Pump not able to flow enough fuel? - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.
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Pump not able to flow enough fuel? by hamradio on 23 May, 2009 23:03
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So, this is a spinoff of sorts from my last thread. I apologize if it is cluttering things up.
Car is a rabbit with turbo'd 1.6 NA. VNT15, 15 psi with about 18 when it creeps, arp studs, etc.
I have a pump from a quantum td on it. 9mm head. I have an issue with not being able to get enough fuel out of it. My max egt's barely even reach 700...maybe a little over 650 on a long pull in 5th gear. I can hammer through the gears and leave only a little haze...no thick smoke...most is not even easily visible.
I have the pump turned up as far as it will go, as far as I know. I have the fuel screw cranked up so much in an effort to get more fuel that I have about 2 threads of the idle screw left for adjustment. I moved the LDA cone to the more fuel side. I turned the starwheel clockwise a bit. I bumped up the smoke screw on top of the lda. Timing is 1.05 mm. Injectors are freshly rebuilt with chevy 6.5l diesel nozzles, and 160 bar.
I did the governor mod, and that did help the car overall a bit. EGT's bumped from about 550 to the 650+ish range it is right now, and it revs awesomely.
For as much as I have the fueling turned up on the pump, it should be filling the road with thick smoke upon normal acceleration and burning holes in my pistons, no?
Any thoughts on the issue? The 9mm head can't be running out of fuel, could it? I thought that was good to a lot more hp than my car is putting down. Could it be that the injectors can't flow enough? However, the chevy diesel nozzles have the same specs as the oem vw ones, and the vw nozzles seem to be able to flow all the fuel the engine can handle...
It is driving me absolutely crazy not being able to figure this out. It's now gotten to the point that one of the only things I can think about is how to get the pump to flow like it should.
Thanks in advance,
Devan -
#1 by Rabbit on Roids on 24 May, 2009 14:48
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When the pedal is floored is the accelerator lever on the pump hitting the stop screw?
If it is being stopped by the max rpm screw, then unscrew that screw farther. Also adjust the cable to have maximum motion. Adjust the ball end of the accelerator lever so that it is as close as possible to the fulcrum of the lever. Adjust the max rpm screw so that with the maximum motion of the accelerator lever, the lever is not stopped by the screw, but by the range of motion of the cable.
Andrew
x 2
that was my last question on the last thread. mess with your throttle cable. mine was out of adjustment BAD when i got my car. -
#2 by hamradio on 24 May, 2009 15:57
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The ballstud was already at the front of its adjustment, but I made a little thing from an old ballstud to extend it further.
I gained about 1/8" more travel at WOT. It still isn't contacting the bolt. I have a feeling someone unthreaded that before I bought the pump...I couldn't even contact it with my little extender thing.
This is what the position of the lever is when it is floored (I had someone floor it and I took note of where the lever is)
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#3 by Jettagli16v on 24 May, 2009 15:59
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and I can absolutely vouch for a totally stock, unmodded Turbo pump
dumping plenty of fuel to keep a 1.6 at 18PSI happy.
Had a bone stock, 200k mile engine and pump.
1650 EGT (Spruce, preturbine) on 4th and 5th gear pulls.
Running at 19PSI, for like 6 months.
It did fail,
but I dont think due to boost...
-Brad -
#4 by Rabbit on Roids on 24 May, 2009 16:46
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i think you need to mess with your throttle cable. and thats a weird pump setup. never seen a throttle arm like that.
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#5 by hamradio on 24 May, 2009 18:08
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It looks completely normal to me, aside from the little thing I made to get the throttle cable closer to the fulcrum.
Could it maybe be that this pump is from a quantum, and therefore somehow different? (though I can't figure out how...)
I'm almost ready to throw this LDA stuff onto my old NA pump to see if it makes a difference. -
#6 by 410 on 24 May, 2009 18:31
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What about trying a more aggressive camplate in the pump. That would really bump up the fuel.
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#7 by hamradio on 24 May, 2009 20:46
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My timing is set at 1.05mm.
I went 160 bar because it seems like many people are running 160 bar, and I kind of half figured it would compensate for wear over time. I thought I once read something about having a higher breaking pressure being desirable when running a bit of boost, or something.
Could it be that for some reason my injectors are holding me back?
The car is pretty zippy right now, but is def. not to it's full potential. Top end is adequate, but it's really lacking midrange. The car feels slightly faster right now than it did with a cranked NA pump and old injectors.
I must say, thanks to everyone for all of the suggestions/insight so far.
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#8 by hamradio on 24 May, 2009 21:07
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It goes all the way to the screw. Sorry about missing that.
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#9 by Rabbit on Roids on 25 May, 2009 08:53
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In that case, jump one spline in the accelerator lever to shaft orientation so that it is moving the shaft further (lever goes Ccw in relation to the shaft) and adjust the idle back down.
Andrew
thats what i had to do. and mess with your throttle cable. or do yourself a favor, since you already have a ***in cherry rabbit, just go buy a new one. and as for your car only being a LITTLE faster with the turbo pump and infectors in there.. when i took off my n/a pump (Fuel cranked up to the bolts) and injectors and swapped them for turbo pieces, my car absolutely came alive. it wasnt just a little gain. my car would barely smoke before, but now it fills the road with piston melting smoke. and it can burn the hell out of the tires, through many gears, without the aid of an e-brake. -
#10 by rabbitman on 25 May, 2009 12:29
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Is it a true TD pump or a NA pump with an LDA put on it?
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#11 by Rabbit on Roids on 25 May, 2009 19:16
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my pump body has a fuel limiter pin sticking out of the side with clear epoxy around the base of it to seal any potential leaks. i took a few parts from this pump, a few from that one, and a few from the other, used all the best/newest looking pieces and built myself a fuel pump. i had never even opened a fuel pump previous to building mine, but i just studied everything as i took it apart. now i have a pretty good understanding of bosch VE rotory pumps. i think
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#12 by hamradio on 26 May, 2009 04:59
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It is a real TD pump. The throttle cable is new, as well.
I tried the moving-over-one-spline thing, and ran out of idle adjustment screw...I had to turn the fuel screw down to get it to idle, and experienced quite a loss of power.
I guess I'm happy enough with it right now...it's still not dumping fuel or barely even able to make more than a light haze of smoke, however. I took it on a 90 mile or so drive with it cranked up as much as I could get it, and it was reasonably zippy. -
#13 by Rabbit on Roids on 26 May, 2009 10:25
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like i said... you will make TONS MORE POWER with a good pump. cause my car acted just like what yours does, but i had a n/a pump on it. and n/a injectors. then i put the turbo stuff on it and it absolutely came alive. smoke equals power, for the most part. when my turbo spools to 10 psi, it feels like it dumps another half again what full throttle would be. try a new pump head or something. something is not right with your pump. your idle adjustment sounds almost exactly how i have to adjust mine. turn the fuel screw up till it will idle off of it, then back it out a quarter turn, and adjust the idle with the idle screw. if i had my pump set so that its only idle adjustment was the fuel screw, i would get hanging RPMs really bad, with pretty much every shift.
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#14 by rabbitman on 26 May, 2009 12:38
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Yes, if you remove the extra pin in the n/a pump.
Andrew
That's what I was wondering is if it was a wanna be TD pump or not