Had my car tuned on Monday. Dyno runs went to 19psi and he set boost cut at 20psi. I didn't have a boost controller so he used his. We took it out on the street for a test drive BUT he had removed the boost controller so it was on 10psi. Ran fine with no issues. It was also like 90 degrees that day. So I buy a mbc from a friend, hook it up and this is where I'm at now. Weather is cooler but I'm not sure how big of a difference that makes. Plugs are set at .022 Is what I'm getting boost cut or something different? If I back the mbc off 1psi the car holds 15psi and runs flawlessly. One turn more and this is the result. I don't think it's boost cut since it's only running 15 and going up 1psi causes this. Unless my map reading to gauge reading is almost 5psi off.
Tuner is 2hrs away so I'm trying to avoid having to go back up there again if at all possible. Thanks for your help H-T

Video 1 - I'm NOT letting off the gas. This is what it does if I turn my mbc up 1psi.

Video 2 - I'm not letting off gas watching wideband to check for a lean condition and that's when I noticed the tach which leads me to think coil or igniter.

Video 3 - Backed off 1psi and it runs fine holding the same amount of boost. 'sorry about the video I had to shift lol'

http://www.youtube.com/watch?v=ePag3...68AUAAAAAAAAAA

http://www.youtube.com/watch?v=s5T55...27AUAAAAAAABAA

http://www.youtube.com/watch?v=u2rlK...68AUAAAAAAAAAA

 

was your gauge shwing 19psi when you were at the shop?

 

Honestly I don't know since he was in the car. I tend to stay out of their way when they are tuning. Nobody want's someone being up in their business following them around. I'm going by the computer screen I was looking at. Showed 19 falling to 16 but he was using the og turbo xs controller which is know to fall off a few psi.

 

the video code you used is HTML, you need BBC

 

^^

You can get the link from the source code.. But its dumbass ****in facebook and the video is secured.

OP: ditch the MBC and buy the PWR or whatever type the tuner used.

 

Tuner used a turbo xs mbc the original one without the bleed off ****. The one known for falling off a few psi. Thus why it dropeed to 16 from 19. I'm using a buschur racing mbc which is about one of the best ones on the market. It doesn't leak off holds boost dead on. Been tested up to 40psi.

 

Move your boost gauge vacuum source to another location, T it off of the huge line that goes to the brake booster, I bet your gauge is way off and your hitting boost cut.....if you move it and the press. reading changes then thats what it is.....it could be that your gauge is not 100% calibrated, and/or the vacuum source your using, but your probably hitting the 20 psi boost cut.

 

I'm experiencing the same issue and I've used 2 different boost sources. First was nipple on compressor housing and the second is T'd off the back of the manifold along with my boost gauge and bov. I have another boost gauge I can try.

 

Just went and swapped boost gauge out for my spare same thing. Actually about 1-2psi lower.

 

Hmmmm only way to know is to do some data logging and see what boost pressure the ecu is seeing when this happens, are you set up to do data logging? If not you should do so.

 

I'm just on Neptune EPROM so no I can't data log anything. When we did our street test which was on Wg pressure he said his laptop was saying 10psi and that's what my boost gauge said. I think I'll just have to make a trip back up there.

 

Taking to tuner is probably your best option for sure man.

 

kinda sounds like boost cut... your gauge is likely off a bit.

 

that is exactly what my car did when the boost blew out the spark. what kind of ignition are u using.

 

Stock ignition with plugs gapped at .022
I'll check the cap and rotor tomorrow. I have a spare coil also.

 

a replacement of my coil with an oem one fixed it on the dyno but i think its still weak. the seals around the cap suck andd let moisture in, might wanna try some rtv in there, i just received my cdi ignition which will be far superior. mine was blowing out at 10 psi though and the coil looked like it had been sitting in salt water.

 

Stock ignition should be good enough for my power level. I've seen people make it and more with stock setup. I'll test my 2 coils and use the best one. I think I even have a spare cap too.

 

yes i have been told that too and have also seen ppl make lots with stock but the honda dizzys are definatley problematic. just spitballin here cuz when my car did it, thats the exact same symptom i had and if i turned it down a touch it was ok.

 

I just checked the cap and rotor. Sanded them a bit with some 600 grit. Noticed my rotor didn't have the screw in it. Got excited hoping that may of been it but it wasn't. I just got back from a test drive. I didn't swap out coils yet. I need to borrow an ohm meter to see if mine is bad or if the spare is any better. I'll just leave it turned down for now till I can get back to the tuner.

 

Looks like an autometer boost gauge but i could be wrong, Ive delt with many autometer gauges and for whatever reason ive never found any of them to be accurate reguardless of boost source. Can you hook up to you neptune or do you have a chip and not rtp ???

Im willing to bet your hitting your deired boost level and that 1psi more is boost cut. One car i tuned a few years back was reading 12 psi and car felt slow. I went into the logs and found it was only getting 8 psi. Autometer ftl

 

Yes, it is an autometer boost gauge. I'm just on the neptune eprom not rtp. I guess I could set my compressor at 19psi and pressurize the vacuum line feeding the boost gauge and see what it's reading. One way to see if it's accurate.