I've got a bone stock '84 GSL-SE with an idling problem. It will start and run on high idle and if you keep it above 1500rpm it runs just fine. As soon as it tries to go to idle is simply quits, no stumble or cough it just simply dies. However, with the AFM unplugged it will idle away no problem. It doesn't idle smooth, but it will stay running. We tested the AFM and replaced it with a used one but that did nothing. I've checked and ajusted the TPS, checked the BAC valve, checked for vacuum leaks, but have come up empty handed. I did a compression test just for fun and it is good that way. I'm slowly running out of ideas other than to try a different computer. Any ideas???

 

ECU. If you are positive there are no vacuum leaks, the power and ground are good, and the BAC/TPS/AFM and Dizzy set correctly, then the ECU is the only other option. Especially if it will idle with the AFM unplugged.

Scratch that, it could be a wiring problem between the AFM and ECU. If you unplug the AFM, the ECU must be running a closed loop program.

 

I may have to check the wiring to the AFM. I think it is definitely running in a closed loop program. I dissconnected the O2 sensor to install my wideband in its place. I went to start it and it just completely flooded itself and wouldn't start at all. After I put the O2 sensor back in and unflooded it it started right back up again but still with it's old problem.

 

Have you made sure the AFM door is not sticking? I've seen a couple cars where the rubber surround on the air filters melted. The melted rubber gets into the door opening and clogs it up.

 

Both of the AFM's we had on the car were clear and free moving. I found a nice pinout test for the ECU that I'm going to go through tomorrow. Gives me all the values that you should see at the ECU connector. Hopefully that will lead me down the right path.

 

Have you taken a look at this?: http://www.nellump.net/peri/epi/firs...gslseIdle.html

 

^ Yep took a look at that a while back. Nothing in there really pertains to the problem I'm having. I went through all the voltages at the ECU. Pretty much everything seems in check other than my 02 sensor signal wire has .3v on it KOEO even with the sensor itself unplugged. Just going through all of this stuff now trying to find the cause. I'm also wondering if I don't have a fuel injector that could be stuck slightly open.

 

Naw, if the injector was stuck open, it would flood the engine every time you shut it off. Gotta be either electrical or a vacuum leak.

 

I've gone over all of the electrical and everything seems to check out fine. Even tried a different ECU and nothing. I smoke tested the engine again today for vacuum leaks and came up empty handed. I'm running out of ideas here. The car does seem to run extremely rich when it does run. I'm starting to wonder if possibly the fuel pressure regulator/pulsation dampener isn't stuck shut. Any thoughts on this idea? I want to check the fuel pressure tomorrow and try and confirm this.

 

Well I finally got to the bottom of this PITA. Turned out it is a stuck open fuel injector. I put a fuel pressure gauge in the fuel line and turned the key on then off. I could watch the fuel pressure drop right back to nothing and when I started the car it just spewed white smoke until it died. Then it wouldn't start at all. Thanks for the help guys.

 

Do you still have the ecu pin out test?

 

No but I could probably get it. I found it in Alldata. If you have access to that program you could get it too.

 

Nope. No access.

 

https://www.rx7club.com/1st-generati...oblem-1006542/

Good to read your post. I've got/still have the almost exact same problem. I've pulled the UIM/LIM off now 3 times in an effort to fix.

The last thing I've done is pull the injectors and sent them to FIC in Georgia to "properly" clean. I cleaned them the "You Tube" way. Not sure if I fried them or not.

Also, before I put the injectors back in , I'm going to double check the connectors. I replaced them 'cuz the older ones, the plastic was toast. Don't think I crossed a wire but I'm pulling at straws at the moment.

I've done this on the other car years ago when I was twice as stupid as today, it ran/still does just fine. I messed something up on this one and STILL can't find the culprit.

jerij

 

Turns out my stupid front pulley was improperly indexed on the hub. This caused it to run very poorly 90' out. Lol. Purring like a kitten now.

One good thing about this ordeal was how much I learned about fuel injection. I went through troubleshooting all systems and the problem with my bouncy idle was fixed in the process. Now off to set my TPS perfectly and get this car out of my driveway.