Hello All, So I have a 1974 Dodge D100 Custom Street Truck, I'll post up some photos soon, it has a 360 Magnum that I believe is out of a 2001 or 02 Dodge Ram 1500. Man I'm tired of trying to fix this issue... after it has been sitting all night its tough to restart and once it does start it has a loud sucking noise through the throttle body and then it evens out and surges a bit, the throttle body parts have all been replaced, new electric fuel pump plus new fuel regulator with pressure around 50, I'm running a duel snorkel ram air breather and headers only, I've had people tell me that the computer needs to be programed and now I'm confused as I've been given a lot of different information... at this point I'm tired of trouble shooting the problem, can anyone recommend a performance shop? Thx.
Tired Of Trouble Shooting.
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65 sporty
Well-Known Member
Used engine or rebuilt? I am assuming your running the factory computer and injection. I have seen plenty of gaskets under the barrel intake get sucked out
Slap Stick
Active Member
Look down through the throttle body with a flashlight. If it is wet you bave a bad plenum gasket.
Odds are you do.
Odds are you do.
7mopar
Well-Known Member
Are we to assume all required sensor have been retained or have you installed some sort of aftermarket EFI?
Richs restoring
Member
Anytime you hear a sucking noise you have a vacuum problem. Like the other guys said, check all the gaskets in the intake, throttle body base etc. You'll find it! Also check all the hoses. They crack with heat and age. If they are hard, replace them.
AJ.
Active Member
My guess is your AIS motor is wide open. which is easy to prove.
If the sucking sound starts to diminish right after the engine starts up, then the programming is dialing it back, which would be the right thing for it to do.
It sounds to me like one or more of your injectors are draining the fuel line overnight., causing a flooded condition. The Wide open AIS motor on a cold start is common, and probably normal. It provides the fast-idle during warm up.
A powerful coil might help. But probably not.
Don't forget that EFI cars dump a shot of fuel into the intake/ports every time you turn the key to the "start" position. So if, I say IF, you are sawing on the key, yur causing the flooding. Just crank it until it fires up, do not saw on the key. If it takes more than 15 seconds of cranking, something is wrong, and yur gonna need to put a scanner on it.
One thing you can try is to pull a few plugs out, in the morning, BEFORE you crank it; and see if they are gas-fouled. If they are NOT fouled, then as mentioned, your plenum-gasket may be out of place. Hughes engines sells a more robust plate and gasket kit.
But my money is on gas-fouled plugs due to leaking injectors.
Well, I suppose the EFI Temp sensor could be giving a bad reading, or the Baro; but the scanner will find that in just minutes. Either of those would call for a fatter pump-shot on a cold engine. Then if you saw on the key....... well she's drowning..... Oklahoma City is at 1200 ft elevation, so it wouldn't take much of a Baro/Map/Maf whatever she's got, sensor-error to cause flooding.
Edit
on a cold-start, the O2s are ignored by the computer. They won't start working until a pre-progtammed coolant temp is seen by the ECM ............. unless the sensor is lieing. As in somebody modified it, or maybe it broke. Any sensor malfunction or one that is sending out of range data will turn the MIL lite on. So, if your lite is on, you gotta put a scanner on it. Buy one and learn to interpret it. If you have headers and do NOT have working O2s, yur just asking for trouble. And you better have installed an IAT sensor in your fancy snorkel. And a working Map/Maf/Baro, which in concert with the rpm sensor, are the two most important sensors on your system.
And finally, the cam sensor on those engines are a known problem . The ECM only checks it during cranking, looking to find the compression stroke of #1 cylinder, so it can begin injecting . After the engine starts and you release the key, it never looks at that sensor again until the next cranking cycle. If the ECM cannot find that signal, your engine will not start. It takes at least one or two engine revolutions to establish that signal.
Same with the Baro sensor, it only checks it during cranking. But the engine will run with a faulty one, albeit not very well at 1200ft elevation.
I agree with 7mopar, below in post #8
If the sucking sound starts to diminish right after the engine starts up, then the programming is dialing it back, which would be the right thing for it to do.
It sounds to me like one or more of your injectors are draining the fuel line overnight., causing a flooded condition. The Wide open AIS motor on a cold start is common, and probably normal. It provides the fast-idle during warm up.
A powerful coil might help. But probably not.
Don't forget that EFI cars dump a shot of fuel into the intake/ports every time you turn the key to the "start" position. So if, I say IF, you are sawing on the key, yur causing the flooding. Just crank it until it fires up, do not saw on the key. If it takes more than 15 seconds of cranking, something is wrong, and yur gonna need to put a scanner on it.
One thing you can try is to pull a few plugs out, in the morning, BEFORE you crank it; and see if they are gas-fouled. If they are NOT fouled, then as mentioned, your plenum-gasket may be out of place. Hughes engines sells a more robust plate and gasket kit.
But my money is on gas-fouled plugs due to leaking injectors.
Well, I suppose the EFI Temp sensor could be giving a bad reading, or the Baro; but the scanner will find that in just minutes. Either of those would call for a fatter pump-shot on a cold engine. Then if you saw on the key....... well she's drowning..... Oklahoma City is at 1200 ft elevation, so it wouldn't take much of a Baro/Map/Maf whatever she's got, sensor-error to cause flooding.
Edit
on a cold-start, the O2s are ignored by the computer. They won't start working until a pre-progtammed coolant temp is seen by the ECM ............. unless the sensor is lieing. As in somebody modified it, or maybe it broke. Any sensor malfunction or one that is sending out of range data will turn the MIL lite on. So, if your lite is on, you gotta put a scanner on it. Buy one and learn to interpret it. If you have headers and do NOT have working O2s, yur just asking for trouble. And you better have installed an IAT sensor in your fancy snorkel. And a working Map/Maf/Baro, which in concert with the rpm sensor, are the two most important sensors on your system.
And finally, the cam sensor on those engines are a known problem . The ECM only checks it during cranking, looking to find the compression stroke of #1 cylinder, so it can begin injecting . After the engine starts and you release the key, it never looks at that sensor again until the next cranking cycle. If the ECM cannot find that signal, your engine will not start. It takes at least one or two engine revolutions to establish that signal.
Same with the Baro sensor, it only checks it during cranking. But the engine will run with a faulty one, albeit not very well at 1200ft elevation.
I agree with 7mopar, below in post #8
Last edited:
7mopar
Well-Known Member
Slap Stick
Active Member
If all is well, turn the key to ON. The fuel pump will run until the system is pressurized fully. You will probably hear the relays (if you transferred the wiring from the donor truck). Then turn the key to start. It should fire within three revs.
Have you checked for a bad plenum gasket yet? This will cause hard to no start.
Have you checked for a bad plenum gasket yet? This will cause hard to no start.
1 MEAN66
Active Member
Easy way to find a gasket leak in any intake system: Way back when ( I,m Old) on non electronic carbed vehicles you simply put your hand over the carb. to try and "cut off" some air (at any RPM that the problem was occuring) if Rpm increased it was LEAN at that point. we took the Choke and manuall closed it Same result same problem. On "modern" electronic vehicle you can still do the same "TYPE" of thing. start it up, let it stabilize. Get a can of carb cleaner spray it over vacuum lines, don't forget the brake booster, then at the base of the "carb" (or throttle body) , intake to head, etc. If it affects ( effects?) it in ANY way you have a air leak! Remember the computer vehicles will try to fix the problem faster than you can think about it. BUT they only have so much range to work in ( they are NOT designed to work with a mechanical - read gasket failure- ! Remember modern engines work the same as 30's engine. They have just replaced jets with "DWELL METERED" injectors, computers that can sense altitude, ETC. Looking down the throat of the throttle body for wet is a good start. But might not be just a gasket leak. On carb. the float could leak, well plugs,etc. On injection It could be a a dirty injector not closing properly! If the injector is "dirty" the fuel pattern gets "screwed up" ! It will not be a fine VAPOR but liquid and LIQUID FUEL DOES NOT BURN!!!! With a computer it does NOT MEASURE FUEL. They are called OXYGEN SENSORS for a reason. If the injector dripps in fuel It may NOT see a rich condition but a LEAN condition. Remember fuel vapor combines with air, the computer measures the air. If the liquid fuel does not mix with some air the computer STILL MEASURES AIR , and sees more of it, will try to add fuel to fix, but that is not the problem! COMPUTERS ARE BLIND!!!!! They do what they are programed to do.
Trouble shooting is slowing down and thinking, about what IS happening and trying to figure out what is wrong. You have to throw the dart at the correct dart board , before you can get a bulls eye. Changing parts can get expensive.
MoparsOnly
The snozberries taste like snozberries.
You can also use map gas to find vacuum leaks. I use to use It with a rubber hose worked awesome.