dfa_crunch

car: 94 z28 lt1 6speed

my car overheated because my fans werent turning on

i replaced the 3 relays, thermostat and sensor and now fans wont turn off. When the car is started the fans will turn on after about 3-4 seconds and wont turn off till the car is powered down
been told the fans will stay on if the ses is on but it is not


i guess this is not such a big deal but i have another problem with my car and i was seeing if fixing this will help

Guest47904

What you should have been told was the fans come on if it sets a DTC. Not all DTC's light the SES. So more than likely your other problem is causing the DTC and running the fans.
A DTC18 is a perfect example of this. With an injector out, the car runs like crap, the fan is on all the time but the SES will not come on.

Scan it for codes.

dfa_crunch

taking it by autozone tomorrow, will post with results

dfa_crunch

thats what i thought, i was actually going to call before i went.

is that the reader you have? i see instructions off to the side as sold seperately. are those actual instructions for it or does it include codes and what they are. if not i could probably look up the codes online righT?

dfa_crunch

when i first searched for a scanner to buy i think the one you have may have been the one i found, it was used for somewhere in the high 100s. i didnt have the money or the desire to spend that much at the time on a scanner so i didnt look into it much.
i did however find the one you listed on ebay for 10 bucks brand new. so when that gets here ill scan it and update here

thanks

dfa_crunch

bought the scanner, doesnt work.
plugged the scanner in and turned the key. Fans came on and my check gauges, skip shift, brake, and low coolant lights came on. They all stayed on and no ses came on. tryed it a few more times and got the same result.
i was told on another thread that that reader wont work the camaros period

shoebox

Nope, that one won't work on a 1994, only a 1993 (which you can do the same thing with a paper clip). You need a real scanner that costs a bit more money.

dfa_crunch

got it scanned, these are the codes

48 - Mass Air Flow System Failure (MAF 8 months old)
32 - EGR System Failure
29 - Secondary Air Injection
70 - A/C refrigerant pressure sensor(fixed bad relay)
34 - MAP signal voltage low

and
11 - Malfunctioning indicator lamp (no check engine light)

48 says bad circuit to MAF, theres a really crappy cut and rewiring job done on the plug, i want to rewire it but i will not have enough wiring left to make the fit. Could i buy a new plug with extra wire to redo it?

as for 32, 29 and 34 im sorta lost. My haynes repair manual says to check the MAP sensor and replace if bad. Waiting on my multimeter to do that.

Injuneer

You can buy a new "pigtail" for the wiring harness = a new connector with a few inches of wire on it. Shoebox has the part numbers for the LT1 pigtails listed on his website.
Does your engine still have the AIR pump and the EGR valve connected and operating?

DTC 29 sets when the PCM detects a fault in the electrical circuit to the AIR pump relay. Check the fuse for the AIR pump. The pump can be disconnected, but as long as there is a good fuse in the circuit, it will not set the code.

DTC 32 sets when the PCM cycles the EGR valve, and doesn't see evidence of the EGR flow in the MAP sensor reading. Generally, the PCM will not run the diagnostic for the EGR system when there is a code for the MAP. Fix the MAP sensor problem first, then work on the EGR code. Is the valve still there? Does it open when you apply a vacuum? Is the vacuum solenoid functioning correctly (opens and allows vacuum to the valve when a ground is supplied)? Are the vacuum lines from the manifold to the solenoid, and from the solenoid to the EGR valve in good condition? DTC 32 is unusual in the OBD-I cars, but may be due to an exhaust system with very little backpressure.... e.g. cat deleted, headers, etc.

DTC 34 sets when the PCM sees a voltage lower than 0.24V and the throttle position is greater than 15%. A very common problem is a bad connector on the MAP sensor. The connector tends to dry out and start to crumble, providing intermittent contact on the pins. Check the connector first. If the connector is in good condition, probe from the gray to black wires to make sure you have +5V with the key on. Then probe between the green wire and the black wire at idle for at least 0.30V, with the voltage increasing as you open the throttle.

unforgiven

Check your fuses. Sounds like you blew the fuse that I believe is marked sensors. It is in the underhood fuse box. Definitely repair that MAF harness.

dfa_crunch

well instead of waiting for my stepfather to bring me his multimeter. im going to pick one up today, i found out i need it for one of my classes so i might as well get it now. Im going to test all the connections and post bad results here. I will check that fuse also.

In the meantime, like i replaced my A/c relay, i replaced the secondary air pump's relays because it was bad

dfa_crunch

Went to test the car, battery was dead. Could be that i havent started it in about 5 days, and also last night with wind chill it reached -25 degrees here.

Got the battery charged up and took some readings.

MAP:
Gray to black: 5V
Green to black: .4mV with key ON .3mV at idle

MAF:
B to A: 5V
B to C: 11.4V

Relay Box:
Air Pump(E4 to E1): 0V, no reading all others had readings of 11.56V

To make sure battery was putting out correctly at 14.4V

Seems like all of these are correct except for the Air Pump relay and green to black for MAP.
To me this connector looks old, even the clip that holds it in place is broken off.(connector is snug, just referencing that as a sign of age)

Guest47904

Put the meter on AC and read from the negative battery post with one of the meter leads to the output post of the alternator with the other meter lead. Should not read above 0.03 V AC.

Let us know

Dave

Also with the power on both E2 and E5 of the air pump relay should read battery voltage when measured to ground.

dfa_crunch

I wasn't very sure about the AIR pump and what it is and where it is located. Looking at shoebox's website, i can see where it is connected to and those tubes arent on my engine and the holes are filled in.

What does not having the AIR pump do for the car?

Guest47904

Air pump is for early warm up of the catalyst and then it drops out. As long as the fuse and relay is in tact. The pump not being there will cause no DTCs