At almost every time the RPM's in my jspec turbo go up to 5500 the car makes a brrrrraraaapp sound and seems to freeze up. Literally throwing me forwards. I know it's running rich but it's not like it's dying, more like something got stuck and the sound is coming very loudly with the exhaust note. Due to leaking exhaust (fixed soon I hope).

I had a problem with my old engine getting too much gas and it seemed to just get bogged down. This thing is literally killing my forward momentum!

Any ideas?

btw the fuel smell went away from turning when we replaced the engine, wierd.

 

sounds like your TPS could be out of adjustment...

 

Do you have a A/F mixture gauge? If so Does it lean out when you drive normally? What mods does the car have? I had the same problem with my first 7.

ps: sounds like fuel cut

 

do you have a boost gauge?

its probably fuel cut.

 

Yes I have a boost gauge, it boosts up 6 to 7 PSI max and we adjusted the TPS when we got the car running initially but we didn't fine tune it.

The engine's modifications are no rats nest, no ACV valve or split air pipe, cone air filter, JDM straight pipe downpipe, O2 sensor's plugged in but I don't know if it's reading.

Fuel plumbing is all custom routed professionally.

And the engine is a jspec 13BT with 100+ compression on the rotors.

 

sounds like fuel cut. buy a fcd.

 

does sound alot like fuel cut to me, try slowly accelerating past 5500, and see if it does it

 

im on the fuel cut boat. s4 boosting 6-7psi? definitely fuel cut.

kevin.

 

I went up and down the freeway today to test the fuel cut theory.

I hadn't noticed it but my engine hits 9 lbs. of boost at about 5500 rpm's and then the car goes brraaaraap..

I read that the ECU cuts fuel at 9 psi of boost and it does it only at 5500 when I'm at near or WOT and the boost gets up there and then blaarg. I accelerated slowly and it never happened.

I'm with you guys, fuel cut... Anyone got a spare FCD laying around?

Thanks for your help guys!

-Landon

 

 

I'll take my spare FCD to the meeting, and let your take it around the block to see if thats your problem. PM me.

 

The fuel cut may be what's keeping your engine alive at the moment. It is there for a reason. I hope you have enough fuel to cope with the extra boost you'll get once the FCD is in place...

 

yes if your getting boost creep then you need to have your waste gate ported, and or get suporting fuel mods to run that high of boost

 

I'm going to a 720cc secondary injector set up. Think I would have a problem? Wastegate porting is not something I can afford to do soon.

 

Just port it yourself. Many writeups in the forum on how to and it isnt to hard.

 

If you have exhaust and intake mods (and you obviously do), then yes.

It doesn't have to be expensive, but it's way cheaper than slapping on a FCD and popping the motor...

Here's mine: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/serious-s4-wastegate-porting%85-343788/ (the missing pics are reposted part way through)

 

Do all turbo's unbolt like that? My wastegate is set down into the side like that but it's behind part of the turbo exhaust housing.. The downpipe connects to the turbo with a circular connection. Not that wierd shaped one. Is that custom?

 

usually that means the turbo has been upgraded i think

 

Man... That does sound like your car needs more fuel... Keep your foot under controll untill you find out more... You don't wanna break any factory apex seals in there...

 

okay I've been doing some research to avoid killing my new found boost levels. Tell me if this will solve my problem..

Rtek 1.7 with 720cc secondary injectors without porting the wastegate?

Unless the car boosts over 12 then I guess I'd have to port the wastegate anyway I can.

I've been searching and found plenty of information on 1.7 but what do you guys think?

 

Forgot to mention I'd be keeping stock S5 T2 fuel pump.. Probably will add FD pump or walbro after a month or two.

 

Yep.

That's what it says... The stock backplate has been removed and replaced with a custom divided downpipe.

Depending on your intake and exhaust mods it probably will.

Don't wait, do it before adding the FCD.

 

Man you are in some serious trouble if you don't do things in a certain order...

1. ported wastegate
2. FCD
3. intake/exhaust/etc.
4. SAFC or similar fuel programming device
5. 720cc secondaries and pump upgrade
6. ECU upgrade
7. FMIC
8. boost controller
9. standalone EMS

How far you progress down the list depends on how much power you intend to make, but just remember don't do #3 without having #'s 1 and 2 done first... And ALWAYS in that order...