SES light and engine fans

[Trans Am]

1995 formula

which codes will cause the pcm to turn the engine fans on at high speed, or any code that illuminates the ses lamp will do that?

i still didnt manage to get an usb obd1 cable or a scanner and i still have the ses light on.
# I am trying to eliminate some of the possibilities , and maybe replace the sensors left in doubt.The light comes on afer about 2 minutes after startup, and goes away at idle after a while, comes back on as soon as i accelerate. engine still runs normal, shifts are ok

I have cleaned the MAF sensor by spraying carburettor cleaner on it, and 2 of the small wires had grime on them , the other one was ok. there was a lot of stuff that looked like pieces of a black sponge stuck in the maf screen, blocking like 30% of it no ideea how that got there (maybe from the air filter?? brand new k&n??)

[Injuneer]

Not a good idea to use carb cleaner on the MAF sensor. Its way too harsh for the sensitive thin-film coatings used on the sensing elements. Not even a good idea to use carb cleaner on something like the throttle body, that has coatings on it that will be removed by the cleaner.

Alcohol or electronic parts cleaner would be a better choice.

[Trans Am]

oh well the damage has been done, i thought it would be ok with carburetor cleaner, but it still ran fine after that, and i disconnected it to see if the pcm switched to speed density mode and it did as the engine revved itself up a bit and then went back to idle. Good excuse toget a granatelli maf though, just in case it got damaged haha

The thing i was wondering is , do all trouble codes turn the fans on , or just the ones relaed to engine coolant sensors, cause if its just the coolant sensors then i just replace them as they are only cheap.

[Injuneer]

Anything that would cause the engine to overheat may turn the fans on.... EGR issues, running lean, AIR pump failure, coolant temp sensor failure, excessively high IAT temp, etc. I can't say with certanity that each of those codes turns the fans on, but it would make sense if they did. I know the AIR pump circuit failure turns on the fans... that's the most common cause.

Do not buy a Granatelli MAF.... that would be mistake #2

[Trans Am]

Do not buy a Granatelli MAF.... that would be mistake #2

Why? are they bad? i thought they were ok, but they dont have that screen , and after the dirt that was on it, i think the screen saved the sensor, what should i get then , an ac delco one?


I am suspecting air pump failure, i know they are electric sealed units, and that stuff that got sucked into the maf screen might be part of the pump , or some sort of filter inside the pump, as it looked loke pieces of some sponge filter thing
.

Is there any way of tricking the pcm into thinking the air pump is still there and works if i remove it? i ve see people doing the air delete mod but cant remember how they ve done it.

[Injuneer]

On a 93-95 OBD-I engine, you can unplug the AIR pump harness connector, and as long as there is a good fuse in the circuit, you will not get a code. Won't work that way on the 96+ OBD-II cars. You might want to check the fuse for the AIR pump now. If the pump siezes up and draws too many amps, it blows the fuse, you get DTC 29 and the fans run all the time.

The Granatelli is basically a cut up stock element, with different "ends" for the housing, and a supposed recalibration of the output signal. The recalibration sends a lower than actual air flow measurement at very high flow levels. This leans out the overly rich stock tune A/F mixture at WOT, and picks up some HP. But the results when using the Granatelli are very erratic. There is no guarantee it will achieve the claimed performance levels. You can accomplish the same HP gain by having your PCM tuned by a mail-order tuner to lean out the target A/F ratio in power enrichement (PE) mode. The tuners will guarantee you 10-15HP, and its permanent and reliable. IMHO, the Granatelli is a huge rip-off. Tuning costs about 1/3 of what the Granatelli costs. You could even do it yourself with LT1_Edit or TunerCat programming software.

[Trans Am]

Thanks, i m going to check that right now. and i ll start looking for an ac delco maf, just in case.

[Trans Am]

You were right Fred, thanks!

The air pump fuse was blown , and i put a lower apmerage one to see if it blows again and it didnt , so i guess the pump is ok, if it does irt again i ll just unplug it.

I ll be looking for a scanner though , to be ready next time the ses light comes on again