Wierd RPM surging problem

[91f2504x4]

I just got back from a couple hour trip in my truck and it ran very well like it always does and then when I got home to park it in the drive way I gave it a quick rev and it sounded fine but when I did it again, the RPMs only went to 2,000 and it sounded like it was hitting the rev limiter and smoke was pooring out of it. I done it again and the same thing, it revved to between 1800 and 2000 and started surging like it was hitting a limiter and smoking like crazy. At idle everything sounds great and smooth but if you rev it up to about 1800 it acts like it doesn't want to go anymore and smoke the entire time. I am thinking it must be injection pump issues although I am unsure why it let go today, it was running perfect prior to that and it still idles and drives fine below 1800 rpms. It has a new filter and fuel pump is pumping as normal and it doesn't seem like it is starving for fuel because of how it will smoke when you rev it. It is actually smoking like a pro stock or something when you hold it down right now, not sure what the deal is.

I went outside and tried it again to make sure that it wasn't just a fluke and it was still doing it and this time it would not rev over 1500. BUT, I figure it out, read next post.

 

[91f2504x4]

I think I might have just figured it out, I feel like kind of a fool but it happens to everyone from time to time I guess. I have never heard of an air filter being so clogged that an engine would not rev above 1500, I guess because they are normally not so close to the ground under the truck. My filter doesn't really look that dirt but it was pretty black and when I took it off, the engine ran like new again. So now I have to get to work on making a way to mount my air filter somewhere that wont see so much crap. I still can't believe the thing wont flow, it is only 6 months old and doesn't look all that dirty, I mean there are no big chunks in it, but it is black. If I try and blow through it I don't feel any air pass through it when I stick my finger right inside of it and blow on it.

So I guess if anyone was wondering about the filter being mounted low on a remote mount setup, it will work but be prepared to change filters often. I wonder how those STS setups do with the air filter mounted right behind the axle on some of them?

 

[Bill-W]

I've been thinking about doing a turbo setup like yours and the STS but my thought was to run the filer intake back up under the hood into a air box and setup a snorkel style intake to get fresh air. I used to get my exposed filters wet when off roading in my old Ranger and they would not be able to flow at all.

 

[91f2504x4]

I tried to run mine back up under the hood when I put the setup together but I was going to be running the intake pipe too close to exhaust pipes and exhaust manifolds for my liking, If I wanted to run something smaller than 3" it would probably work but I would rather not run anything that small. I will probably end up mounting the filter up in the bed side or something similar to that. I thought about running a snorkel up behind the cab, similar to the old cab over trucks but I am not sure if that would look decent on a pickup. I might mock something up and see how it would look.

 

[razorback]

i think im going to try a 4 inch somewhat ridgid dryer ducting.. they are like 10 bucks for an 8 ft section at lowes.

ive considered running something under the cab up front than up..but decided against it due to clearance issues.

 

[Agnem]

This is why Barney's truck had the air filter mounted in the bed.

 

[hesutton]

Wow, that does seem like a short life span for the filter, but I guess it sees a lot more road grime under the truck. I really would like to see you rig one of these days. I know I keep saying it, but I really wish it was done in time for the Rally. It would have cool to see it and see what kind of numbers that DT466 turbo would put down on the dyno.

Maybe we can meet some time in Frankfort or Lexington, or whereever.

Heath

 

[OLDBULL8]

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Here is what I did . Like you said , use the 8' drier duct and not stretch it gives a good smooth interior. To mount it to the intake I used a PVC 4" to 3" reducer,fits perfect. Made 2 tabs to fasten it to the intake. Put a bead of RTV on the end and let harden, forms a seal. Used a 90* ell at the filter end. Got the filter at Azone, biggest one they had, been on for 2 years with no problem's. Did the zoodad down by the filter. Pics look kind of ******, but redid it to look nice now. The covering is 1/2" noise padding W/Alum facing from JC Whitney, used aluminum tape on the joints now. That is on my 90 IDI.

 

[91f2504x4]

I tried the 4" rigid dryer duct and was having a hard time getting it to fit without mashing it down is some spots, maybe I will just have to mash it down in a few spots and wrap it with heat sheild to keep it from soaking up all the exhaust heat. I gotta do something, it went from operating normally to not wanting to rev at all in just a few minutes. I noticed on the way home in the last 10 miles of the trip that I could only build a couple psi of boost when climbing the hills before it would start smoking really heavy, so I would let out of it. I was kinda chocking it up to how hot it was outside and I didn't want to smoke everyone out so I would just let out of it. I guess I know now it couldn't build boost because it couldn't breath.

 

[91f2504x4]

Wow, that does seem like a short life span for the filter, but I guess it sees a lot more road grime under the truck. I really would like to see you rig one of these days. I know I keep saying it, but I really wish it was done in time for the Rally. It would have cool to see it and see what kind of numbers that DT466 turbo would put down on the dyno.

Maybe we can meet some time in Frankfort or Lexington, or whereever.

Heath

Just let me know when you are going to be in the area.

 

[hesutton]

Just let me know when you are going to be in the area.

Sure. I'll PM you if I'm heading that way, or if I have a free weekend. The wife love Lexington and it won't be too hard to get her to make a trip. If she's not up for it, then I can cruize that way in my IDI.

Heath