Idles Low dies when "revved"

[7MGFY]

Hi I'm new to Supramania and I've been having a strange problem. Its a PITA to start the car when it's cold like 2 or 3 tries to get it to idle without stalling out. Once I get it to idle it sticks around 500 rpm and occasionally lopes a bit. When I go to give it some gas (In the car with the gas pedal or under the hood with the throttle linkage) It just cuts out and dies. I have a WB02 (Innovate LC-1) It's showing a constant 12.4:1 at idle I ran a diagnostic and come up with a code 51 and a code 31. after these codes were cleared I came up code free but with the same issue just no codes. Also when the revs drop a little too far (like 300rpm) the check engine light momentarily comes on and then turns off when the rpms go back up to 500. Any insight would be much appreciated.

1988 MA70
7MGTE Stock CT-26
Mods:
Full 3" exhaust with BIC DDP to big tardlike MKIV style aftermarket muffler I stole.
Home depot boost controller
Custom intercooler piping
HKS SSQV Recirc
LC-1 WB02
Filter mounted on AFM
Master power switch with airplane solenoid
Aeromotive FPR
550cc Injectors
Walbro 255lph fuel pump :1zhelp:
No Lexafm awaiting Fullthrottlespeeds Redonkulus shipping times for receipt of my MAFTPRO..... :icon_evil

 

[7MGFY]

bump:1zhelp:

 

[jdub]

One bump in a 24 hour period.

If the CEL illuminates with the engine running, it indicates a code. Might want to pull them again.

Sounds like you have a massive IC piping leak or your AFM, connector, or the wiring is the problem. Did you happen to clean the AFM recently?
Are you getting black smoke with that 12.4 AFR?

 

[jetjock]

Also when the revs drop a little too far (like 300rpm) the check engine light momentarily comes on and then turns off when the rpms go back up to 500.

Based on your mods I'll withhold comment on the other symptoms but the above behavior is normal. Whenever rpm falls that low the ECU initiates an MIL burn out check. It exits that test when rpm crosses back over 500. The same check is performed when the engine is started.

 

[7MGFY]

One bump in a 24 hour period.

If the CEL illuminates with the engine running, it indicates a code. Might want to pull them again.

Sounds like you have a massive IC piping leak or your AFM, connector, or the wiring is the problem. Did you happen to clean the AFM recently?
Are you getting black smoke with that 12.4 AFR?

My AFM may have taken a massive dump I have no boost leaks I redid the whole piping and made extra sure. No black smoke the tsrm indicates something like a 15kohm resistance between ground and sensor power yet i get something like 154kohm is that a common reading for a S^%T AFM? if so Oh well my MAFTpro will arrive hopefully before I get gray hairs...

 

[7MGFY]

Based on your mods I'll withhold comment on the other symptoms

LOL Whadaya mean by that junk? :3d_frown:

 

[jdub]

Whenever rpm falls that low the ECU initiates an MIL burn out check. It exits that test when rpm crosses back over 500.

Learn something new every day

 

[jetjock]

OP: It means: 1) I see things in your mods that could cause those issues and 2) I don't often reply to those who modify their cars without an understanding of what they're doing. Frankly, you should be grateful I made an exception.

Dub: Page 127...

 

[7MGFY]

OP: It means: 1) I see things in your mods that could cause those issues and 2) I don't often reply to those who modify their cars without an understanding of what they're doing. Frankly, you should be grateful I made an exception.

Dub: Page 127...

I am grateful I Just can't seem to be an expert on any one type of car I keep buying selling and trading. I had an ae101 3sgte rolla a 2nd gen H22A swap Teggy and a 84 MKII with a 5MGE before I got my MKIII 7M I guess I thought alot of my learnings from the MKII's m series would kind of carry over to the 7MGTE but boy was I wrong.

 

[Supra87T]

I am grateful I Just can't seem to be an expert on any one type of car I keep buying selling and trading. I had an ae101 3sgte rolla a 2nd gen H22A swap Teggy and a 84 MKII with a 5MGE before I got my MKIII 7M I guess I thought alot of my learnings from the MKII's m series would kind of carry over to the 7MGTE but boy was I wrong.

You are running 550cc injectors with stock AFM if I'm reading your mod list correctly? That's gonna cause you to run hella rich...

 

[7MGFY]

You are running 550cc injectors with stock AFM if I'm reading your mod list correctly? That's gonna cause you to run hella rich...

for some reason I don't run hella rich no smoke I just jumped the gun on the install of the injectors fuel pump and fpr in anticipation of the arrival of my Maftpro ... but alas the people who make it take forever to restock therefore I have been forced to wait .. 2 weeks now from the day I ordered it and it still hasn't been restocked or shipped. I know my way around a few diff cars and I anticipated that the AFM would cause it to run super rich But I have no prior exp with KVA style AFMS... Another question sorta on topic is what is the frequency range of the KV signal I know it's a square wave but what is the range in hertz from idle to WOT. I'm currently experimenting with a homebuilt translator that converts MAP to KVA frequency and I'm hoping to sell it for cheap once I have a prototype. This would make alot of supra addicts happy I assume. It just requires a 555 astable oscillator chip in a square wave out put that wouldconvert the map resistances to square wave output. I have already succeded in a proof of concept with a variable resistor and a 555 timer attached to e1 and kv out and it changed the afr.

 

[Supra87T]

The car is too rich. That's why you are having these problems and why Jetjock said he would withhold his comments....

 

[7MGFY]

Anybody have the frequency rang of the AFM KS output? I know its a square wave somewhere around 1-100 hertz I need the correct scale does anybody have it? as in frequency in hertz @ idle and frequency in hertz at WOT

 

[GrimJack]

I don't recall the freq at idle, but ~1400 Hz will trigger fuel cut, so an upper limit a bit over that would make sense.

 

[grimreaper]

15-20 hz at idle. and increasing with rpms.

 

[7MGFY]

Thanks I'm working on a circuit right now

 

[7MGFY]

I hooked a 3000gt AFM up and the car ran fine just a little rich