BigJohnnyturbo

Thank you to everyone for your input.


sorry for all the questions in one post and if I'm moving the discussion in a 100 different directions.. I'm hanging out the door while typing this.


Current rom is 94170015(trying to get this issue figured out before going to tephra v7) close loop is off. Once fans start up and/or lights/radio/wiper are on, that's when the issue occurs.


reason why I'm running the 450 is because I plan on switching to e85 once all issues are fixed. Also I didn't have the issue prior to injector upgrade.




Last time I tried to log fuel pressure I got nothing from the ecu (I currently do not have a FP gauge installed on the car) Is the ecu capable of seeing FP and if so, what should I check in evoscan settings to get it to log?


My day is pretty booked so I wont be able to check wiring and grounds until later tonight. I will and get back to you guys on that.


Im a little confused on the resistor part. Does the resistor need to be removed? And if there is a high and low circuit, would I need to replace both with the 10 gauge wire?








As for my second issue with the surging at higher boost. I believe its the load limit and fuel limit patch. I can not set the hex hex value due to it not showing up in the rom. I am going off Merlins guide for setting it up. And if you guys can double check my address table to verify, it would be much appreciated.

2winscroll

He's not having issues with his idle AFR's and running open loop, nor is he running monster sized injectors . He's having an intermittent problem drilling the siphon is not necessary. If his fuel pressure is high at idle it doesn't matter.
Pump rewire is a good idea.
Fuel pressure is not monitored by the ECU so you need a gauge with logging capabilities.
Do you still have the ground wire that runs firewall to intake manifold?

2winscroll

If your going to run V7 rom I would go with 9653 it has more features and less issues.

LetsGetThisDone

iTrader: (1)

OP stated AFR goes weird when system load varies. Having a return that may be overrun when the pump has proper power (and this is what the tune is set for), vs not over run when the power irregularities start could cause an issue. The siphon should be drilled regardless of these issues, so he might as well pull the sending unit out of the tank and drill it.

2winscroll

Not the issue. The Load he is referring to are electrical loads, not engine loads. Not to mention the car has already been tuned around any variations in fuel pressure due to restrictions. This is obvious because he can drive at times for hours without an issue. It's more than likely an electrical connection issue.

You should really stick to non tuning related threads since you don't do any tuning yourself.

Yes you should drill the siphon but only after finding the real cause.

LetsGetThisDone

iTrader: (1)

Varying electrical loads (and therefore available amperage) can vary pump output. Combined with that changing the injector latencies required, it could have a large effect on fuel pressure if the return goes from being overrun to not overrun.

It could be other issues too. But drilling the siphon is something that needs done, so OP might as well make the setup correct before chasing other issues.


Once again, you have no idea what I do myself. I'm not even saying you're wrong and you're getting your panties all in bunch.

BigJohnnyturbo

The siphon tube is the plastic tube that connects to the 2 return lines in the pump assembly? Because that and the rewiring is the only thing i did not do with the install.

Im going to check the wiring right now.

LetsGetThisDone

iTrader: (1)

Yes. This may not be the fix to your issue, but it could be a contributing factor. And it needs done regardless.

BigJohnnyturbo

Got to love it


drilled out the siphon tube and it helped and didn't.
Helped out a lot when the a/c is on but not at idle.


all grounds to engine, manifold, and chassis are good and no corrosion.


The first log; first half is idle no additional loads. AFR was a tad rich, then after a few minutes, started to jump all over the place. Second half is with the A/c on. And with the A/c on the Afr was perfect. no jumps and stayed around 14.7


During cruising, when trying to maintain speed, the afr drops off lean. but with a light release of the pedal, fuel starts to to come back then drop off again once throttle is maintained again for consistent speed. Second log is of the drive/cruise

2winscroll

There are reasons for not drilling the siphon before fixing the original problem. If his fuel pressure was off a great deal and he drilled the siphon before fixing the real issue, he would have a car that wouldn't even be drivable.

I know you don't tune your own vehicles, that's all that needs to be said.

merlin.oz

OP, regarding your ISC table values - you will never get sensible results with those values.
I suggest you load the three 2D step position tables with stock and expect the best result to be not many steps from that. Like less than 6 steps deviation.

Also, with the 3D step position demand map, two points:
Set the vertical Y axis to steps, not % demand. You cannot make a sensible correlation otherwise.
And yes the actual axis is in steps, the 2D table values feed into 3D step axis directly.

The second point, set the 82*C column the same as the 77*C values.

Perhaps I should also point out that when the ISC tables are fixed you probably will need to adjust the BISS screw on the throttle, using EvoScan actuator function, when the engine is fully warmed up.

As you have cams, set the rpm to about 800-850 with the ISC parked.

2winscroll

The A/C turning on is not a large electrical load, it's definitely engine loading. I was lead to believe it was wipers, headlights etc. it's hard to diagnose a problem with bad information.

2winscroll

https://www.evolutionm.net/forums/la...stions-38.html

Merlin is on to something here good info on post 570.

LetsGetThisDone

iTrader: (1)

If his fuel pressure was off a great deal, one would want to correct that before continuing to tune the car. What you say makes no sense sometimes.

Again, you don't know what I do.

BigJohnnyturbo

You are correct. It was jumping at high electrical load.

Now that i have updated and adjusted iscv and biss its acting differently. With whipers, headlights, fans, a/c on it maintians afr and rpm. With just a/c on, it maintians afr and rpm. Just idling with no electrical loads it maintians afr and rpm.

Once fans turn on to bring engine temp down from 206F to 195F, thats when the afr jumps. And rpm drops about 50 and stay at 750rpm. Until cooling fans turn back off and and returns to maintianing afr and goes back to 850rpm.

Issue is varrying a little once another step is completed. So i will try to keep the symptoms as updated as possible.

I am using a stock fpr solenoid. I hear that a lot of guys bypass it and connect the fpr directly to the manifold. Is this common practice?

Im going to pick up a fuel pressure tester a little later today.