I have 87 rx7 non turbo. the car drives fine untill i get it at 4,000rpm then it bucks, acts like its not getting gas, so i changed the fuel filter and its still doing the same thing, and i also changed the plugs but nothing helpd any suggestions would be great. Also i was wondering if i removed the cat and put a glass pack there instead if that would be ok for my car as my new exhuast doesnt sound any better then my original one, i just dont kno if i remove the cat if itll mess up the motor as im new to these cars and dont wanna do anything to kill my car. thanks for the help

 

the hesitation is from the secondary injectors failing to come on at 3800rpms. it's actually very common (my car does it as well) . most of the time it's a grounding problem where the engine isn't grounded to the body well enough i believe. as for the glasspack, rotary exhaust is supposed to be a lot hotter than regular piston engines which can melt most glasspacks, so i've heard. hope i answered your questions. and if that wasn't clear enough you could always search, just type in something like 3800 hesitation.
peace

 

thank you very much, ill check the grounds and ill see if i can get new injectors( the parts stores where i live dont carry nothing but pklugs for my car =( ) i wonder if i just put a pipe there if that would b ok instead of the glasspack i just dont want to loose power or mess anything up by taking the cat off, thanks alot bro for the help

 

i'd check the grounds before you even think about buying new injectors, they can be quite expensive. and a "test pipe" instead of a cat will be much better than a glass pack.
you're very welcome.
peace

 

omg injectors are alot , ok looking for any problems with the grounds, ok now i have to find a test pipe , thanks again bro

 

I had a hesitation close to yours. It ended up being the ground under the intake manifold. As for your exhaust, I have a test pipe off of a stock exhaust manifold running to the drivers side with one cheap $80 Pilot muffler. Most mufflers that are made will blow out because of the heat. The muffler I got sounds good, but didnt cost me a lot and if it blows out and sounds like **** one day I wont feel bad about spendin such littler cash. I hope this helps!

 

kk ill have to look there for that ground, where did you get ur test pipe from? also how many injectors do these cars have i only see 2 .? thanks bro

 

I dont mean to thread jack but i have the same hesitation that cannot blow an apex seal could it?? I mean as long as the rotor is still getting oil it should be ok untill i get it fixed right?

 

Yeah I only thought there were two until I found that there are 4 of them you will have to take off the UIM ( upper intake manifold ) to get to them . the computer ground is under there to but its toward the driver side of the engine . I just spent a bunch of money on new injectors cuz the old ones were crud . Took me a while to get them all to seal up though . I would get the primarys on put the engine back together and they would leak so have to do it all again . I found that the trick may be put the injectors in the engine hole's first with the hookups attached then put the fuel rail down on top of them when I did this they sealed just fine . As for the hesitation yeah the whole reason I did all that was because of the hesitation I regrounded everything under the hood . I also have a new TPS ( throttle postion sensor ) because that can cause hesitation to if its bad as can a vac leak . Anyway I did everything I was supposed to and I am still gettin hesitation . So I am still askin around what it could be . If you wanna get stock injectors for it this is where I bought mine I spent 272 bucks on them but thats way better than the 560$ I could have spent at the parts store .
http://www.fiveomotorsport.com/Injector_SetsMAZDA.asp

 

All this talk about injectors and shiit. Did you forget about the 5th/6th port actuators that open up at 3800 rpm's and uses the back pressure from the exhaust? I would check the actuators to make sure theyre working right. That shoulda been checked first!!

Chris

 

I've a 87 non turbo that the only thing that stopped the hesitation was going to the ECU plugs and finding the ground wires. Traced the ground wires up the harness til I found where they all three splice together. At that point I soldered a new wire to all three of the gnd wires and put a ring terminal on the other end of the new wire. Attached the ring terminal to one of the studs that hold the bracket for the ECU in place.

I can make hesitation come and go by just removing this single new wire from the bracket. This might work for you, might not. Very little money involved. New injectors are not the way to go in my humble opinion.

 

if you remaove the cat make sure you have a place to put the pipe for the 5th/6th port actuators that get the pressure from the cat. and that could also cause the hesitation.

 

I agree I thought I did everything regrounded the engine bay , new injectors all kinds of things until the last thing I looked at was the ECU grounds reground them now my car runs like new injectors can be costly and this is very inexpensive