1988 F150 Running Rich and bad!
#17
08-26-2009, 02:07 PM
First take the vac line off and check for fuel, if you have a hand vac pull a vac on it and see if it holds.
With it running at idle should have about 30lbs with vac line on, should jump up to 40lbs pressure with vac line off fpr.
Doubt its the problem but worth a look see.
Sounds like your 02 sensor is reporting lean all the time, the computer dumps in fuel trying to make up for it. A sensor doesn't work or B you have a bad vacuum leak and its dumping in fuel trying to compensate would be my first guess.
If the fpr was by passing fuel via the vac line the o2 sensor should read rich and the computer back off the fuel, shouldn't read lean.
With it running at idle should have about 30lbs with vac line on, should jump up to 40lbs pressure with vac line off fpr.
Doubt its the problem but worth a look see.
Sounds like your 02 sensor is reporting lean all the time, the computer dumps in fuel trying to make up for it. A sensor doesn't work or B you have a bad vacuum leak and its dumping in fuel trying to compensate would be my first guess.
If the fpr was by passing fuel via the vac line the o2 sensor should read rich and the computer back off the fuel, shouldn't read lean.
#18
08-26-2009, 02:12 PM
The garage that I took it to a few weeks back did tell me to try to unhook the 02 sensor and drive it like that for a bit. They told me that it will go to the backup settings in the computer and if this makes it run better then there is a problem with the 02 sensor. Does this sound like something to try? I haven't tried this yet.
#19
08-26-2009, 02:27 PM
The garage that I took it to a few weeks back did tell me to try to unhook the 02 sensor and drive it like that for a bit. They told me that it will go to the backup settings in the computer and if this makes it run better then there is a problem with the 02 sensor. Does this sound like something to try? I haven't tried this yet.
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#20
08-26-2009, 02:30 PM
#21
08-26-2009, 03:59 PM
Post Fiend
I forgot to mention the 02 sensor was replaced also.
I am not sure the brand of plugs that I put in.
1. The plugs and wires, cap and rotor, air filter, exhaust manifold, 02 sensor, pcv and the sending / low pressure pump was all done at the same time.
2. Still having trouble I replaced the coolant temp sensor.
3. Still having trouble I replaced the egr valve.
4. Then the map sensor.
5. Believing I may have had a vacume leak I replaced the intake and pletum gaskets along with the fuel injectors.
6. Still having trouble I replaced the distributor with a new pop up coil and ignition module.
We set the timing after the new distributor was installed.
All this in the past 4 or 5 months. I don't drive the truck that much. Weekends for racing.
And, I have no idea how that smiley face got into my post. If anything it would have been a sad face at this point.
I am not sure the brand of plugs that I put in.
1. The plugs and wires, cap and rotor, air filter, exhaust manifold, 02 sensor, pcv and the sending / low pressure pump was all done at the same time.
2. Still having trouble I replaced the coolant temp sensor.
3. Still having trouble I replaced the egr valve.
4. Then the map sensor.
5. Believing I may have had a vacume leak I replaced the intake and pletum gaskets along with the fuel injectors.
6. Still having trouble I replaced the distributor with a new pop up coil and ignition module.
We set the timing after the new distributor was installed.
All this in the past 4 or 5 months. I don't drive the truck that much. Weekends for racing.
And, I have no idea how that smiley face got into my post. If anything it would have been a sad face at this point.
did you read codes before all this?
what brand of wires, pliugs and cap?
if not motorcraft then that may be your problem.
find out if plugs are fouled by pulling one, and see if they are plats at the same time.
you have done so many things that it will be hard to figure out what is really wrong.
#22
08-27-2009, 07:31 AM
I unhooked the 02 sensor last night and drove the truck for about 30 - 35 miles. This is not the problem, still ran bad.
The code is "Running Lean" (although it is running very, very rich)
The cap, rotor and plugs are not Motorcraft but they were all checked and they look good. I beleive they are all Bosch parts.
The code is "Running Lean" (although it is running very, very rich)
The cap, rotor and plugs are not Motorcraft but they were all checked and they look good. I beleive they are all Bosch parts.
#23
08-27-2009, 08:30 AM
I didn't think that would show much but it was worth a try.
You get a system lean code but you know its rich, as long as the computer thinks its lean its going to continue to dump fuel in trying to make it go rich making a bad situation worse. That is unless you are wrong and it is in fact lean, doubtful as a rich condition is fairly obvious. Soot black tail pipe reeks of unburnt fuel.
Ok so a lean condition measured as a very low voltage reading from the sensor, rich condition is higher. Have you checked the wires to the sensor, a weak/bad connection, a frayed wire etc etc could cause resistance and interfere with the sensors ability to report the higher voltages needed in a rich condition. Sensors is reporting it, the computer just not getting it for example.
Does the heater in the sensor work?
Myself I think I'd just replace it at the same time fully inspecting its wiring while I was at it for any possible issues.
You get a system lean code but you know its rich, as long as the computer thinks its lean its going to continue to dump fuel in trying to make it go rich making a bad situation worse. That is unless you are wrong and it is in fact lean, doubtful as a rich condition is fairly obvious. Soot black tail pipe reeks of unburnt fuel.
Ok so a lean condition measured as a very low voltage reading from the sensor, rich condition is higher. Have you checked the wires to the sensor, a weak/bad connection, a frayed wire etc etc could cause resistance and interfere with the sensors ability to report the higher voltages needed in a rich condition. Sensors is reporting it, the computer just not getting it for example.
Does the heater in the sensor work?
Myself I think I'd just replace it at the same time fully inspecting its wiring while I was at it for any possible issues.
#24
08-27-2009, 08:47 AM
Post Fiend
one last time: are the plugs platinums?
#25
08-27-2009, 08:52 AM
The 02 sensor is only a few months old and it still looks new. The wires look really good too. I am going to make an appointment today to have the truck diagnosed. I am at the end of buying parts and wasting time. Maybe they can figure it out, maybe not, I have to try. I fix everything by myself but I need to get this thing figured out and fixed so I can move on with something else.
#26
08-27-2009, 08:55 AM
#28
08-27-2009, 11:44 AM
Have you pulled the codes on this thing yet? Put a jumper between the STI and Sig-Rtn wires on the EEC test harness, turn the key to run and the codes will flash on the check engine light. You'll need a pen and paper to copy them down.
www.fordfuelinjection.com has all the details and pics of where to find the EEC test harness, code definitions, and so on.
www.fordfuelinjection.com has all the details and pics of where to find the EEC test harness, code definitions, and so on.
#29
08-27-2009, 11:55 AM
The code was checked and it is a lean code which includes a whole list of posabilities. They checked it at the first garage I took it to. They told me to put a new coolant temp sensor in and if that didn't fix it to unhook the 02 sensor and see if that makes a differance which it did not do.