Man if it's not one thing it's another. So I finally hook everything up and start the Max up. It sounds ok but not totally. almost like it had a cam.
I rev it and it hesitates and sputers a little so I double check plugs and coils. #6 not firing, damn! so I check coils and the wiring. It's the ECU.

So I go to the junkyard and find one. There goes my dyno tuning money. I hook it up and hmmm sounds good. Quick revs are really responsive. I let it set for a bit, to see where it idles after it warms up. It seems to idle well at 700 rpm. Check to make sure fans kick on. everythings good. I rev it quick with some good throttle and it revs nice.

But when I rev it with low throttle it hessitates at low rpms. So I'm like let me see what it feels like on the road. Man was it tough to take off.
It hesitates a lot off the line, unless I punch it. Once in gear and moving it's ok. It responds really well.

So here's what I checked:
*Plugs are new
*20 vaccum at idle
*this is NOT an issue for like the first minute when you turn the car on.
after it goes back to its normal idle rpm it starts the hesitation at low throttle.
*the big vaccum line that goes into the factory air box near the throttle is plugged. (this maybe the cause not sure)
*I'm running new NGK5 but have NGK 7's in the glove box.
*Front O2 is not hooked up to the ECU nor the rear one. The O2 is only going to the A/F guage


I'm all ears if you guys have any suggestions, Thanks!!!

 

O2 sensors not hooked up to the ecu? That would explain why it runs good until the engine warms up. Once it goes into closed loop mode the ecu uses O2 sensor information to maintain an afr based also on throttle position sensor and maf information.

Get your O2 sensors hooked up and try it again.

 

I agree with Stephen. Cold, the engine runs a preset open loop program. Once it warms up, the engine wants to go closed loop and rely on the 02 sensors.

 

Well alrighty let me give that a shot.

 

Whats up Uncle Max, I am the person in Houston whos car lookes just like yours. That was funny that one day when you were trying to drift in your 240 at the corner of Fountainview and Westimer.
Haha, anyway you finally got you car running, I want to come down and see it? How did you get your ECU tuned? I want to come see that turbo in action.

 

Hahahah yea I remember. Almost lost it, but I got skillz. heheh we all think we do. I'm doing good. Got the car running, but still trying to get some bugs worked out. Feels good other than the hesitation. I'm going to the shop tonight to mess with it if you wanna swing by and check it out?

 

Thanks Stephen and Jeff. I'll post the results tonight. Just got a new O2. I'll play with the used one first since I may have burned it up with the 110 Octane.

 

So what are the turbo guys doing with the big vaccum hose that goes into the air box next to the TB? I plugged it and it seems to keep the car running nice. Should I tap it into the charged pipe right before the TB?

 

What shop Uncle Max? Where is it located?

 

the IAC (idle air control) hose? I can't remember the exact probs I had, but I do remember I had driveability problems until I moved it directly before the TB.

 

Yea I'm thinking I'm gonna have to tap into the piping right before the TB. I just got back from the shop and it still hesitates.

But it could be with my setup. Because I had Haltech i never needed the O2 to make the car run. I had a bung in the downpipe where I stick the O2 for the Air/Fuel. I pluged that O2 into the connector and it seemed to respond a bit better. It still hesitates though.

So I'm thinking I may need to drill a bung hole ( hehe he said Bung Hole ) on each bank of the exhaust piping coming from the header to the turbo.
I'm thinking if you guys used a reversed Y-pipe the hole were there for you to screw in the O2's. I'm hoping this is the case. But I wonder if I'll need to have the O2 near the cat installed as well.

I'm hoping to avoid taping into my piping before the TB because I already got it plated, but if it points to that then I guess I'll need to.

 

Sorry I didn't see your post before I left work.

It's near the corner of Bellaire and DairyAshford. call the shop @ 281 495 4027 next time I'm there. I may be there Fri. night helping MCMIKE work on his max and maybe taking my piping off. for the above hole

 

Yeah, you're going to need to tap it. With Jason's car, we started the car without that hose plugged up and it ran like crap. Welded a bung for it, hooked it up and everything is great. All the other lines could be tapped into a vacuum tee, but that one is too big so it needs to be hooked up to the charge pipe. Sucks that you just had it plated though. They make threaded fittigns, maybe you can use one of those so you wouldn't have to weld and rechrome the pipe.

 

You need the IAC line for it to run good...

as for the o2 sensor by the car, the car will run perfect, but will most likely throw an almost-constant CEL.

 

Did you mean as for the sensor by the cat or do I not need the 2 O2 sensors at each bank? I think it's easier at this point to remove the intake pipe and add IAC hose rather than remove the exhaust pipe to the turbo. But if it doesn't run very well with out both O2's either then I'll have to do it.

 

He probably meant the O2 sensor at the cat. That one is not used by the ecu during closed loop control of the afr.

 

Thanks I'll start with AIC and then see how it runs and move to the O2's.
So I guess the PFI kits come with the O2 holes since the regular y-pipes come with them.

 

That is the order I would go also. the IAC/AIC whatever its called haha should make a big dif! It did for me.

I put bungs for the two front o2 sensors, I assume PFI does also

 

Lol yea the IAC.

 

When I do my turbo project this summer, I hope people can help me so I can save on labor costs!

 

Ok so I was at the shop last night. Welded a connection to the intake pipe. I tried just drilling a hole and just bolting a nut from the inside to the connector, but I was too scared it would come loose and get sucked into a piston. So I gave welding a shot. Lets just say I had to do a bit of grinding, it looks ok. I trashed the chrome around it when I made the hole so I didn't care about welding it.

I went to HiLo during my lunch to buy the hose and hook it up.
I turned the car on and it idles just as good as before, but it revs smooth at low throtle now. But I also forgot to hook up the Boost something sensor near the radiator ( a little black box that looks like a MAP sensor). So I'm hoping the hose cleared the funny throtle response and hooking that Boost sensor brings the idle back down to about 750rpm. After I hooked the hose and the car warmed up the car idled @ about 1200 rpm. So I'm going to hook up the sensor and if it doesn't fix it I'll manually bring it down. I messed with the setting way back in the Haltech days.

The real test is tonight if I go to the shop. I'll give it a test run and see how it responds. If it works ok I may not hook up the O2 bungs just yet.
We'll see...

 

That is the EXACT problem I have. EXACTLY, to the T on the idle numbers as well.

I bought a new MAPS sensor ($142 from nissan), and hooked it up and nothing changed. On my car it idles at 1200 for about 3 minutes and then drops to 750, i can not figure it out to save my life!!

 

Without the sensor I'm currently running 1200rpm then it drops to about 1000 rpm. I gotta pull that map sensor off my moms cars to see if it goes back down to 750.

I thought the stock ECU always bumps up the rpm when the car is cold then drops to it's normal idle when it warms up?

 

that is quite a lot to bump up though.

jason

 

So here are my findings.

*First I installed the IAC hose into the intake pipe with both O2's not plugged in.
It didn't hesitate as much but the idle was @ 750. This is with the boost sensor plugged in. My needed her car back so I replaced the boost sensor back on her car.
* Over the weekend I welded to bungs for the O2 and hooked them up. The car responded beautifully. The Idle was really high @ about 1400 and back down to 1200. I think it may have to do with the boost sensor not pluged in. I lowered the throtle manually and it's down to about 900. I need to plug the boost sensor in to see if the idle lowers some.

Over all I'm glad this helped and those O2's make a huge difference.
The car feels really torquey but I'm too scared to get into boost until I get it tuned.