Run eye tearing rich, blowing efi fuse....

[s383mmber1]

Got the car actually moving a few days ago, and legal on the road. Ive been taking it real easy, and not getting into much boost (but hey, it is a turbo supra so i do have some fun).

I was sitting at a garage with my car idleing, and it jsut shut off. We traced the problem to a efi fuse, well, actually thats more of the result. I realised the problem was one of my CPS wires touched the valve cover and shorted out.

I then fixed that, and the car ran great. Boosted STRONG and didnt run real rich that i noticed.

Yesterday the car started to run rish enough that i could see the rich smoke comming through the shift boost, and was almost filling the car. This only happened on occasion. THen today i let the car warm up, drive it to school and smell it running a little rich, but figured that what open downpipe smells like.... I blew about 9 EFI fuses and BARLEY made is home. Running WICKED rich, if i stopped the car, it would jsut shut off and blow the EFI fuse.

I havnt pulled codes yet, as jsut got home and had to go grocery shopping with my other car.

Does this problem sound as if caulty CPS wiring could cause it? Something else realted? Would a bad 02 sensor kill the EFI fuse over and over again...?

THanks!

 

[3p141592654]

an o2 heater wire touching metal will blow the efi fuse.

Are you getting any codes set?

 

[flubyux2]

beat me too it... the only time i had this happen was when the o2 sensor harness melted on the turbo. other times i ran really rich was when the AFM signal was faulty... i had an Emanage then.

 

[Poodles]

what they said ^^ would also explain the super rich condition...

 

[shaeff]

i would look at everything that you worked around. when i had the car at my place, i drove it up and down my road a LOT, (probably a few hours worth)- and it didn't even hiccup.

as several have stated, if the o2 sensor heater wire shorts, it'll pop the EFI fuse.

-shaeff

 

[jetjock]

Shorting any of the CPS signals to ground will not blow the EFI fuse. Or any fuse for that matter. As pointed out shorting the O2 sensor heater power will. It won't cause a rich condition though. That's tough to have with a blown EFI fuse

 

[Poodles]

if the heater circuit isn't working he would run rich from fouling the O2 sensor out, no?

 

[flubyux2]

if its run Long enough, yeah it can foul out... especially if the car is already running rich in limp mode.

 

[s383mmber1]

Problem fixed ---->

Power steering leak shot fluid all over my AFM causing code 32 which apparently made my car run rich...

Cleaned it out and the car runs great!

 

[jetjock]

^ Doesn't make sense as that can't blow the EFI fuse. Not to mention code 32 in a 7MGTE has nothing to do with the AFM. A goofy AFM signal could cause richness though.

if the heater circuit isn't working he would run rich from fouling the O2 sensor out, no?

No. If the heater shorted and blew the EFI fuse the engine wouldn't run at all. If the heater (or any other O2 related fault) caused an invalid lambda input the ECU would run the engine at it's default of only slightly rich. The O2 sensor in an EFI system has the least amount of authority of any trim sensor and is the first to relinquish what little it has. Think about it, if it had greater authority it could easily flood or starve the engine under certain conditions. Since the sensor is first and foremost an emissions device, put there solely for the benefit of the catalyst, what you're suggesting wouldn't do at all.

if its run Long enough, yeah it can foul out... especially if the car is already running rich in limp mode.

The TCCS has no such thing as "limp mode" and what might be even remotely equated to it will not make the engine run rich. Again, the system was designed with one thing in mind: emissions. Why do you think OBD was developed in the first place? While the law states any condition that may cause 1.5 times the federal emissions limit to be exceeded shall illuminate the MIL the ECU is coded to try and prevent it from happening even when a fault occurs. It's done because studies show a great many people ignore the MIL. Course, all this assumes the rest of the engine is healthy.

 

[s383mmber1]

32 Air Flow Meter Signal(7M-GE)
HAC Sensor Signal(7M-GTE)

Diagnosis(Air Flow Meter Signal(7M-GE))
Open circuit in E2 or short circuit between VC and VS.
Trouble Area
Air flow meter circuit
Air flow meter
ECU



Are you saying this has to do with the wiring going to the AFM or sometihng like that?

 

[3p141592654]

HAC sensor is an ambient air pressure sensor. For the 7MGTE, in 89+ ECUs its internal, and for earlier cars its an external sensor. It is unrelated to the AFM.

The fuse blowing is almost certainly related to a wiring problem. Besides teh o2 sensor wiring, I would look at any place the harness rubs on the engine. One area to look at is where it passes by the EGR and intake runners.
Sine the engine twists under load, it can be shorting for some condition, and okay under others.

 

[jetjock]

^ What he said. The power for the AFM (Vc) is not only current limited but not 12 volts. Shorting it will not blow the EFI fuse. I suppose PS fluid across Ks and ground (or Vc) might cause weirdness in Ks but I sort of doubt it since the fluid is likely a dielectric. None of it makes sense but hey, it's a long way from here

 

[Poodles]

hmmm... I've been having seriously rich issues as well, no codes, and a brand new wiring harness and many new sensors...

I'm suspecting a boost leak and will be solving that shortly with better piping, but after that, what else really can trim the richness level?

 

[flubyux2]

so then what exactly is happening when the CEL illuminates when there is no AFM signal?

when it rains sometimes, i beleive water drips onto my air filter and gets sucked into my AFM. when this happens, the CEL lights up and i it feels like all timing advance is zeroed out and smells rich.