breaking down on highway and odd pedal

Hello all For a couple of weeks my AHU corrado has been breaking down more and more on the highway ill be driving along and then i will lose power and it will start dying and throwing blue smoke out the back and goes back and froth on coming back to life sometimes it goes to slow and i pull over and let it idle for a while if i stop it its really hard to start back up.2nd thing it also feels like it will go into limp mode on the highway all of a sudden it wont go anywhere fast but the way it does this is by making the first bit of my pedal responsive and the rest dead even more than the normal amount i have that is dead. Every time i start the car and pull away it hits 1200 rpms stays there no matter if its on the floor and waits till i lift up and then hit the pedal again then its back to normal. and i was noticing once i hit 60% of my pedal the rest keeps it the same(acceleration, noise, everything) using an obd2 to scan the throttle responsive it goes up to 100 but from 60 to 100 nothing changes. sorry for the long post but a lot is going on.

Did you solider any of the splices in the circuits going to the accelerator? Did you use bare fingers to twist the wire?

If so, could be there is some resistance that the ECU is picking up! Mine did almost the same thing until I cut out all those solider splices. Sometimes a "restart" two or three times would get me back to my garage as this all happened when trying to iron out the bugs!

EDIT: Yeah, what Vince Waldon said down there vvv. Occasionally, my "rigged" brake stop for the brake switch doesn't always rebound to complete the circuit (brake switch for the cruise cut-out). So, when that happens, the engine only idles... but not above the 903 RPMs. And, it is really dangerous letting off the brake to accelerate away from a Stop or Traffic Light... momentarily it will actually feel like it is going forward like it suppose to then suddenly falls on it's face to just an idle/crawl ..... quick work with my foot pulling up on the brake pedal solves the issue.... only happens occasionally!

Throttle-wise, if the ECU thinks the brakes are on it will behave exactly like this: ignore the first throttle movement after 1200 RPM and hold the RPM there, and then wake up and listen to the second throttle movement.

If you've got VCDS you can confirm that *both* brake light switches are doing what they should be... they can be problematic, particularly on conversions if someone did some jury-rigging or skipped a bit of the harness.

Dunno about the blue smoke etc.

I will go through it all soon don't think it's has any solder or extra connectors. But last night it had the loss of power and then kept dying and I pulled the code it was a p1248 got it to my buddy's house let it idle and it died. Got it started again didn't sound like it was getting fuel ran a minute and died when I pulled the return line there was pressure in the fuel filter cleaned out the filter and the lift pump a couple of weeks ago to make sure is it a problem with the ip internals? Stuck at my buddy's house now till I fix it

Lucassayers7, how cold is it there? Although I believe you may be experiencing a combo of problems, you may also be experiencing fuel gelling!

Here is a link to Ross-Tech's web site relating to DTC P1248. Notice one of the possible causes is running out of fuel (gelling is a form of running out of fuel).

http://wiki.ross-tech.com/wiki/index.php/17656/P1248/004680

I got winterized diesel in there i had thought that was it but I was driving it a while ago and the same thing happen thought I ran out of fuel but had 8 gallons in the tank and that was a very warm day just refilled my fuel filter back up today with diesel going to try to start it soon need to fix what ever this issue is it wouldn't be the check valves from the lift pump into the fuel lines right? Or could it be a solenoid in the ip giving up

Got it running used a gallon of diesel bypassed the filter by putting the feed and return in there ran great no bubbles put it back into the filter it runs but big long bubbles and it almost died on the way home so I'm guess it's the line has a hole or something will try the filter and bypass the line next

ran clear lines in the return and for the fuel filter intake to see the bubble intake with the T fitting looped and the return just coupled i had less bubbles because they wernt return back to the filter but after 30 seconds a solid stream of bubbles come from the tank that float on top and then it create long air bubbles in the feed tube every few seconds. swapped the filter with another one i had lying around helped a bit (think the t was leaking a bit)

What size tubing do i need from the tank to the fuel filter is it 8mm ID? guessing its a leak in that somewhere

lastly im thinking about getting an old filter with no pre heat t on it and running a cheap diesel pump that has an output of 3 to 5 psi with 18.5 gallons per hour with 12v. maybe putting a switch on it to help prime the system if its easy for it to suck through when its off or run it all the time

Not a single bubble anymore but i seem to get my limp mode more often now( only uses 40% of peddle input and the rest keeps it at 40%) but it still has boost and everything so i think its limiting the fuel? Can't figure this out.

lucas... the loss of power with a big puff of black smoke, followed by the sometimes ability to "finesse" the power back on using the throttle is very likely the actuator on the turbo. If this scenario occurs--WOT, power is coming up and then engine hiccups, and then a big puff of black smoke, followed by what feels like limp mode is the turbo not being actuated correctly. It could be the actuator going south or there may be some soot hanging up the movement of the turbo vanes.

I have solved the highway breaking down and coming back it was the injection pump losing its prime due to the fuel filter leaking only enough to let air in the lines. I found a small boost leak where the iat plugs in the seal was gone now it is running much better.

My new issue i notice it in higher gears easier is the turbo is surging rapidly above 2,200 RPM's just making that swwpshing sound over and over if im giving it good amount of peddle. Replaced the hoses to the n75 today still doing it and unhooked the egr and the intake is pretty clean little grimy but not built up at all on the sides. It is also a waste gate turbo and not a vnt.

Dont want to blow the turbo so im taking it easy, what would cause this?

lucassayers7 said:

I have solved the highway breaking down and coming back it was the injection pump losing its prime due to the fuel filter leaking only enough to let air in the lines. I found a small boost leak where the iat plugs in the seal was gone now it is running much better.
My new issue i notice it in higher gears easier is the turbo is surging rapidly above 2,200 RPM's just making that swwpshing sound over and over if im giving it good amount of peddle. Replaced the hoses to the n75 today still doing it and unhooked the egr and the intake is pretty clean little grimy but not built up at all on the sides. It is also a waste gate turbo and not a vnt.
Dont want to blow the turbo so im taking it easy, what would cause this?

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I would triple check that you have a 100% tight system between the turbo output and the intake manifold. Put a rubber bung in the intake manifold to 100% block it off and re-install the intake pipe. Make a cap for the turbo side of the intake pipe with an air compressor fitting and then pressurize the system to 3 bar / 45 PSI and listen over 30 seconds or so. You should hear any air escaping. I have seen lots of good "looking" intercooler systems, but once pressurized, you may flush out other issues. It's a good place to start with this issue.

Started gathering bits and pieces to do leak test, in the process decided to switch to the egr valve and i dont know if its because it takes vacuum but it did not open my waste gate or it does but waits till 20 something psi but it went into limp eventually (like it should) switched to an n75 i have on another ahu motor and the things still jerking around at low speeds and doing the weird noise at higher rpms still limp after a few minutes.

so the trip home i decided to put the output of the turbo to the actuator and took it easy no limp then took it up to speed and it stayed at 11psi on the dot sounded great felt great then i started getting on it and still not limp so far less jerking as well. my next guess is the wiring for the n75 must be doing something funny would that make sense or do i need try a different style n75?