Boost issue

[93_jdm_fd]

While driving in 5th just cruising at 120km/h i always noticed like a slight hesitation while just cruising along. I figured it was normal because my boost gauge shows just slightly in boost(just about the zero).

Anyway yesterday on my usual cruise to work on the highway at 120km/h some dude was on my ass so I decide to step on it and it went to 0.5 bar at about 140km/h and that was it. I let off and tried it again and it started bucking and popping and only went to 0.5 bar.

I took the next exit feeling like and idiot and just driving down the street boosting in 3rd it would only go to 0.5 bar. So today I warmed the car up and went into the industrial park by my place and did some tests. In all gears I could get full boost or just under 0.7 on my stock boost gauge with the restrictors removed. I left the industrial park and went to another place where I could get up highway speeds to try full out in 5th. It started doing the bucking and popping again under full throttle and only went to 0.5 bar, then in all gears it would only get to 0.5 bar or whatever half is on the stock boost gauge.

New plugs, newer coils, could be actuators sticking open after my first few good pulls prior to the straight away test?

[bobbo]

Popping as in backfiring? Could be a hung waste gate. I checked mine last year by hooking the vacuum line up to compressed air (turned Waaay down). It takes only the slightest pressure to move them.

[93_jdm_fd]

Well now that my car is finally running the way it should I can focus on other issues. This seems worse now that my car is breathing right. Anyway the actuators were my first place to check but of coarse everything is locked up at work until tuesday. It is like a popping backfiring and i do have a few extra actuators to try out. It's getting there and I have a week left now before it's loaded onto a train and shipped to Edmonton.

[Dragon Humper]

Train? SeaRail?..........Eeeep.


If you have a PowerFC, set the rev limit to 3500 and pull the commander out. If not, pull the plugs of the coils and the injectors of the two cyl that are about equally apart according to the firing order (I don't recall off-hand). That way the car will get around under its own power but will sound terrible and the yard monkeys will think there is something wrong with it and leave it alone. I have heard waaaay too many horror stories about those butt pirates bagging the crap out of hot cars.

You could try re-soldering and cleaning your mafs to fix that boost issue.



Jon.

[93_jdm_fd]

Well my wife does pretty much everything for my as far as bills and taking care of this whole move, lol. I guess it's being shipped through Livingston Freight. That's who we used to get my rx7 here from Edmonton last year and they were great. I've heard the storied of SeaRail as well.

I did clean the Maf's with crc cleaner a few months back and re-soldered both already. I think it's going to be a jammed up actuator but still weird that it boosts great for a little while and then drive normal and go hard at it again and it only boost to half on my stock boost gauge and the same when I have the aftermarket one hooked up. I get board with cars when they run normal anyway, so this car has always given me something to do, everynight,day, weekend and even on vacation, lol.

[93_jdm_fd]

Another thing I was wondering is about removing the boost restrictor(s). Mine has already been removed and some people say you get like 1 bar when removed. I can only get to about 12psi or just under the +7 on my stock boost gauge and the same on my aftermarket one.

I noticed after the 3rd time having my intake manifold off that there is another vacuum line with a yellow band around it and a restrictor in it. I have a spare parts bin with all kinds of rb26 hard lines and found the same thing with another set of vacuum lines. There is one for the boost solenoid and also one farther down the intake manifold, right beside the big vacuum line for the AAC valve.

It T's right into the hard lines for the boost solenoid and runs around the back of the head to the actuators. Maybe if I remove this other one I will get the almost 1 bar like everyone else. I still have to fix my boost problem first but was just wondering about this extra one that doesn't seem to be mentioned anywhere.

[93_jdm_fd]

So today I got to test my actuators and they both seem to open at 8 or so psi. I even swapped out all the vacuum lines thinking one was broken or plugged but they were fairly new. Anyway the problem is still there.

If I cruise in 3rd, step on it and boost to like half, let off and slowly step into it again it bogs and pops then starts to go again. Is this normal? I didn't get a chance to take it out on the highway yet to really test it out.

[MattiasJacobs]

Bov?.

[93_jdm_fd]

I have both stock ones, but they could be sticking or one of them really? It's a weird one for sure. Just cruising on the highway in 5th when it's slightly in boost it feels like it's chugging, like on and off or what a shitty warped flywheel would feel like with a new clutch disc, that kinda feeling while cruising at 120km/h with the boost gauge reading just above the zero.

[bobbo]

That sounds like a misfire.

[93_jdm_fd]

It could be a misfire but only under boost? It boost great then I let off and it's almost like something stuck open/closed because when I go to give it gas again it bogs and then starts to pick up speed and will start boosting. I was hoping to get this straightened out before the car is shipped out because I won't have a place right away to work on it. I think I'm going to be work at a Porsche dealer and probably won't be sliding this car is for some "tuning" while on my lunch breaks, lol.

[92GTSTproject]

you have an a/m dump pipe? my waste gate was getting stuck on mine and causing the same issue

[93_jdm_fd]

Both stock but I'm gonna pull them apart today and test them.

[bobbo]

It boost great then I let off and it's almost like something stuck open/closed because when I go to give it gas again it bogs and then starts to pick up speed and will start boosting.

If that's the case then probably not. It would always misfire when you squeeze into it if it were an ignition problem.

I think I'm going to be work at a Porsche dealer and probably won't be sliding this car is for some "tuning" while on my lunch breaks, lol.

Yea most Starbucks cruisers don't like when a sub $20k, 20 year old, Japanese car can spank their $100k German sports car

[Skym]

I let off and tried it again and it started bucking and popping and only went to 0.5 bar.

Boost cut. The popping, etc is the ECU hitting the load / boost cut rev limiter (fuel cut) or basically MAF maxing out. It can reach boost / load cut earlier if have airleak between airfilters, MAF's (common problem if have airfilters that clamp onto adaptor plates, which the adaptor plates bolt onto MAF's), as makes MAF max out with voltage thus hits boost / load cut on ECU. If have Consult or access to Nistune tuning software + Consult cable, laptop, should notice MAF voltage maxing out on digital MAF voltage gauge.

Also don't remove boost restrictor in hose, as it helps stock boost control solenoid control boost level properly. Buy Nistune and raise boost level properly via ECU. Or fit aftermarket boost controller.