IROCThe5.7L

Warmed car up, all is fine. Change oil, restart car, SES light, code 34.

I did a search and can't find a thread with good info on code 34, I realize it's MAF related...


Car is running well


[Edit]

Just started the car, SES light, poor as hell idle, running pig rich. Checked all the connections, restarted, same thing.

Restarted again 10 minutes later, no SES light, good idle with a very slight search/surge, but runs way cleaner.

Restarted once again 10 minutes later, no SES light, good idle with a very slight search/surge.


When it was running poor, I unplugged the MAF and it made it no better (I shut it off, unplugged the MAF, then restarted). When I also tapped the MAF it made no difference in idle.


Any suggestions on what I should start to replace? I am going to replace both MAF relays tomorrow. Is it true they are the same part #?

ShiftyCapone

iTrader: (7)

Code 34 is EGR related (unless for some reason it is different for TPI cars). It sounds like the EGR valve was stuck open.

IROCThe5.7L

I believe it if MAF related with TPI (low voltage).

dimented24x7

iTrader: (2)

Sounds like either the MAF took a dump or there is a wiring fault somehwere. The other possibility is that there is a vacuum leak that causes air to bypass the MAF sensor. I suppose its possible for a stuck egr to cause it as well.

rezinn

Sounds like possibly you knocked something and messed up a MAF connector. Check all of the connections to the relays and the sensor itself and see if it looks like they're making contact. The relays are pretty inexpensive, <$20 for both (yes they are the same p/n as the fuel pump relay as well).

You might also try cleaning the hot wire of the MAF sensor with some electrical cleaner or whatever you have. Won't hurt to clean the relay connectors either and make sure the pins are all in tact.

IROCThe5.7L

Thanks for the replies guys. Wish an autoparts store was open now

After browsing through a tun of threads, I did find some good information. When I unplug the maf, it does not help. If I tap on the maf, there is no change. From the diagrams trickster posted, this means it's most likely not the maf (it was also replaced a year before I bought the car).

I went over my motor with a strong stream of propane when I put my TPI back together and there were no leaks anywhere. I'll try it again tommorrow though. I am really hoping it is a relay.

The pins on the maf connector look nice and clean and it plugs in tight. When I took the car out this year, it would have small fits of poor idling, then just go away and no SES light. Since then the car has been running great, then out of no where today I got the SES and the same poor idle but worse.

I just graduated college this week and just wanted to take it easy for a while and enjoy the car

Just thinking though, on the passenger side valve cover, you know that hose that plugs into it (I don't know what it's called, it's not a pcv valve), it dosent fit very tight, the gromet must have went bad. Could this cause it? It has been like that for a while though with no problems until now.

rsn932

this could be way off base, but i got a code 34 out of nowhere last year with the same terrible idle, SES light, but then once it was warm, idle was fine with the slightest hint of a surge. a new distributor cap and rotor fixed it. i have no idea why and it makes no sense. this probably doesnt apply in your case, but its a good reminder to just check the basics of a regular tune up.

IROCThe5.7L

Thanks for the reply. My whole ignition is new with MSD parts.

rezinn

The passenger side valve cover grommet connects to the throttle body and I believe allows the pcv valve to function by relieving vacuum (sort of a fresh air supply on the other side of the engine as the pcv sucks on one side). It tends to work in the opposite way though, depositing oil vapor in your intake sometimes. It isn't likely to cause the MAF to malfunction since it's downstream.

If running is the same with the MAF unplugged then your problem is that the MAF isn't working. That could be due to the power relay failing, the MAF being bad, or the burnoff relay not working and so now the wire is coated in crap. Cleaning it might show you that the burnoff relay isn't working if it temporarily fixes the problem.

IROCThe5.7L

Thanks for the reply rezinn, I remember you from way back


I'm gonna do everything suggested and pray

rgarcia63

They're not the same on my '88, the MAF burn-off relay has only one normally open contact while the MAF power relay has 2 contacts one normally open, the other normally closed.

IROCThe5.7L

Update:

I figured i'd take the easy route first and replace the relays first before I cleaned the MAF. They are both the same relay, so I got two of them. Well one of the new one's I bought was defective and too small, the other one fit perfect on both. So I replaced the MAF power relay and it is idling the best it has in a long time.


Thanks guys

rgarcia63

As I said the MAF power (oval shape) & burn-off (rectangular shape) relays are not the same, and do not interchange.
The fuel pump relay (oval shape) is the same as the MAF power relay.

IROCThe5.7L

Ok, I am getting confused here. Vaders pic, tricksters pic, and my book's pic of the relays are all different.


Is this picture correct? If so, I replaced the Burn off relay. All auto parts stores say they only have one relay for both. Any suggestions where to get a MAF power relay if the pic I posted is correct?

Relays in my car (Labeled my trickster):

IROCThe5.7L

Vader pic:

IROCThe5.7L

The picture in my book: