y33 cleaning out EGR valve-PCV valve-intake plenum-throttle body with seafoam

[Qproject]

do you guys think seafoam cleaner is safe to clean out EGR valve, PCV valve, intake plenum and throttle body ? what other cleaner would u use ?

and where exactly is EGR valve and PCV valve ?

[maxnix]

A conventional carburetor cleaner will work better.

Check your FSM. It's very explicit.

[elwesso]

Carb/TB cleaner, brake parts cleaner its all the same stuff. Honestly what I do is just buy brake parts cleaner and use it for everything, its nice because it doesnt leave a residue behind like carb cleaner does sometimes. Minor since it will evaporate once the engine gets warm, but its nice to see it dry instantly...

If you want to clean that much, i would personally take the plenum off and clean it really good. If you're taking the plenum off you can use many chemicals. Ive used paint thinner on mine (not sure if Y33 plenums are painted), oven cleaner really helps remove some of the caked on stuff... You cant really clean the plenum that well on the car because much of what really needs cleaned you cant reach.

[dodiho]

elwesso...I sure enjoy all the advice you guys give us! Thanks! I have a '99 q with 124,000......I need your help! I have cleaned out my TB and MAF..both very dirty..but the problem still exists: it will start fine..idle up to 750 or so when cold....then when I put it in gear-it idles down and dies quickly.....after it warms up to center of gauge I can put in gear and EASE it up to 55 or so on the highway...but when I ask for more speed or passing gear-it sounds like it runs out of fuel as I can hear the TB sucking massive amonts of air but the speed decreases....I let off pedal and it will continue to lose speed down to about 20 mph ,then I can gently pedal it back up to 55 or so....my code reader -new one- just says air flow problem...??? I am at wit's end.....I put in new oem filter,too...stay with me on this one...thanks,guys!

[elwesso]

I might check fuel pressure and see what that does....

Otherwise you're going to look at replacing the MAF.

[Qproject]

check out this link:

zer...12366

it can be the knock sensors

elwesso...I sure enjoy all the advice you guys give us! Thanks! I have a '99 q with 124,000......I need your help! I have cleaned out my TB and MAF..both very dirty..but the problem still exists: it will start fine..idle up to 750 or so when cold....then when I put it in gear-it idles down and dies quickly.....after it warms up to center of gauge I can put in gear and EASE it up to 55 or so on the highway...but when I ask for more speed or passing gear-it sounds like it runs out of fuel as I can hear the TB sucking massive amonts of air but the speed decreases....I let off pedal and it will continue to lose speed down to about 20 mph ,then I can gently pedal it back up to 55 or so....my code reader -new one- just says air flow problem...??? I am at wit's end.....I put in new oem filter,too...stay with me on this one...thanks,guys!

[AlabamaDan]

I pulled the throttle body off and cleaned it with carb cleaner.

Took the EGR off and cleaned it with gas (the old fashioned method.) It does have some rubber stuff in it so I didn't soak it or anything.

With the throttle body off I just reached inside the plenum and wiped and such until I was happy.

There was a little hole in the plenum that connects to the EGR. Mine was completely blocked and had to be cleaned out.

[dodiho]

Thanks...I just played with the MAF harness connection and slightly wiggled it and the motor died! I have cleaned the connections with q tips,etc..they look good....and how can u tell if the small silver MAF sensor inside the housing is bad? It looks OK.....so: either the MAF connector is bad or the sensor itself is bad...'cause when I wiggle it with engine idling,it will die or stutter.....these cars are so "finicky" compared to the Mercedez,Cadillacs, Lincolns,Corvettes I have owned.....! I am not wanting to take it to the dealership just now,but might have to soon....this is the best tech site I've ever encountered!

[96Qowner]

It's most likely the connector if it changes when you wiggle it. This is a common issue with the 90-96 series - not so common on Y33s. Joe has the replacement pins and housing for the G50s. You might call 1-888-216-5328 and ask for him. Ask him if he has the parts for your 1999.

[dodiho]

Thank u! I will try to call in a bit...I do hope it is something this small! It was easier to work on my serial number 03-3rd one produced in 1963....Fuelie 'vette with the only set of side pipes factory installed that year by a GM exec who drove it than to work on these Infinitis! Now to show you guys that I'm hard headed,we have a new '06 Lincoln Towncar that sits in the garage 'cause we really like to drive these Infinitis....but I'm so old fashioned as I was raised on drag racing way back in high school in the early 60's and can build a big block in my sleep....but I am not so computer chip savvy like you younger guys! Doug in Texas

[maxnix]

It's probably the connection between the harness and the plug which is at fault. Might need to be resoldered.

[elwesso]

Before taking the connector off and messing with that, i would try SLIGHTLY bending the pins on the MAF itself so that it gets a better connection.... Should be worth a shot, id think... I doubt they carry just the MAF wires for the Y33s.

[dodiho]

El wesso...I just found out from an Infiniti tech in Dallas that one way to check the MAF/sensor housing is to tap on it near the connector and if it causes the car to stutter...then it's bad! He uses his pocket knife and taps in several places....he said it should not hesitate or stutter or die at all when one does this procedure.....so I think it was worth a cold beer and a real Texas BBQ sandwich on me to find this out...I saw him in line at a Dallas BBQ place.....!!! So i drove the 100 miles home and opened the hood of my '99Q and started the motor...tapped with my pocket knife and the damn car died instantly! The tech said road vibrations over time cause the circuit board to crack or wire solder joints to seperate! Have just ordered a Cardone rebuild and will let u all know if this stops the herky/jerky idling/driving problems!

[Qproject]

how much did the rebuild one cost you ?

but yeah good find my man!!!

El wesso...I just found out from an Infiniti tech in Dallas that one way to check the MAF/sensor housing is to tap on it near the connector and if it causes the car to stutter...then it's bad! He uses his pocket knife and taps in several places....he said it should not hesitate or stutter or die at all when one does this procedure.....so I think it was worth a cold beer and a real Texas BBQ sandwich on me to find this out...I saw him in line at a Dallas BBQ place.....!!! So i drove the 100 miles home and opened the hood of my '99Q and started the motor...tapped with my pocket knife and the damn car died instantly! The tech said road vibrations over time cause the circuit board to crack or wire solder joints to seperate! Have just ordered a Cardone rebuild and will let u all know if this stops the herky/jerky idling/driving problems!

[dodiho]

The rebuild MAF cost me about $220 with a $45 core charge...from RockAuto Parts online.....and it is a Cardone unit...should be here in 2-3 days...am REALLY anxious to install it and fix my problem! I hope!

[Qproject]

I ran chevron techron concentrate on full tank (y33) , did a top engine cleaning and cleaned out my air intake. Also changed my differential fluid to Royal Purple.

my mechanic said my throttle body intake was very clean and didn't really need it. Oh wells.

good news is my TCS and SLIP lights have not come on in over 4 days. I don't know if it was the chevron techron or not.

even at 140,000 miles, my y33 is probably one of the cleanest, best kept y33 out there.