Engine not reving over 4000 RPM?

[Q45tech]

Reving up sitting still is not a valid test you MUST ATTACH GAUGE TO WINDSHIELD AND DRIVE THE Q UNDER MAX LOAD AND RPM. The PSI should be very stable [+- 1PSI centered at 43.4 so 42.4>44.4] at WOT thru the rpm range of 4,000 to 6900 redline.

[jimbyjimb]

No, actually, I "could" not. So unless you have spactular hearing, an insanely quiet cabin or a very loud pump I very much doubt the validity of your claim. I can hardly hear it run from the trunk and I have NO driveablity issues or at speed air leaks in my cabin seals and can hear myself whisper at 60mph, and I very much doubt my hearing ability is challenged. The 96 has thicker glass and is quieter on the inside than a 92, so maybe that has something to do with it, other than that I either have a very quiet pump or you have a very noisey one.

[Q45tech]

It is possible for FPCU to fail in one or more of 3 modes. You check this by measuring the current flowing thru fuel pump fuse [3 different steps].By reading the pump rpm vs current. Make sure the ecu is sending 3 different contol voltages to FPCU.

When dealerships replace oem pump they almost always demand you replace FPCU because it may be damaged from the pump failure.

You have to understand that the FPCU is progressive in the way it works to creaste an effective resistance drop. THREE DIFFERENT CIRCUITS IN PARALLEL................so some can fail without affecting idle or the converse can be true..............a failure only affecting high rpm or high load.

We always check fuel pressure and test for WOT HIGH RPM problems.

I always carry a known working spare FPCU because I've learned they can fail in many different ways. No idle, no middle speed, no high speed.

[Denver90Q]

QUOTE=Q45tech]Reving up sitting still is not a valid test you MUST ATTACH GAUGE TO WINDSHIELD AND DRIVE THE Q UNDER MAX LOAD AND RPM. The PSI should be very stable [+- 1PSI centered at 43.4 so 42.4>44.4] at WOT thru the rpm range of 4,000 to 6900 redline.[/QUOTE]

Unfortunately, all I could do as car did not go over 2000 rpm in gear.

I found the problem however, when I pulled the tank today to replace the pump, the filter sock was completely caked with about a quarter inch of a thick clay like substance. I had some corrosion in the tank before but nothing on the sock. I'm surprised the car ran at all. I guess it was the last tank I got at a discount station. I usually go to a tier one or Costco which filter their gas. Won't be going back there anytime soon unless it is to cuss them out.

I did not notice the problem until I used about half the tank because I had a loose connector on one injector and was not doing any WOT's. What are the odds? Restores my confidence in the Nissan pumps.

Anyone need a brand new OEM pump?

[maxnix]

I found the problem however, when I pulled the tank today to replace the pump, the filter sock was completely caked with about a quarter inch of a thick clay like substance. I had some corrosion in the tank before but nothing on the sock. I'm surprised the car ran at all. I guess it was the last tank I got at a discount station. I usually go to a tier one or Costco which filter their gas. Won't be going back there anytime soon unless it is to cuss them out.

Hopefully you will pull and steam clean the tank this time since you know it is dirty, change your fuel filter and rinse your lines.

And only buy fuel from new Tier 1 stations!

[Denver90Q]

Hopefully you will pull and steam clean the tank this time since you know it is dirty, change your fuel filter and rinse your lines.

And only buy fuel from new Tier 1 stations!

Washed tank out with hot water and flushed with acetone (had some extra I probably won't need anymore). I'm thinking of reverse flushing the fuel rails while I have them hooked up to the pressure gauge. Any suggestions?

[maxnix]

If you haven't done it, replace all rubber in the fuel lines. Need about a foot under the plenum, but I am not sure about the solid line connectors under the car. If it is the same hose, by in bulk (there is a Nissan part number for 1 m.) from Joe as it is cheaper than by the foot.

[Denver90Q]

Just completed BG fuel injection service on "95 Q and pickup. Car runs and idles perfect now, as good as ever. Even with junkyard MAF I left in.

Ran can of BG induction system cleaner, 1/4 can BG 44K (rest in tank) and 1/2 can of gasoline for about 10 to 15 minutes.

I should have done this to begin with as engine runs and revs great just with air pressurized canister. Also pulsed lines and intermittently turned up pressure to 60 psi to dislodge dirt. Old fuel filter was also full of clay like slurry.

Wonder what the trick is to tightening the rear fuel rail hose clamps? You'd probably need hands half my size.

[maxnix]

So you had both the injection rail service and intake fogging done?

Change fuel and air filters once per year. X that service station that dispenses mud.

Fuel rail hose clamps are best done with plenum off if clamps not oriented perfectly. How did you replace these hoses without removing the plenum?

[Denver90Q]

Hopefully you will pull and steam clean the tank this time since you know it is dirty, change your fuel filter and rinse your lines.

And only buy fuel from new Tier 1 stations!

I don't think there is anyway to steam clean tank with all the baffles inside but it should be pretty clean now. Maybe I should filter the gas before I put it in the tank?

QUOTE=maxnix]So you had both the injection rail service and intake fogging done?

Change fuel and air filters once per year. X that service station that dispenses mud.

Fuel rail hose clamps are best done with plenum off if clamps not oriented perfectly. How did you replace these hoses without removing the plenum?

[/QUOTE]

I previously cleaned the intake manually as noted above. Used about half a dozen cans of carb cleaner. However, I do have about 10 cans of BG air intake cleaner which I have never used.

Fuel hoses looked good on 95 Q (with only about 80k miles) and it has never had a fuel leak that I know of. I was able to tighten rear clamps by tightening with short stubby screwdriver-just in case.

I did replace fuel hose on my 1990 recently with viton lined hose. Is that what IOS sells?

[maxnix]

The hose I got is just high grade rubber fuel line, but it is the correct inner diameter and lasts 14 years in my case and could have gone longer.

Q45tech has a post on fuel lines and ethanolized fuel that might be owrth looking up.