CEL, codes 171, 174 300, 720
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CEL, codes 171, 174 300, 720
01 SportTrac 4.0, 5spd manual, 104K miles, 4wd
last time the CEL came on (about 2 years ago) had codes 171 & 174. The wonderful resources on this forum recommended replacing the MAF sensor. So we did and disconneted the battery for 1/2 hr. Worked like a charm!
This time i preformed the same feat, figuring i got hold of a "bad" MAF sensor or maybe the Arizona heat and dust caused it to fail . Unfortunatly the CEL returned after a few days driving.
Runs ok, idles really rough, occasionaly dies at a stop sign.
Wife is a real trooper but it's beginning to get on her nerves..
I throw myself on the mercy and wisdom of all you experts...
in advance, many thanks, Karl
last time the CEL came on (about 2 years ago) had codes 171 & 174. The wonderful resources on this forum recommended replacing the MAF sensor. So we did and disconneted the battery for 1/2 hr. Worked like a charm!
This time i preformed the same feat, figuring i got hold of a "bad" MAF sensor or maybe the Arizona heat and dust caused it to fail . Unfortunatly the CEL returned after a few days driving.
Runs ok, idles really rough, occasionaly dies at a stop sign.
Wife is a real trooper but it's beginning to get on her nerves..
I throw myself on the mercy and wisdom of all you experts...
in advance, many thanks, Karl
Cargo Master
Joined: Aug 2003
Posts: 3,263
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From: BC Canada
ok, lets start with the codes
171 Lean bank 1 (passenger side)
174 Lean bank 2 (driver side)
300 Random Missfire
720 multiple injector fireing
I would first look for the missfires(300), because it will send a rich signal to the O2's which would then trim to a lean mix (171,174), which ultimatly will not allow a clean burn so the injectors will be commanded to add additional fuel (720).
So
1. pull the plugs (wash/blow out dirt/dust before you take plugs out) and check the colour to verify the mixure and the burn,
2. Pull the MAF(it will give a lean burn as well), clean with brake cleaner or contact cleaner,
3. pull the AIC(regulates the idle) and clean with Brake cleaner,
4. Check condition of High tension wires, replace if chaffed or too much resistance.
5. replace plugs with new ones
6. reinstall MAF and AIC
7. Replace Air cleaner.
you should now clear codes, and drive
171 Lean bank 1 (passenger side)
174 Lean bank 2 (driver side)
300 Random Missfire
720 multiple injector fireing
I would first look for the missfires(300), because it will send a rich signal to the O2's which would then trim to a lean mix (171,174), which ultimatly will not allow a clean burn so the injectors will be commanded to add additional fuel (720).
So
1. pull the plugs (wash/blow out dirt/dust before you take plugs out) and check the colour to verify the mixure and the burn,
2. Pull the MAF(it will give a lean burn as well), clean with brake cleaner or contact cleaner,
3. pull the AIC(regulates the idle) and clean with Brake cleaner,
4. Check condition of High tension wires, replace if chaffed or too much resistance.
5. replace plugs with new ones
6. reinstall MAF and AIC
7. Replace Air cleaner.
you should now clear codes, and drive
Posting Guru
Joined: May 2002
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From: Phoenix
Lettk - the misfires can come from your basic tune up. I was getting this similar code (EEC-iv not -v like yours) and even though the wires all ohm'ed out OK, I replaced them and the problem was solved. If you have 104K on the original wires, it may be time to bid them farewell.
Go through the exercises already posted. Check all the plugs and find out what's going on inside the motor and then make your choice on what you want to replace. not sure where you are in AZ - I'm in Chandler. If you get stuck, you can bring it by and we can take a look.
Go through the exercises already posted. Check all the plugs and find out what's going on inside the motor and then make your choice on what you want to replace. not sure where you are in AZ - I'm in Chandler. If you get stuck, you can bring it by and we can take a look.
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THX! i'll try a major tune-up first. and yes - the wires are original :-)
I'm outside Queen Creek so Chandler is just up-the-road.
Biggest concern is getting this thing thru her 1st smog check.. up to now it's been exempt. Won't be able to get to this until Sat morning.
will let ya know!
I'm outside Queen Creek so Chandler is just up-the-road.
Biggest concern is getting this thing thru her 1st smog check.. up to now it's been exempt. Won't be able to get to this until Sat morning.
will let ya know!
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Stopped at the parts house for plugs, wires, air filter, brake cleaner. $110 later i headed out. Jumped outa bed Sunday to resolve this issue.
1) had a helluva time trying to get the sparkplug boots off (know i had a boot puller - damn kids!)
2) how do you get to the #3 plug??!?!?!? (passengers rear)
3) decided to remove the AIC & MAF, replace the air filter for starters.
lo and behold found a cut/slice/tear in a black hose (elbowed & about 2 inches long) that connects to a pipe running along the passengers side valve cover. repalce that hose, cleared the codes via ODB III reader.
Runs Great! Will let wifey drive it for a couple days and see what happens.
Still didn't change the plugs or wires.. -
thx, k
1) had a helluva time trying to get the sparkplug boots off (know i had a boot puller - damn kids!)
2) how do you get to the #3 plug??!?!?!? (passengers rear)
3) decided to remove the AIC & MAF, replace the air filter for starters.
lo and behold found a cut/slice/tear in a black hose (elbowed & about 2 inches long) that connects to a pipe running along the passengers side valve cover. repalce that hose, cleared the codes via ODB III reader.
Runs Great! Will let wifey drive it for a couple days and see what happens.
Still didn't change the plugs or wires.. -
thx, k
Posting Guru
Joined: May 2002
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From: Phoenix
I have no problem getting to #3 plug but my 1993 is set up a little different. Your AC box is a lot closer to the motor than mine. Most guys go through the fender wall, remove the tire if you have to.
Ford only recommended 100K miles on a set of plugs so you'll probably need them anyway. Wires maybe not right away. I thnk i got clser to 150K on my wires before it really started running like crap. But at least this way, doing a little at a time, you can see what makes the most difference. Nice catch finding the vac leak!
Ford only recommended 100K miles on a set of plugs so you'll probably need them anyway. Wires maybe not right away. I thnk i got clser to 150K on my wires before it really started running like crap. But at least this way, doing a little at a time, you can see what makes the most difference. Nice catch finding the vac leak!