mikey13b

Hi guys, my series 8 makes full boost on both turbos perfectly, but I have an issue where if I'm WOT on full boost and then I let my foot off the throttle for a split second (eg loss of traction) and then put my foot back down to WOT again, I completely lose all boost. Is this likely a solenoid problem, and if so which would be the culprit?
Thanks

boostin13b

Are you saying it won't build boost again after getting back on the throttle? If so then yes it could be solenoid along with a bunch of other issues with the sequential control system. Do some testing to see if this is only during secondary operation or with both turbos just by letting off the throttle and getting back on when the primary and secondary.

Redbul

iTrader: (26)

What do you mean by WOT?

When an FD floods, deflooding procedure includes putting the accelerator to the floor * and cranking.

* This supposedly cuts of the fuel flow.

I don't know if that would be the case when the car is actually running.

In any event, time to "run codes" (if you still have stock ecu).

Redbul

iTrader: (26)

Running codes is easy.

Redbul

iTrader: (26)

Perhaps check your TPS. I wonder if it might be sticking

Likewise the ISC valve.

Likewise any of the blow off valves.

gdub29e

iTrader: (16)

It’s probably a sticking turbo control solenoid. They’ve been known to act like that. Give this thread a read.

https://www.rx7club.com/3rd-generati...ctive-1120259/


Being a series 8 with the black box, you will have to replace the whole assembly or split the box and replace just that solenoid. There’s a few write ups on how to do that here. You’ll have to search a little bit to find how others did it.


~ GW

Redbul

iTrader: (26)

https://www.rx7club.com/3rd-generati...c-box-1162514/

mikey13b

Yes correct, it wont build any boost when i get straight back onto the throttle after lifting it off for a split second.

mikey13b

Wide Open Throttle. There is no flooding

mikey13b

Im running an Adaptronic

mikey13b

Thanks that thread does sound very similar to what im experiencing, so it looks sticky solenoid is probably it. Yep ive replaced my charge control solenoid in the black box before so ill be ok with that. There are 2 turbo control solenoids, one in the black box and one connected to the acv, do you think both need changing or is just one the likely culprit?

gdub29e

iTrader: (16)

I’ve actually never tinkered with the S8 black box and did not realize the solenoid mounted on the acv was not relocated into the assembly. The us cars got the rats nest of spaghetti.

In my experience it was the one in the rats nest labeled “E” in the vac diagrams here >
https://www.rx7club.com/3rd-generati...2/#post8113663


Solenoid “E” works in tandem with the vacuum one mounted on the acv. I wish there was a rhyme or reason to why some work and why others stick. Some have said it’s due to running higher boost than they were designed to ( factory 10 psi ) others with completely stock cars have suffered from it. My personal opinion is that it was a short cut for the designers to just convert the vacuum solenoid design over to be used with pressure rather then redesign something new, specific for that circuit. I feel as if it lacks the correct internal spring pressure required to overcome the force applied, but I digress.

Also, just to note. Adaptronic has made a name for itself with high failure rate. Just keep an eye out as support for that ecu is discontinued.

~ GW

mikey13b

I just read through the link you posted again and it seems like it's just the pressure side turbo control solenoid that has the issue. Im running 18psi so that probably doesn't help. I think I'll just attempt to do his TCA check valve mod, it looks pretty basic and should improve the system and fix it at the same time by the sounds of it, plus saves me having to go in and open up the black box. Win win
Btw my adaptronic has been great, I've had it since it first got released (its the 2nd version) and cant fault it apart from a lose wideband connection which they soldered up and hasnt been an issue since, but thanks for the heads up, I hadnt heard any bad reports before.

Redbul

iTrader: (26)

Yes there remain a few solenoids outside the black box.

The green twin solenoid on the UIM comes to mind.

If it is still there perhaps swap in a spare from a friend.

Don't break the nipples.