3RZ Help

[dillza_69]

Does anyone know if the fuel reg gets manifold vacuum or ported vacuum?

Also, does anyone know if the IAC valve has an adjustment screw?

The motor appears to be running lean at idle and low revs, when driving at 60km/h motor speed is 2000rpm, at this speed it appears to be surging or misfiring (its not a misfire but feels like it). I have changed the leads and plugs with no success. I then clamped off the fuel return line and the problem disappeared. I am assuming the fuel reg is shagged. I have it hooked up to ported vacuum, is this correct?

Secondly, the motor is idling a bit high (1500rpm), made worse when the fuel return is clamped, when the motor is at idle and i block off the IAC air feed the engine continues to run, Just. I think this is the root cause of my high idle. I cant find any leaks so i have come to the conclusion the TPS is farkd and sending incorrect signals to ecu causing IAC to open more than necessary.

I am not a mechanic so please correct me on anything i have misinterpreted.

Cheers

[sloshy]

Mine runs off manifold vac.

[Rory]

stock they go into the air expansion box on the intake pipe.

I had the same prob with the IAC, i pulled the throttle body off, and then pulled the IAC apart as it was stuck open giving me a 1400rpm idle. Once that was freeed up, my engine idled up one cold start and then dropped down to 800rpm.

What fuel pump are u using? mine surged n drove like crap when my fuel pump couldnt give enough presure.

Ditching ur fuel reg for a decent rising rate is the go, will give it a lil extra go, altho use a lil extra fuel

[dillza_69]

Ok cheers i will give it a go. I am not using the air expansion box. The air expansion box would be considered ported vacuum so the way i have it hooked up is correct? I am using a VL pump but didnt get it new so that could be an issue
I will pull the IAC valve out tonight and have a go at that but i doubt thats my problem as when i block off the inlet for the IAC the engine still idles (JUST) where it should stall.

Also did you make and adaptor for your fuel reg or is there a commercially available adaptor?

[Rory]

i didnt make an adaptor, i drilled the internals outta the stock one so it flows threw. U can get a adaptor tho, i just chose to do it the cheap way

[berad]

Is it turbo?, if not just a normal malpassi etc fuel reg will do, rising rate is for turbo motors, it adds 2psi of fuel for every psi above atmospheric pressure.

Take the vacum line off the fuel reg and see if it fix's it, fuel reg's work by pulling fuel pressure down by pulling a diaphram open in the reg

eg, with the ign switched to on, the fuel pressure will be say *50 psi, when you start the motor it will lower to say *28 psi. If you take the vac line off it thinks the motor is running at 0 vacuum so runs its peak fuel pressure.

[berad]

Ok cheers i will give it a go. I am not using the air expansion box. The air expansion box would be considered ported vacuum so the way i have it hooked up is correct? I am using a VL pump but didnt get it new so that could be an issue
I will pull the IAC valve out tonight and have a go at that but i doubt thats my problem as when i block off the inlet for the IAC the engine still idles (JUST) where it should stall.

Also did you make and adaptor for your fuel reg or is there a commercially available adaptor?

Throttle bodies butterflies have holes machined in them so as to not block 100% of air, so it could still keep running just.

What color were the plugs, white = lean, excessively black = rich, although if it is fine at other revs they wont appear to bad.

If your not using the air expansion box, are you using the oe spec intake between the air box and the throttle body, if you increase the size etc it will alter the motors air/fuel ratios, the air sensor takes a reading of air flowing by, by increasing the diameter it is reading a lower air intake, than what is actually being drawn in.

Standard ecu's are temperamental, small changes throw a stock ecu out. Such things as, o2 sensors, faulty water temp etc, every sensor like that compensates to the fuel %, as in on cold mornings the air is more dense, needing more fuel so the ecu compensates for that, and thats why cars/trucks/bikes run better in cold temps.

In the engine bay there is a box labeled diagnosis, its about 50x25mm, bridge connectors T1(or te1) & E1, then turn the ignition to on, the engine light in the instrument cluster will flash a code if any sensor etc is not giving the ecu a "acceptable" resistance, it will give you a guide as to what/if any sensor is faulty and could be causing it.

At the bottom of this page is what code means whats.

http://www.off-road.com/toyota/tech/codes/

[dillza_69]

eg, with the ign switched to on, the fuel pressure will be say *50 psi, when you start the motor it will lower to say *28 psi. If you take the vac line off it thinks the motor is running at 0 vacuum so runs its peak fuel pressure.

If the reg was actually shagged would this still be the case? I will try this tonite. Plugs looked fine.

Im using 76mm tube for the intake i did consider that this may play havoc with the Af readings but it shows no adverse effects throughout the rev range. My only problems are at around 2000rpm.

My understanding was that the motor would generate more vacuum at higher rpm?? This would then apply more vacuum to the diaphram in the fuel reg causing it to pull closed or partially closed thus increasing fuel pressure which would be the desired result at higher rpm (increased fuel usage)? Unless i am misreading your post my theory is a direct opposite to yours. Can anyone clarify?

I stress i am not a mechanic so please correct me.

[berad]

Start the motor, with the car not on the grass so you dont kill the grass, pull the return fuel line where it connects to the chassis, see how much fuel is coming out of the return line at idle, rev the motor in neutral obviously and the fuel coming out should be less, this is with the vac line connected, if no fuel comes out the pump is no good or the reg is stuffed,the reg being blocked will over fuel the motor at lower revs..

Vacuum is more at idle, put your foot down and it will rise to close to 0 vacuum. At cruise it will be running with some vaccuum.

Think of it like this, at idle with the throttle body closed, the motor is trying to draw in more air than its being given because the butterlfy is closed, causing a vacuum effect in the intake, when it is wide open it can take in as much air as it wants/needs causing no vacuum effect.

There could be 500 things causing it, another is a sick coil pack, i've had a sick one where the motor would break down/misfire at mid range rpms and then would be fine above or below, although this is a turbo motor so boost would have been blowing the spark.

[smaddock]

when driving at 60km/h motor speed is 2000rpm, at this speed it appears to be surging or misfiring (its not a misfire but feels like it).

My 3rz has been having this exact same issue since I got it running. I actually just started a thread on 4wdAction forum regarding this. Mine isn't running the standard intake piping, having had the standard throttle body removed and a 180degree bend put on, then a gas research throttle body mounted on this before feeding straight into the standard airbox.
However the MAF is housed in the standard plastic housing which I hacked off a 3rz airbox so it shouldn't be due to incorrect piping size in my case. I've also got a Haltech interceptor ecu in and tuned, and the guy tuning didn't mention anything about it being lean.
New plugs and leads didn't fix anything, and since its been checked on a dyno and fuel mixtures are fine then I'll assume my fuel pump and reg a fine.
The only thing I can think it "may" be is a coil pack... but my question is, if it is a coil pack in a N/A engine, would this cause the spark to break down only a little at a limited engine rpm range?

From the your description it sounds to be the same issue I'm having, where its not a big misfire scenario, but more just a feeling of the engine surging a little from about 2000rpm to 2500rpm or there abouts, and only under slight load to medium load.

Does anyone know how to check if it could be the coil packs? Preferably without having to swap in a known good pair as I don't have access to any that I know of


Lastly, with the high idle, mine did this a bit until I had the gas reasearch carby fitted which moved the IAC to an adaptor plate (new casting, etc...) and is now damn stable at 800rpm all the time, except when cold obviously. Not sure what the prob was, something to do with the standard throttle body me thinks

[Kingston_99]

has anyone fitted a snorkel to their 3RZ??

[dillza_69]

when driving at 60km/h motor speed is 2000rpm, at this speed it appears to be surging or misfiring (its not a misfire but feels like it).

My 3rz has been having this exact same issue since I got it running. I actually just started a thread on 4wdAction forum regarding this. Mine isn't running the standard intake piping, having had the standard throttle body removed and a 180degree bend put on, then a gas research throttle body mounted on this before feeding straight into the standard airbox.
However the MAF is housed in the standard plastic housing which I hacked off a 3rz airbox so it shouldn't be due to incorrect piping size in my case. I've also got a Haltech interceptor ecu in and tuned, and the guy tuning didn't mention anything about it being lean.
New plugs and leads didn't fix anything, and since its been checked on a dyno and fuel mixtures are fine then I'll assume my fuel pump and reg a fine.
The only thing I can think it "may" be is a coil pack... but my question is, if it is a coil pack in a N/A engine, would this cause the spark to break down only a little at a limited engine rpm range?

From the your description it sounds to be the same issue I'm having, where its not a big misfire scenario, but more just a feeling of the engine surging a little from about 2000rpm to 2500rpm or there abouts, and only under slight load to medium load.

Does anyone know how to check if it could be the coil packs? Preferably without having to swap in a known good pair as I don't have access to any that I know of

I say you should be the one you buys a new coil pack to test this theory

The reason i think it is fuel related is when i block off the fuel return, the problem goes away. This points to not enough fuel pressure, whether that's due to a shagged reg or a problem with he fuel pump im not sure.

I am going to try disconnecting the fuel return after the reg and see how much it is flowing at idle, im told it should be around 1 litre a minute

[dillza_69]

has anyone fitted a snorkel to their 3RZ??

yes i have, if you are chasing power a snorkel will produce results that are barely noticeable if at all. You would be better off with a piggyback ecu such as "Haltech Interceptor" and a tune.

[berad]

start the motor, pull of a lead off a plug at a time and see if the any one of the leads is producing a weaker spark (unable to jump as far as the other to earth out).

It's a long shot, but worth a try, with you having an aftermarket ecu, the problem doesn't seem to point at the ecu not liking a reading being fed to it.

[Kingston_99]

has anyone fitted a snorkel to their 3RZ??

yes i have, if you are chasing power a snorkel will produce results that are barely noticeable if at all. You would be better off with a piggyback ecu such as "Haltech Interceptor" and a tune.

can you post up a picture of your set up with the snorkel. i just want to see how the air box sits and all the air hoses ect etc.

and is the snorkel that is affecting your engine sinse u put it on? or is this related to something else?

[dillza_69]

has anyone fitted a snorkel to their 3RZ??

yes i have, if you are chasing power a snorkel will produce results that are barely noticeable if at all. You would be better off with a piggyback ecu such as "Haltech Interceptor" and a tune.

can you post up a picture of your set up with the snorkel. i just want to see how the air box sits and all the air hoses ect etc.

and is the snorkel that is affecting your engine sinse u put it on? or is this related to something else?

I dont think my setup would be of any use to you because my lux is an 89 model. I have done a 3rz swap and im using a diesel air box (not sure which model) with all custom intake piping. The snorkel would not effect the way your motor runs, if anything, it would run better.

[Kingston_99]

has anyone fitted a snorkel to their 3RZ??

yes i have, if you are chasing power a snorkel will produce results that are barely noticeable if at all. You would be better off with a piggyback ecu such as "Haltech Interceptor" and a tune.

can you post up a picture of your set up with the snorkel. i just want to see how the air box sits and all the air hoses ect etc.

and is the snorkel that is affecting your engine sinse u put it on? or is this related to something else?

I dont think my setup would be of any use to you because my lux is an 89 model. I have done a 3rz swap and im using a diesel air box (not sure which model) with all custom intake piping. The snorkel would not effect the way your motor runs, if anything, it would run better.

oh ok, cheers mate thanks for the info

[dillza_69]

i just tested my fuel return and there was about 1L returning in about 30-45 seconds. With this in mind the only other thing would be the fuel reg.