Well Im haveing a bit of a starting problem and I wanna know how you guys have your Pathy TB hooked up.

I have it all done with the IACV hooked up/ 3/8" hose from the rear of the IACV to the Manifold, and on start up it kinda revs and starves really bad then dropps to about 500-400 then kicks back up and then stays at around 1000-1100 for warm up. Is 3/8" on the IACV enough maybe ??? Now if I open up that set screw on the Pathy TB up a bit, to have the TB open via the screw, it definetly starts better, but then I have a really high idle and thats not good at all.

There is a Vac line on the bottom of the TB that I am NOT using at this time. I have it blocked off. Do I need to hook vaccum up to that ?? Also Im not using coolant through the TB but I dont think that has anything to do with it if you ask me.

Let me know guys.

-matt

 

bump it up

-matt

 

kinda OT... but the symptoms you're describing are the issues i had, when i bypassed the coolant hoses in the TB. As soon as i ram coolant through the lines, everything was fine..

 

+1, same thing happened to me, but it was on the stock 4th gen TB, so I reattached the coolant lines and everything was A-Okay.

 

There are No coolant passages on the Pathfinder TB. All I have on the bottom is a plate with a vaccum source that I have blocked off

-matt

 

any ideas guys with Pathfinder TB. There are no Coolant passages on this TB

-matt

 

YES there is a coolant passage on Pathy TB. its in the piece on the bottom that bolts on with 5 bolts.

as for the coolant my idle with or without it is the same ,even when i removed coolant from my 3.0 TB.I say IACV setup is your prob.

 

Maybe it is. What size line are you guys using on the rear of the IACV plate ?? 3/8" ? Im using that on the back of the IACV plate, under the TB up and around the I/M. Maybe the IACV is shot.

-matt

 

Matty when I first put the VI on 1.5 yrs ago I used a 3/8" line and it started and ran fine, even cold start. Only this year did I have cold start issues, so I'm not convinced it's the line size, probably something else but I never got around to figuring it out...

 

3/4 inch i had my attach to a block so it acted like the 3.0 stock

 

Kris since I'm using your old block, what size hose do you recomend?

Are there any pics of what part is used for the coolant lines on the Pathy tb?

:edit: I also dont want to highjack but since it's about the Pathy tb....will the a/f ratio be messed up if I only use an rpm switch and not a s/v-afc II?

 

no hose needed its not like what these guys are saying what you have is the best thing its like a 3.0 IM mount point.

and for coolant i wouldnt hook that up does nothing ,i have went back and forth both ways have seen no difference .

 

Do you have a Vaccum line to the bottom of the Pathy TB ??

Maybe this problem is my bigger injectors ??

-matt

 

Ok so just block that all off?

 

nothing gets blocked off you use a brass coupling and bring the lines together

 

Ok so connect them. How many are there to connect?

 

I have one of Krismax's finely made adaptor blocks and I've never had a problem with cold starts or a funky idle.

The Pathy TB has it's vacuum assit IACV removed and im using the 4th gen IACV setup. The 4th gen IACV block is TIG welded to the side of the adaptor block going towards the firewall. Also there is a backing plate on the bottom and a brass vacuum nipple that is not used. The port vacuum nipple on top of the throttle body sends port vacuum to the EGR system, just like the OEM 4th gen setup. I've been running this setup for years now and never had any issues with it.

The throttle set screw is setup so that it rests at 650 RPM once the IACV is done doing it's thing. This is risky but I would let the car warm up for 10~20 mins and adjust that throttle set screw so that your idle RPM is what you want. Also I adjusted/calibrated the TPS on the Pathy TB when I got it, that maybe worth trying as well. There is a good write up on how to do this in the Haynes manual.

 

Do I adjust that set screw lower to try and fix my problem ?? My idle is at about 1100 now and I have that surging problem.

-matt

 

Matty
Warm up the car first, neglect the iacv, set the throttle body screw, it's on the cable attachment area, try to get it to desired rpms exact and lock it up tight. Make sure you then check the TPS voltage ranges while doing this, you need to turn the TPS and calibrate it back to the FSM range. Forgot the values.

Then settle your car to cool for a day, and upon cranking up the car, disconnect TPS plug and set IACV to your desired Idle speed by turning that plastic screw on top of the IACV. This should perfectly settle your idle rpm target values.

I also noticed another thread of your surging problems. In addition to what others had said, I think by-passing the coolant hoses in my point of view does contribute to this problem. I know for sure that if you have air pockets in the cooling routes, your Coolant temp sensor will pick up temp surge readings and control your engine rpms that way. You should try bleeding out air bubbles in your cooling system. Other than this, I'd resort back to IACV like Kris said. Hope I've helped.

-Peter-

 

I dont think it has ANYTHING to do with the coolant lines at all. Ive had the coolant lines bypassed from the TB for over three years with NO type of surging problem that I am experiencing now.
The IACV is new

-matt

 

I see, then I'm out of clues on your situation.

I also have the pathfinder tb, except it's on my mevi. Apparently, I don't have this surging problem. However, I am in the midst of putting on a 00vi with a pathy TB and stephen max's adapter. I hope I wouldn't end up having the same problem. Hence the reason I'm interested in subscribing your recent posts...please keep us informed about your solutions.

-Peter-

 

im runinng coolent by pass on the dek throttle body with no problems

 

My coolant lines are bypassed on the PF tb and I don't have surging. Idle is a little high (1.2 or so) but no surging. TPS is the only thing causing me problems.

 

Old thread but it's very helpful. Also having a fluxacting idle. Gonna adjust tps and see what that does. I have no iacv so that doesn't help either

 

Any reason why you aren't running the Pathfinder IACV?

I haven't had any issues with mine.

 

I bought the pftb already mounted on the intake manifold