1988 F150 CEL problems
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
1988 F150 CEL problems
I have a 1988 Ford F150 4.9 standard tranny regular cab with an odd problem. Truck runs great now that I replaced both in tank pumps except that, like clockwork, every 8 minutes or so the check engine light comes on. If I shut it off and restart it, the CEL goes out, only to reappear 8 minutes later. Yesterday, I took it for a spin and did this about 10 times...truck runs great, no prob except for the CEL.
Codes I get are 33 and 41 with KOEO continuous and KOER.
Within the last 3 weeks, I have replaced the O2 sensor, the egr valve, its solenoid and position sensor, the fuel regulator, and fuel filter.
Any ideas where to start looking?
edited to add.......the CEL business started after I replaced the O2 sensor...the old one had frayed corroded wires going into the sensor body. I'm assuming it didn't work but no CEL came on before the change.
Codes I get are 33 and 41 with KOEO continuous and KOER.
Within the last 3 weeks, I have replaced the O2 sensor, the egr valve, its solenoid and position sensor, the fuel regulator, and fuel filter.
Any ideas where to start looking?
edited to add.......the CEL business started after I replaced the O2 sensor...the old one had frayed corroded wires going into the sensor body. I'm assuming it didn't work but no CEL came on before the change.
Last edited by doodad; Aug 2, 2005 at 07:26 PM.
Post Fiend
Joined: Mar 2002
Posts: 19,402
Likes: 38
From: Bonita Springs FL
Have you tested the EGR? There's a procedure for checking the EGR and the EVP in the haynes manual.
You can also hook a vacuum pump to the EGR valve itself. The engine should stumble when you give it vacuum.
Also, try disconnecting the battery for a few minutes, drive it around, then pull the codes.
You can also hook a vacuum pump to the EGR valve itself. The engine should stumble when you give it vacuum.
Also, try disconnecting the battery for a few minutes, drive it around, then pull the codes.
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
Originally Posted by andym
Have you tested the EGR? There's a procedure for checking the EGR and the EVP in the haynes manual.
You can also hook a vacuum pump to the EGR valve itself. The engine should stumble when you give it vacuum.
Also, try disconnecting the battery for a few minutes, drive it around, then pull the codes.
You can also hook a vacuum pump to the EGR valve itself. The engine should stumble when you give it vacuum.
Also, try disconnecting the battery for a few minutes, drive it around, then pull the codes.
I'm puzzled why the code 33 is there.....egr not closing...my mechanic friend put on a new egr...I'm wondering if he didn't clean the tube out and there is blockage causing an open egr code. This would also likely trigger a code 41 I think from what Ive seen on these forums.
I just find it odd that it takes 8 minutes for the CEL to come on each time unless that is some kind of of normal reaction for an O2 sensor to register a CEL as it attempts to regulate the mix and maxes out the limits of the computer.
As well, Im a little confused...my code book says 33 is egr not closing yet I see lots of posts here claiming 33 is egr not opening....wassup with that?
I had HC's of 328 at idle on the emission test (max-200) and the pamphlet says one cause can be an egr partially stuck open, and I do have an obvious exhaust odor at idle. Course that result was with the old egr, but now with the new one I get that 33 code and still have odor, so......
Last edited by doodad; Aug 6, 2005 at 06:50 PM.
Posting Guru
Joined: Jun 2004
Posts: 1,781
Likes: 1
From: Central NY
33 = EGR opening not detected.
Possible culprets include, wrong/bad egr valve, EGR stem not hitting the position sensor, bad position sensor or wiring, bad egr vacuum regulator (EVR) module or wiring, bad vacuum or line. I would start at the EVR on this one. If its diaphram sticks open then its always venting the line to the egr to atmosphere...
41 = O2 sensor detects an always lean condition. If you think this is being caused by a stuck open egr valve then I would block it off and the vacuum line to the EVR , clear the codes, and see if it comes back. Otherwise I would start with a thorough check for exhaust and vacuum leaks followed by an O2 sensor esp. If its got 50,ooo or more miles on it.
I hope you find the culprit!
Popa Tim
Possible culprets include, wrong/bad egr valve, EGR stem not hitting the position sensor, bad position sensor or wiring, bad egr vacuum regulator (EVR) module or wiring, bad vacuum or line. I would start at the EVR on this one. If its diaphram sticks open then its always venting the line to the egr to atmosphere...
41 = O2 sensor detects an always lean condition. If you think this is being caused by a stuck open egr valve then I would block it off and the vacuum line to the EVR , clear the codes, and see if it comes back. Otherwise I would start with a thorough check for exhaust and vacuum leaks followed by an O2 sensor esp. If its got 50,ooo or more miles on it.
I hope you find the culprit!
Popa Tim
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
Originally Posted by Popa Tim
33 = EGR opening not detected.
Possible culprets include, wrong/bad egr valve, EGR stem not hitting the position sensor, bad position sensor or wiring, bad egr vacuum regulator (EVR) module or wiring, bad vacuum or line. I would start at the EVR on this one. If its diaphram sticks open then its always venting the line to the egr to atmosphere...
41 = O2 sensor detects an always lean condition. If you think this is being caused by a stuck open egr valve then I would block it off and the vacuum line to the EVR , clear the codes, and see if it comes back. Otherwise I would start with a thorough check for exhaust and vacuum leaks followed by an O2 sensor esp. If its got 50,ooo or more miles on it.
I hope you find the culprit!
Popa Tim
Possible culprets include, wrong/bad egr valve, EGR stem not hitting the position sensor, bad position sensor or wiring, bad egr vacuum regulator (EVR) module or wiring, bad vacuum or line. I would start at the EVR on this one. If its diaphram sticks open then its always venting the line to the egr to atmosphere...
41 = O2 sensor detects an always lean condition. If you think this is being caused by a stuck open egr valve then I would block it off and the vacuum line to the EVR , clear the codes, and see if it comes back. Otherwise I would start with a thorough check for exhaust and vacuum leaks followed by an O2 sensor esp. If its got 50,ooo or more miles on it.
I hope you find the culprit!
Popa Tim
I tested vacuum to evr during a drive and it was ok....put manifold vacuum to egr and it stalled. Put it all back together and cleared codes....did a KOER and 33 is gone!!!! Maybe I put something back that was loose or dislodged something.
41 is still there....replaced that O2 sensor 2 months ago so guess I will start investigating the 41 code. Haven't run it long enough yet to see CEL just KOER but will clear and run it tomorrow. In the meantime, any help about 41 codes from ya'll will be appreciated. Have an emissions test scheduled Wed afternoon.
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
Took off throttle body this morning...gasket was sucked in so I replaced that and cleaned the heck out of everything with throttle body cleaner. No change in code 41.
Failed emission test in pm.
HC at 40kmh went from 75 to 156 since last time. Pass is 79
CO at 40 k went down from .67 to .12. Pass is .44
NOx at 40 k went down from 2426 to 657. Pass is 845.
HC at idle went from 328 to 715. Pass is 200
CO at idle went from .86 to 3.96. Pass is 1.0
Arggggghhhhhhhh!!!!!!!!!
Tester said he thought he felt a miss. Big rainstorm just before the test but it seemed to be running ok. Wonder if something got wet?
Manager asked me if the air injection system was working. Must admit I hadn't ever looked at that.
Only code Im getting is 41, KOEO continuous and KOER.
Failed emission test in pm.
HC at 40kmh went from 75 to 156 since last time. Pass is 79
CO at 40 k went down from .67 to .12. Pass is .44
NOx at 40 k went down from 2426 to 657. Pass is 845.
HC at idle went from 328 to 715. Pass is 200
CO at idle went from .86 to 3.96. Pass is 1.0
Arggggghhhhhhhh!!!!!!!!!
Tester said he thought he felt a miss. Big rainstorm just before the test but it seemed to be running ok. Wonder if something got wet?
Manager asked me if the air injection system was working. Must admit I hadn't ever looked at that.
Only code Im getting is 41, KOEO continuous and KOER.
Trending Topics
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
Air Injection Sysytem
The combo valve and pump appear to work ok according to the tests I did per the Haynes manual with air coming out of where it is supposed to each step of the test. Not much info there about solenoids tho but since the combo valve seems to be working can I assume the solenoids are working?
At the combo valve, the air goes to the manifold on startup, then, a short bit later, the vacuum stops and the air goes to the cat. Is this the way it is supposed to function? Anyone know?
It was nice to see the dramatic reduction in NOx and CO at 40kph....assume that's the egr working right now but those nasty increases on the others has me stumped, especially since the air injection seems ok.
At the combo valve, the air goes to the manifold on startup, then, a short bit later, the vacuum stops and the air goes to the cat. Is this the way it is supposed to function? Anyone know?
It was nice to see the dramatic reduction in NOx and CO at 40kph....assume that's the egr working right now but those nasty increases on the others has me stumped, especially since the air injection seems ok.
Last edited by doodad; Aug 12, 2005 at 01:05 PM.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
No Codes!!!! Yahoo!!!!
Put the old O2 sensor back on. Cleared codes by removing negative from battery. Tested KOEO and KOER after a 15 minute run....no codes! Guess the new O2 sensor was bad.
Now if it will just pass emissions.
Now if it will just pass emissions.
Freshman User
Joined: Jan 2004
Posts: 40
Likes: 0
Originally Posted by doodad
Put the old O2 sensor back on. Cleared codes by removing negative from battery. Tested KOEO and KOER after a 15 minute run....no codes! Guess the new O2 sensor was bad.
Now if it will just pass emissions.
Now if it will just pass emissions.
Thread Starter
|
New User
Joined: Jul 2005
Posts: 16
Likes: 0
I have heard about the methyl hydrate; may give it a try...thanks. Have been considering a new cat but at 1/2 the price of the truck I'm cautious with no guarantee that will pass me for sure. Maybe I could do it cheaper with a universal and some welding.
Thread
Thread Starter
Forum
Replies
Last Post
spartan29307
1994.5 - 1997 7.3L Power Stroke Diesel
8
Aug 16, 2014 10:53 PM
Larry Placido
1987 - 1996 F150 & Larger F-Series Trucks
8
Jul 26, 2008 11:44 AM