cold start blues
Thread Starter
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Senior User
Joined: Feb 2006
Posts: 335
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From: in my house
cold start blues
hello all, hoping to get some more diagnostic help
early 99 7.3 4x4 dually auto with AFE stage 2 and 4" MBRP turbo back
i plug the truck in most every night lately, and until the truck really warms up
it is acting progressively worse. it will pop the ses light at different times while running at speed, and pressing the go pedal does nothing while ses light is on.
light is only on for about 3 seconds at most and then goes out. when ses light goes out, truck returns to normal. this just started today and happened on and off for ten minutes. before that, and still, when cold, i get a whooshing noise from the engine compartment every ten seconds that goes away if i blip the throttle or let up on the throttle. this too will go away as the truck gets warm, but takes a long time to go away(the temp gauge shows operating temp and heater temp is hot)
anything that would lead me in the right direction would be appreciated
early 99 7.3 4x4 dually auto with AFE stage 2 and 4" MBRP turbo back
i plug the truck in most every night lately, and until the truck really warms up
it is acting progressively worse. it will pop the ses light at different times while running at speed, and pressing the go pedal does nothing while ses light is on.
light is only on for about 3 seconds at most and then goes out. when ses light goes out, truck returns to normal. this just started today and happened on and off for ten minutes. before that, and still, when cold, i get a whooshing noise from the engine compartment every ten seconds that goes away if i blip the throttle or let up on the throttle. this too will go away as the truck gets warm, but takes a long time to go away(the temp gauge shows operating temp and heater temp is hot)
anything that would lead me in the right direction would be appreciated
Post Fiend
Joined: Feb 2006
Posts: 11,892
Likes: 2
From: Middle Tennessee
Get it scanned for a code. The whooshing is the Exhaust Bypass Valve, EBV and sounds like it is trying to cycle according to input sensors such as brake and throttle. Perhaps it is getting stuck. The code should tell you or you can disable the EBV just to see how the truck runs. Hard for it to run/accellerate when the exhaust is choked off.
Look up the EBV for info on that.
Look up the EBV for info on that.
Thread Starter
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Senior User
Joined: Feb 2006
Posts: 335
Likes: 0
From: in my house
ok, thanks
got it scanned today and i think that you are right, it was a throttle position sensor code, the one on the pedal. so this whooshing of the ebv is controlled by these sensors?
if this fxes this, it would make my year
got it scanned today and i think that you are right, it was a throttle position sensor code, the one on the pedal. so this whooshing of the ebv is controlled by these sensors?
if this fxes this, it would make my year
Post Fiend
Joined: Jun 2006
Posts: 5,497
Likes: 7
From: Central, Al
The IVS (Idle validation switch) is part of the pedal assembly as well as the throtle position and both play a role in the cold ambient warmup cycle. As well as throtle position having its input into the PCM's controll of the backpressure valves position
Post Fiend
Joined: Feb 2006
Posts: 11,892
Likes: 2
From: Middle Tennessee
I'm going to bump this post for two reasons.
1. Yes those sensors in the throttle pedal can affect the EBV operation but I would recommend disabling it and trying that before spending the $$ on that assembly.
2. While toiling through my shop manual today to answer some GP system questions I came across a diagram that explained why my EBV cycles on and off like it does now that it is cold here. I suspect that my zip tied IAT sensor is suffering from some bigtime cold air fan wash since it is just sitting there exposed. I noted my EBV cycling on and off several times due to what I thought was the IAT catching fan wash well beyond the point where it should have quit because all else met the parameters. Just throwing it out there for you 6637 guys.
1. Yes those sensors in the throttle pedal can affect the EBV operation but I would recommend disabling it and trying that before spending the $$ on that assembly.
2. While toiling through my shop manual today to answer some GP system questions I came across a diagram that explained why my EBV cycles on and off like it does now that it is cold here. I suspect that my zip tied IAT sensor is suffering from some bigtime cold air fan wash since it is just sitting there exposed. I noted my EBV cycling on and off several times due to what I thought was the IAT catching fan wash well beyond the point where it should have quit because all else met the parameters. Just throwing it out there for you 6637 guys.
