kinser86

It has been a while but I still owe some videos for everyone. We took the fuel rail return directly from the rail and dumped it into a jug and go 40-PSI. Thankfully this helps relieve any thoughts of the hard line to the tank and/or tank being the culprit. I did notice a kink in the rail on the outlet side, but I haven't pulled the regulator to test it outside of the car due to a busted air compressor system right now. Unfortunately we have been busy tackling many things and the weather has been garbage for a while so we haven't gotten out yet but we are still going down here. Maybe I'll find another factory rail and put it in if I come across one.

Great video! I can do the same with the fuel pressure regulator I got. The one I purchased is more zinc than the yellow cadmium chromate in your video. I have not cut the old one apart either so I can perform the test on it as well. Agreed Zed Head. I'll look a that new regulator similar to the video Dave WM posted to see if the new Bosch compares to the old.

Alright so it has been a few weeks, funds were allocated and other projects were tended too. We swapped in a new Bosch 64018 Fuel Pressure Regulator and the pressure on the rail stays rock solid at 40-PSI. Before it would steadily climb to 42/44-PSI if you raced the engine a bit. At this point, we are going to drive the car on the street/highway a bit and check the plugs. I've banged my head around other possibilities.. maybe the voltage supply is high at the fuel pump and the stock regulator still can't keep up even though this is a 'stock' replacement. One way to check is to see what the pump pressurizes the system with the oil pressure sensor unplugged and the car turned off. The car does have the alternator swapped for a 60A ZX alternator. I have reached out to Delphi for a map of their pump for reference. Has anyone else run the Delphi pump with factory rails and measured fuel pressure? It almost seems inevitable that a palnet rail and adjustable fpr is needed in this application in order to bring the pressure down. The engine is the most responsive I've ever experienced and initial issues seem to be gone but I wouldn't be surprised to see fouled plugs in the near/distant future to recreate some of those issues. As always, I appreciate everyone's help and the car has improved leaps and bounds prior to the start of this thread.

Plan is to replace with an OEM replacement Bosch 64018.

I'll do that and get a video too.

I have about the same two thoughts, rigid diaphragm or blockage. It definitely is not leaking but that would be an opposite symptom. I think it is worth replacing and seeing if it improves. If it does, I want to cut the old one apart and see the damage. That is a BIG if.

Well the new gauge gives the same numbers, 42-PSI. In the video, the first clip has the High and Low side hooked up to the gauge. The second short clip is just the high side. I haven't tried running the return off the rail into a bucket yet to see if the hard return line is causing the issue. I am running the Delphi FD0035 fuel pump now as I mentioned a few posts back. Right now this has to be isolated to a few things: Fuel Pressure Regulator No fuel is leaking from the vacuum side I don't know how this could fail and yield higher pressure Hard return line to tank Dump fuel return from rail to bucket to see if pressure is still high or not ?

Just for future reference, Fuel Injection Specialties did not charge me the second time and were extremely diligent and supportive of my concerns towards correcting them. I don't want people to be discouraged from using them nor do I want to tarnish their name. In the end, I got the injectors flowing evenly. It could have been my fault letting the injectors sit to long before reinstalling them. None taken. Quality and cost go hand in hand which is why I keep opting to spend money on better testing equipment rather than throwing it at the car. Like you mentioned, I am more interested in the measuring than driving the actual car ?. There doesn't seem to be any higher quality 1/4" NPT fuel pressure gauges readily out there. I am keeping my fingers crossed that the ΔP gauge will read better. Who knows, maybe the OTC vacuum gauge is incorrect and I don't really have 20inHg and I do have a vacuum leak somewhere which is why my fuel gauge is reading what it is. Time will tell, just have to wait for the gauge to come in.

Here is a snapshot of the mechanics of the gauge: Gauge Mechanics Gauge Datasheet I ordered the one from eBay and it is on it's way. I will post videos of course of it in action. For the time being, we are going to clean up some of the car and drive it some more and I will keep an eye on the plugs.

I think so too Zed. I plan my methods during the week and attack during the weekend. My hope is that any unfortunate individual who has to go through what I am/did with this car can reference this at some point and use the numbers to make the right decision rather than throwing money/time where it shouldn't go. Fortunately Ashcroft has very good documentation on their website. The item currently on eBay is: Model: 25-1130FL-25S-XV2-60# 25: Size (2.5") 1130: Series F: Body Material (Aluminum) (The stainless bodies have a higher max pressure rating of 6,000-PSI) L: Case Fill (Glycerin Fill) 25: Process Connection Size (1/4" NPT Female) S: Process Connection Location (In line) XV2: Options (1-SPST switch with terminal strip) 60#: Range (60 PSI) More importantly, the o-rings are Buna-N so gasoline should not be a problem. For the cost it is worth a shot.

Very interesting. There are some Ashcroft differential pressure gauges on eBay currently for a decent price. 0-60 PSI with a max pressure of 3,000PSI and 1/4"NPT(F). Something like this should work in this application correct? If so then it would be worth a purchase to have in the toolbox.

I still need to check if the fuel pressure is high or not. The gauge seemed to do fine with the compressed air sweep but still seems to read high on the car even with 20inHg at idle. If it truly is high, then I am not done yet ?. I have blown through the fuel rail and hard lines on the chassis with compressed air at about 120PSI with a clean towel covering the outlets and did not observe any particulates. I need to try a different gauge and see if I get the same results.

I think it might be the exhaust you hear. It does have a header and exhaust system. One way to check would be to let it engine brake and see if it makes any noticeable sounds but again it might be the exhaust.

Update time. I had taken the injectors back to Fuel Injection Specialties and they agreed that two were flowing irregularly. They cleaned them again and got them back to flowing where they should have been. The discrepancy occurred because the cleaning solvent dried in the two injectors and clogged them back up. I took them back and did the same out of car test and got all of them to match volumes. After this, I put the rail back on the car and put in new plugs on every cylinder. At this point I felt the fuel pump was too much for the car and we pulled it and replaced it with a Delphi stock replacement. We hooked everything up, set the timing again, and tried to drive it again. From the video, the car is driving much better now. The resister between the coolant temperature sensor is turned all the way back as if it was never installed right now. With the stock pump replacement, the fuel pressure still seems a little high but not as high as with the previous pump. I pulled the plugs after we drove it around for a bit and took some pictures. I need to put the AFM cover back on and clean up some of the engine bay before really driving it. Any thoughts on fuel pressure/vacuum reading?

Alright, I got the some parts off the car and brought them home. I evaluated the gauge first before I do anything else. I had 100PSI on the compressor supplying the line. I swept it to 80-PSI before the video and also did a couple of these sweeps before recording.