HJ30 Maxima Issue

[Nismo_Freak]

Having idle issues with a 3rd generation Maxima with the VG30E engine. It has over 200k on the clock.

We are having issues with maintaining the idle with the car due to a miss.

The idle was jumping but seemed to want to hover around 600 rpm when the timing via the distributer was set with a good amount of retard.

This is what we began working with.

I looked over most of the IACV vacuum lines and we cleaned the IACV as well. We found a few cracked ends but nothing was leaking according to our highly technological water spray method lol .

I ran down the list of components and he had replaced just about all of them ranging from ignition components (plugs, wires, dist. cap, rotor), 02 sensor, MAF, TPS, etc. The only components I could come up with that could cause a miss are the timing, fuel pressure regulator, vacuum or intake leak, plug gap, plug choice, and the EGR.

No vacuum leaks detected but I do hear a faint hiss that is intermittant; sounds similar to a vacuum leak.

Car has the miss even at ~3000rpms.

When we advanced the timing the miss got worse, and the idle was raised 100-150 rpm. Timing set at a slight advance, car ran better at higher RPM according to owner.

We plan to replace the fuel pressure regulator because the car has a hesitation on start-up and blows black smoke (fuel) out the exhaust. This possibly could be the source of our vacuum leak as well, because without vacuum the FPR is gonna run full pressure.

I know I'm kinda vague but I'm trying to fill you in on everything.

[NISTECH]

check your temp sensor very common for these things to make the cars run way to rich. the miss sounds more like a belt out of time on one or both of the cams. use a dvom or dmm as some of the guys call it on here to check your temp sensor see if the circuit is open at the temp harness. if all tests ok there remove the upper timing cover and inspect the timing marks for proper alignment.

[Nismo_Freak]

check your temp sensor very common for these things to make the cars run way to rich. the miss sounds more like a belt out of time on one or both of the cams. use a dvom or dmm as some of the guys call it on here to check your temp sensor see if the circuit is open at the temp harness. if all tests ok there remove the upper timing cover and inspect the timing marks for proper alignment.

K thanks.

[Nismo_Freak]

BTT,

The car has a miss from idle to 3000 rpms then it seems to clear out in terms of audible missing.

The car blows a good amount of fuel out the back when it's revved and driven hard.

The car now has a problem with it's base idle on lift off. Driving along, put in clutch and the car will die.

Also about 2000 rpms and on, there is a high pitched whine that sounds like the kind produced by RF's in the ignition system. Could this possibly be due to a charge somewhere being created due to a bad ground?

Just looking for some new ideas.

I cleaned the MAF and IACV yesterday and it didn't get any better.

I need to bring home the multichecker and run through all the grounds and the CTS.

[NISTECH]

your altenator can also resinate the frequency whine your hear in your speakers.

check your cts circuit and sensor though cause this will definitly cause the car to load up on fuel especially under little or no load.

I know this dont sound good but you could have a leaking injector or 2 . do a leak down check. Let me try to explain how to perform this test. this will also test the FP reg as well.

hook up a fuel pressure gauge on the engine side of the filter.run the vehicle and check your pressure it should be about 40psi with the FP reg disconnected and about 35 psi with it connected. precision is not important just that there is an increase when disconnected this is all done at idle. if this tests ok your FP reg is ok. now with the FP reg disconnected shut the car off it should maintain the pressure for some time. if it drops imediately you need to locate the source of the leak. start the car back up have a pair of pinch of pliers handy. shut the car down and imediatly pinch off the fuel line between your gauge and the fuel filter. if the pressure still drops you have either a leaking injector or a bad fuel pressure reg which the test above would have indicated.

You can still test the injectors even if the FP reg is bad. when you shut off the car pinch off both the return line and the fuel line between your gauge and the fuel filter. at this point you are trapping the pressure in the fuel rail. if it drops it is definitly an injector prob.

[NISTECH]

do you have a check engine light on at all?

[Nismo_Freak]

Thanks... I knew how to test all that before hand :p, just haven't gotten around to doing it. Was gonna test it all at once.

The main problem is that the FPR is below the manifold and difficult to access as a result.

We'll run a diag. on the CTS soon.

No CEL.

Leaking injectors are no suprise on the VGs... they always go out on the single cams.

Thanks for the ideas