1988 GTU NA

So I've been working on this freebie RX-7 that runs like absolute poop and the best I have got so far is for it to idle at 1,000 rpm and its still pretty rough. Gets worse in the lower rpms.

I have a plan of action to fixing the cause but what is current concerning me is when I go to start the car it cranks a few times, I have to pump the gas a few times then I get a kickback right before it fires up. I mean literally split second before firing up.

Could the timing be way off? I have to get a new timing light because I loaned mine out and got it back broken. I thought the timing was auto adjusted or is that only while its running?

Could this also contribute to my poor revs and rough idle?

 

with the haltech stuff, they kick back with too much timing, so i would check that.

 

I found my timing was off but I still dont know if its 100% correct + I need a new timing light.

Now the car starts up without any gas and no backfire or kickback but when I try to give it anything over 50% throttle its like it cuts fuel or spark completely. I know it could be a combination of things but Im just trying to get this thing in the ballpark at this point.

 

Ok looks like the TPS connector was fucked, I found when fiddling with it the TPS would drop signal completely so for now I cut out the connector and put on some but connectors. Took it for a drive and now its driving within reason. I still need to get it in tune but now it actually drives and not like total ***-**** dog-snot.

Mystery solved thus far

 

Timing light at Harbor Freight was $18 last I checked. Mine works great. A good, used TPS goes typically for $50-$60. You can get the timing approximately right by pulling the CAS, lining up the marks per the FSM info, and re-"stabbing" the CAS.

When a car tries to run backwards like that, it is usually timing. When it is that far off, it usually means someone stabbed the CAS wrong.

 

I wanted to get another nice digital timing light so I will wait.

I restabbed the CAS but I cant be 100% sure the front pulley was installed correctly. Another thing I was wondering is everywhere I read it says stab the CAS at TDC however I can only think of this, Is there 1 TDC or 3 TDC's per full rotor rotation cycle?

I used to know this kind of stuff and maybe Im just thinking too far into it but think about it, the crank must rotate something like 1080 degrees in order for the rotor to make 1 full 360 degree rotation sparking on all 3 sides. So if I spin the motor 360 degrees it will be at TDC but only 1 of 3 TDC's. If I spin it again 360 degrees it will be at TDC but on a different rotor face. Does this make no different in timing or is there a SPECIFIC rotor face that needs to be facing the plugs for true Top Dead Center?

Today I am going to inspect the BAC and adjust the idle and mixture screw (it was tampered with) and reinstall my SAFC (for monitoring only). I plan to know if I have any vacuum leaks today and will try to get it running as good as possible before ripping it down for a quick engine bay cleanup.

 

There is a discussion at...
http://www.teamfc3s.org/info/article...fying.html#TDC
on how to find/define a new TDC. Basically, it says #1 rotor is a TDC when #2 is halfway between the point where an apex seal is visible in the trailing spark plug hole and visibile in the lead leading plug hole. It does not discuss the selection of any particular rotor face, so it would appear that the TDC can be defined on any one of the three faces. This makes sense, as the faces are exactly 120 deg apart (evenly spaced) and the rear rotor is offset 60 deg from the front rotor. Someone else may have a different view, but I cannot see how it can make any difference whatsoever which of the three rotor faces is referenced for TDC.

 

^I believe this has been argued before. Spark plug timing (location) varies between series and will not result in determining the proper TDC. The REAL way to do it if you fear a mismatched pulley is to use the fluid displacement method. I believe hailers came up with it.

OR

The racing beat underdrive pulley will work. It's one piece, keyed with timing marks.

 

At this point Im going to assume its correct because it starts up normal now but still revs and drives like ****.

The other thing Im wondering is when I lined up the button with the line on the CAS the CAS wants to turn when I stab it. This throws the marks off once its stabbed. I can counter turn the CAS slightly to counter this effect but then it is off in the oppisit direction.

 

yeah its supposed to be like that.

i actually just center one of the two big teeth in the hole in the CAS cover, while the engine is on the L mark.