Herk

I just returned home with a meticulously maintained 94 rx7 after traveling 350 miles. The car has 28k miles on it and was serviced regularly at Mazda by the one and only owner. The car has some turbo boost issues that has me close to feeling sick. The owner assures me that nothing was wrong with either turbo in mid october when Mazda inspected the car prior to offering it for sale. The only work done between now and then was to replace the battery. When the accelerator is depressed and the turbo kicks in it goes into a stall and the reboots and then stalls. It happens with both turbos. I am aware of how expensive these repairs can be and will be visiting the local Mazda dealer on Monday. I need some good news here if you have it. Please avoid addressing the sellers integrity, or my lack of judgement. The car performed perfectly when not boosting. I need some advice from a knowledgeable source about what could be going on here. Thanks

bajaman

Just wanting to understand here, as your description of "reboots" sounded at first like a computer problem, then I realized you must have wanted to say "re-boosts", so what I am hearing is the car starts and idles fine, but hesitates just after the primary turbo kicks in, and then hesitates again during or after 'transition' (the time between the primary and secondary turbo sequencing), and that these 'hesitations' are very pronounced?

You will find a wealth of information here in the forum, there are thousands of topics with hundreds of thousands of replies. The SEARCH function is invaluable, just type in keywords you want to look for. There are also many, many people who love to share the knowledge they have gained via experience.

Just from what you have so far described, I am not entirely sure it is turbocharger related or not. This could also be a fuel starvation/fuel cut problem.

Can you please describe in a little more detail the problem? Does the car have a boost gauge in it? If not, that would be one of my first things to do, especially if you are having troubles. You see, if you can say, "The car boosts to 10 psi but then goes to 4 psi, then to 6 psi and then suddenly nothing." you are telling us a lot more. These cars in stock form have a known and factory set "10-8-10" boost pattern, meaning the primary boosts to 10 psi, then during transition you will see a momentary fall to 8 psi, then once the secondary turbo is up and singing you should see 10 psi again.
The factory stock ECU monitors the system and if it sees much higher boost than 10 for prolonged periods it will cut the fuel for a duration of time, until the overboost is eliminated.

So you see, the more info you can share, the more we can help.

dgeesaman

iTrader: (7)

1) Give the dealer a cap on the money you're authorizing them to spend. They are very unlikely to solve anything more than the basic problems. You need to find a rotary specialist like KD Rotary.
2) Try changing the fuel filter, plugs, and plug wires.

Where in PA are you?

DGblk93

There are a couple of good rotary shops in the Delaware Valley if you are anywhere close. Bajaman's response is right on.

I'm a bit of a newbie - but I would start checking vaccum lines Herk. The sequential turbo on this car is a complicated system. One little loose hose could cause the car to behave terribly wrong. When I bought mine, I had the same sort of boost issues. I went to this site and read up on what I can do:

http://www.autosportracetech.com/RX-7/rx7stuff.htm

Then I decided I didn't have the time or experience necessary spend on replacing all of the vaccuum lines. It was obvious that mine were old and brittle. I took it to KD Rotary (www.kdrotary.com) andthey fixed everything for a couple hundred bucks (there were a few bad solenoids as well). Car ran perfect after my visit and I was grinning ear to ear as I stomped on the gas as I left.

nickpapagiorgio

1.) Don't take it to a Mazda Dealer. The mechanics there probably know about as much about the workings of that car as you do. I suggest you search for a rotary specific shop in your area, such as KD Rotary.

2.) The problem you describe sounds like a problem called the "3k hesitation" problem. Very common in these cars. I suggest you do a search first because if that's the problem, there are a number of solutions you should try before taking it anywhere.

Good luck to you and take care of the car.

Herk

Thank you for your reply. I did mean to write boost. I must tell you up front I am not able to work on this car and must depend on others to repair it. I am located in the Pittsburgh area and am not aware of rotary shops other than Mazda dealers. The car idles perfectly and it drove beautifully for 350 miles. When i pushed the pedal too far or too fast when starting or going 65 the car appeared to begin to boost and then go into a stall and then boost again then stall. I would then back the pedal off and the car would resume running normally. I tried accelerating a few more times with the same results and then began to worry if I were causing more damage. I cannot tell you much more than that. I did pull off, checked the battery terminals and a yellow relay that the owner removed and put back while showing me how to keep the car from being stolen. Please be patient with my lack of technical knowledge or skills.
Herk

Herk

thank you for the link and vacum line tip. I am in Pittsburgh and it looks like KD rotary is out east. A couple hundred bucks is reasonable and would have me grinning as well.

Herk

thank you i will search for "3K hesitation."

Herk

Pittsburgh. Thanks.