FP-Limp at 1.5 bar / 6000rpm

TimTaylor
Posts: 21
Joined: Fri Oct 19, 2012 5:17 pm

FP-Limp at 1.5 bar / 6000rpm

Post by TimTaylor »

Ok, this is a long story, that began in Summer 2013 but with my latest problem so quickly solved thanks to "stevieturbo" I am now confident to solve this as well :) And maybe it is helpful to others, too.

Well, I built my MR2 3sgte rev3 turbo with some upgrades: JUN 264 cams, Mahle pistons, Eagle rods, 880 Delphi injectors, BMC CDA airbox, chargecooler, 1ZZ cop, 100m 100cell metal catalyser, japspeed exhaust, Borg Warner EFR 6758 turbo

I went to Ryan, to get it mapped and it was a great pleasure. Unfortunately my wastegate actuator spring was too weak, so it couldn't hold the 1.5 bar all the way till redline and so I had the boost dropping from about 5000rpm to 1.2 bar at 7000rpm. I "only" achieved 388bhp and around 350 ft-lbs. Caused by the boost drop the torque dropped quite a bit which made the whole curve a bit sad.
Image

At home I installed a stiffer wastegate spring and now the turbo holds the 1.5 bar fine..... until about 6000 rpm where I hit fp-limp
Image

I am using the Toyota Supra Turbo fuel pump and my fuel lines are stock from the fuel pump to the fuel filter, which is a new but OEM Toyota MR2 one.

I am not sure, what could cause this as Ryan told me, "The Fuel pressure was dropping slighty but not that bad as it was running very rich and the Ecu was pulling out 10% also to try achieve the target CLL"

I wanted to change my fuelpump for a Bosch 044 and the fuel lines for a full set of AN-6 which they are from after the fuel filter to the injectors. My fuel pressure regulator is the sx performance one available via wolfkatz. But after Ryans answer, I am not sure, if this would cure the problem :(

If you need any other sensor readings, I can upload them.

Thank you very much
stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by stevieturbo »

upload the datalog and map
TimTaylor
Posts: 21
Joined: Fri Oct 19, 2012 5:17 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by TimTaylor »

here you are :)
Attachments
2013-07-12 19-46-54 plus 0h00m00s S6#0650 RUN-043.SD
(356.5 KiB) Downloaded 955 times
Last edited by TimTaylor on Thu Jun 18, 2015 11:02 am, edited 1 time in total.
stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by stevieturbo »

It is quite apparent that from 5k upwards fuel pressure is not being maintained in accordance with manifold pressure. The trip is valid and fuel supply problem needs resolved.

Yes its is a little too rich, but sorting that isn't going to make enough difference.

You need more fuel to the rails.
TimTaylor
Posts: 21
Joined: Fri Oct 19, 2012 5:17 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by TimTaylor »

Ok, thank you again :) So you think, that my fuel delivery is the problem, too.
I already started to drop the tank. Let's see what the new pump and bigger fuel lines can do :)

Thank you
stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by stevieturbo »

Injectors are only around 56% duty, so must be a decent size, so they are more than adequate. Obviously when fuel pressure/flow/AFR's are restored to a sensible level this duty will drop further.

Given the IDC's are plenty safe, you could ignore the fuel pressure aspect and work away on the understanding it is poor. But it would not be the correct or sensible thing to do.

No idea what size the OEM lines are, but the problem could simply be the pump needs upgrading, or wiring to the pump etc.

When fixed re-check relative fuel pressure and adjust the trip so it kicks in quickly if there is a supply problem
AGsTony
Posts: 4
Joined: Thu Sep 25, 2014 7:57 am

Re: FP-Limp at 1.5 bar / 6000rpm

Post by AGsTony »

Why are u not mapping it leaner. Thats way too fat?
Then ist look like too low ign timing for that engine, have u tried whit higher ign timing?

Just trying too help :)
stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by stevieturbo »

Presumably it was never tuned at the boost level he is now trying, either way the fuel supply problem is of more concern.

It looks like you have enough I/O's to achieve traction control and use a Cal switch for TC too.
TimTaylor
Posts: 21
Joined: Fri Oct 19, 2012 5:17 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by TimTaylor »

yes, it was only tuned to 1.2 bar at over 5000rpm due to the weak wastegate actuator spring. I wanted to do a full throttle run in third, so Ryan could tweak the rest for the 1.5bar above 5000rpm but as now my fuel supply is too weak I will have to fix that first.

And thanks for looking at the TC. Good news :)
TimTaylor
Posts: 21
Joined: Fri Oct 19, 2012 5:17 pm

Re: FP-Limp at 1.5 bar / 6000rpm

Post by TimTaylor »

Hey everyone :)

It has been a while but finally I've managed to change the fuel pump and do some test-runs. No more FP-Limp :D
But I guess it is now time to adjust the calibration file.
If anyone is interested, I've added the datalog of the run with the map that was mapped when the boost dropped at 5000rpm from 1.5bar to 1.2 bar at 6000rpm till redline. A stiffer wastegateactuator spring solved this problem but brought up the FP-Limp as the fuel pump was too weak. Now I guess everything is fine and it is time for a remap?

cheers
Attachments
2013-07-27 14-44-11 plus 0h00m00s S6#0650 RUN-049.SD
(253.44 KiB) Downloaded 912 times
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