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-   2nd Generation Specific (1986-1992) (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/)
-   -   dreded 3800 poop out! (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/dreded-3800-poop-out-284159/)

rotoboy20 03-17-04 11:31 PM

dreded 3800 poop out!
 
well, i did read the FAQ reguarding the "flat spot" in the torq curve around 3500 to 4000 rpm, but its not helping me out very much. i just installed an air fuel ratio gage and when i get to 3800 it goes from stoich to off the scale lean.

what also could cause this besides a bad ground connection? could it also have something to do with the 5 and 6 ports not functioning properly? help! id hate to have to change all of the ground wires. but if that is the only way out, please, tell me what is up wit dis shizle!

-chris

RyoFC3S 03-18-04 12:10 AM

Adding a FCD got rid of my 3800 rpm hesitation. You might try that, but i'm still a noob.

(Yes, I know I didn't answer your question). :p

-Andrew

J-Rat 03-18-04 01:12 AM

you dont have to change all the ground wires. Just add new ones. Check the archives, there is a write up.

SOIA 03-18-04 02:55 AM

My problem, and sounds like yours was the MAF sensor connection. Disconnect it and get a good electronics cleaning spray and clean it up, my car worked like new!

ddub 03-18-04 02:59 AM

grounds helped me a bunch in my n/a, it was having hesitations a little before 4k and then would pick up again... here is a good list of grounds to do along with the gauge wire you should use

Leading Coil 10
Trailing Coil 10
Pressure Sensor 10
ECU 10
Firewall to bell housing 4
Battery Negative to body, body to Block (2 seperate wires) 4
Fuel Injection Harness Under UIM 10


the formal writeup is in the archives i believe, or somewhere in the 2nd gen forum, but that gives you an idea of what to do

J-Rat 03-18-04 03:05 AM


Originally posted by SOIA
My problem, and sounds like yours was the MAF sensor connection. Disconnect it and get a good electronics cleaning spray and clean it up, my car worked like new!
FYI, we dont have a MAF sensor.

SOIA 03-18-04 04:52 AM


Originally posted by J-Rat
FYI, we dont have a MAF sensor.
you say what now?
ok why don't we call it the AFM then Mr. genius!
I'm sure he's smart and figured it out.

J-Rat 03-18-04 01:34 PM

Little too much caffiene this morning? A MAF and an AFM are completely different, just trying to point that out.

rotoboy20 03-18-04 03:38 PM

now now, lets play nice.
im just trying to figure out what else could be causing the lean out at 3800. thanx for the list dDub!

n-e-1 else have a different cause for the lean out, please post your explanation.

thanx
-chris

rotoboy20 03-18-04 03:39 PM

oh and by the way....what the hell is an FCD? what does it do?

RX7nSC 03-18-04 06:04 PM

im having the same problem you are. dies at 3800 when your heavy on the throttle. have you tried barely depresing the pedal. if u do it will rev right to red line. i dont know what that means but it still sucks. and once in a blue moon it will rev fine. then cut it off let it cool and start it up again and it wont rev right anymore. i replaced the engin ground, battery ground, O2 sensor. i have a new fuel pump, fuel filter, pressure regulator on the way. just trying a few different things. ill let u know what works. i dont know what a fcd is either.

SOIA 03-18-04 06:08 PM


Originally posted by J-Rat
Little too much caffiene this morning? A MAF and an AFM are completely different, just trying to point that out.
meh does the same job, and it was the cause of my trouble (AFM connector)

WAYNE88N/A 03-18-04 06:17 PM

I've never had this 3800 thing you guys keep talking about, but from experience with other related problems it sounds like maybe the 5/6 ports aren't opening as soon as they should, so the ECU is not sensing that extra boost pressure it needs to get those secondaries goin' (for a couple seconds anyway). just a guess...


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