petros_rx7

I have post again with that problem but now I have more info about.
First of all my car start very easy even if I have to drive 1 week.
The pressure gauge show me 0,8bar with 5 gear and 140km with gaz pedal to floor.
With 3 gear I see maximum 0,6bar
with 2 gear maximun 0,4bar
with 1 gear 0,2-0,3 bar

My car didnt have any cat and it have custom made exhaust from the engine to the end.

I have add ground points to my car.

The problem is that my rx7 didnt run smooth some times even with 1 gear I can not spin !!!!!!!!!!!!!!!!!!!!! with 2 gear is very hard and with 3 gear runs like a fast car with 100 horse power.
Also if I press the gaz pedal to floor with 2 gear for example they do a stumble for a long time and didnt increase rpm.
I have make a compression test and I have 7,8 -8 both rotors.
That mean that engine is in good if I have low compession theshape otherwise car didnt start so easy.
I have change spark plugs , air filter with k&n , and fuel filter.

What go wrong with my car ?What you suggest me to check or replace?It can be the twins turbo?Engine harnness?ECU?Injectors?

Thank you for helping me.

recon fd

I honestly have no idea.

Can anyone help him? I am interested in learning what is causing this! Someone help our FD brother from Greece.

thanks,
-josh

JONSKI

Do you have an automatic transmission?

petros_rx7

Thanks recon
I have read all the fd3s and all the f section of service manual and I can not understand.
I think that maybe is silicon valve problem but i am not sure and is very painfull to check all this valves because I have to dissasembly all the hoses.
So before I try this I wait for some opinions.

petros_rx7

No I have manual transmition from factor no conversion

tiger18

iTrader: (1)

when you driving fast in 2 gear,, and gas pedal pressed all the way down,,,, can you hear any air leak (maybe turbo air leak)

tiger18

iTrader: (1)

PETROS,,, ive just thought of something else,,,,if you are running the standard ECU,, have you tried getting the ECU to do a self diagnostic to see if there are any sensor problems.

dgeesaman

iTrader: (7)

The FSM doesn't do anything to explain the turbo system - it only shows some basic tests for some of the components. It also lacks any organized troubleshooting procedure.

This website provides that missing info: http://www.autosportracetech.com/RX-7/rx7stuff.htm but it truly is complex. Even this site takes plenty of studying to begin to understand.

I agree - usually it's a check valve, loose or damaged vacuum line, or a bad solenoid. Most of the lines are not immediately visible, but IMO the turbo control lines are the most accessible.

You have some options:
1) do a 'hose job', and replace the rubber hoses with silicone hoses, and replace all the solenoids, too. (expensive, but very thorough)
2) do a hose job, and test the solenoids and replace only the ones that don't work. (tedious, requires a vacuum pump, but also thorough).
3) attempt to find the exact source of the problem to fix it with the least cost. (cheap, but can be tedious)
4) find a shop that can solve/fix it for you. It seems there are enough FDs in Greece that you might find such a shop. (most expensive)

If you have patience and don't mind taking some time to find the problem, 3) makes the most sense. We can try to solve it here step by step. The first thing to do is get a second boost gauge (or vacuum pump with a gauge built into it), and temporarily install it so that you can observe the pressure in the important vacuum lines. You will need some spare 4mm vacuum hose and a "T" fitting.

My guess is that you are losing vacuum or pressure, and new check valves will fix it. Or there is a leak, and this will help you find it. Let us know what you intend to do.

Dave

rynberg

You have boost creep coupled with a boost leak, which is why you are boosting higher in the higher gears. Once you've isolated and fixed your leak, your boost in 4th and 5th will likely be out of control.

DaveW

If that were the case, wouldn't he be able to go more than 140 KPH (from his initial post) in 5th?

Bad_Karma7

Something doesn't make sense to me. If he gets his boost reading at the UIM, then boost is getting to engine (even if it's irratic). Why is his power down? Would it make sense that his problem is after the UIM? Maybe a bad gasket? Maybe clutch is gone? He has no cats, so it's not an exhaust restriction.

petros_rx7

If you have patience and don't mind taking some time to find the problem, 3) makes the most sense. We can try to solve it here step by step. The first thing to do is get a second boost gauge (or vacuum pump with a gauge built into it), and temporarily install it so that you can observe the pressure in the important vacuum lines. You will need some spare 4mm vacuum hose and a "T" fitting.

My guess is that you are losing vacuum or pressure, and new check valves will fix it. Or there is a leak, and this will help you find it. Let us know what you intend to do.

Dave

Today I found a shop in Greece who have check valves not the same but do exactly the same work in very low price so i replace first of all this check valves.
That mean that i take off only manifold if I guess right so it is easy to do this.
If that didnt work then I have to check solenoid valves and replace the hoses (( I afraid to take off all this stuff from my car.

Now for the first job I have a question while you look the manifold from the front bumper I see 2 check valves with green and white body ,and one different and I dont mean the pcv valve i mean this who is connected to manifold and to solenoid valve (purge control)
What is the difference why this valve have different body ? The service manual check this valve with the same way who check green and white.Can I replace it with green and white type?
Also for the second step what cost have brand new solenoid valve?
Here in Greece there only 2 service center who can fix correct rx7 and is many km from me so I have to do it alone.

Bad karma:

Something doesn't make sense to me. If he gets his boost reading at the UIM, then boost is getting to engine (even if it's irratic). Why is his power down? Would it make sense that his problem is after the UIM? Maybe a bad gasket? Maybe clutch is gone? He has no cats, so it's not an exhaust restriction.

This I can not understand too?!?!

dgeesaman

iTrader: (7)

There are only 2 check valves that affect the turbo function: both come as black/green from the factory. Sometimes they look brown and black because of the oil inside them. You can see the black/green ones on this diagram: http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

Yours may not be black/green, but they will be in the positions shown on the diagram. You do not need to remove the UIM to access them, only remove the pressure chamber. The other ones are for emissions purposes and do not affect boost. The replacements that you can buy at the shop will probably work fine and will be very cheap. Try that first, and look for broken or leaking hoses while you are replacing them.

Solenoids cost about $60US to buy from Mazda. Most solenoids are interchangeable, so I also buy used solenoids and use my vacuum pump (a Mityvac 4050) to test them, which costs me less than $10/each, and they will work just fine. I think for now it is best to try the check valves, then troubleshoot more if that does not fix it.

Dave

Force13B

iTrader: (19)

Your car is not hissing abnormally loud under aceleration is it?

dgeesaman

iTrader: (7)

If he's consistently getting 0.8bar in 5th gear, but not the other gears, I would expect it is not a boost leak.

Dave

petros_rx7

My car change the sound become more loud when I press the pedal to floor but I think that this is normal.

In the diagram I am planing to change the check vlave in blue,red,green,yellow,lines.
Also in line with mustard color, that one with catch tank, the check valve is differend from others can I replace them with same type like others?
I replace all because it is cheap and after that I know that this valves are new so I can go further.

dgeesaman

iTrader: (7)

No, leave the metal check valve in the purge control circuit alone. I would change the valves only that are colored black/green and white/green in the diagram.

Dave

trini

iTrader: (2)

if its not a boost leak?? can it b that the ecu isnt senceing any LOAD in teh lower gears, therefore not providing the right fuel/ignition timing??? just my 2 cents

EFS.O

Probably a bad solenoid or a check valve.Eipa na se boithisw,alla esy ekei theleis na pedeuesai me tis wres.....

HINT.You can check all the solenoids without removing a single bolt from the UIM....

dgeesaman

iTrader: (7)

If you have a boost leak, you have it before the MAP sensor and throttle body. So there should never be a tuning/ignition problem as a result of a boost problem - it will read the lower boost and inject fuel accordingly.

The reason why I feel it's probably not a boost leak is because he reported 0.8bar in 5th gear - if this is true, then there is no leak. A leak would not care what gear the car is in - the boost would be the same in all gears.

The point that the boost is lower in lower gears suggests a check valve problem, which is best if you simply replace them as step 1. It's quite possibly a solenoid problem, but if he can get check valves easily IMO it's best to eliminate that first.

Dave

DMoneyRX-7

iTrader: (2)

Pull out your crossover pipe and poor water in it and see if some comes out. Their is where one of the major boost leaks come from. My car was having some issues and i had alot of boost leaks. Turns out my secondary turbo wasnt kicking in for some reason. Maybe you have a sequential solenoid issue or turbo actuator issue keeping the main exhaust flapper from opening and directing exhaust to the rear turbo at transition. Anyway im getting this fixed now and waiting for a dp and pfc to come in to finish it all up.

EFS.O

Locate the harness connector that goes to the ECU according to the pic.Remove from ECU,and ground each pin(key on).Have someone to the engine bay listening for a clicking sound each time you ground a pin.

dgeesaman

iTrader: (7)

That's not a very effective test. It's better to wait until the solenoids are removed from the car, so you can test them with pneumatic load on them.

petros_rx7

With that test you can test and harness if it is ok.
Ofcourse the best test is to remove the valves and check it with pressure but for the first step I think that is good method.

DMoneyRX-7

iTrader: (2)

I had the same problem like i said and am getting it fixed. Once i get the car back ill tell you all that the mechanic did.