I recently purchased my car and am experiencing very poor performance when accelerating from standstill. When I step on the gas the engine moves from 800 to 1100 RPM rather quickly but takes quite a while to move from 1100 to 2000 RPM, almost three seconds. Once the 2000 RPM mark is reached, the car appears to return to normal operation. The engine's response time through the lower RPM range is so slow that I have to think twice before crossing traffic in an intersection. I tried a few 0 - 60 runs and averaged around 10 seconds, which is not what I expected at all. The car has an automatic transmission, pettit base performance package, and has recently checked out with good engine compression. Any direction on this problem would be helpful since I'm quite new to the RX-7. If the problem turns out to be too complex, I don't have a problem taking the car to the shop for servicing. I just need an idea of what kind of problem I might be facing.

 

I'd like to say, "Welcome to the Forum." Anyways, the problem could be a number of things. If your motor is bone stock, then the problem could lie within the rat's nest. Because vacuum hoses are prone to cracking and breaking. If it's not that, then it could just be a seloniod (I'm not sure if i spelled that right) problem.

 

rotaries dont have very much torque down low. when they do 0-60 mph test, they rev up pretty high.

even if you do have a auto, they torque brake it pretty high. how high did you rev before you let go of the brakes?

 

Yes, from a roll it takes a while to get the car from 1000 to 2000RPM (when the turbos start to build some boost).

 

shouldnt take 3 seconds..

although i have a 5 speed. the low end torque is teh sucks.

but she pulls like a bandit after 3k

 

whoops, disregard. Thought I was in the 2nd gen forum

 

Thanks for the welcome DrunkenBowler. All hoses have been replaced with their silicone counterparts. As for the solenoid, is there any particular solenoid whose failure can contribute to my car's condition?

RX7Wishing, it takes almost four seconds to move through the RPM range from 800 to 3000 with most of the time being spent between 1100 and 2000. After doing a few test runs, what I saw was fast movement from 800 to 1100, very slow movement from 1100 to 2000, then fast movement from 2000 upward. This doesn't make sense to me since I expected to see consistent movement through the entire lower RPM range. Is this similar to your driving experience cruiser?

skunks, I tried to torque brake it to at least 2500 before releasing the brakes but the engine will not rise above 1500 RPM with the brakes depressed. I see how this technique would work, but it simply takes my car too long to reach 1500 RPM, and then it won't move past that.

 

Replace your plugs and plug wires. Probably not your problem but you should always start with the simple stuff.

I doubt it, but you could be experiencing what is know as the "Shitty Auto FD Syndrome". Lets hope not, the only cure is strapping in a 5-speed which will run you a couple k, even if you do all the work yourself.

 

The plugs were replaced a few days ago and I'll do the wires next. Thanks for the advice.

 

this may sound stupid but are you sure its not running non-sequential??

 

spekdah, at this point nothing sounds stupid but I'm a little new to the terminology so bare with me. I assume you are referring to the sequence that the turbos spin up and engage. If you are, then they appear to be performing properly. I don't have a boost gauge installed yet, but my problem appears in the lower RPM range right before the boost. The car hardly moves from 1100 RPM to 2000 RPM then returns to normal operation. I'm sorry if I misinterpreted your question but that is the best I can make of it.

I tried a more aggressive torque brake tonight and found that I could rev the engine almost past the problem area of 2000 RPM but it exerted too much force on the brakes for too long a period and they started to slip. I think the torque brake relies on the engine reaching a higher RPM in a reasonable amount of time (probably well under 2 seconds), then the release of the brake to take off. Unfortunately my car still takes up to four seconds to move to the 2000 RPM range with the brakes applied rendering this technique useless.

Is there anyone else that can confirm the 3 second lag time between 1000 to 2000 RPM? It is quite a dissapointing feeling to step on the gas and go nowhere. If this is normal operation I would imagine many others would experience similar performance.

 

downshift? which gear are you in, in an auto fd, i found that D is just about 3rd gear i think so your not gonna get any torque in that gear, much less in a rotary hehe

also, are you holding on to the hold button?

 

get a boost guage. even if you were not generating boost it shouldnt take you that long. and i agree with the plug wire comment. i changed mine and the cars performance was like night and day.

 

skunks, I tried all three position of the transmission without the hold feature. Starting from rest in L and repeating with S and D, I observed the same problem. If the hold feature is on while in D, the transmission will start in second, shift to third, then remain there. If the hold feature is on while in S, the transmission will start in first, then shift to second and remain there. Finally, if the hold feature is on while in L, the transmission will start in first and stay there. Just to make sure the hold feature wasn't always on (there is a dash indicator that says "hold") I pressed hold then started in D. The problem was twice as bad since I was starting in second. I disengaged the hold feature, started from rest again, and verified three shifts while driving normally. So it appears that D starts in 1st gear unless hold is activated.

What bothers me about this problem is that I get enough torque from 800 - 1100 RPM, the engine shoots right through this range normally, but bogs down at 1100 RPM, just as if all the power was sucked out of it. I thought that I might be shifting to second too soon, but verifying three shifts put that idea to rest.

I will replace the plug wires, since the previous owner didn't provide maintenance records, but if they were contributing to the problem I would expect poor performance throughout the entire RPM range. Boost gauge and fuel filter are also on my list.

Thanks for all the input so far.

 

How about changing the tranny fluid?

 

does it smell rich between those rpms?

You might have answered this already but if you rev it while idling does it do the same thing while driving?

 

Ok, changing tranny fluid is on my list now. Thanks for reminding me, reza.

RX7Wishing, if I rev it while idling, it does not do the same thing while driving. It moves through the entire RPM range without a problem.
I'm not entirely sure what rich exhaust smells like, but while idling the exhaust smells like fuel. I torque braked it into the problem RPM range and the smell of fuel wasn't nearly as apparent.

I've also noticed that the car idles anywhere from 750 - 800, but will drop to 700 when in gear. Not sure if this is normal operation or if it has anything to do with the problem or not but decided to include it just in case.

 

That idle is normal. You have a very odd problem. I wonder if this is an ecu issue. If it is indeed an electrical issue you may have to take it to the dealer. Most wont agree but the dealers generally can diagnose and repair electrical problems better than the majority of the aftermarket shops.

My advice would be to take your car to a well known rx7 shop in your area and see if they have any ideas. If there are none near you, go to the dealer. Dont let them tell you, you need a new motor though. Those bastards have been know for that. What ever they tell you is wrong, post it here and let us see if thats possible. I had a boost problem and my car kept hitting the fuel cut years ago when I first got it. I took it to the dealer and they told me I needed a new motor. I took it home, got on the net, and discovered that there were other people having the same problems. Turns out it was just the vaccuum hose that runs to the wastegate act. No joke. So do be careful with the dealer but like I said, they're pretty good with the electrical stuff.

 

Plugs, plug wires first. If you still have the problem, try making a big battery ground strap out of some 4 gauge wire and terminals bought from your local wirehead shop. Some 8 gauge grounds to the intake manifold and block wouldn't hurt anything either.

If you still have the problem after all that new wire, I'd say it's probably a more complex electrical problem rather than a mechanical one.

 

Thanks for all the feedback. I'll get as much of these things done as I possibly can, starting with new wires. When I've exhausted my list of possibilities, I'll take it to the shop as a last resort. If anything sounds fishy, I'll post it here for further scrutiny.

 

The plugs and plug wires have been replaced. I also made a secondary ground to the battery, and grounded the intake manifold and block. When changing the plug wires I noticed that the trailing #2 wire wasn't plugged in (this also accounts for a flooding problem that I had at startup).

These changes managed to move the "trouble" range from 1100 to 1300 RPM, but I attribute most of this to finding the loose plug wire. So the orginal problem remains basically the same. My car is experiencing poor performance between 1300 - 2000 RPM.

I still have yet to change the fuel filter and transmission fluid.

 

Hi Damien,
I just joined this forum because I had a customer car with this same problem. You might want to take the precat off or just loosen the four bolts that hold it onto the turbo some and see how it works then. That was one of the problems with this car. Now it's back with a auto that won't shift out of second gear. Oh and the waterpump died.

 

Ok...I'll try that this weekend to see what happens. Thanks for the advice.

 

Man I know where you are coming from, my previous FD was an automatic and it was a dog off the line!!!

 

Damien -
BWAH!!!
If you still have the pre-cat, replace it with an aftermarket downpipe (dp).
This is highly recomended mod #1. A dp will significantly decrease the lifespan of the turbos.

I think what Hudson is trying to say is that your pre-cat or main-cat could be clogged.

you haven't solved this problem yet?!?!

Also, I can't friggin' believe no-one with an auto said "yes this is normal" or "no, that's friggin' skrewed up!".