3800rpm hesitation ONLY at half throttle?...
 

as the thread name says, i have the 3800rpm hesitation ONLY at partial throttle....

i'd say when i'm about 30%-60% on the throttle it'll hesitate, sometimes really badly, and it's not only odd but annoying....

anyone have any idea's?...

As you know, the secondarys won't come online unless they see Load at approx 3500-3800 rpm, so that gives me the idea that you've possibly a problem with the boost/pressure sensor.........perhaps.

In case you forgot, in the series four FSM (I know you have a series five), there is a checkout where you disconnect the vacuum hose from the pressure sensor on the n/a and then rev the engine to approx 3500 rpm and above. Once you reach that rpm you listen for the secondary injectors to be clicking, verifying the secondarys came online.

So, if the boost/pressure sensor has it's plug/vacuum hose connected, then take a look and see if the output of the sensor is reaching the ECU...or Not.

I don't see it being an injector problem since the secondarys should not have been opening under light throttle.

i have an S4 keg in my S5, dont know if that helps or not....

i get this weird shuddering sensation when i get off the throttle, i watch my AF guage blip back and forth 2 or 3 times and i can hear my blow off valve almost futtering as if i was on and off the gas quickly....

any idea if it's mabe a TPS problem?...

I have the same problem. No hesitation at low throttle, no hesitation at wot, only at partial throttle around the staging rpm, near 0 psi.

ecu grounded, lim ground cleaned, driver's strut ground cleaned, battery ground cleaned (relocated to pass bin), no tps spikes

its got me stumped, ill try the boost line thing hailers mentioned

edit: its an 88 TII, rtek 2.0

you should let me know what you find or when you find something to cure your problem....

:(

ok i just did some rtek logging, revving in neutral with the boost sensor tube unplugged. (capped the boost nipple on the intake manifold)

boost reads exactly 0 psi, and it will rev fine up to the staging rpm (set to 3k). After that, the 2ndaries turn on, the wideband goes crazy, showing AFR in the 18s, and wont rev any higher without giving a lot of throttle. the log shows when the 2ndaries are on, it has a really high AFR, like in the 16 to 18's, until after 3800, then it starts dropping down to 13's.

??

what does that mean exactly?...

i have no idea, hence the ?? lol I was hoping hailers would know

i have +15% correction at boost>0psi at all rpm on the rtek, so if anything it should be running rich

Did you already found the cause? Got the same problem on my S5 T2..

At part throttle it just lean out, and when apllying a bit more or less throttle its's gone, also above 4000 rpm it's gone, airpump is removed, but that shouldn't be the cause because first it ran fine and then it just happened..

I had a similar problem and it turns out that running lower ohm resistors made it go away. This is on an 88 T2 with 720 secondarys. I used 6 ohm, but you could go as low as 3 ohm.

https://www.rx7club.com/showthread.p...=ohm+resistors

dammit someone haxored my account sorry about my last post lol didnt notice that until now

anyway im still getting the same problem, but the 10ohm to 6ohm injector resistors helped. also, if you have a way to control staging rpm, if it is set lower than stock, it will make the hesitation worse too