Turbo issues
 

So I have an 87 rx7 and it was my grandpa's track car before I got it. The car has a HKS aftermarket turbo system on it as well as it is tuned by DP racing and when it is running well it is a beast. And here is where things go wrong. My friend who is supposedly ASE certified was helping me clean up the engine bay and we didn't really know what we were doing so we cut wires where we didn't know where they went. After that night of chaos the car didn't start... so after that my dad and I decided that we should call a more reliable mechanic to work on the car. He came over and got the car running and starting. So after that I took it out for a run to see how it was doing. That night I figured out that during the night of chaos we did way more damage than we thought so when I put my foot down there was a strong lack of power no matter which gear I was in. As well as the car having a lack of power the car would "blubber" all the time and I'm not sure what is causing this. Does anybody know what is causing the car to "blubber" or is causing the lack of power? So I brought it back home and said to my dad we need to have the mechanic come back over because it wasn't running well at all and I wasn't sure what the cause was. At first we thought it might be a ignition problem so we replaced the spark plugs and wires and that did not seem to do anything. After that the mechanic said it could be the boost controller so we jumpered two of the vacuum lines together to in theory take the controller out of the equation. Sadly jumpering the controller didn't seem to do anything and it seemed to make the issue worse. When I took it out with the lines jumpered the car would die any time I pushed the clutch in. So now what he has said is the current issue is that it is related to a wastegate actuator failure. I have called around to see if I can find a part number for the part to order it and they said they don't know if HKS makes the part anymore. Here is the email I sent the HKS support team

Dear HKS support team,


I have gotten my grandfather's 87 rx7 and it has an aftermarket HKS turbo system on it. I have been having a mobile mechanic come over to diagnose some of the issues and he has recently said that the current issue we have been having is directly related to the wastegate actuator. I cannot find a part number in the paperwork that I have acquired or on the part itself. I have called around to some authorized dealers and they said that they didn't know if HKS made the part anymore. Help! Do you make the part anymore and what is the part number so I can order it? The documentation I have for the car, I have the installation manual for the integral wastegate / EVC system. It has the part number for the kit but it does not have the part number for the part that I am looking for. If you need more information please let me know but this is all I have currently.

Does anybody know where I can find a part number for this and order it? Or does anybody have any other ideas to how to get my car running great again.

Thanks,
Dillon.

Should probably go through the full service manual wiring diagrams to ensure you have all the necessary connections.

should also post pictures of the items in question or even a video of how it’s running.

should test the wastegate with a vacuum pump to ensure the wastegate bellophragm is in good condition. I had an external hks wastegate with a torn bellophragm and I sourced a replacement bellophragm from hks years ago.

Dr Knight,

I have been in contact with HKS directly and I cannot get them to help me find a product number. So now I am trying to find parts online. And one of my next posts will be a video of the car running to see if that helps diagnose some of the issues.

Thanks again,
Dillon.

a picture of the Wastegate would be helpful. they have a couple/few different ones depending on the size and when it was made.

Did you um, reconnect the wires that you "cut"(my lord) because... you didn't know where they went? I think you actually said you cut them because you didn't know what you were doing. LOL. I hope the answer is yes. You know, those are the two best reasons NOT to cut wires.

Rotary Alkymist,
I did have a mechanic come over and reconnect the wires that we cut. He went through a few different iterations and we have decided recently that the issue is the wastegate. Here are a few videos of the car how its running currently. We repalced the spark plugs and wires a couple of months ago hoping that would help but it did not. It is still running extrtemly rich. Hope this helps!
https://cimg4.ibsrv.net/gimg/www.rx7...49244561bc.jpg
Here is the photo of the wastegate in the car as it sits.

Judging by the sound of the car running 3 things come to mind.

Firstly, I would want to be certain there are no vacuum leaks. So I would inspect intake system and vacuum lines for leaks.

You MUST be certain that you have no vacuum leaks to proceed.

Now, once you are CERTAIN that you have no vacuum leaks, only then would I now inpect the throttle positioning sensor(TPS) and throttle body settings.

Are you running a stock ECU?

Edit: Post results of step one and ECU info and then we can dig deeper.

Rotary Alkymist,

As far as I know, the ECU is stock. The modifications to the car that I am sure of is that it has an HKS exhaust and turbo system as well as a tune by DP racing. Last night I checked the vacuum pump's lines and it had two lines mixed up so I put them back to where they were meant to go. I started the car and the switch of the lines seemed to help with how it was idling. But when I took the car out around the block it still had the "burble" when I would accelerate. It also kept stalling when I would push the clutch in and take my foot off the gas. I believe why it kept stalling was because it was flooding itself with fuel. I appreciate all the help and this weekend I will go and pick up a vacuum tester and test the vacuum system. Once I have tested the vacuum system I will report back and we can go from there.

Thanks Again,
IslandFC

Alright so I did the testing and here's what I found. Out of the 4 lines that I tested with the vacuum tester, 3 of them went to the control valve, and the only two vacuum lines that had any vacuum were a mysterious line coming to a mysterious part ( a picture is attached ). The other one was the vacuum line coming from the intake manifold to the EVC control valve. The line that was bringing pressurized air from the cold side of the turbo to the control valve had no vacuum even though it was showing the turbo had vacuum on the gauge for the turbo in the cabin. The line going from the control valve to the wastegate actuator had no vacuum either. Anyone got any ideas for the next steps?

Thanks again,
IslandFC
https://cimg0.ibsrv.net/gimg/www.rx7...d2d337191c.jpg
https://cimg3.ibsrv.net/gimg/www.rx7...f599b3c6a7.jpg
https://cimg6.ibsrv.net/gimg/www.rx7...b608687de5.jpg

Hi there, I've been away for a bit.

Try this:

1. Locate G/R wire on TPS(throttle positioning sensor)
2. Start up and warm up car(operating temperature)
3.Backprobe with a paperclip and test the voltage with meter set to lowest setting.
4. Record your voltage measurement.

Post results.

Two things I see that may help:

1. That "mystery part" in your picture is the MAP sensor. One of the wires appears to have been repaired with a crimp, so you should inspect it to make sure it is okay. Try putting a multi-meter on the connector spade and another in the back of the crimp. Should be zero or nearly zero resistance.

2. Your MAF is sideways. These MAFs use a flapper door to measure airflow, and in the stock car they are horizontal with that black plate facing up and the ribbed side down. Yours is on it's side, so the weight of the door can impact the MAF reading.

Good eye. This could be verified if you pull the codes.

Although it wouldn't cause the surge but it would fix your signal at 760mmHG and would shoot a code 13.