Okay I'm in need of some brain storming to help me figure this out. I have a 94 bronco 5.0 efi fuel pump went bad last year around this time. I put the fuel pump in it then and then it would not start I was having same issues I am now with it. so i ran out of time and had to park it and mess with it at later time. So I recently started messing with it again. I have power at fuel pump relay, fuel pump turns on. when I go to crank the engine it turns over but it floods my engine. I then take the pump relay off to burn the gas up in the cylinders and the engine fires up till the raw gas burns out. I have fouled 3 sets of plugs so far, and it's not just one plug that get soaked with gas it's all 8. I hook a fuel pressure gauge up to it and it holds 40 bls. the pressure does not drop it holds 40bls. I have changed the fuel pressure regulator 3 times with new ones thinking I been sold bad ones and same thing happens as before. I have taken the injectors out cleaned them. but first I pushed air thru them with no power to the injectors to see if any of them are stuck open and all seem to be working fine. I have checked the injector pulse with a noid light pulse is good I have changed the temp sensor(the rite one) I have checked to see if my return line is restricted by blowing air thru it and no clogs. I am at a lost with it I think I have covered it all and still can not figure it out. I even unpluged bout every sensor possible on it 1 by 1 and still nothing. I have tried 2 other computers and nothing. If anyone can shed some light on this nightmare I would really appreciate it.
5.0 flooding issue
- Thread starter hector79m
- Start date
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Rons beast
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Have you checked for codes, both KOEO and KOER?
There isn't a logical reason that the injectors would allow so much fuel in the cylinders. The O2 sensor would tell the computer to dial back the injector dwell time to almost nill. Apparently that isn't happening. So maybe the problem is that fuel gets in the cylinders and isn't being burned, because there is no spark.
Have you checked when the engine is cranking, fuel pump running, to see if you are getting spark?
When you unplug the relay and crank, are you getting spark?
If no spark with the relay plugged, you have some electrical gremlin.
Are you sure all the injectors are indexed correctly, ( all have the correct electrical plug). They may be opening but not when the cylinders want the fuel.
You changed computers, fuelpump, temp sensor, fuel presure regulator, Correct?
Either the injectors are bad, not indexed correctly, or not getting the correct signal, or there is no spark.
What happens when you crank the engin, fuelpump on, and put the accelerator to the floor? ( an emergency start situation)
Get back to us on this. It's very interesting.
Good Luck
There isn't a logical reason that the injectors would allow so much fuel in the cylinders. The O2 sensor would tell the computer to dial back the injector dwell time to almost nill. Apparently that isn't happening. So maybe the problem is that fuel gets in the cylinders and isn't being burned, because there is no spark.
Have you checked when the engine is cranking, fuel pump running, to see if you are getting spark?
When you unplug the relay and crank, are you getting spark?
If no spark with the relay plugged, you have some electrical gremlin.
Are you sure all the injectors are indexed correctly, ( all have the correct electrical plug). They may be opening but not when the cylinders want the fuel.
You changed computers, fuelpump, temp sensor, fuel presure regulator, Correct?
Either the injectors are bad, not indexed correctly, or not getting the correct signal, or there is no spark.
What happens when you crank the engin, fuelpump on, and put the accelerator to the floor? ( an emergency start situation)
Get back to us on this. It's very interesting.
Good Luck
Yes I have spark It Actually starts with the fuel that it got flooded with when I take the relay off. Iv'e checked it for spark and it's a nice strong blue spark. I have tried to hold the gas all the way to the floor and it acts as if it wants to start but the more I crank it the more it floods. So I go out take relay out and go back in the truck hold it to the floor and it starts long enough to burn the gas. It's as if it's getting to much fuel. I don't understand changed the regulator and injectors are not stuck open. I'm puzzuled.
Seabronc
New member
Go back to Ron's first question. Have you checked the codes?
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>-Okay so I'm very curios bout code 542 that I got.(Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits) Fuel pump open what does that mean??? The other ones I'm not sure but probably got from disconnecting sensor to see if it was my problem. Not sure
Rons beast
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That's alot of codes! Probably because of you unpluging sensors. Erase all the codes and try with the test again, and see what codes then pop up.
Good Luck.
Good Luck.
K thanks for the reply. Is there any other way to erase the codes besides taking negative cable off the battery? If not I already have the negative cable off and will post the new codes. Only reason I ask is cause I have tried 2 other PCM from the salvage yard and they both have codes on them, and they both do the same thing compared to the original PCM. They both make the truck act as if it's starving for fuel, where the original floods the engine.It takes it awhile once it starts to build up RPM with both PCM. I figure I throw that in here see if you make sense of that?
Rons beast
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My cheep code reader erases any codes.
It's good info that the other PCMs act the polar opposite of your original. That info leeds me to think the the original PCM is the culprit.
but let's not guess, see what codes come up.
It's good info that the other PCMs act the polar opposite of your original. That info leeds me to think the the original PCM is the culprit.
but let's not guess, see what codes come up.
but just incase I took the ignition module off the fender last night and took it to work with me today and went and had it checked and it came out bad. I have heard of them not working when it gets so hot. I have spark but could it actually be my problem? Now this is just thinking and asking without re reading the codes.77
Krafty
New member
if the ignition control module is failing it could provide spark but the timing would be off. the icm interprets the pip signal from the distributor/ ecm and if its not telling the coil to fire at the right time then your spark is too early and they get hosed with fuel too late. icms are not cheap at 120 a pop in Ontario, i would replace it and try the new one with each of the pcms you have to see if it works.
Krafty
New member
also before you install the new one get some thermal paste on it before you mount it otherwise it will overheat again. you can find thermal paste at any computer repair location.
Okay thanks Krafty, So I have always been a big fan of checking before guesing for it can get expensive. So lets say the ICM is faulty, And in this case I'm checking for right timming (Electrical Speaking) cause I know my engine is in time I have checked But to reply on what you say about the faulty ICM on not sparking at the when it should, I can hook a noid light to the Injector of the number 1 cylinder or any other cylinder wich ever it's easiest to get to as long as they are they are the same, and take that spark plug out of the same cylinder as if I'm checking for spark. Should the noid light and the spark be at same time or should they be off set???
BroncoJoe19
Active member
I can't find a definition for code 156 (Counting error?)
Try disconnecting the DPFE and see what happens.
Otherwise the codes are voltage above or below expected values. That sounds to me like crappy connections or bad grounds.
Check your battery cables at both ends, and the little grounds at the left and right upper radiator support as well as the one to the PCM at the driver's side hood hinge.
Oh... to delete codes just disconnect the jumper wire at the self test connector while it is displaying codes.
Also... the computers that you pulled out of the junk yard would not have stored codes, once they were removed from POWER they would no longer have any codes, just like when you disconnect the battery cables in your truck.
Try disconnecting the DPFE and see what happens.
Otherwise the codes are voltage above or below expected values. That sounds to me like crappy connections or bad grounds.
Check your battery cables at both ends, and the little grounds at the left and right upper radiator support as well as the one to the PCM at the driver's side hood hinge.
Oh... to delete codes just disconnect the jumper wire at the self test connector while it is displaying codes.
Also... the computers that you pulled out of the junk yard would not have stored codes, once they were removed from POWER they would no longer have any codes, just like when you disconnect the battery cables in your truck.
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