Mattias

Hello,

Just gotted my first fault on my FD, had it for a month now.

When i push the pedal the car starts to accelerate and the boost goes up for about 10psi.
But the car just pulsates and the boost sinks down lower and lower and the more the boost sinks the better the car accelerates...
But it still pulsates, it feels like you are pumping on the gaspedal wery fast.

Anyone know wats wrong?
I have done a searh but i could not find anything!

Excuse my bad english, im from Sweden =)

Mattias

no one who knows what to look for???

sparkplugs?
fuelfilter?

I have looked for leaks but i cant find any

rx4ur7

disconnect the battery for 20to 30 seconds and push on the brake a couple of times and hook the battery back. this may not solve your prob,but it is a good start. this procedure clears the ecu of any codes. lets start here and keep me posted. if this doesnt work try to explain to me a little better what the prob is and i might be able to give you a better suggestion

Mattias

its an god idea!

i will test this as soon as i get the car together again.
I just gotted in from the garage and the car is in pieces=)

Is it safe to put on a Downpipe and not have any other mods?
the car has no mods at all now, but im thinking of putting a downpipe on it now when the precat is down on the garage floor=)

Mattias

I gotted the car together lastnight and took it for a run.
The battery has been disconnected and i have pushed the brake....

And there was no differens at all.
I also putted on a 3"custom made downpipe.

The only thing i could see was that the turbos was hot! and i meen realy hot! they glowed and about 10" of the downpipe glowed to.

Should the turbos be this hot when i just driven the car for 20minutes. i did one big acceleration up to 140-150mph and then let the car cooled down for about 5minutes and still the turbos was realy hot!
the car felt powerless and it pulsted all the way up, i realy had to push it....

The car feels like it has no power and it doesnt accelerates smooth its kind of pulsates.... hope you understand what i mean?

whats wrong whith my car??
should the turbos glowe?

Im bying a new fuelfilter today, and get new sparkplugs on wednesday.
hope that will help....

Mattias

I just gotted an idea of how I should explain the pulses,
Its just like the one when the second turbo goes in.
you fel a little hesitation.
But now its in all the rpms when you accelerate.....
and the more the boost drops the the more powerful the car feels.

Fd3BOOST

iTrader: (7)

Hummm maybe a clogged manifold?
Not really my thing.
where is ole Jimlab?
Somehelp here fellas. This is a strange one.

ThirdGenRX7

I had a clogged catalytic converter and it ran just like you describe. I don't know if you would want to do this, but what I did is got a big crow bar and beat all of the stuff out of the converter and it ran awesome.

Mattias

Did your car hessitated allover the rpms just like when the secondturbo kicked in?
and did your turbos gotted glowing hot? the engine isnt hot.

catalytic converter?? is that the big main cat?
can you explain that in a simple way?

I have removed my pre cat as written above.

Im thinking of the fuelfiler, if its clogged the car must run lean and lean=hot, lean=hesitations.

Mahjik

iTrader: (1)

I would wager it's the main cat as well.

However, if you have not had the fuel filter changed on the car, I would do that as well and change the plugs and all other fluids. Just preventive maintenance so you know where you stand with the car.

ThirdGenRX7

I'm running non sequential, but what would happen is when i would get around 10 psi the car would start to stutter like it was trying to go faster but couldn't. I never looked at the turbos to see if they were glowing, but one thing I did was drove the car for about 5 minutes and looked underneath, and my cat was smoking. That was the main cat since i have a downpipe.

CYM TKT

iTrader: (4)

https://www.rx7club.com/forum/showth...threadid=66808
maybe that will help.. dunno though

rajeevx7

iTrader: (11)

hey, bud, i know ur doing everything we suggest ot try and solve the problem..heres another one, ujpgrade all your ground wires to about 4 guage with goldplated connections. sounds like youve got the ability to take cat out, so do the crow bar thing and make sure there is a big hole for exhaust to pass, change fuel filter...you can do that yourself, and ad some injecter cleaner to your gas. i wager my dog that this will do the trick

Mattias

Thanks for your ideas!

I have just ordered new sparkplugs and fuelfilter, i will change that
and if it doesnt help ill have to check the mid cat.

keep you posted!

Mattias

Hello again.

I just changed my sparkplugs and the car runns smooth now!
No pulsation att all!

But the boost pressure isnt to good.
Just when i shift the car get full pressure 10psi and after a secound the bosst sinks to 7psi.

Shouldnt the bosst be steady 10psi up to atleast 7000rpm?

Im thinking of the mid cat, can it be so that its clogged an the exhaust cant comes out so the turbos cant hold up pressure for any long time?

jimlab

Main catalytic converter, more than likely. If it's blocked by debris from a pre-cat that disintegrated, it would behave as you describe. It would allow enough exhaust volume to flow at lower rpm so that the car ran fairly well, but would cause extreme back pressure at higher rpm, resulting in excessive heat (which you've witnessed), poor or erratic boost response (which you've also witnessed), and possibly the hesitation you describe. It sounds as though when you let off the throttle partially (and boost level drops) that the car is running better as exhaust flow drops (lower rpm).

Get your catalytic converter swapped out or replace it with a midpipe, but be forewarned that if you do, you will need to control boost level (boost controller, manual or electronic) to avoid an overboost condition without fuel modifications to cover for it. If you have to pass emissions and/or don't have the money for a fuel computer/reprogrammed ECU at the moment, I'd recommend replacing the catalytic converter with another stock unit or at least a high flow aftermarket unit. And above all, don't run the car hard again until you get this issue resolved.

Hope that helps.

jimlab

The vacuum line to the MAP sensor is a good place to start whenever you have problems that involve erratic boost response, but I believe that the excessive heat he's seeing in the turbos and downpipe are an indication of a blocked catalytic converter at the very least.

Of course, there may be more than one problem, and the poor boost response may be the result of a (momentarily) disconnected or faulty MAP sensor as well, so check that too, Mattias.