'01 Lack of acceleration when cold?

[BIGBORE]

I just started here at this forum and find it's really great. I need to ask a question but, hope it isn't a re-hash of something that's been posted before. I did a preliminary search but, couldn't find the topic.
I have an '01 7.3 Excursion that occasionally has no acceleration upon starting. It seems to happen in cool-cold temperatures only when, I don't let it idle to warm up. You can hear a loud hiss and the exhaust pukes black smoke like crazy when trying to bring it up to speed. After it warms up things return to normal immediately after I hear something close/open under the hood. Sometimes, upon start up, I detect the hiss and can goose the accelerator at which times it stops and all is well. Unfortunately, it is not always the case and it has to warm up before it stops. It wouldn't be such a pain in the ass except it always seems to happen when you are in a real, for real, hurry!
It did this when I first test drove it at the Ford dealer. The salesman said a hose/connection must have been loose from the power wash of the engine compartment. He also stated he had the service department decode the CPU and could find nothing wrong. I kind of believe he wasn't being truthful. They are a truck dealership and I believe the service department would have recognized the problem by the description if in fact it didn't show any code. Perhaps I'm just cynical?
Anyway, any help/opinions in this matter on diagnosis/repair would be greatly appreciated.
Jay

 

[oi8228oi]

have in engine block heater... then use it if not http://www.shopdiesel.com/index.cfm/action/shop_by_subcat/category_id/237.htm
all diesels are extreamlly sluggish till they warm up i start mine 15 mins before i leave... probably the warm up valve that your hearing although hiss is more of a description of the turbo.


also fill out your signature and let us know a little about your truck... easier to ifigure out problems with it listed..

and lastly welcome aboard....

 

[DaveBen]

Diesels are heat engines and they won't run at full power until they are at operating temperature. Warm it up before you get on it.

Dave

 

[CSIPSD]

The noise you are hearing is the exhaust back pressure valve (EBPV), it is used to speed the warm up of your truck in cold climates. When the oil temp and air temp are below a preset temp, it will close. This builds back pressure in the motor, speeding warn up. Normal, try letting it warm longer, the idle should jump to about 1000-1100 as well.

If you are in a hurry, you can start the truck, let it run for a few seconds (30) and turn it off again. Restart and the valve will normaly not close again...

Where are you that its still that cold??? LOL

 

[BIGBORE]

It's not still cold that's the problem! It does it when the weater is in the 50's. I think it is the EBPV that might be sticking but, I thought it was supposed to release when you applied the throttle, or so I've read. I know diesels are cold blooded and need to warm up. This is far and above that, it won't go over 25mph. I read the following bulletin but thought some of you might have a different approach, it might as well be written in Greek to me:

Lack of acceleration when cold; Limited RPM; Hissing noise under hood; Possible DTC's P0470-P0478:
Exhaust (back)Pressure Regulator valve/servo.
When the engine is cold--EOT less than 140 degrees--and the ambient temperature is less than 37 degrees, the PCM activates the EPR solenoid to divert oil pressure to the EPR sevro which closes the EPR valve at the turbo outlet. This causes exhaust backpressure to help the engine warm up more quickly. The PCM monitors the amount of backpressure through the Exhaust BackPressure sensor. On accel, the EPR is deactivated, but if the valve sticks, it will cause the above symptoms. You may or may not be able to duplicate the concern, since it normally only occurs on initial start-ups when the PCM activates the EPR for prove-out. If you are able to duplicate it, inspecting the position of the EPR linkage can confirm the problem (the servo linkage will be extended and the bellcrank tang will not be on its stop). To repair, replace the turbocharger pedistal.
A similar condition can occur if the EBP sensor tube plugs up with carbon, causing the PCM not to see an increase in exhaust back pressure resulting in the PCM not deactivating the EPR solenoid. Remove the tube and inspect for blockage. Clean as necessary.

Sounds Expensive! Jay

 

[CSIPSD]

Its not that bad, have you pulled any codes? I would guess a bad EBP sensor.

Might try replacing it.

I use mine as an exhaust brake... There are several DIY kits out there to do that, which will give you control over the valve.

 

[BIGBORE]

No, I have to look in to puling the codes. My buddy has a station and has offered but, I haven't had the time as of yet. Best to try that first unless I want to go on the proverbial goose chase!

 

[dpantazis]

where are you located in illinois?

there is a group in northern illinois area, www.midwestoilburners.org. they could be of assistance.

dennis

 

[BIGBORE]

Dennis,
Thanks for the input. I'm in Libertyville, near the Wisconsin border at Lake Michigan. I'll follow the lead. Thanks again, Jay.

 

[SMOKNZ]

I've read about similar problems when the line to the Exhaust Back Pressure sensor is plugged. You can see the tap for it on the Pass side manifold thru the wheel well on the front of the manifold. Remove and clean out the line. Unplugging the EBP sensor should cause the valve to open as well, though might cause a code. I can't offer any first hand experience, but I was having some issues last winter with the EBPV cycling while I was driving at light throttles. I was doing quite a bit of research on it!