truck is chugging and topping out at 35 im assuming this is limp mode? ok its a bone stock 96 f350 dually 2wd only thing I can think of is that I put a filter directly on the intake tube and removed the box and just left the sensor hanging in the engine bay that came out of the intake box would this cause problems ? please help me I need this truck running properly by tomorrow p.s. it does have 300,000 miles and it has run PERFECT all week no problems

 

Well, mine this morning ont he way to church, I forgot about the exhaust valve, used to warm up the truck, so I drove mine 30 mph to the high way, then it ran fine, it dawned on me what it was. So IDK may have to lets yours idle a while then drive it. But thats from my experience this morning. And that sensor, I did the same thing, it doesn't effect the truck any (That I know of)

 

The sensor in the air box will not make this happen. If you do not have a code reader, take the truck to an Auto Zone and they can read the codes for you. Other auto parts stores may be able to do this for you as well.

 

whats the exhaust valve? and wow you guys are quick

 

Off the turbo is a big butterfly valve that closes when its cold out, and it stays closed till the truck is warmed up enough to be able to run at its full potential. Most people gut there's out of there truck, or wire it up to also be a exhaust brake valve. Just start it, let it idle for a while and see if it came out of it. Is there a CEL (Check engine light) on?

 

well its my dad driving it right now he called me telling me what its doing I will def check it out when he gets home , ill call him back and see if the cel is on

 

The exhaust back pressure valve is located next to the turbo. There is an arm connected to a solenoid to operate the valve. It is designed to stay closed to help the engine warm up faster. Once it is warm the valve opens and remains open. Here is a picture of it.



A lot of guys wire in a switch to make it an exhaust brake. I hope this helps.

 

Do that, but if the CEL is on, you'll have to get the code to fix the problem. Like my ICP threw codes about the #5 and #7 injectors not getting enough oil, and it was all cause my ICP wasn't plugged in a hair (Litterally a hair)

 

Ok so I just called him back , theres no check engine light on and he says it wont go over 1500 rpm this is definately limp mode right? and as for the pic above do I unbolt that iron piece from the stainless piece to get at the valve? sorry for all the lil questions im a newb

 

Here is a picture of the arm at the bottom. I believe the valve is open when the arm is to the right (drivers side) of the unit. You should be able to move it left and right a little bit.

 

Hmmm no CEL and its doing that? Mine wouldn't go over 2000 rpm, so I don't know. Check the exhaust valve. I hope everything is okay. Don't want your guy's truck down.

 

alright so we shut it off for bout 15 minutes after he got home and then started it back up and it held rpms anywhere you wanted so then I took it for a spin to see what exactly it was doing so pulled onto the road and floored it , acted just like it had been first day we got it PERFECT but as soon as i stopped its idle dropped to 4-500 rpm and it started shaking and repeated the "limping process" all over again ,, ugh this sucks , and for all I know CEL could be burnt out being an older truck with this many miles

 

If it's stuck closed it would be making a loud sucking (hissing) sound. If that's the case just unplug it. It is the two wire plug just in front and at the bottom of the turbo. Most of us just unplug it anyway as it has little use.

 

Did you check the position of the arm?

 

My truck has 278,XXX miles and my CEL just works cause it came on the other day lol XD (Laugh, trying to make you feel better) and thats odd, if it runs fine then doesn't. Check the ICP sensor connection, cause my CEL would be on, and it ran perfect, got my codes read, ran like ****, got home, fixed it, and BAM, no CEL and ran like a champ. I don't knwo what it could be unless its the fule filter is clogged some, and no letting it get enough fuel, or something. But if I remember right are trucks have a light on them when the filter needs changed. Anyways, point is, I hope these guys can help you, cause I am stumped, if I think of anything else I will chime in.