I'm getting some popping off idle. Not sure if it's due to running with no exhaust, or if the timing is off, or if it's something else...
Well, I scabbed my old exhaust back on, just so I could do some troubleshooting without earplugs. With the exhaust back on, I am still getting severe popping/backfire as soon as I touch the gas. It's so bad, it won't rev past 1500.
I did some research and found that a faulty TPS may cause this behavior, so I checked it out. Mine checks out good, smooth transition from ~.75V at closed to ~4.8V WOT.
While researching, I realized I hadn't verified the fuel pressure at the fuel rail. So, I went down to AZ and borrowed their fuel pressure test kit. I hooked up the fuel pressure gauge to the schrader valve on the rail and started the engine. 110psi!!! I thought the WJ fuel filter (Wix 33750) was supposed to cut that back to 49 or so?
So, I need to figure out how to get the pressure down. Either a different regulating filter, a standalone regulator, or maybe I can make an earlier XJ fuel rail (with integrated FPR) work.
Can you may want to look at putting on a earlier fuel rail that has a vacuum pull off on the fuel regulator. This should help with your high pressure on your fuel rail I know that later model jeeps had the fuel pressure regulator in the tank.
yeah, I thought about that. The earlier rails/regulators are setup for ~35psi. The later setup needs 49psi.
Also, I think it may have something to do with the fact that I am using an aftermarket E2000-type external fuel pump (~120 psi?). If the stock in-tank pump with which the WJ filter/regulator is meant to be used puts out significantly less pressure (~75psi??), then my regulated pressure using the aftermarket pump would be higher than required, which is what I'm seeing. So maybe switching to an earlier rail/regulator would net the lower pressure I'm looking for.
Or am I not understanding how pressure regulators work?
Ida know, Ken. Gut told me there was something "amiss" with the WJ filter concept. I had bought one also when I was going OBDII. But I changed it all to OBDI for the greater ease of connecting everything. I am using the earlier model fuel rail. The fuel pressure reg is ridiculously expensive (for what it does)! I have read that it doesn't make a significant amount of difference about a few pounds of fuel pressure, so I would maybe not be too worried about that.
Why couldn't/wouldn't a ball valve on a return line work for pressure regulation? It works very well in irrigation. Seems like all you have to do is attach a ball/gate valve on the return line and adjust the amount of return to the tank. More return = less fuel rail pressure.
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Yeah, I was really concerned when I saw over 100psi. 60 is still high, but I don't think it should have as much negative effect as I'm seeing. I guess my next step is to get a code reader so I can see exactly what the computer thinks is wrong...