ive searched but i couldn't find much info so heres my problem.

just recently installed my boost gauge and checked my boost pattern and i get 8-6-8 in 3rd gear, when i do it on 2nd gear i get about 8-5-8. just replaced a hose ( ABV to y pipe hose) hoping it would solve the problem but i still have the boost problem.

also when i change gears i hear a little swooosh sound coming from the engine compartment but i dont hear any leaks while i boost.

anyone have experience with a loss of 2 psi? could it be an exhaust leak, bad pills, actuator precontrol/wastegate, rods out of specs? would any of these cause a 2 psi loss?


next thing ill try to do is the KOKO test, check valves and switch the ABV, any other ideas of what i should check? what could be causing the loss of 2 psi?


thanks in advance


already have a silicone hose job, brand new solenoids (less than 2 years)

stock fd, 82,000 miles with a rebuilt engine less than 8k (vacuum 17-18)

 

Do you still have the stock precat or did you replace that with a downpipe?

 

stock fd , stock everything (including precat)

just got the car less than a month ago

 

I would carefully check the wastegate actuator hose from your primary turbo first before you look at anything else. It sounds like your car has enough mileage on it to where the hose gets old, expands, and leaks too much pressure past the pill, causing your lower primary and secondary boost.

Hope that helps.

 

I suspect that your boost gauge may be the problem. Some gauges do not read accurately. I suggest that you hook up another gauge, and confirm that you have a problem.

Don't try to fix something that may not be broken

 

And for the love of god, get a downpipe on there!

 

thanks for the answers, yea rynberg i just got this fd less than a month ago and i was about to order a downpipe but this problem came up and i want to fix it before i put the dp.

adam_c i will try to use another boost gauge, i happen to have another one laying around.

also i forgot to add on my post that in one of my test runs, 2nd gear boosted really slow. it went like this 1 2 3 4 5 6 7 8 with no transition. it didnt instantly raise to 8, it went slow like 1 second in between each psi, i didnt feel much pull, only engine reving to about 5500 rpm

this only happened once, i did 5 more runs on 2nd gear after this and it never happened again.

 

I was going to say this also..

what kind of boost gauge and does it read 0 when everything is off!

 

^ speaking of that i have a VDO gauge that has ALWAYS read like a 1/2 psi below zero when the car is off?? Seems that when it starts my vaccuum reads perfect, my wot in neutral always will hit 4psi, and when im driving and im at those throttle posistions of no vacuum and no boost it will read 0 on the dot.

basically my question is, is my guage off, or is it possible for it to read a tad off when off and then zero up when the car is started.

 

Well, to me, this is really sounding like a problem with both the turbo pre-control line (which also has a pill in it) and the wastegate actuator line. The pre-control door is venting most of the boost, and because you're not building to 8 psi on the primary turbo quickly enough, there's no transition. The fact that it built up progressively makes me think that the lines are old, and they're expanding/contracting at varying rates. I'd check both of those hoses (turbo pre-control and wastegate actuator) very carefully.

 

Yes Get a Downpipe ASAP!!!

My boost pattern used to be 5-0-0. That equals Primary only boosted 5 PSI, and no secondary anywhere to be found.

I installed a downpipe and threw away my precat and all was well 10-8-10 boost pattern. Thanks in part to my AVC-R My boost pattern is now 10-9.5-10, 95% linear like the non-sequentials but they are sequential.

Hope this helps.

 

ill try replacing the pre-control line and the wastegate actuator line, could someone help me with the part number of these? i cant seem to find it on mazdatrix or other sites. also do the new lines come with the pills? or is that a different part i have to order

i have a spare 93 turbo could i use these lines on my 94 fd?

thanks for the help kento

 

Those lines are just silicon vaccum hose. Take the pills out of your old lines. You can order some quality stuff from any one of the aftermarket sites (like mazdatrix). You only need a little for those areas and you want it now you can go to Pep Boys. I was in a bind one time and got some there. They sell a kit of silicon vacuum line (just like you need) that has various sizes in like 10 foot lengths. It'll be like $20.00 but you'll have a lot extra if you need it.

I asked about the pre-cat because one of the worst things it does when it's clogged is back a TON of heat back into your engine bay AND it will affect the way your turbos boost. If you replace it and do nothing else, you will not jepordize the engine as long as you keep the boost at stock levels. I would replace the precat as a way to try and solve the boost problem first. It needs to be done anyway. If you still have issues after that - then go hunting for the next thing that could go wrong.

go here:
http://fd3s.net/boost_problems.html

Or here (better):

http://www.autosportracetech.com/RX-7/rx7stuff.htm

Good luck.

Dave

 

heres a little update

i just switched boost gauges(had autometer sports compact II in before, using a defi d boost gauge now).

the only other thing i did is changed the ABV with a spare i had, went out on a run and my boost is now at around 9.5-7.5-9.5

constantly hits 9+ on primary but never reaches fully 10

ill be going out on a run later today with the old ABV just to be sure that it was that, and not a faulty boost gauge

btw whenever i shift gears i still hear a swooooosh sound, any ideas? i remember reading that it could be an exhaust leak but im not sure, it doesnt happen while i boost.

 

that swoosh is likely your blow off valves if it only occurs when you shift (results from letting off the throttle and is normal). Your boost pattern seems normal now but if I were you I would install a downpipe.

 

double post

 

Sounds like you got a bad boost gauge. If you just bought it, I would send it back, and get a refund. VDO makes quality guages at a price you can afford. The gauge on the top of the link is the one I have. It's only $30, and works very nicely. I suggest that you call the 800 number. If you decide to get one, have them send you an orange bulb cover. This will make the lighting match your stock gauges perfectly.

http://www.egauges.com/vdo_mult.asp?...s=Vision&Cart=

 

Is your ABV routed into the airbox? Are the clamps on your airbox broken or loose? That could explain the swooosh.

9.5-7.5-9.5 is a 10-8-10 for all intents and purposes. Your gauge might be off a little bit, but .5 psi is nothing to worry about.

Yes, the lines from a 93 turbo should have pills also. Just make sure you don't switch the ones for the precontrol and wastegate. Keep in mind too that your 94 *might* be one of the units with the restriction built into the nipples on that tree that inserts into the compressor housing.

Dave

 

You said nipples.

 

Vacuum hoses suck on nipples.