Miata Turbo Forum - Boost cars, acquire cats.

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-   -   Bucking at full throttle? what do I do (https://www.miataturbo.net/prefabbed-turbo-kits-3/bucking-full-throttle-what-do-i-do-4409/)

olderguy 08-24-2006 10:09 AM

Do you have any other items added that you haven't told us about? Emanage? Bipes? WI? anything that would cut your ignition in error?

chowser2 08-25-2006 07:34 PM

is the gap suposed to be .35 or .28

chowser2 08-25-2006 07:35 PM

no other items

yes the vortech is connected properly
yes I had a mechanice change the timing too

olderguy 08-25-2006 08:09 PM

Can you take a picture of the whole installation and post it? Maybe we will see something.

chowser2 08-25-2006 08:16 PM

yeah I'll try asap

And i want to thank everybody for taking the time to help me out

chowser2 08-25-2006 09:51 PM

are the gap in my plugs suposed to be .35 or .28

Pop VII 08-25-2006 10:37 PM


Originally Posted by chowser2 (Post 41685)
are the gap in my plugs suposed to be .35 or .28

Suggest starting at .035, and if you like to tinker gradually keep enlarging in small increments. The stock gapping is .044, but that may be too wide for the spark to arc thru the higher pressure during boost.

olderguy 08-25-2006 11:00 PM

I will be away from the computer for the next day, but what I wanted to look for in the pictures was any hose on the intake side of the turbo that might be collapsing and cutting off the airflow, then opening, and closing again.

mightymiata91 08-26-2006 04:48 PM

Its that stupid fuel pressure regulator that comes with the kit, same thing happend to me. you have the fuel lines mixed up. Rev2Red wrote this to me when I posted the same question on miata.net. He said "Go over the FMU and make sure the lines are correct. It should be tapped into the return line. So the line comming off the far end of the fuel rail (firewall) should be going into the offset fitting on the FMU. Then the center fitting should be going back the the hard line." and bam!!! my car was hauling ass!

lazzer408 08-28-2006 02:44 AM

I was just wondering if his problem was ever figured out. I have a drop in power at 4100 that comes back on about 4800 but thats a totally different issue but just for curiosity sake I'm wondering if it's related. I run my gaps at .028

-LAZ

olderguy 08-28-2006 08:48 AM


Originally Posted by lazzer408 (Post 41921)
I was just wondering if his problem was ever figured out. I have a drop in power at 4100 that comes back on about 4800 but thats a totally different issue but just for curiosity sake I'm wondering if it's related. I run my gaps at .028

-LAZ

At about 4000 RPM, you are probably going to open loop on the ECU. If you are not running an O2 clamp, you probably have pretty high fuel pressure at that point when the ECU moves from trying to maintain Stoich with the oxygen sensor to a preprogrammed map. This extra fuel can cause a lack of power until your engine brings the AFR up as the RPM's (and fuel requirement) increases.

lazzer408 08-30-2006 02:21 AM


Originally Posted by olderguy (Post 41930)
At about 4000 RPM, you are probably going to open loop on the ECU. If you are not running an O2 clamp, you probably have pretty high fuel pressure at that point when the ECU moves from trying to maintain Stoich with the oxygen sensor to a preprogrammed map. This extra fuel can cause a lack of power until your engine brings the AFR up as the RPM's (and fuel requirement) increases.

I'm boosting 6psi by about 3000 and the air/fuel meter is sweeping away. At 4000 it drops off the scale red till about 4500-5000 then it goes into green and the power comes back. Between 4000 and 4500/5000 I'm running on borrowed time. :sadwavey: bye bye pistons if I can't sove this. Explain the egr clamp? What exactly is that? I'll have the AEM EMS in about a month but untill then is there a "quick fix" that might help?

-LAZ

lazzer408 08-30-2006 02:22 AM

EGR? wtf am I thinking. o2 clamp.
sorry.

-LAZ

olderguy 08-30-2006 08:11 AM

An O2 clamp sends a phoney lean signal to the ECU as you enter boost so that the ECU tries to add more fuel to compensate for it. It only operates until the ECU goes to open loop, then it has no effect.

olderguy 08-30-2006 08:13 AM


Originally Posted by lazzer408 (Post 42232)
I'm boosting 6psi by about 3000 and the air/fuel meter is sweeping away. At 4000 it drops off the scale red till about 4500-5000 then it goes into green and the power comes back. Between 4000 and 4500/5000 I'm running on borrowed time. :sadwavey: bye bye pistons if I can't sove this. Explain the egr clamp? What exactly is that? I'll have the AEM EMS in about a month but untill then is there a "quick fix" that might help?

-LAZ

What pump are you running? Sounds more like a lack of fuel being available there.

Braineack 08-30-2006 08:33 AM


Originally Posted by mightymiata91 (Post 41729)
Its that stupid fuel pressure regulator that comes with the kit, same thing happend to me. you have the fuel lines mixed up. Rev2Red wrote this to me when I posted the same question on miata.net. He said "Go over the FMU and make sure the lines are correct. It should be tapped into the return line. So the line comming off the far end of the fuel rail (firewall) should be going into the offset fitting on the FMU. Then the center fitting should be going back the the hard line." and bam!!! my car was hauling ass!

you and like ten others were having the same problem and it seemed to help. (btw I'm Rev2Red over there)

I'd like to know if chowder fixed the problem....:confused:

Pop VII 08-30-2006 11:24 PM


Originally Posted by lazzer408 (Post 41921)
.... I run my gaps at .028 ....

That could be your problem right there if you already checked your fueling as suggested. That stubby short spark may not be long enough for complete or consistant combustion.

lazzer408 08-31-2006 12:04 PM

I don't think it would be the plugs. Incomplete combustion should read rich on the gauge then wouldn't it? But it's easy enough to try. What gap is suggested? Just to verify... The fuel into the regulator is on the side and the outlet (return) is on the bottom? I think I tried it both ways with no noticable change. Read: "same problem" My fuel pump is OEM and dead-head pressure is about 80-85 psi depending if the car is running or not. Ironiclly it's higher while running. I would think the pressure would be a bit lower being that the engine is using fuel but it could be due to the voltage being higher while running.


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