88 Injectors
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88 Injectors
I am currently working on a 1988 F-150 with the 4.9 300 Straight 6. I have been trying idfferent things to no avail for a good while now, and finally have found what may be the problem. Two of the electrical wires have melted causing a poor connection. The lack of power and the inability to run, combined witht eh fact that it does run sometimes, makes me think a poor connection on these injectors could cause this. I guess what im asking is what is your take on my diagnosis?
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When does it run and when does it not run? Melted wires are never a good thing but, depending on the severity, it might be inconsequential.
Have you pulled codes from your computer yet?
Have you pulled codes from your computer yet?
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There is absolutely no rhyme nor reason as to when it does or does not run. I dont think the wires being melted are the problem per se, but them being melted caused a loose connection. I pulled the codes and got KOEO codes 23 and 67, and CM codes22, 33, and 96. I cant remember exactly what tehy are, but it seems to me i have explored all the codes to no avail, including new/used MAF sensor and EGR valve. timing has been checked and TPS has been checked to the best of my knowledge, which im pretty sure covers the KOEO codes.
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23 Closed throttle TPS voltage higher or lower than expected.
67 Neutral safety circuit failure.
22 MAP/BP sensor out of self test range.
33 EGR valve opening not detected.
96 Fuel pump secondary circuit failure. The EEC did not sense battery voltage on the Fuel Pump Monitor circuit.
Fuel Injection Technical Library » How To Run a Self-Test
When it doesn't run, check for fuel and spark. Pull a plug wire, insert a screwdriver, hold it next to the engine block as somebody tries to start it. You should see a strong, blue spark.
But, look at 96 - fuel pump secondary circuit failure, something is amiss there. What is your fuel pressure like? Output flow rate at the engine?
I don't think you have a MAF sensor, I think you have a MAP sensor.
In any event, check & fix the fuel supply problems, then worry about the MAP and TPS would be my course of action.
67 Neutral safety circuit failure.
22 MAP/BP sensor out of self test range.
33 EGR valve opening not detected.
96 Fuel pump secondary circuit failure. The EEC did not sense battery voltage on the Fuel Pump Monitor circuit.
Fuel Injection Technical Library » How To Run a Self-Test
When it doesn't run, check for fuel and spark. Pull a plug wire, insert a screwdriver, hold it next to the engine block as somebody tries to start it. You should see a strong, blue spark.
But, look at 96 - fuel pump secondary circuit failure, something is amiss there. What is your fuel pressure like? Output flow rate at the engine?
I don't think you have a MAF sensor, I think you have a MAP sensor.
In any event, check & fix the fuel supply problems, then worry about the MAP and TPS would be my course of action.
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The fuel has been checked and is in the correct range according to the local mechanic, and the voltage to the TPS is right in the middle of the range. I ran these tests last fall so they numbers are not remembered but i do remember that they were acceptable. This truck has been worked on by 2 local mechanics who both attempted to fix this problem with no success. They have tested fuel pressure, put different computer in, air and fuel filter have been changed, MAF/MAP has been tested and fixed as i mentioned, and i am quite honestly running put of things. I will recheck these codes and see waht i come up with ASAP. Thanks
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Well i checked and rechecked all the codes, and they have been fixed to no avail. right now the only thing left is the injector plugs. So back to my original question, would this cause virtually power? At an idle it runs great, but and gas at all and about 90% of the time it either dies or trys to.
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Clean the connections on the chassis mounted high pressure fuel pump .
Also check the connections on the fuel pump relay .
Post results please ...
Also check the connections on the fuel pump relay .
Post results please ...
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https://www.ford-trucks.com/forums/a...989&pictureids[]=99366&pictureids[]=99367
I could not figure out how to post pictures into the forum so i put them in this album and pasted the link above. As you can see pieces of the plastic plug completly melted onto the injectors, yet when i removed these plugs they nearly fell off. I can not find the actual plugs themselves, but hopefull this is enough to convey what happened. Thanks. I will clean these connections but i wont be able to test the results until i replace these plugs. the upper plenum manifold thing (the big silver piece that says Electronic Fuel Injection) was removed to get to the injectors. As soon as i get the plugs and get them on i will see what happens.
I could not figure out how to post pictures into the forum so i put them in this album and pasted the link above. As you can see pieces of the plastic plug completly melted onto the injectors, yet when i removed these plugs they nearly fell off. I can not find the actual plugs themselves, but hopefull this is enough to convey what happened. Thanks. I will clean these connections but i wont be able to test the results until i replace these plugs. the upper plenum manifold thing (the big silver piece that says Electronic Fuel Injection) was removed to get to the injectors. As soon as i get the plugs and get them on i will see what happens.
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TPS idle voltage should be between .8 and 1.3 volts.
Low Fuel Pressure
Bad MAP Sensor
Plugged Air Filter
Are the three main no power causes. A lot of people only check the fuel pressure at idle, but not under load. You're going to want to check this for sure.
As far as the melted wires go, you'll definitely want to fix those, but the question is why did they melt? Does your truck still have the injector cooling fan setup?
Low Fuel Pressure
Bad MAP Sensor
Plugged Air Filter
Are the three main no power causes. A lot of people only check the fuel pressure at idle, but not under load. You're going to want to check this for sure.
As far as the melted wires go, you'll definitely want to fix those, but the question is why did they melt? Does your truck still have the injector cooling fan setup?
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The cooling setup is no longer on my pickup, which i found odd however it is not on teh parts truck i have or, according to my dad, on any of the pickups he remember working on with similar motors. I will probably need a new one, but i will cross that bridge when i come to it i suppose. The MAP sensor was replaced, as well as air filter, and the fuel pressure has supposedly been checked by 2 different mechanics all throught the load range. 2 others have worked on this truck before me so its hard to tell exactly what has been done but i know these things have been checked and rechecked.
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The cooling setup was later replaced with a heatshield, but an '88 should still have the fan. If you can't find the fan, you should at least try and find a heatshield from the later trucks, otherwise the injectors are probably getting baked by the exhaust.
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Of all the things you list, and after looking at your pictures, a few things come to mind....
The pictures show one injector and, while it doesn't look real good, I've seen worse. And, a single bad injector will not cause an engine to not start or run.
I've seen a bad TPS cause weird things but never keeping the engine from starting. I suppose if one is failing in the right manner it could do that, though.
The fan / heat shield will help keep the injectors from soaking up heat when the vehicle isn't moving and/or the engine isn't running.
Since you seem pretty confident in your fuel pressure (and, presumably, flow rate) the other component coming to mind that can cause weirdness like this is a failing TFI ignition module. You might remove it and take it to a parts store to be tested (actually, might call them first and make sure they have somebody who knows how to use the machine) but heat-related failures can be hard to detect on the bench.
While it refuses to start/run is the perfect time to do some diagnosis, this should help you perform some ignition tests:
Ford Ranger/Bronco II TFI Ignition Diagnostics
The pictures show one injector and, while it doesn't look real good, I've seen worse. And, a single bad injector will not cause an engine to not start or run.
I've seen a bad TPS cause weird things but never keeping the engine from starting. I suppose if one is failing in the right manner it could do that, though.
The fan / heat shield will help keep the injectors from soaking up heat when the vehicle isn't moving and/or the engine isn't running.
Since you seem pretty confident in your fuel pressure (and, presumably, flow rate) the other component coming to mind that can cause weirdness like this is a failing TFI ignition module. You might remove it and take it to a parts store to be tested (actually, might call them first and make sure they have somebody who knows how to use the machine) but heat-related failures can be hard to detect on the bench.
While it refuses to start/run is the perfect time to do some diagnosis, this should help you perform some ignition tests:
Ford Ranger/Bronco II TFI Ignition Diagnostics
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there were 2 injectors affected similarly, but i will check the TFI as soon as possible. one more question, is the heat shield installed before or after the upper plenum? thanks for the input, i will get back to you as soon as i can
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