The official Honda Thread

[ChasingSand]

EastMT was correct about the fan signal. I hooked up a test light to the battery positive terminal and the fan wire. Sure enough the light came on at about 204 degrees when the temperature sensor sent the ground signal. So then I rewired the fan relay to have the ground connected to that wire and started it up again. I have been letting it just idle on it's own without touching the pedal until it gets up to temperature - it is idling at around 1500, no surge. Fans pop on at about 204 degrees. So then I blip the throttle to 3k and the surge starts again. Good to get the fan start up worked out though. I will look for a new sensor that has the fan come on at a little earlier.

The fuel pressure regulator looks like a stock part to me, but it has been relocated from the fuel rail to a block on a bracket (previous owner). The blue fitting is the fuel in line and I don't know what the plastic part is beyond that. The fuel return line seemed small to me, so when I plumbed it back to my tank, I increased the sized of the tube I added. That is something different on the engine from when I bought.... I don't know if that makes a difference on how the fuel pressure regulator performs ??

The other thing that is different that you guys have been pointing me to is the fuel pressure. I'd like to switch fuel pump out for one that does not push as much pressure. Can someone recommend one? J35A4, NA. Thank you all.

View attachment 128040

Looks like an OEM unit which should be fine using a stock pump. I would say maybe try a new aftermarket one from a reputable seller.

Maybe pick up a use OEM one from a wrecking yard tomorrow to see if it changes anything.

 

[MPC]

Looks like an OEM unit which should be fine using a stock pump. I would say maybe try a new aftermarket one from a reputable seller.

Maybe pick up a use OEM one from a wrecking yard tomorrow to see if it changes anything.

10-4. I think the fuel pressure regulators are about $20 at my local yard, so might as well do that and rule it out. If there are recommendations for an aftermarket FPR, I'm all ears.

I got to thinking maybe that barb fitting is restricting the return flow. Notice the tiny orifice of the return port, so I don't think that's it. I just now replaced that return line with one continuous smaller hose (same size that was originally on there). No change. But it one more possibility off the list haha.

 

[EastMT]

I'd like to switch fuel pump out for one that does not push as much pressure. Can someone recommend one

I use a Walbro GSL392BX from Summit. No surging. Buyer beware of chi com knock off parts from not so reputable sellers.

 

[MPC]

I use a Walbro GSL392BX from Summit. No surging. Buyer beware of chi com knock off parts from not so reputable sellers.

Interesting. That one is rated at 87 psi, 255 LPH; pretty much what I have now. Mine is a Walbro GSL392, 255 LPH.
I think my next task will be to leave the stock fuel pressure regulator (replace with junkyard oem) and add in line right after the fuel pump an adjustable regulator like this: Evil Energy Fuel Pressure Regulator and dial it down to various psi and see what happens.

 

[ChasingSand]

Where are you seeing the 80psi of fuel pressure? How are you testing it?

 

[MPC]

Where are you seeing the 80psi of fuel pressure? How are you testing it?

I have an inline gauge right after the fuel pump. That jives with the specs on the pump.
Picture taken with pump switched on and engine running at idle (1500+/-).

 

[ChasingSand]

So that is not the pressure your injectors are seeing. You would want to check the pressure after the regulator.

 

[EastMT]

Interesting. That one is rated at 87 psi, 255 LPH; pretty much what I have now. Mine is a Walbro GSL392, 255 LPH.
I think my next task will be to leave the stock fuel pressure regulator (replace with junkyard oem) and add in line right after the fuel pump an adjustable regulator like this: Evil Energy Fuel Pressure Regulator and dial it down to various psi and see what happens.

The stock fuel pressure regulator regulated the pressure on my stock J35A4. That was verified by a pressure gauge between the regulator and the engine.

 

[Rockwood]

So that is not the pressure your injectors are seeing. You would want to check the pressure after the regulator.

After the regulator isn't correct: this is just the return fuel and any pressure there would just be from fuel being restricted from going back into the tank.


80psi is waaaaaaaaaaaaaaay too much fuel. That being said, right off the pump isn't the best spot for the gauge. Should be in/around the fuel rail.


Surging idle on a Honda is usually vacuum leaks. If you have access to a smoke tester, that's the easiest solution. Next would be making a pressure tester:

6-7 psi should be plenty to start hearing a hiss from wherever it's leaking.

 

[MPC]

Point noted regarding the fuel pressure being high and the gauge location. I have an aftermarket pressure regulator on order.

While I'm waiting for that to arrive I'll work on doing a smoke test for a vacuum leak. I thought I had that ruled out because now I can cover the throttle with my hand and the engine immediately dies, but I will still smoke test it. I agree, it sure acts like a vacuum leak, but I have yet to find one.

Longer term, I'm wondering if regulating the pressure down will adversely affect my current fuel pump. I'll happily swap it out to gain reliability, but I'm not sure what the ideal pump would be. If I go down to 100LPH I'm finding stuff like this one:

which isn't going to cut it. I see some Walbro pumps that put out less, so maybe the GSL393, 155LPH would be better fit? I have the GSL392 now.

It feels like I'm just throwing parts at it, but the season is here and I am missing out on trips.