Intermittent miss up to 2k and idle when warm NA-T

[Travis89Turbo]

Hey guys. Having a small issue with my Na-T on my 70k miles 2jzge I am running the 4 runner cap on stock dist. To clear turbo. Although still touching intake pipe. Car idles and runs amazing until it gets a little below mid operating temp then it starts to stumble on idle goin to almost 16 on afr. And I loose vac. Down to about 10. Sometimes if I shut it off and start back up it goes away until I warm it up again. It stumbles and hesitates up to about 2k rpm. Never had this problem before the NA-t I haven't really boosted until I get this sorted New cap, New 2j rotor new wires. Will be pulling plugs today. Gone through all connections. No vac leaks, have sprayed everyone. Help me I'm stumped. I have inspected the Bov, and wastegate diaphragms which are in good shape.


Edit..... Car is 95 Supra SE. 70k miles. Stock HG, stock fuel system. New o2 sensors. There is no Check engine light or codes.

Update. I took it for a ride at lunch. This time it started missing and stumbling before even 1/4 to temp. I have no idea what is goin on. I did find that my O2 sensor plug was melted but it is and was still making contact. Any ideas at all. Also I sprayed again every vac Lin and intercooler line with starting fluid including the throttle body. No leaks found at all. I'm lost. Please help

Pretty sure this problem is with my Ignition system. I did have to order a set of spark plug wires so i could run the 4runner cap, i needed #2 wire in the #1 spot for length. While it was idling yesterday i pushed on the plug wire at the dist. and BOOM shocked the hell out of me. I changed it to another one from the "new" kit and it seems to be running better but still intermitenttly will miss and stumble but not near as much. Does any one have ideas??

Okay. Its not the ignition system. I built some MSD wires for it another new cap and rotor from Toyota this time problem with missing got worse and afr are even leaner now. So I went to the fuel system, I unhooked the vac line off the fuel regulator and capped it and it smoothed out a bit but still in the 15s instead of 16.5 on the afr. It also does not take long at all for this to start happening so the problem is getting worse So I am ordering a fuel pump. :crazy2

[pwpanas]

Apologies for the delayed response...and thank you for posting your question.

To begin with, please note that I'm much more familiar with the 2jz-gte...so you may take my advice with a grain of salt.

Here goes:

Originally Posted by Travis89Turbo

Hey guys. Having a small issue with my Na-T on my 70k miles 2jzge I am running the 4 runner cap on stock dist. To clear turbo. Although still touching intake pipe...

Just offhand, this doesn't seem like a great idea. Is there any way you could re-route the intake pipe to completely clear the distributor? Also, is the 4 runner cap a standard solution for an na-T Mkiv?

Originally Posted by Travis89Turbo

...Car idles and runs amazing until it gets a little below mid operating temp then it starts to stumble on idle goin to almost 16 on afr. And I loose vac. Down to about 10. Sometimes if I shut it off and start back up it goes away until I warm it up again. It stumbles and hesitates up to about 2k rpm. Never had this problem before the NA-t I haven't really boosted until I get this sorted New cap, New 2j rotor new wires. Will be pulling plugs today. Gone through all connections. No vac leaks, have sprayed everyone. Help me I'm stumped. I have inspected the Bov, and wastegate diaphragms which are in good shape.

Edit..... Car is 95 Supra SE. 70k miles. Stock HG, stock fuel system. New o2 sensors. There is no Check engine light or codes.

Update. I took it for a ride at lunch. This time it started missing and stumbling before even 1/4 to temp. I have no idea what is goin on. I did find that my O2 sensor plug was melted but it is and was still making contact. Any ideas at all. Also I sprayed again every vac Lin and intercooler line with starting fluid including the throttle body. No leaks found at all. I'm lost. Please help

Pretty sure this problem is with my Ignition system. I did have to order a set of spark plug wires so i could run the 4runner cap, i needed #2 wire in the #1 spot for length. While it was idling yesterday i pushed on the plug wire at the dist. and BOOM shocked the hell out of me. I changed it to another one from the "new" kit and it seems to be running better but still intermitenttly will miss and stumble but not near as much. Does any one have ideas??

Okay. Its not the ignition system. I built some MSD wires for it another new cap and rotor from Toyota this time problem with missing got worse and afr are even leaner now. So I went to the fuel system, I unhooked the vac line off the fuel regulator and capped it and it smoothed out a bit but still in the 15s instead of 16.5 on the afr. It also does not take long at all for this to start happening so the problem is getting worse So I am ordering a fuel pump. :crazy2

Is your Supra an Mkiv? If not, this question may be in the wrong section...

What spark plugs are you using? How long have the spark plugs been installed?

Fwiw, I don't think it's the fuel pump. You should check the fuel pressure before replacing the fuel pump. If anything, replace the fuel *filter* first.

That's it off the top of my head, for starters. Please let me know your thoughts about these suggestions, and any updates you have for us.

Take care,
Phil

[Travis89Turbo]

Originally Posted by pwpanas

Apologies for the delayed response...and thank you for posting your question.

To begin with, please note that I'm much more familiar with the 2jz-gte...so you may take my advice with a grain of salt.

Here goes:
Just offhand, this doesn't seem like a great idea. Is there any way you could re-route the intake pipe to completely clear the distributor? Also, is the 4 runner cap a standard solution for an na-T Mkiv?
Is your Supra an Mkiv? If not, this question may be in the wrong section...

What spark plugs are you using? How long have the spark plugs been installed?

Fwiw, I don't think it's the fuel pump. You should check the fuel pressure before replacing the fuel pump. If anything, replace the fuel *filter* first.

That's it off the top of my head, for starters. Please let me know your thoughts about these suggestions, and any updates you have for us.

Take care,
Phil

Yes my car is a 95 mk4 SE na. I have not yet updated my signature.

Spark plugs (Bosch copper super plus 7956 gap at .028) were changed when I built the new MSD spark plug wires. Old ones were in great shape but did show a lean condition due to this problem. Also when I changed to the new plugs I bought another 4runner cap this one from 91 as the 92 had the lock tabs for the factory supra wires and the new wires are the slip on style like the 91 4 runner which match the ends of the 8.5mm low resistance MSD wires..

Both yrs of The 4 runner cap are very successful and idely used solution to clear a the turbo intake. I got the idea from Club Na-T FAQ. The only other solution is to run a 7m cps and COP which requires intense more amount of modification.


Also note that after I replaced the Cap for the second time with new proper working spark plug wires my AFR went even leaner. Almost maxing out my AEM Uego.

Fuel filter has been replaced 5k miles ago.

I have also considered the thought of maybe a bad batch of fuel.
.
.

Update--- Installed fuel pump and no change.

What are your thoughts on pullin the turbo and manifold off plugging the oil feed and drain putting na header back on and then trying to trouble shoot. A lot of time I kno but am sick of dumping money and getting nowhere.

[pwpanas]

I agree with your plan to temporarily put it back to n/a to troubleshoot.

As a test, could you remove the turbo intake and put the oem distributor cap back on? As long as you don't run the car in a dust storm and you don't have frozen chickens falling from the sky nearby, running the turbo wide open to atmosphere isn't all that risky.

Lastly, have you *pressurized* the intake yet? You do n/a vacuum testing with spray (or smoke), but pressurizing the intake (with an air compressor, for example) is what's needed for a turbocharged intake system. It should be able to hold about 50psi cold. Clamp your air hose adapter in there tight or it will turn into a cannon. (amhik)

[Travis89Turbo]

Well after driving the car today I finally got a check engine light- Code 26= running rich. So Im leanin towards possibly a fuel regulator. Checking the fuel pressure on the GE is hell due to all the egr and related parts being above the feed line. I looked around for another port before the regulator but see nowhere else to go other then the banjo on the fuel sender but that is far from accurate.

I bypassed the turbo system and hooked up the afm directly to the intake mani with all vac lines hooked up. Fired it up, but still idled badly so I went back to find a vac line from the Bov still un capped. Oops! Then my great friend of mine without asking me unhooked my battery clearing the code so the cel went out. Not what I wanted to do. I wanted to see if the light would go out on its own.

Anyways, fired it up and it running rich right now with the cel cleared.

Afrs now at idle are 13.0-13.8 and at 1500 rpm no load afrs go to 11.8-12.5. And runs smooth no hesitation at all. But I'm sure as soon as I went down the road it would start droppin off lean again.

Any ideas greatly appreciated! The current set up jerry rig intake I made does not allow me to close the hood at all so I'm working on another setup to drive with. But those afr do not sound right to me.

I pulled the 4 runner cap off today to look at the spark trace on the cap poles, everything looked good. I am lookin in to getting a fuel pressure gauge if that checks out I will be doin a compression test aswell as leak down test. Really hoping there is a fuel problem thou!

[pwpanas]

Originally Posted by Travis89Turbo

Well after driving the car today I finally got a check engine light- Code 26= running rich. So Im leanin towards possibly a fuel regulator. Checking the fuel pressure on the GE is hell due to all the egr and related parts being above the feed line. I looked around for another port before the regulator but see nowhere else to go other then the banjo on the fuel sender but that is far from accurate.
...

What about an inline T sensor adapater right after the fuel filter? That's where we splice in on the MKIV TT...

Originally Posted by Travis89Turbo

...I bypassed the turbo system and hooked up the afm directly to the intake mani with all vac lines hooked up. Fired it up, but still idled badly so I went back to find a vac line from the Bov still un capped....

Speaking of BOV do you have the output of the BOV routed to atmosphere or is it routed back into the intake system? If the main BOV itself is leaking, that could explain your rich condition (since the air ejected through the BOV has already been metered by the MAF)...

Originally Posted by Travis89Turbo

...
Oops! Then my great friend of mine without asking me unhooked my battery clearing the code so the cel went out. Not what I wanted to do. I wanted to see if the light would go out on its own.

Anyways, fired it up and it running rich right now with the cel cleared.

Afrs now at idle are 13.0-13.8 and at 1500 rpm no load afrs go to 11.8-12.5. And runs smooth no hesitation at all. But I'm sure as soon as I went down the road it would start droppin off lean again.

Any ideas greatly appreciated! The current set up jerry rig intake I made does not allow me to close the hood at all so I'm working on another setup to drive with. But those afr do not sound right to me.
...

Agreed.

Originally Posted by Travis89Turbo

...I pulled the 4 runner cap off today to look at the spark trace on the cap poles, everything looked good. I am lookin in to getting a fuel pressure gauge if that checks out I will be doin a compression test aswell as leak down test. Really hoping there is a fuel problem thou!

Are you still planning to replace the oem distributor cap, just as a test?

Also, a short run with no hood shouldn't be too big of an issue, right?

[Travis89Turbo]

Update!

I bought a new Mac tools pro fuel pressure test kit and it had a banjo bolt adapter that I hooked into the top of the fuel filter...

Results- with Vac line disconnected and plugged 51psi. Factory spec 38-44

With vac line hooked up 42psi. Factory spec 28-34

1500 rpm 55psi with vac line hooked up. That is out of factory specs so I will be replacing it.

I apologize for not adding the info about the stock distr cap. I reinstalled the original with no change. Although I did have to change plug wires back to OEM as well. So I put the 4 runner stuff back on and doubled checked that the timing is at 10btdc.

Is it possible that the added pressure from boost could damage the factory fuel regulator?? Should I stick with OEM or go to an aftermarket in your opinion.

My BOV is an HKS SSQ that I bought a recirculation nipple for so it has been blowing back into the intake post MAF, pre turbo!

[pwpanas]

Originally Posted by Travis89Turbo

Update!

I bought a new Mac tools pro fuel pressure test kit and it had a banjo bolt adapter that I hooked into the top of the fuel filter...

Results- with Vac line disconnected and plugged 51psi. Factory spec 38-44

With vac line hooked up 42psi. Factory spec 28-34

1500 rpm 55psi with vac line hooked up. That is out of factory specs so I will be replacing it.

I apologize for not adding the info about the stock distr cap. I reinstalled the original with no change. Although I did have to change plug wires back to OEM as well. So I put the 4 runner stuff back on and doubled checked that the timing is at 10btdc.

Is it possible that the added pressure from boost could damage the factory fuel regulator?? Should I stick with OEM or go to an aftermarket in your opinion.

My BOV is an HKS SSQ that I bought a recirculation nipple for so it has been blowing back into the intake post MAF, pre turbo!

Regarding the FPR, I'd try with one from an Mkiv TT if it's a different part number and if it fits. You could even try a used one (yours is the first I've heard of one that has problems). Just a thought - do you think your fuel return line could be blocked/kinked/crimped in any way - that would raise fuel pressure regardless of how well your FPR works. You could always go to an aftermarket FPR (a lot more expensive, especially after the adapters, braided hose, etc.) if a different oem fpr doesn't do the trick.

To bad you don't have a fuel controller (eg. A'PEXi AFC) - you could just dial down the fuel at idle based on the higher fuel pressure, then the additional fuel would be available under boost. Capiche?

[Travis89Turbo]

Originally Posted by pwpanas

I hope you don't mind me tooting my own horn a bit, but I did suggest you should check the fuel pressure before replacing the fuel pump.

Regarding the FPR, I'd try with one from an Mkiv TT if it's a different part number and if it fits. You could even try a used one (yours is the first I've heard of one that has problems). Just a thought - do you think your fuel return line could be blocked/kinked/crimped in any way - that would raise fuel pressure regardless of how well your FPR works. You could always go to an aftermarket FPR (a lot more expensive, especially after the adapters, braided hose, etc.) if a different oem fpr doesn't do the trick.

To bad you don't have a fuel controller (eg. A'PEXi AFC) - you could just dial down the fuel at idle based on the higher fuel pressure, then the additional fuel would be available under boost. Capiche?

I actually have a friend sellin a AEM ems v2 for the ge for $1000 with COP setup and a gm 3 bar map. I've been consodering but I have spent a lot of money this year! Buying a 32ft boat didn't help either.

Like you I have never had a regulator go out on me and the Walbro 255 is cheap insurance. Not to mention was way cheaper then the fuel press. Kit I bought!

I was just lookin into the gte regulators from what I have read they are interchangeable. I will be ordering one in the next few minutes. Thanks for your help Phil!

I'll keep ya posted if this resolves my issue for good!

[Travis89Turbo]

Okay. I installed an aftermarket Aeromotive regulator with steel braided lines set within factory specs.

All seemed great yesterday afrs were where the should be around 14.7 so I parked it and then while driving to work this morning guess what came back! The lope in the idle.

Agghh. The CEL did come back on and I will be checking that at lunch time and will update that info. I have no idea what's goin on.


Is it possible my headgasket is seeping? Although I am not missing fluid.



I put some new fuel in it with some injector cleaner so time will tell of that helps at all.