Darivative

My friend has a 94 rex and his second turbo kicks on for a sec then you here a loud sound and the car won't rev over 6100 rpm constantly. Could this be the wastegate flapper is open or a wastegate gasket? He gets boost until this problem occurs. Could it be the worst and the turbos are blown?

Thanks

Darivative

^ Help

Darivative

Is anybody familiar with what I'm asking?
Any assitance is appreciated...

rpm_pwr

So hang on - the turbo's work fine but it won't rev past 6100 rpm? That's not a vacuum hose that's fuel / ignition. Dunno about the loud sound though, maybe you've sucked up a cat?

-pete

Darivative

Yeah he had the vacuum hoses done recently but everytime I bring the car to mva something else goes wrong. The car gets from the 1st and second turbo but it sounds like he's hitting the rev limiter and no boost after 6,100 rpm.

Thanks for the feedback

Bucrx7

Does the car rev to redline without any boost?

redrotorR1

Sounds like a fuel cut. It may be the fuel filter or the fuel pump. It could also be if the car is overboosting ... the stock ECU has a defencer that will induce a fuel cut if the boost is too high. What does your boost pattern look like? How much boost are you seeing? Or better yet, what else was done when the vacuum hoses were replaced?

Edit: Actually, now that I remember having a similar problem, it was the plugs and wires. I also had a timing issue. I also replaced the fuel filter at that timeframe. The timing issue was a problem with the dashpot and the idle screw ... that is, the guy who worked on this car previously didn't know what he was doing.

Dragueur

it happens to me someitmes too......i have to shift(mainly in 1st gear) then its good again.......boost spike!

Darivative

Well the car won't rev past 6,100 period, it seems like that's the rev limiter. The car has 2 fuel pumps so I don't know if it's the pumps. I will change the wires and fuel filter and see what happens. My shop says it has something to do with the wastegate so they want to remove the turbos to see. They think the turbos are blown but the car is getting boost from both so I don't know.

Thanks

redrotorR1

A few things I would check before you bring the car in:

1) What's the boost off the primary? If it's getting 10psi (or pretty close to it), then I doubt that the primary turbo is the problem.

2) Then, what's the boost at transition and at 5K rpm? If it dips way low at transition (like 4 psi), it might be the secondary turbo having problems pre-spooling. But, if you're still getting 10 psi at 5K rpm, then I dunno what to tell you.

3) Check to see if you get any smoke out of your tailpipe and/or in the engine bay around the turbo assembly. White smoke that smells like burning oil is a good indication that your turbos have failed. In case you didn't already know, check around all the intake hoses in the engine bay ... any smoke coming from there would also indicate this.

4) Are you getting a funky idle? Kinda high around 1000 rpm? It could be a number of things, if this is the case. Luckily, they're all pretty cheap to fix. Replace the MAP sensor and pull the dashpot. You need a jig to do that; but it should seat and unseat without much effort. If you have to pry it out, them somebody crammed it on wrong. From there, also make sure your idle screw isn't cranked all the way down. Both of these things are signs that some idiot couldn't fix the idle properly to begin with.

Definitely replace all the plugs and wires, first. That's going to be the quickest and easiest diagnostic. The fuel filter ... might be, but if you're only getting the fuel cut at 6100 rpm, then it's probably not the root cause. Good luck.

Darivative

The car gets anywhere from 6-8 psi when the second turbo turns on til 6,100 rpm then it cuts off. It has a midpipe and the car has been smoking alot lately. Also there is a foul fuel smell coming from the exhaust. I will do the minor stuff to the car and hopefully it's nothing major...

Thank you for the replies!

redrotorR1

I think your shop is feeding you some crap. The wastegate only knows two positions, open or close. It doesn't sense RPM and it won't open until all the pressure behind the restrictor pill bleeds off. Since you are seeing boost and it appears that both your primary and secondary are working, I highly doubt you have a wastegate problem. My advice, once your stumped, take it to someone who knows RX-7's.

Darivative

Yeah i was a little iffy about the wastegate being the problem. I will do some of the little stuff now and hopefully that will repair the problem if not I will be forced to take it to a shop!

Thanks