Try to make a long story as short as possible with as much information as i can remember off the top of my head. I got this car, it had a simplified twin turbo set up, stock ecu, stock fuel pump, and all the rats next sort of dangling there or laying under the intake manifold. It ran and drove, it had some bucking and stuttering sometimes but nothing severe. Just enough to be annoying. So,

I drove it a total of 30 miles when i got it before i bought a single turbo set up, power FC, and aeromotive 340 pump. I took it up to the garage and threw it on the lift and got to work on the single set up. Installed everything at once, and fired it up to make sure it was installed correctly. So for the first start, it fired up, and idled good. I did not drive it as i had a bad oil feed line, and my homemade radiator hoses were leaking. It is a v mount set up. So I finish it up, go to start it and it wont start. Would only hit a little when i held the pedal to the floor. After fooling with it for a bit, i flooded it. The next day i bought new plugs and it started hard and filled the garage with smoke. Next day is ready for a drive, i fire it up, moderate smoke, nothing unusual. I let it warm up, and i take it down the road. It has a terrible buck, wont build boost, seems like its cutting off with more than 40 percent pedal. Check for vacuum leaks and what nots and cant find anything unusual. So i just park it. The next day, i go to drive it, and it cleared up a little bit. It would build about 4 pounds of boost, wasnt back firing, but it seemed to be running very rich still yet.

I go to work on it today, i check the map sensor, stock fpr, and wastegate to make sure they all have good vacuum sources. They did. I started it up, and it sounded awful. Like it was running on one rotor. I did not realize that at the time, I backed it out of the garage, and could hardly get it to pull the hill back into the garage. It would want to die. I then realized it sounded a bit weaker than normal. Still no EXCESSIVE smoke, just normal start up smoke. I threw it back on the lift and started it up, it would nearly die if i gave it over 20 percent throttle. It was backfiring, popping, shooting flames, running obviously rich.

So here is where i am stuck. I've narrowed it down to about 10000 things it could be.
It has:
New plugs
power fc that reads good on sensors, water sensor is showing temp
new battery

Narrowed it to:
Bad grounds?
Bad leading coil pack
water thermosensor
bad air intake sensor?
limp mode on power fc? lol nah
vacuum leaks
bad mechanic (me)

 

Checked out the car today again.
Pulled the plugs, checked some vacuum hoses, checked loose wires on injectors and ignition coils, all checked out. The plugs were dry.
The car fired right up first go, it was weak but it was running. It was popping and idling rough. It was definitely weak. I looked under the hood while it was running and played with some wires to see if it had any impact on the performance.
I pulled the vacuum from the map sensor and it died shortly after.
I went to start it back and it would almost hit every time, like it was firing but not enough. Just a weak fire. Who knows.

 

Um, did you tune the car for the single setup? You probably blew it up. Id do a comp check.

 

check your grounds...

 

Sounds like a shot map sensor. What voltage do you have on it on the power fc Sensor check?

Spec.

 

All sensors check out via the power fc commander. Don't know the exact voltage, i can find it out. But i checked the sensors and they were all in the relevant range.

Yes, definitely need too. I have looked online to find some. Need to check the engine grounds and ecu grounds, i relocated the battery to the trunk and my primary ground is on the driver side shock tower. Is this reasonable?

Meh, maybe. Its possible. No I didn't tune it to run a single yet, but it was doing the same thing prior just not as severe. Anyways, i am getting a compression tester this evening to check tomorrow.

 

Yeah.... its not a very good idea to go into boost with an unknown tune. Just sayin.

 

I mean, you're right. Lol its not like it was a high boost situation, wastegate is 10 pounds, didnt even get 4. I know, i am just justifying it. Anyways, i will do a compression check and then determine if thats it.

 

I do doubt that hitting a small amount of boost on the new turbo could have caused any problems. But, DEFINITELY start with a compression test, if it passes then you know to continue on your troubleshooting. Had a buddy I helped once who had been KILLING himself for months going through every system on the car trying to find why the car ran rough. I did a compression test, it had a stuck side seal and was losing compression on just one face. Motor had to come apart, but went back together even better and was money after that.

You've most likely got something fundamentally wrong going on here. Things to check after you see compression is OK -

- Make sure plug wires are good and on properly. Real easy to get them mixed up.
- Fuel pressure is good with that fuel pump - not too much or too little. Could even be something dumb like a old clogged fuel filter.
- Sensors are reading properly in the PowerFC. There are a few basic sensors that are critical to the engine running right - MAP, water temp, air temp, TPS, crank angle sensors. Had a car that ran weird once, the fuel temp and water temp sensor plugs were swapped. Don't just check the sensor check screen, go into the gauges and look at the readings.

The good thing is there are a lot of RX-7 resources in your area, if push comes to shove take advantage of them.

Dale

 

PIM voltage should be around 1.57V to 1.62V when on ACC. But since you say car is worst than it was before the install, have you ripped a vaccum line or changed where they hook up? Is the map sensor's vaccum hooked up on the right nipple on the intake/TB?

Spec.

 

I appreciate that. That's help for sure. Waiting on a second hand to run the compression check this evening or so. I was skeptical of the water temp sensors and it running right, because it was almost as if it was at a constant cold start, i.e. running way to rich because the water temp sensor was bad. Anyways, I will troubleshoot more things later on after the compression check. Thanks a ton for the input.

That voltage is where its at. I have the map sensor hooked up in the nipple on the upper intake manifold, closest to the driver side. I do know for sure, the car dies if you undo the map sensors vacuum. Which leads me to believe, it is hooked up correctly. Correct me if i am wrong though.
Thanks again.

 

It's supposed to be plugged in on the TB, firewall side. Car should still run, though really rough, but it should still run if you unplug the vaccuum line from the map. If it doesn't you might have stuck open injectors or weak spark.

Spec.

 

UPDATE:
And a good one at that,

Started the car, it sounded awful as usual. Let it get to operating temperature before I did a compression check.
Did the check, Decent numbers all across the board. Nothing detrimental. Above 90 all around on a moderately weak battery. (piston compression checker)
So this was good news to me. But still made me chase the issue.

So after that, i put the plug wires back in and let it sit for a while while i cleaned up the shop. I went to take it off the lift and i started it up, and it started fine. Sounded healthy, no miss fires. Still running rich. but was definitely running on both rotors.

So lets trouble shoot, this sounds like an ignition issue. It seems like its intermittent. Which seems like, coil or wire? Alright let me know whatcha think after this info.

 

Mine, did same thing, but it would back fire at 3900 rpm and would not go into boost.
changed the coils, spark plugs and wires, cleaned grounds( i have a bunch of grounds). I know a spark plug wire was arching and i know i had one bad trailing coil. For some reason i had to reakust the duel presure, cause it went down like 5 psi. Good luck..

 

What kind of plug wires do you have and how old are they? If not sure, I would get some new wires. The NGK wires fit awesome, work great, and are DIRT cheap, $25.


If that vendor doesn't have them, search NGK ZE30, that's the wires. Color coded, fit right, and last forever.

Dale

 

Gonna order these now. Going out of town for three weeks so that is kind of annoying. Plug wires may be the culprit since apparently it is intermittent. I am not sure of age but for 25 bucks it doesnt hurt to buy them.

 

Sounds like you inverted the wires...

Spec.

 

Back to it. So i got back into town and went to start the car. It started right up, but had a slight miss. Just like a stutter in the first bit of rpm range, after 1/4 throttle it revs fine. Well, i put new coils, plugs, and wires, and it started and still had the same stutter under 1/4 throttle. I let the Power FC self learn idle so the idle bounce quit and it would idle at 800 rpms or so. but when you hit the gas pedal, it stumbles for a second then revs. I figured the ignition system was the issue but who knows.

 

I just went through this. Mine was a bad coil. But then the other reason was leaky secondary injector.

 

what were the leaky injector symptoms

 

What about a bad TPS sensor??

 

If you heat the engine up and shut it off, you can use the powerfc to check the voltages from the TPS and make sure it's in spec. There are two reading to check, and you want to check them when off the throttle, at part throttle, and full throttle I just did this a few days ago myself on my fresh rebuild. It took me a week to get the PowerFC to idle correctly.

I'm no expert on FDs and I'm not a professional mechanic, but I'm also in Knoxville if you need any help. You might look at getting your car tuned at Addicted Performance in Maryville too when you're ready. They deal with a lot of FDs out there and should know how to handle it.

 

It may be worth checking the coil packs just to be certain they are good. There is a simple test in the shop manual that you can do with a multimeter, I've found that test to be spot on.

Dale

 

Update, issue solved for now.. Changed fuel filter and put another new set of plugs in. Also fixed a boost leak... my bad., so boosting fully and not surging at low rpms. Unsure of if the plugs solved it or the filter. Combo of both i guess.