1158

Also posted this on Hondata forum but the more views the better.

For those of you running Hondata and data log fuel pressure are your values noisy. For example I am using analog 2 for my fuel pressure and I will see values vary 6-8psi under full boost. This happens on the order of a few tenths of a second and my AFR stays fairly consistent. I wonder if this is a result of sampling rate?

For what it's worth the setup is a built B18C1 with a TR3030R turbo. I'm running ID 1000s, a fuel lab mini regulator, and a walbro 400lph (but I was also seeing this with my stealth340 pump and stock fpr). My base fuel pressure is around 40psi cold but drops to about 35psi when warm. I will use today as an example: fuel pressure went from 66psi to down 60psi up to 68psi in between 2-3 tenths of a second. This was top of 3rd gear at 20psi. As reference my AFR went from 11.8 down to 11.7 then up 11.9 during the same time.

TIA

Turbogixxer

Lets start out by asking what pressure sensor are you using?

After logging a bunch of cars, I noticed the same thing. After more research, it is really not the reading you are getting. It is more of your system. I am not talking mostly pump and FPR, it is sometimes the lines and fittings you are using. Most pumps do not have a consistent flow, but restrictions make that even worse.

1158

Sensor is from Innovate. I am not sure if it is their sensor or not. It is listed under their 3rd party section.

As for the setup, I should have added I have the pump wired through a 30 amp relay, using 10 or 12 gauge wire (I can't remember which I used) and a 30 amp fuse. Stock lines to filter. I was using an AEM filter that had less than 10K miles on it but switched to new Purolator stock replacement just to see if it would make a difference. It did not. I have 6AN to feed from filter (this is where I have sensor mounted) to GE fuel rail then 6AN line to Fuel Lab regulator and 6AN line to stock return line. I was also seeing the same fluctuations before I added the fuel lab regulator when I was using Stealth 340 pump and stock reg mounted on GE rail. I even replaced the feed line from the filter to the rail. To mount the sensor I used a 6AN nitrous pressure fitting with 1/8NPT port.

I have checked fuel pump/battery/alt voltage at idel (both hot and cold) all checked out good. Next thing I was thinking about was going for a ride and hooking up alligator clips to see if I am getting voltage drop at pump under load. The fact that I am seeing fairly stable AFR is what is making me think it is either the sensor or something related. I have the sensor grounded to the thermo housing ground is very clean.

yungmulacrx

Are the fuel curves on your map steep when this happens? Is there any place to, put the sensor closer to the fuel rail?

1158

I could put it in the fuel rail but I have a feeling that wouldn't be a good idea. It is really about as close to the rail as I can get it without putting it on the rail.

I am not sure about the steepness of the fuel curves. I will have to check the tune.