MAF

that about sums it up. i can't figure it out. my 86 is the worse but isn't my major concern since the 89 is the daily driver...


86 305tpi- this is just aggravating, it started out similar to the 89 except didn't randomly stop running or die rarely. currently the car is on its last leg. if i figure the engine out i can fix her body. i have changed the fuel regulator, put a cold start block off kit on it thinking that may help, new MAF, replaced a knock sensor, one O2 sensor, new computer chip, new plugs, wires, and some other things i cant think of but may come back to me if mentioned. the car runs rich. and when i say rich i mean horribly rich. the plugs will fuel foul in a couple min. of run time and wont restart unless cleaned. when trying to start it turns and tries to fire, and if the plugs are clean then it may just start if you have your foot on the gas when it slightly fires. well if you get it started it runs bad, smoke out the back with a smell of fuel. low RPMs has a rough idle, mid range RPMs is a decent but not good idle, and high RPMs it will on sometimes pop and at full throttle will all but almost cut out and die. it also says that the MAF sensor is too low(i think it was too low, been a while since i worked on it) at one time i also had a code for the spark control module but that went away. i had my plentem apart to replace a sensor under it (forgot name of it) on the inter parts of my plentem it was coated in a black residue. so that to me was evident it was running too rich.

please, help me. i am on the breaking point with these damn MAF things...

thank you

 

The black in your 86 plenum is from the egr running exhaust gases back thru the engine. I would check all your vacuum lines for breaks or cracks. I struggled with my 87 for weeks, and found bad vacuum lines under the plenum and a leaky throttle body. Hope this helps.

 

ok i'll take a look

thanks

 

vacuum leaks or unmetered air (air entering the intake post MAF)... fo sho.

Break out several cans of starterfluid or brake cleaner and get to spraying areas of the engine, intake ducting and vacuum lines. If your engine rev's or stumbles when you spray, then you've found a leak.

edit: One more thing. Try disconnecting the MAF and see if it changes the way the car runs. That will tell you if the MAF is working.

 

dont forget to ohm the injectors. sounds like one or more are sticking! do a search on here about how to do it.

 

Just curious if you have ever replaced the MAF relay's, not the sensor, but the burn off relay and the MAF relay. A code 33 or 34 can be tricky to find.

 

if i unplug the MAF it runs different. little better actually.

as for they MAF relay's...which ones are they? jw

 

There are 3 relay's by your brake booster on the driver side firewall, 1 is fuel pump relay, (closest to the booster) then the MAF power relay, then the MAF burn off relay. They are black oblong with the wires on the bottom.

 

alright. i knew where and what they are, just not which one was which.

 

on the 89 the maf relays are oval shaped, on the 86 they are square but in the same place.

 

Your 86 may have a faulty coolant temp sensor. An open or high resistance in the CTS circuit will cause the engine to run very rich. Generally you will get a code 14 for this but not always. You might check sensor resistance. Do you have a good repair manual? You should. I recommend you complete the diagnostic sequence for code 33.