I just bought a 89 GTU, and it wont rev past 6100 rpms, and it missfires at idle and lops a lil, would that be from bad sparkplugs?

Look under the hood. Maybe somebody snuck a five-oh in there without telling you. https://www.nopistons.com/forums/pub...1047683785.gif



Sparkplugs and wires are a possible easy fix and you should do it anyway, seriously though. https://www.nopistons.com/forums/pub...IR#>/smile.png

Definetly change the plugs and wires. That should help out. Drive it again and let us know if that helped.

ok, I will pick up the plugs, from a local kragen, man they charge 5.99 each for the plugs, is that normal?

Yea thats about right. Rotaries use a different type of plug then a piston engine. You will know what I am talking about when you see them.

https://www.nopistons.com/forums/pub...1047683329.gif yeah the NGK plugs are around $5.00-7.00 and the wireset should be less than $30.00. Remember to put anitsieze on the plugs and the boot protector grease. Do a tune up. Change the belts if they look crappy and other necesary items





Good lUck

The only place around my area that had the right plugs available charged like $10 for mine! Pretty harsh.

Your TPS could be at fault as well. Also, check the tube that goes from the air filter to the throttle body for cracks. It wouldn't hurt to change the fuel filter too.

Ok, I got the plugs and wires, and that guy had four leading spark plugs, well anyway, it runs alot better but it still cant go past 6k,

my suggestion is compression test, although its not nice news but you should do that first off! and check for vac leaks, and fuel sys overview

let us know how it goes

check timing

its possible that the secondary injectors dont come online for some reason, unlikely but possible



mike

yeah but the secondary injectors have nothing to do with his idle...

yeah but the secondary injectors have nothing to do with his idle... [/quote]

yeah, thats true



mike

Ahh, troubleshooting at its finest..

If it was the secondary injectors, wouldnt i notice that at about 4k when they activate? And I also found out that my alt is bad, thats why it lopes and when it lopes all the idiot lights flash and the volt meter drops. Some guy told me that when his alt went bad he could rev past 3k could the alt cause this problem? And how do I check timing on a rotary engine? what is there to time besides ignition and how would adjust that?

and yeah compression check is a must before you start pulling your hair out... if the results come back positive then you can justify going crazy.

well the ecu needs power to work right, and they dont like ow voltages. before you condemn your alternator, check all the battery/ alt connextions they get old/dirty and cause all kinds of wierd problems



mike

Def test the alternator. As far as the rev thing, my GSl=se would go past 6. Turned out it was a clogged cat/s I replace them with racing beat header, high flow Catco cat, Generic ebay can muffler. Now it revs freely.

When you couldnt rev past 6k did it feel like you were hitting a fuel cut? And like a pulsating jolt like you riding fuel cut?





I dont think compression is bad because it feels good like al the other NA Rx-7's I drove (including one rebuilt) up intill 5.5k.

well i did a compression test, and it was just under 100psi on the gauge so about 90 psi in both rotors, is that good?

I've read anything over 85 on both rotors is acceptable, 100+ is good.

well when i tested it i didnt have the peadal down, so now i did and the test came out 100 and 103.

well what could be causing me not to rev over 6000 rpms?

Did you check your timing yet and TPS? Once you rule those out and the compression results were good, then I dont know.

how do i check timing and what do i check on the TPS?

Try this link for the TPS:



TPS



I still cant access the old fc3s pro link for some reason....

Here is what I used for timing... worked great:



"basic FC timing"

https://www.nopistons.com/forums/pub...1047683358.gif https://www.nopistons.com/forums/pub...1047683358.gif



Well I changed my fuel filter, and my timing is dead on and now it can rev to 6300-6250rpms, But thats preety far from the 8000rpm redline. What elese should I check?





Will the tps keep it from reving? because it feels like i am hitting a fuel cut not like just going there and stop revving.







https://www.nopistons.com/forums/pub...1047683358.gif https://www.nopistons.com/forums/pub...1047683358.gif

Well I took the car to a shop that does rx-7's and he did the tps for me he said that the car always thought it was cold because of the positons so he changed out the thermal wax pellett and that fixed that and it idles much better now and he redid the timing, but then it still doesnt rev past 6k, So I changed the fuel filter and air filter. and still no go he though my cat was clogged so i hollowed it out and still no go. What elese could be the problem?



https://www.nopistons.com/forums/pub...1047683358.gif https://www.nopistons.com/forums/pub...O_DIR#>/11.gif

ECU?? https://www.nopistons.com/forums/pub...IR#>/dunno.gif

could cold solder points in the ecu cause this?