Nistune Forums

Hello,

I'm having problems trying to enrich my fuel map.

My setup:

Engine: CA18DET
Chassis: S13
Injectors: GT-R 444CC, measured and matched
Fuel pump: Walbro 255lph
Turbo: GT2871R
MAF: Z32
Exhaust: XS-performance manifold/outlet + magnaflow 3" cat and 3" cat-back
Intake: everything changed except throttle body and plenum/runners
Fuel: E85 ethanol
Boost: 1.1 Bar

Measured 347hp with 98 pump fuel (1,5bar) two years ago. After that I changed to ethanol. After that my (new) clutch started slipping and this summer I improved my charged air piping and changed to bigger intercooler. Clutch slip was so bad I had to change ACT heavy duty pressure plate and Street mass disc. Everything was fine with the old cooler and E85. But now when I improved significantly the IC and piping I ran troubles trying to enrich my fuel maps. I have rewired everything with the fuel pump, tried with another fuel filter (Bosch) and another Walbro 255lph fuel pump. Still I'm having problems after 5000rpm. I increased my Injector multiplier from 680 to 800 and changed map AFR ragings from 12 --> 10 and it did not enrich my mixture one bit. Also copied everything to knock map. According to Nistune I increased my duty cycle from 69% to 85% and it did not enrich my mixture by one bit.

The reason I'm asking about enriching here is that I had weird troubles with ignition timing a while back.
Is there something I might be missing?
My fuel map scale max is 105 (don't know what unit that is) and ECU is using the rightmost cells from the map. Is the problem with the scales? Or how about when the cells start moving from right to upwards? It caused weird problems with my ignition timings, tough it showed on the logs. With this mixture problem I'm seeing increased duty cycles but my Innovate MTX-L says I'm running too lean. From 5000rpm AFR goes to lean and about 6000+ it's about 15:1...
Too dangerous. I want it to be closer to 10 or otherwise I will melt my engine.

Anyone

I'm still using stock fuel pressure regulator. The first fuel filter was an aftermarket CA18DET filter, the second filter was from volkswagen van (200hp+).

In this picture you see at top right the enrichment that did absolutely nothing. Also tried to increase Injector multiplier to 800. It clearly affected before 5000rpm, AFR went from 12:1 to 10:1.

now the intake cooling factor has been improved,

injectors are about 400cc short of making your original HP target.
I doubt the walbro will keep up with fuelling demands @ 1.5bar.
I've noticed Walbro overstate flow rates under pressure, and bosch seem to understate them.

So you are saying I'm having too small injectors? Well I kind of knew this answer coming... but how come increasing duty cycle does not enrich my mixture? In my opinion with 69% should still have plenty of margin for enriching the mixture. I'm having the exact same situation with 69% vs. 85% duty cycle.

Also I think Walbro 255lph should be capable for my aplication.

BTW I'm planning to go only 1.1bar boost, 1.2bar tops. The plan is not to increase horsepower, but torque.
Tomorrow I will install a 300zx fuel filter and discover that nothing has changed

1. e85 cleans everything in fuel tank, so there is a lot of chances that your fuel filter is jammed.
2. if its not fuel filter, than buy in plumbing store almost any cheapest pressure gauge and check for fuel pressure on the load. If it is falling, when your fuel pump is dead (or its too weak).
3. if fuel pressure is ok, when change into bigger inejctors.

MIL-Tec wrote:So you are saying I'm having too small injectors? Well I kind of knew this answer coming... but how come increasing duty cycle does not enrich my mixture? In my opinion with 69% should still have plenty of margin for enriching the mixture. I'm having the exact same situation with 69% vs. 85% duty cycle.

Also I think Walbro 255lph should be capable for my aplication.

BTW I'm planning to go only 1.1bar boost, 1.2bar tops. The plan is not to increase horsepower, but torque.
Tomorrow I will install a 300zx fuel filter and discover that nothing has changed

The fuel supply can't keep up or the regulator is fluctuating at certain boost level and not appling correct pressure.
As soon as you start to really rev this engine more the injector duty will max out very quickly.

as UNEX mentioned, check filters and the obvious things that can cause this.

Yes, that is what I'm planning to do next. I have the gauge and adjustable pressure regulator. But the first thing is to install 300zx filter. I already cut out the fuel pump filter to ensure it is not the problem.

put the filters back in or you might just make more problems to troubleshoot.

Flow test the fuel system. don't just rely on positive pressure test result as it's only ever half the picture.

another topic: what is the distance between the first cylinder and the intake pipe? looks like its almost rubbing on it.

You are using too small injectors and you are seen the duty in nistune but you know that after +-3800rpm the duty that is showed you need to double it, see in your logs the duty and you will see it beeing split because of batch injection. And the 440cc are 440cc @3bar fpr and ca18 is 2.5bar.
I max out the 440cc in ca18det after 5000rpm with only a gt2560r at 0.9 bar...

bachig24u: That charged air tube -picture is old. The second picture shows updated version... it still is pretty close but It will have to do for now. I will turn the compressor housing just a littlebit when I take the turbo out.

I changed the 300zx filter and it did nothing. Then I rised fuel pressure to 4bar (5.1bar@boost) and it did the trick (kind of) so small injectors... Also needed to lower boost to 0.85bar.

BTW: I measured these injectors @ 3bar being 480cc and they are from GT-R skyline. Anyways, the car is running rich with that high fuel pressure but I think I won't bother adjusting the ECU but rather get larger injectors and then do the tuning.

But thanks for your help! I did not realise the duty cycle being way off at batch injection

69% vs. 85% duty cycle.....
90% of the problem come from weak fuel pump,
did you check on boost fuel pressure ?