spedy7

Curious to know if it is possible to find one of these? Tried googling it, but can't find a single thing on it. Would make it easier to narrow down problems, especially being a noob to first gens. I know you can rig up a TPS light to check simple codes that way, but it seems like it's not as thorough as manufacturer specific tools (as usual).

KansasCityREPU

iTrader: (9)

A homemade checker will get the same results.

https://www.rx7club.com/1st-gen-arch...ite-up-285461/

spedy7

Thanks, kinda figured as much. Built one, no codes (kinda good), but finally found out I have a very leaky lower intake gasket. Hopefully those will arrive by thursday.

mazdaverx713b

iTrader: (91)

Do you have any pictures of the original unit? Are you leaking coolant from the o-rings on the lower intake?

spedy7

No pictures and don't see any coolant, but a hefty spray of carb cleaner sprayed there smooths out the engine. It's a SE so I don't think there's a coolant passage in the manifold.

mazdaverx713b

iTrader: (91)

Good call on that. The SE does not have the coolant passages through the manifold. Sounds as if the gasket is failing and there is a leak at the gasket as you already know. I have never seen a lower intake gasket fail on an SE but it's possible. Vacuum leaks are common given the age of the car and can cause a rough idle and exhibit the same results if carb cleaner is sprayed near a vacuum leak. Its worth looking into before pulling the lower manifold as that can be a tough job an SE.

GSLSEforme

+1. I have only ever seen two lower intake gaskets fail and both for same reason,reman engine installed and fasteners not properly tightened and worked themselves loose with heat/cool cycles.
One was an emissions test failure,the other was a random intermittent misfire.
Much more common to find split or cracked vacuum hose as source of vacuum leak.
Worth a more specific leak test before disassembly,would be unfortunate to tear down only to find gasket ok. If on disassembly you find loose hardware on lower manifold,good chance intake gasket is compromised. You can reach some but not all fasteners(air motors for 5th.6th ports in way). Worth your time to check to see if ones you can reach are tight,if they are gasket failure not as likely. Recheck for leak and focus on what is near where you spray carb cleaner. Engine vacuum/leaks can pull fumes from further than you might imagine.

spedy7

Don't know if there are any lines that run under/in between the manifold and irons (still a noob to rotaries), but spraying specifically there and only there it smoothed out. Since I got it from my uncle its had a rolling idle around 1100rpm on a cold start that will settle to a slightly rough 800 when warm. Cleaned out the throttle body and that helped out with a random rough idle issue I had recently, but didn't fix it completely. Richening the variable resistor helps it (which tells me vacuum leak). Sprayed the rats nest, intake, and all the lines on the passenger side and found nothing there. I do want to replace all the vacuum lines with silicone ones, just don't have the money for them.

I've been burned by an intake gasket on my Mustang before - oil fouled plug #2 and finally found a compromised gasket sucking oil galley fumes. Don't know when this motor was rebuilt last (my uncle said it was done sometime recently), but it's otherwise decently taken care of for having 250k miles.

GSLSEforme

Well...since you know its been apart,possible something left loose.You can get to all lower intake fasteners except for two to check for hardware being tight/loose.Split/cracked vacuum hose at top of list of suspects. 250k miles,i'm sure it needs vac hoses renewed. You don't HAVE to use silicone hose,nice but expensive. Regular jobber vac line will work fine.

j9fd3s

iTrader: (3)

in practice the GSL-SE ecu isn't really smart enough to make the tester helpful. codes are only set for open or short circuits, and there are only a few of them

GSLSEforme

^^^^This,it really is a primitive system. Originally found on European cars in early 80s,built on license from Bosch,all Japanese cars began using it,technology trickled down to motorcycles.
It is very dependable,always ignored reading codes,even when working in dealership,they only pointed to generic areas to check. Multimeter,oscilloscope,understanding how it worked was much faster diagnosing/repairing than troubleshooting trees in fsm.

spedy7

Well that's nice to know. I thought they were pretty primitive but wasn't sure. Just wanted to make sure it wasn't a problem I couldn't see but the ECU could.

j9fd3s

iTrader: (3)

its the other way around, ECU Sgt Schultz's its way through life...