 because it was 10-15 degrees cooler. This was 72 degree day; engine heat is a culprit in the equation since I drove twice as long the last time.
I replaced the ignition coil with a brand new one while troubleshooting, but did not change anything. My current guess is something is overheating in the Ready to Run Distributor. Maybe the ignition module. Luckily, AAA towed the wagon to my mechanic, I was still in Brooklyn and not attempting a longer drive, there was plenty of space for the tow truck because of the upcoming marathon, and I didn't break down on a bridge like last time. However, the last three times the car would start again after 30 or so minutes. I had no joy after 1.5 hours.
RANT WARNING: Don't think its a stretch saying I am a bit beat up. Everything has been an crap show from the engine swap installation to now. My mom doesn't even want me driving it because she is worried the next break down is on the BQE or a highway the doesn't have a shoulder and I cause an accident. She doesn't trust it, and every time I build that trust up again it severs it. Its becoming costly. The engine swap has made my car more unreliable (I have so much more respect for the CCC and the ease of plugging in a laptop and getting the error message) than ever. And it seems everything breaking or causing the issue is a new part, not the 35 year old parts. I almost wished I kept it stock and just enjoyed trying to drive a slow wagon fast. I'm just tired. I want to take it on long roadtrips across country. I want to take it to a drag strip. My friends, and myself, are banking that it will be the Ecto-1 for one more Halloween, and I refuse to put them in a car that I don't trust. And I want so start spending my time and money on the things like bodywork, paint, getting tailgate working again, junkyards for doors, etc.
I just don't want to get beaten by this. I don't want to give up. It is just taxing, both mentally and financially. She was always a reliable ship and I fear I took that away.
Sorry for the rant. A bit low. A bit drunk.
Chin up, sometimes things roll your way, sometimes they don't. Some of the aftermarket high performance ignition modules are very sensitive to voltage spikes. I happens to us all, sometimes it is luck of the draw.
Chin up, sometimes things roll your way, sometimes they don't. Some of the aftermarket high performance ignition modules are very sensitive to voltage spikes. I happens to us all, sometimes it is luck of the draw.
Going to find out soon enough. My mechanic threw gas into the carb and it started right up. He thinks the dent in the fuel tank might be the culprit, though I have to admit I am skeptical. The dent has been there for years, the gauge read 3/4 tank when I stalled, and the tripmeter had either 16 or 23 miles since the fuel reset. The hard fuel lines were replaced within the past ten years. And if that was the case, how did I restart the car the previous times it bogged after waiting 30 minutes. Unless I was actually experiencing vapor lock the first time and this is a new / different issue. Regardless, I was due for a new tank anyway, and I am having him wire the vacuum switch for the lockup converter since he has it there. Either this is the fix... OR... I will be making another post later about breaking down again after getting the car back.
How about the tank vent system is plugged and creating a vacuum in the tank as you burn up fuel. Next time it stalls, stop and remove the gas cap. If you hear air rushing around the cap as you unscrew it, then that's your problem.
New fuel lines, new sender, new tank.
This thing starts better than it ever did since the swap. The acceleration is night and day difference; what this car could do at 1/4 throttle is now happening at 1/8th throttle. FYI, the old 307 had 130 hp, I've driven a CRV with 130, a Crosstrek with 140, and Ford Econoline vans; I dont know what 515 HP and 550 TQ is supposed to feel like. I actually thought the switch from 1650 to 2000 stall converter was a factor in its low acceleration initially. Starving an engine of fuel certainly will do that.
That's why if there is ever bogging, I recommend putting a temporary fuel pressure gauge outside the vehicle, on the hood or cowl, that you can easily see, in the situations where it bogs. I found on my built 425 that neither the factory fuel pump, nor the high flow carter mechanical fuel pump could keep up. I'd see the fuel pressure drop around the same time the car bogged. I ended up installing an electric pump near the fuel tank which permanently resolved the issue.
What does it have for exhaust? I actually found D9 regular stall converters flash around 1900 rpm. Of course your 2000 stall may flash much higher behind that torque. Good stuff.
I've been following your build for a while, and I just wanted to say it's been a huge inspiration for me, trials and all. I'm doing the same engine swap in my '82 Custom Cruiser, albeit with a slightly milder build, so this has been really motivating me to keep going. So glad you were able to find some answers to your problem!
I was curious, are you still using your charcoal vent cannister with your setup? I've been trying to sort out where the best place to reconnect mine will be since I'll be going from the CCC to a Holley 4150 carb. The best answer I've been able to come up with is T-ing into the PCV hose to the carb, but I'm not sure.
I've been following your build for a while, and I just wanted to say it's been a huge inspiration for me, trials and all. I'm doing the same engine swap in my '82 Custom Cruiser, albeit with a slightly milder build, so this has been really motivating me to keep going. So glad you were able to find some answers to your problem!
I was curious, are you still using your charcoal vent cannister with your setup? I've been trying to sort out where the best place to reconnect mine will be since I'll be going from the CCC to a Holley 4150 carb. The best answer I've been able to come up with is T-ing into the PCV hose to the carb, but I'm not sure.
Ported vacuum (not manifold like the PCV) and it needs to be restricted. Put a plug with a 0.040" hole or so in the line going from the carb to the can. The can has no restriction in it so it'll flow as much air as the carb wants to pull from it. Not good. Only need a tiny trickle of air to clear out the charcoal.
Free-up your exhaust next and find more power and mileage.
Originally Posted by olds 307 and 403
What does it have for exhaust? I actually found D9 regular stall converters flash around 1900 rpm. Of course your 2000 stall may flash much higher behind that torque. Good stuff.
The engine has brand new cast iron manifolds (C240268); when it was dynoed it had them so the power was with them to start. Kind of annoyed that they are already rusting but that could just be because they are cast iron... or because the shop who installed my engine flooded...
Using a G Force Performance Products double hump crossmember. The exhaust itself is 2.25 true duals with Dynomax Super Turbo 17749. It originally was using Flowmaster Delta 50s, which sounded nice with the 307, but the drone was exasperated with the 455 so I had to change them out. My old time mechanic was sad because everyone turned their heads when he test drove with the Flowmasters. Which I get at 0-30 mph. Highway, unbearable. And I wanted my car to sound loud with the throttle down, not at idle.
I've been following your build for a while, and I just wanted to say it's been a huge inspiration for me, trials and all. I'm doing the same engine swap in my '82 Custom Cruiser, albeit with a slightly milder build, so this has been really motivating me to keep going. So glad you were able to find some answers to your problem!
I'm glad you are able to learn from my experience. Which is funny because I would follow other threads that would convince me to keep going after learning from their trials. I tried to document the stuff that might have been mentioned in my research but not fully explained.
Question about EFI Fuel systems. More and more I am thinking of making the plunge to multiport EFI before summer. I know in-tank pumps are the preferred method for EFI with a blockoff plate for the mechanical fuel pump. Inline pumps I wouldn't consider. However, one method that exists that I do not see a lot of info / reviews on are the "surge tank" method. This is where the original mechanical fuel pump feeds fuel to the small tank, and then the tank sends the fuel at much higher psi into the fuel injection system. Is it more of a gimmick than a viable solution?
They are a possible option, but if you have the ability to properly install an in-tank pump, that would be the preferred method. You'll need to run high pressure EFI fuel line the whole length of the vehicle.
An in-tank pump is a no brainer if your vehicle has an aftermarket EFI ready tank/pump combo available. If you have a less common car without an EFI ready tank available, or oddly shaped tank which makes it difficult/impossible to retrofit an in-tank pump, then the surge tank begins to make more sense.
They are a possible option, but if you have the ability to properly install an in-tank pump, that would be the preferred method. You'll need to run high pressure EFI fuel line the whole length of the vehicle.
An in-tank pump is a no brainer if your vehicle has an aftermarket EFI ready tank/pump combo available. If you have a less common car without an EFI ready tank available, or oddly shaped tank which makes it difficult/impossible to retrofit an in-tank pump, then the surge tank begins to make more sense.
I know a lot of people swap 91-96 plastic B-body tanks in the 80s wagons when they do LS swaps. I hate to do that after just replacing my metal tank with a new one, and I do not even think the 91-96 plastic fuel tanks are made aftermarket. Some modify the existing tank with a Walbro 255, but end of the day the tank would have to get dropped. I feel like I am in the "less common car" section already with the Oldsmobile powered Buick wagon and considered the surge tanks because they seem more abundant now than they did years ago.
Since everything is new, give it a shot. Probably spend the extra $30 and get the middle one. I am planning on trying the Holley A body drop in with the big Hydramat pick up in my stock tank. I need to remind Mark to send my SEFI converted RPM and injectors my way. What SEFI system are you planning on?
Think I found out why my car doesn't start easily and turns off hard. My choke is wide open, and what I didn't capture on the first key turn is that it was partially open. I assumed you press the pedal down which would lock the choke closed, but it seems to progressively open more and more. I assumed after the last mechanic trip it was fixed since it would have problems starting but also ran extremely rich. Its a Street Demon 750, btw. Anyone have this experience before with this specific carb? I feel like I can fix this myself vs sending it out again.
Was the car cold before you started it? What was the outside temperature? Did you press the gas pedal to the floor once before starting it (this sets the choke closed)?
Take a photo of the choke side of your carb and post it here.
As for the not shutting off cleanly. What is your idle speed before you turn it off? Preferably measured with a dwell tachometer (in car factory tachs are notoriously inaccurate).
Okay. Take #2 with better angles. The temperature was the same, 55 degrees. Also a week between start and drive, like the last start up. I noticed the choke did close initially. I did through a jumper on the battery for the last dragged out start. Also watch your ears from the starter.
I am sure that others here can answer you better, but after watching your video, I have a couple of questions and suggestions.
Questions:
1) Are you sure that your timing is good? It sounded like it was trying to backfire through the carb a couple of times.
2) Are you getting consistent spark?
As far as suggestions are concerned:
1) That choke looks REALLY closed in the latest video. It might be too closed. If that video was taken at 55F, I would expect it to be more open than that. You might want to check your adjustment.
2) I heard you pumping the gas pedal a few times when you struggled to get the engine started. I always pump twice before my first attempt, one to set the choke and the second to give it a little more gas. If it has been sitting too long (way more than a week), I might do this a second time, but never much more. Another thing to try would be to hold the gas pedal to the floor after your second or third attempt. If this works, you probably flooded the engine or the choke is too closed.
There are several types of EFI systems that work well for the street/strip cars. The good news is that MSD Ready-to-Run distributor will work great with the Holley SNIPER if you decide to go that route. I've installed several of them and they work great!
