Injector rail noise on 1UZ.

[MacroP]

In my MX83 1UZ conversion, I have a tapping noise similar to having bad valve clearances when the engine is at idle or low revs. I pulled both rocker covers and measured clearances on all 32 valves and all were spot on except one(#1 intake) which was only 2 thou out of speck. The oil filler cap in directly over this 'out of spec' valve so if you remove this whilst the engine is running I would have expected the noise to become louder but it doesn't. The noise seems to come from both sides of the engine near the intake anyway. It sounds like a valve issue but I coming to the conclusion it maybe something else like the fuel side of things.

I was wondering if this could simply be injectors, their rail, the regulator or pulsation dampener noise? I currently don't have the Fuel ECU running hence the Cressida fuel pump is running at full speed constanty even at idle.

Any thoughts or ides? Cheers.

[The Witzl]

Dude - its your ISCV more than likely.

My UZS131 crown made the same noise, and it was most definitely the ISCV there

Pull it off, clean it out (it will be gummed up to death) and put it back. The noise might reduce a little, but in reality you shouldnt worry, because the noise is normal for a stepper motor like that.

[joecoolmk2]

try the screwdriver in ear trick, it might help you locate the noise.

is it a quiet gentle tick or a bit heavier? it might just be an injector.

[MacroP]

try the screwdriver in ear trick, it might help you locate the noise.

is it a quiet gentle tick or a bit heavier? it might just be an injector.

It's quite loud, much louder than I've heard from a bank of injectors before. I can (just) hear it through the bonnet when idling. I'll persevere with the checks and see where I get.

[kingmick]

id say injectors! at times they sound exactly like big clearance on the buckets! but without hearing it it a bit hard to tell.

[3sgte]

Fuel rail noise can be affected by fuel pipe and hose configuration.
Are the original fuel dampers from the 1UZ fitted?

Also, given that you are running the Cressida fuel pump at full tilt, the flow through the regualtor/rail will also differ.

I would try adding another damper if you can fit one in there, and also try to get the resistor fitted for the fuel pump (assuming that the noise irritates). LS use a plain jane resistor, SC use a fuel pump control ECU. Depending on the electrics/hardware you have kicking around, I might be tempted to go for the simplicity of the resistor.

Usually when those motors generate valve clearance related complaints there is in excess of 20 thou clearance. This is typically as a result of a bad bucket.

Can you post a short video of the noise?

Edit:
Just for shits and giggles, pull the ignition wires and check that the plugs are tight.

Also, pull the wires and see if the noise is associated with only one cylinder. It is possible for a rod small end bush to make a similar noise.

Does the noise change when you "float" the engine (rev slightly and release the throttle)?

[MacroP]

Fuel damper is original 1UZ spec. With the engine off but with ignition ON(and pump running) the fuel flow is quite loud through the rails and so forth. I'm using a Soarer/SC spec engine and ECU so the existing Cressida fuel pump resistor and two speed operation is incompatible with my setup. The Cressida pump is just barely noticable when running with the engine OFF.

What I think I may do is, is setup a variable DC power supply to supply the pump to reduce fuel flow at idle to check for a difference. From memory the Soarer fuel ECU outputs around 8 volts to the pump in the low speed, 10 volts for mid speed and 12 volts for full speed obviously. If that is successful, I'll obtain the proper fuel ECU(and loom plug from a wreck) and and hook that into my loom behind the glovebox. The setup I have now is not really safe anyway. My intention was to add this eventually after everything else was performaing OK(which it is).

I'll use my MP3 player to get a audio recording of it.

Cheers.

[30psi 4agte]

I second the screwdriver motion !!!!

I onece had a noise and i swear it sounded like an injector / tappet noise !!! But upon further inspection with the car on jack stands . I listened to it with a screwdriver and found it was an imput shaft bearing . It was a noise i had NEVER herd fron a bearing but it deff was the cause of the noise.

Im not saying this is your prob but you that you should not rule anything out !! and check all possibilities