Rhyno2050

Hey fellow rx7 peeps, I just did my first engine swap into my 86 n/a and everything seemed to have gone smoothly but not until the car would just not idle. At first the idle would begin to get rough and then it just died. The car continued to act like this for a while, and would only stay running if I would constantly be giving it gas but would run very rough. So I just started checking the fuel pressure, spark, any intake leaks, egr valve, vaccum leaks, compression, but used a piston compression tester but seemed fine, and im completely stumped. The car ran fine yesterday and for today it ran like **** for like 15 min. But then after a few more starts and running it, not letting it die, the idle returned completely to normal. Now the car idles beautifully but im afraid that this problem might return. Im asking if anybody could have some knowledge of what the heck it could be the help would be greatly appreciated.
Thanks

Rhyno2050

anybody have any idea? I was thinking something electrical such as a some kind of sensor but not sure

jreynish

iTrader: (2)

Did you take the check valve out of the Compression tester? If not then you won't be able to discount compression issue.

Rhyno2050

Yea I tried both ways and it seemed a lot better with the valve out, commpresion looked to be between 90 and 95 for both rotors.
Update: two days ago the engine got flooded, I did the defloodinb procedure and manage to turn on afterwards easily. Could it be fuel related or a sensor controlling the fuel?

satch

iTrader: (1)

Most likely an injector related problem.

Rhyno2050

ive been driving the car as much as possible lately, well the last couple days, and the car has been running beautifully. This car is just confusing me. And if would be an injector it would have to be one of the primaries right?

jjwalker

When it was idling poorly, did it sound like a single piston motorcycle?

I had a freak issue a year ago where the primary injector on the rear rotor was working intermittently. I was stumped because injectors usually work or don't but freakishly, the injector was the actual issue.

Rhyno2050

yea actually that's how it sounded, like one of those old motorcycles, kinda like a deep tone to the exhaust but it struggled to stay on. But what could cause an injector to work properly, then stop working, and then working again? Also another clue to this weird problem is that at idle the engine seems to misfire slightly, but doesn't really affect the idle, put as soon as I touch the gas it revs very smoothly and nicely, could the injector cause that as well?

Rhyno2050

or could it be the signal coming from the harness?

satch

iTrader: (1)

A loose injector plug or a wire pulled back within the plug could cause the injector to not act properly.

jjwalker

Most likely cause. My situation was different, as my injector was actually working sporadically. Caught it in the act on an injector tester. My situation is unlikely, but it can obviously happen.

Satch is right, it is probably what he described, but don't instantly rule out the injector.

Rhyno2050

ok thank you guys, ima probably have to wait to later this week but for sure will give the connectors another look.