surging bad, idle high
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 214
Likes: 0
surging bad, idle high
Ok slowly working the kinks out of this truck, seem to be allot of them. I had a code for the \EGR system complete failure, TPS below voltage, running lean, HEGO switch. I cleaned the IAC and that made the idle much better, I then replaced all the vacuum lines. The truck then idled really good espeacially when cold. Today I was driving down the road in second just kinda letting the truck go on its own. By the way it is a standard five speed 351w 89. k It seemed once it warmed up a bit it started to surge allot. It also started to idle high and then drop down. The check engine light will come on only after running for a bit then go off and on. I assume that would be the EGR system. I have also done the spark plugs, air filter, and sea foam. The truck also seems to lack a bit for acceleration. Any help thanks.
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 214
Likes: 0
Also when I shut the engine off it is like I hear a small hissing sound coming from the drivers side. could this have something to do with the smog air injection system. could that be why it is running lean.
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 214
Likes: 0
Well so far it looks like I am talking to myself so far except for one person. Well hopefully if nothing else this will help someone.ok the sound of hissing comes from around the air injection system only happens when engine is off or That is when I hear it. If it had a crack in it could that cause the HEGO code. Not to sure what else would effect the TPS sensor other then a bad TPS, Which is what the code is saying( voltage low}. Then their is the case of the EGR just replaced all vacuum lines so that is not the problem. Would a bad EGR cause any of the codes I am getting.
Trending Topics
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 214
Likes: 0
Some one must have run into this one time or another. Also when I did the koer test. Their were no flashes or anything when it was supposed to switch to CM codes just stopped after the first set of codes.
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
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
I suspect it is your EVR. This valve regulates the vacuum applied to the EGR valve. Mine did and still does the same thing after replacing it. I had the same noise and issue on my last '93 Lightning. I am not sure what causes the "fluttering" noise, but otherwise the truck(s) run fine with no DTCs or driveability issues.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
Look for stored codes in the KOEO portion before trying to do any KOER tests.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
How to Run EEC-IV KOEO/KOER Tests
The PCM is waiting for user input before it procedes with it's more self-tests during the KOER test.
Don't ignore the codes you are getting for the TPS and HEGO. A bad or poorly adjusted TPS can cause high idle, erratic shifting (yours is a manual so not applicable) and other issues. A lean HEGO symptom can be caused by ANY leaks in the exhaust system as well as the intake. You said you replaced a lot of vacuum lines, but the upper intake gasket can also be a source of vacuum leaks as well as rusted through metal vacuum reservoirs.
I found a lot of small leaks on various hoses and components all combined to create a high idle issue and spurious DTCs on my '92 F350. Every time I found one and fixed it, it got a little better. Now after replacing yards of vacuum hose, two vacuum reservoirs, intake gasket, plugs, wires, cap,rotor, and a completely new exhaust my idle is normal and I have ZERO DTCs. Not to mention a much better sounding truck with a better butt-o-meter feel and a few more overall MPGs.
The PCM is waiting for user input before it procedes with it's more self-tests during the KOER test.
Don't ignore the codes you are getting for the TPS and HEGO. A bad or poorly adjusted TPS can cause high idle, erratic shifting (yours is a manual so not applicable) and other issues. A lean HEGO symptom can be caused by ANY leaks in the exhaust system as well as the intake. You said you replaced a lot of vacuum lines, but the upper intake gasket can also be a source of vacuum leaks as well as rusted through metal vacuum reservoirs.
I found a lot of small leaks on various hoses and components all combined to create a high idle issue and spurious DTCs on my '92 F350. Every time I found one and fixed it, it got a little better. Now after replacing yards of vacuum hose, two vacuum reservoirs, intake gasket, plugs, wires, cap,rotor, and a completely new exhaust my idle is normal and I have ZERO DTCs. Not to mention a much better sounding truck with a better butt-o-meter feel and a few more overall MPGs.
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 214
Likes: 0
Yeah I basically replaced every vacuum line. What a nightmare. I want to replace the exhaust system later on. The thing is when it is cold idle is fine but when it gets warm it is idle is high and when rolling in second truck wants to surge like crazy until i hit the gas. Under gas it is ok. Went out and bought a knew PCV valve, going to throw that in as well could use one regardless. TPS I think I just need a new one. I think the egr system is responsible for the surging once warm I don't know.
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 214
Likes: 0
Ok got a new PCV valve. When I pulled the old one out it did not seem that bad. However I did make a new problem my valve is in a bad spot. The PCV valve is on the back end of the motor on the passanger side. their is a tube that the pcv valve sits in. the tube runs down a short ways to a connector that goes into the valve covers. I accidently pulled this fitting out. It seems to be right under the upper intake. I am having a heck of a time getting this back in any suggestion. Ok found the hissing noise when I shut off the truck it is not the emission stuff it is the EVR, by the TAB and TAD. Don't know if this is normal but I do have a code saying system failure. I also let the truck warm up for a half hour. took a flash light, and raised the rpm by hand did not see the EGR move at all. Also all the diverter valves and what not are motorcraft so they have been replaced when cold the exhaust gets dumped into the air then when warm it seems to stop dumping fuel is this a good thing. does this mean the HEGO is working. ANy help would be great thanks.
