50 mile drive check engine/bouncing idle/shut off
 

I took my FD for the first 50 mile drive,the stock gauge was a hair less than half way the whole time. Now at some point i noticed my check engine light comes on during stop and go traffic and my idle starts bouncing from 500 to 1000 rpm and it shuts off. when i start driving again at a speed of 40+hr the check engine light goes away. as soon as i stop it come on again with the bouncing idle. the temps in the engine bay are ridiculous by touch.I can barely open my hood but the stock gauge stays the some.

I was wondering if this was happening because i eliminated the air pump and got a greddy pulley kit with no idle pulley or is it because i need better cooling?

Hmm something similar happened to me withouth the bouncy idle/shut off.

I come to find out that there was ALOT of air trapped in the coolant system. The water pump housing hose and rad hoses were PIPING hot yet the AST was cold.

I was thinking of tapping at 3/4 boiler temp gauge on the thermostat housing and a small probe in the intake manifold so when i open the hood i can monitor the temps on there. I am not sure if these gauges can last as they don't last very long an boilers.

Im sure a boiler temp gauge on the pump housing will work. Most of those gauges read up to like 250F which is far than what our cars should be running at.

You dont have an aftermarket water temp gauge?? That was like the first mod i did when i bought my car, well that and the AST.

no i don't have one.I usually read the temps off my laptop but by dad took it to tune his turbo II and he has not given it back. also i was going to buy a temp gauge but i read a thread where you and a couple of other guys said that autometer gauges suck, so that kinda set me back a little since the good gauges are $200+ bucks. gotta work some side jobs "you know what i mean" sh*ts slow right now

Sounds like you are using a PFC?

Used water temp gauges are cheap.

If you're gonna go through the hassle of getting a boiler temp gauge, plus the fittings, hooking it up, you might as well get an aftermarket gauge for a bit more and be safe.

When i bought my brand new DEFI water temp gauge, it was like 108 plus shipping. Im sure used you can get for like 70 bucks or so.

You're a plumber no? You should have no problems financially lol :D

you got me there. lol

Check if you have air in the system first. If you still have an AST, remove the cap while filling the coolant from the filler neck. This works best for me at getting the trapped air out. After cooling down from a short drive, check the system again by removing both caps. By the 2nd fill, you'll have almost all of the air out.

I'm not convinced that your temps and your bouncing idle are related though. You may want to check your TPS to make sure it's reading the correct voltages. Have you messed with the TPS or the throttle body recently?

Are you using a PFC or a stock ECU?

If you are using a PFC, you can check this thread about getting your idle adjusted:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-make-your-untuned-pfc-basemap-safer-idle-better-no-datalogit-needed-841706/

If you are on the stock ECU (or a rechipped stock ECU), the idle will suffer when you remove the airpump. You'll need to adjust the idle adjustment screws on the TB and probably raise the idle to around 1100 rpms.

i don't have a PFC. What i have is the old PFS purple box because my FD was an automatic.

well what drives me insane is that the car idles smooth as hell at 800rpm until i drive the car for more than 2 hours straight.When temps under the hood are at the highest point then the check engine light comes on and the bouncing idle starts.

I have not messed with the TPS they only thing i have done is remove the UIM to install a fast acting AIT censor.

Then best thing to do now is pull the code (s).

Im guessing coolant thermosensor?

my car was doing that. after re tune it dosnt shut off but idle bounces. getting the vac lines checked now.

You might try putting the stock AIT back. Most of the people who have been adding those are running pure replacement aftermarket ECU's (i.e. no stock ECU in place). At least you can rule out it not being the problem by putting the stock one back in place and testing out the car.

i agree with mahjik ^.\

also check if while you did that mod you didn't knock off any lines or forgot to plug something in :)

correction on what i posted before. This problem happened before installing the AIT. one of The reason why I installed the fast AIT censor is because i though this was the problem.

i will pull the code to see what it says.

ok now i am confused. As i stated above i replaced the stock ait with the fats acting AIT last sunday and i also made a heat shield out of an aluminum street sign to shield the intakes from the radiator fans. I drove the car all day long today and no bouncing idle no shut off no check engine light. It idled at 800rpm all the time (but) today has been a 75 degree day compared to the 90 degree days last weekend.

Go ahead an pull the codes anyway. If it threw a code previously, it will be stored. Also, most likely whatever it was will come back.

look what we have here. On Tuesday i decide to install a digital water temp gauge.I was looking to install it on the throttle body coolant line when i notice that i don't have one.I take off the intake to look for the rear plate nipple as the front coolant nipple is visible and i found the rear plate nipple capped off by the fuel rails.2 hours of extensive struggle between the rats nest,fuel lines and wire harness i finally pull the caped off hose. I see no coolant coming out of it so i take off the radiator cap to vent it and there it goes, a huge air pocket that was probably causing my car to run extra hot and check engine light to come on. I am going to take a 100 mile drive to NJ on Sunday and see if that was contributing to the problem.