I got a code 34 on my 86 yesterday. After starting up the engine, the engine light came on. I ran the code, and it was a code 34. The car sat not running for maybe another 20 minutes, then I started it up again, and the engine light did not come on. Also in the last couple of days, I noticed that the exhaust has kind of a strong odor that kinda makes your eyes burn. Any ideas? The only thing that I changed recently is brand new MSN 8.5mm wires, and brand new Bosch Platinum 4 plugs. That was all. The old plug wires were so bad that they were cracked, and one was burnt all the way through. Any ideas??

 

I was recently fighting a code 34. It's a MAF low voltage code. It'll set when the maf is bad, or the power relay(the one to the outside in the pair of relays located behind the batter; the other's the maf burnoff relay). It'll also set when the idle is bad.

Mine actually turned out to be an injector not firing. What would happen is that the car would be hard to start and idle badly cause one cylinder wasn't firing. The SES light would come on at engine start up. After switching out the maf and it's relay, the code would still come one. After changing the injectors, it was gone.

Until I was on a long highway trip and the light came on again, same code. Turned out I hadn't snapped the relay connector completely in and it worked it's way a little loose.

The car will most likely run rich when your maf isn't working properly, since the computer will go to a default table instead of using the possibly bad maf values.

If the code set immediatly, I would guess it has something to do with the plugs/wires you put in. If you accidently swapped a wire, it would cause a rough idle and may set the code. Double check that the wires are hooked up correctly and make sure they're snapped in to the plugs. some are hard to reach. It is also possible to have a bad plug, even if new. I've heard mixed reviews on the bosch plugs in general.

Chris

 

Code 34 (for your year) references the mass air flow circuit. The fact that it did not reappear after a short period means that the computer saw an issue at start up that does not exist now. It would be stored as a history code.

 

MAF code.

Replace the 2 relays on the firewall behind the battery first. If the code comes back, its the MAF itself.

Even if the SES goes away, the problem is still there and those relays must be replaced. Theyre only about $20 together.

 

:iagree:

I had the same problem, but mine didn't throw a code till the power relay finally quit all together.

I was getting fluctuating voltages to the MAF causing rich and lean conditions at different times.

Also, all the positive leads to the sensors get their power at a single terminal between the battery and the firewall. Clean all of them up shiny and power to all the sensors will be better

:seeya

:steering:


[Modified by jackdaroofer, 1:41 PM 4/11/2004]

 

Just because there's a maf code, doesn't always mean it's a maf problem. Especially when we're talking about an intermittent. If the code appeared at startup and went away, most likely the motor didn't run quite right at startup and the maf didn't have enough air pass through it, cause it to send a lower voltage signal to the ecm than it was expecting. If all he did was change the plugs/wires, I'd think there's something going on there. I don't really buy into a coincidence where the maf relays died the same moment he changed plugs. If the relay was bad, the code wouldn't set right away. When my relay was partly unpugged, the code set when the motor reached a certain rpm, around 1200 or so. When my injector was bad, the code set the moment the motor started up.

 

:iagree: I think he might be right. I've thrown MAF codes when the engine was crapping out on a few occasions, (2 bad injectors, and while running out of gas.)