Sensors
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Freshman User
Joined: Jan 2001
Posts: 44
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From: Canada
Sensors
My truck pukes & sputters when I first start it & intermitantly
while I am driving, also it runs really rich(my neighbors parking
spot is now black. They engine off code says my power steering
pressure switch is open(does anyone know what this is & how to fix it). The continuous codes are; egr pressure feed back fault &
O2 sensor signal fault switching not detected( I have put in a new O2 sensor about a week ago). The engine running codes are
fuel mixture rich(like I didn't already know that) & power steer-
ing pressure switch open. I have had all the sensors out & clean-
ed, I took off the throttle body & cleaned it & what I could get to of the upper intake manifold. Power is way down, gas mileage
has dropped by half & idle can be erratic when I stop at a light
(possible something to do with the power steering pressure switch).
89 F250 4X4,302,5spd,K&Nfilter,3"flowmaster exh.(from half way down Y pipe,single high flow cat,2 chamber muffler), splitfire plugs, 8mm taylor wires,MSD coil,accel cap & rotor,centerforce
dual friction clutch. reg cab long box.
while I am driving, also it runs really rich(my neighbors parking
spot is now black. They engine off code says my power steering
pressure switch is open(does anyone know what this is & how to fix it). The continuous codes are; egr pressure feed back fault &
O2 sensor signal fault switching not detected( I have put in a new O2 sensor about a week ago). The engine running codes are
fuel mixture rich(like I didn't already know that) & power steer-
ing pressure switch open. I have had all the sensors out & clean-
ed, I took off the throttle body & cleaned it & what I could get to of the upper intake manifold. Power is way down, gas mileage
has dropped by half & idle can be erratic when I stop at a light
(possible something to do with the power steering pressure switch).
89 F250 4X4,302,5spd,K&Nfilter,3"flowmaster exh.(from half way down Y pipe,single high flow cat,2 chamber muffler), splitfire plugs, 8mm taylor wires,MSD coil,accel cap & rotor,centerforce
dual friction clutch. reg cab long box.
Postmaster
Joined: Jul 1999
Posts: 3,172
Likes: 4
Sensors
Check the fuel pressure & any signs of fuel leakage at the fuel pressure regulator , Id get rid of the Splitfire plugs & go back to the Motorcraft plugs . The Ps pressure switch idles the engine up when a load is placed on the engine from the ps . Also check that the Egr valve isnt sticking open & operates smoothly .
Tuned
Joined: Nov 2000
Posts: 426
Likes: 1
From: houston, texas (now Berli
Sensors
Yes, unmetered air causes erratic idle. Since you have taken off TB and intake manifold (replaced all gaskets?) intake air should be fine, leaving exhaust and vacuum to check.
The idle air control valve is a frequent culprit for erratic idle. I was once told by a mechanic my power steering pressure switch was shot. When I checked the codes myself, that code never came up, so I assumed he just forgot to turn the steering wheel during the KOEO test. Did you get the codes yourself?
As for working sensors: you can measure the output of the sensors to the computer to make sure they actually give the correct readings. For me just working the EVP sensor helped getting rid of an EGR code, strangely enough.
The idle air control valve is a frequent culprit for erratic idle. I was once told by a mechanic my power steering pressure switch was shot. When I checked the codes myself, that code never came up, so I assumed he just forgot to turn the steering wheel during the KOEO test. Did you get the codes yourself?
As for working sensors: you can measure the output of the sensors to the computer to make sure they actually give the correct readings. For me just working the EVP sensor helped getting rid of an EGR code, strangely enough.
Thread Starter
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Freshman User
Joined: Jan 2001
Posts: 44
Likes: 0
From: Canada
Sensors
Thanks alot for all the advice. I checked all the sensors with a voltmeter & vaccuum pump(where needed) & they are all working perfectly. There was no fuel leaking but I haven't checked for pressure. There is no vaccuum leaks & the exhaust is good. I reset the engine codes(yes I checked them myself) & now the only code I get is 42(fuel mixture rich) in the running test. Will have to wait & see if other codes come back. The power steering switch is in the high pressure line(whoever owned the truck before me had the electrical connecter off). There seems to be a problem with it though as idle drops off when you turn the wheel
(with the switch plugged in anyways).It seems to run a bit better
now but it is still running rich.
(with the switch plugged in anyways).It seems to run a bit better
now but it is still running rich.
Freshman User
Joined: Aug 1999
Posts: 42
Likes: 0
Sensors
disconnect the battery for about 5 minutes. Then reconnect. This will allow the computer to re-set everything when you restart. Drive around to let the computer re-set everything then re-check your codes.
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