The vette died on the way home just now. With the MAF plugged in, the vette wont start. With the MAF disconnected, if I hold the gas pedal down (like with leaky injectors) the vette will start, idle, but I cant give it gas or the vette will die. No codes thrown until I pulled the MAF. Any ideas? Im currently sitting in the lobby of the dealersahip I used to work at so I would REALLY like to see if I can fix this QUICK. What is the part numbers for the 2 MAF relays? Could it be the ESC even though the symptoms change with the MAF disconnected? Is it the MAF? TIA.

I have an 86 Auto.

 

Sounds like the MAF sensor to me. Mine was not tripping any codes when mine went south. If your at a dealer, good chance that MAF Sensor will run you about $400 :eek: If you can limp home, do it and find a MAF sensor

 

yup...bad MAF. might as well order a high performance one while youre at it :yesnod:

 

Well....I dont think it is the MAF. Here is what I have done so far.

1. Bought new MAF from Autozone.
2. Bought new MAF Burn Off and Power relays.
3. Tried new MAF with old relays. Still broke.
4. Tried old MAF with new relays. Still broke.
5. Tried new MAF with new relays. Still broke.
6. Tried old MAF with old relays. Like this would suddenly work.... :rolleyes:

-MAF unplugged, the vette will start and idle just fine, but it backfires and dies if I try to give it gas.

-Either MAF connected, it doesnt want to start.

Could this be TPS sensor?
IAC sensor?
Bad spark plug wires?
Cap/coil/rotor gone bad?

I dont think this is a fuel problem. I REALLY smell gas when it does run. It runs a bit better with the MAF completely off and unplugged.

It was raining today, but I dont recall hitting any puddles.

Does this help any? Please...... :crazy:

I'll check this in the morning and if you guys are as stumped as I am, Im calling a tow truck. The vette was left on the side of the road by the dealership I used to work at.

 

A car will drive with the MAF disconnected (i tried it the other day).

 

I tried to drive it, but when I give it gas, it dies. (with MAF disconnected)

So do you think this is an electrical problem? Why would the symptoms change when the MAF is unplugged? That is where I am stuck. If it is not MAF related, why does the MAF change what happens?

ECM dead?


[Modified by VetteNoob, 10:45 PM 10/8/2002]

 

Ok do you or the dealership (should) have a scanner handy?

You probably saw the crap I went through a few days ago trying to diagnose what I thought was a Bad MAF. Turned out to be my O2 sensor.

If you have a scanner put it on the car. With the key "on" but no engine running watch the TPS values. What are they at idle? Smoothly and slowly press the gas and watch the TPS for smooth increases all the way to WOT.

Put a fuel pressure gauge on the car (can't hurt) and turn the key on so that the fuel pump primes the fuel rails. On the scanner see how much voltage is being sent to the fuel pump relay and check the fuel pressure.

If you can get the car to start, what does the O2 sensor say in millivolts with the car in closed loop (heated up)? At idle in closed loop a properly working O2 should cycle from 999 through 0 millivolts over and over and over. I saw mine was dead because at idle in closed loop it was reading 4mV totally static, it wasn't moving. Bosch O2 sensors have a 3 month warranty on them and are around $28 from Pepboys or Autozone. They are returnable.

I doubt it is the IAC because cracking the throttle just a little should take care of that.

As for cap/coil/rotor check it out. When were they last changed? Perhaps the ignition control module? Electrical parts suck because you can't return them once bought.

 

O2 sensor, Ignition, TPS

Wouldnt be the IAC, doesnt feel like the plugs/wires either. Seems like it would be a total ignition failure with the HEI

 

I havent got around to buying one because I was planning on getting a laptop instead and unfortunately I used to sell Hondas, so they dont have a GM scanner.

I can take my multimeter and test the TPS the old fashion way.

I just bought an electrical (Auto Meter) FP guage and dual pod from Timspeed, but it will take a few days to get here. Im not 100% excited about spending $40 for something I just bought.

O2 sensor....I have headers waiting so I'll probably need heated ones anyways. Can I use heated sensors w/o headers? Do you have a good part number? Since I need one (heated), I dont mind springing for one right now.

Cap/ rotor/ coil/ wires. All look stock. I need to replace them, but was planning on ordering the Hypertech thing. I suppose I can make life easier by replacing it with good ol Wells parts for now to eliminate this as the cause. I have some wires that 85WhiteZ51 gave me that only have a few miles on them, so I can give those a shot. Would the ignition control module have this kind of effect on the car? Dont have one, I guess I can check to see what they cost.

Oh and the AZ I went to today actually take returns on electrical stuff as long as it hasnt been 'installed'. You can buy it 'just in case', but dont install it if you want to return it. Saved me $225 because of that policy. The MAF was $145+$80 core charge.

 

Had the same problem with my 86 vette about three years ago. It turned out to be a bad fuel pump.

Frank :flag

 

Ok do that. :)

Ok get a towel. Prime the fuel rail and then press in the valve core on the schrader valve. Does fuel shoot out with pressure?

You can, I don't have one handy.

At Autozone an Accel HEI Supercoil (white/red wires) is $59.99 I think, i just bought another one there the other day when I thought mine might be cooked. Also at Autozone the same Bosch O2 sensor you'd get at Pepboys for $28.99 is $18.99 with 3 month warranty. A Wells ignition control module at AZ is $14.99.

Sweet! I did not know that. I almost took the $225 plunge for a MAF before Fastguy let me borrow his to test.

 

I think an EGR valve stuck open cause this type of stall. You should be able to reach under there and feel/move the diaphram while the engine is running. Perhaps there's two problems occuring simultaneously?

 

Well...so this kinda blows. Austin Corvette tells me the fuel pump is dead. It was spitting fuel from the shrader valve when I pressed it, but evidently there was not enough pressure to keep the vette running. Parts and labor $350ish...DAMNIT. Since they had to take it apart to test it, no since in asking them to put it back together to do the work myself. So for $350, Im getting a stock replacement pump and filter that they say will support a 383 with an AFPR and potentially 30lb injectors. I bet I could have done it for MUCH less had the vette been home and not on the side of the road 30 miles away. Total for this problem.....$450 after towing, relays, parts and labor.

[sarcasim] Life doesnt get much better [/sarcasim]

 

A new OEM pump is $75 from autozone and takes 30 minutes of your time to install with a torx bit, screwdriver, and 10mm socket.

 

I was going to ask what the FP was untill I got to the bottom of the thread. I am doing a Walbro GN pump this week.b

 

Is there a crack in the air tube between the MAF sensor and the throttle body?

 

Scorp,

You should become a Corvette Specialist and take the show on the road. Do a sort of Gordon Killebrew thing up North. You always give the most helpful and detailed advice- whatever you do for a living, you may consider that you missed your calling- unless you are really good at whatever it is that you do also!

 

Everything I learned I learned from my dad, friends, and knowledgeable people here. I can't take credit for it, but thanks. :)

(p.s. I'm a network administrator by day.)

 

Ive been a Network Admin for about 6 years, now I am working for a consulting company.

I used to love my work- now it seems more like a job than it did for the first few years. I find myself sneeking on the forum, and taking days off to play around whereas at first I never did!!!

The receptionist is well trained to recieve all my engine and car parts and stash them in my office for me!!!!

I used to work in a shop where the rules where so strict, not even the admins could get around the proxy and surf control!

Now I run the shop, and can do whatever I want!!!!

 

Just wanted to thank all of ya'll for trying to help me out with this problem. If the car had been at home and not parked on the side of the road somewhere, you guys would have helped me fix this cheaper AND I would have some nifty tools to show for it too.

I definitely agree that Scorp is an asset to CF and Frank, you were dead on.

The shop told me the FP bag shredded and sucked into the FP along with various contaminates in the fuel itself. They 'offered' to change my filter for a low low price of $80, I grabbed my keys and thanked them for their time and work. Looks like I will be replacing the filter in the next day or 2.

I think you guys can see my point in not wanting to leave the car parked on the road while I swapped parts after work. Sucks spending the money like that, but it was the fastest way I could get her home, running.

Thanks again guys!