'89 GTA w/ the L98:

*Note; I have read a few threads where similar problems were discussed but I don't think a concrete solution was presented in any of the threads. I have not had the car for too long and I am still very "green" when it comes to troubleshooting some of these issues that seem to be electrical.

Here is what the ol' gal has started doing (all within a month or so - coincidence? )

1) Intermittent starting tendencies: Yup, I've seen a few threads about this very problem: Starter won't engage but everything electrical works; lights, windows, lighter, radio, etc....... Go away for 10 minutes and come back and it starts right up. I did notice that when it doesn't start, the "Security" light stays on (I read in 1 thread where it is supposed to go off after a few seconds; something it does when the car will start). I have not been able to determine by reading any post what is causing this. I do know that a few members have attempted to change many pieces of their ignition system and have had no success.

2) "bouncing" idle; In Park or Drive the idle bounces between 500 and 1000 rpm's for a few minutes until the engine gets up to a good running temp.

3) High Idle speed: upon start-up or even after driving for a while, in Park or Neutral it is not uncommon for the idle to go way up to 1300-1500 RPM's for a few seconds before coming back down to about 600-800.

4) "Service engine soon" light just started coming on today (this afternoon). I drove the car for ~ 5 minutes with the light on before parking it for an hour. The next time I started it, the light came on again and that is when the car began it's "bouncing idle" issue.

After reading numerous threads and seeing what changes in certain components people have noted when changing those components, I get the feeling that everyone is dancing around something that if fixed or replace will correct these four issues. Is it EGR, injectors, intake plenum, or the ignition module or all or none? I am going to look through some of the service manuals tonight and try to think about what is going on with the car before going crazy (or going on a spending spree) and replacing all these peripheral parts. Any help or suggestions, as always are appreciated. And yes, I will soon have pics of my car up on the web. I have just been lazy about recharging the batteries in the digital cam. Thanks to anyone who gives feedback.

peace,
Lampropeltis

 

check the codes first . . . that should at least give you a place to start

 

My car does similar, well, did similar My starter was actually just on it's way out. I had replaced the O2's a while ago in an attempt to get through emissions, but the computer didnt really take much note of them through the long-term rich/lean condition. So when I unplugged my battery to change out the starter it reset the computer to factory standards.

The car started dying once I replaced the starter, with a rough idle, but it is taking the readings from the O2's and has a very smooth idle now. I also had the SES light come up.

I doubt that it's all a problem with one thing. You should disconnect your battery for a minute (actually only takes 30 seconds, but you never know lol), the starter thing... well, you can live with it until your car leaves you stranded I supposed?

SES light you should check for codes and post em

 

For problem number one do a search on vats problems. You will be able to find some troubleshooting techniques and common part failures there.

2,3,and 4 are most likly caused by the same failure. Pull your codes and tell us what they are.

 

Well, I have never done a code check on my own and I am not sure which daignostic piece to buy for the car. I looked at one @ Autozone ($150). I then asked them to run a code check on the car and they ended up NOT using their piece of equipment. Instead the lady took a flattened key (looked like it was made just for this job) to read the codes. From what I understand, you insert that (I did not ask which # hole she inserted it into, though I do remember somebody here posting that info) and count the # times the SES light blinks. If that sounds right let me know. Anyway, she came back with the codes:

33 & 36.

Their computer system indicated that "36" means the ECM has detected a failure in the Mass Airflow Sensor burnoff function, or in the related wiring/connectors

"33" they were a little less clear about - as in I did not get a printout of what the code "33" indicates. Rather, they wrote down on the back of the "36" printout what 33 means and told me that it meant the Mass Airflow Sensor or circuit voltage is out of range. OR there may be some issue with the vacuum lines.


Now, the last part troubles me a bit. One of their managers insisted the MAF was a square unit residing along the firewall. I was shown an MAF by a different manager and told it was located along the rubber ducting for the air intake. In my car I found what the 2nd manager showed me. Upon closer inspection I did notice that there was a hose on the passenger side of the engine block that was just hangin'. It had markings on the open end from a clamp - telling me it was at one time, well, clamped I did not try to stretch the piece to see if it would reach the MAF (or at least the cylindrical thing I was told by one manager was an MAF) mainly becuase I still have to hold the hood up with one hand (still have to install the hood struts I bought a couple of weeks ago ). So now I have to figure out where that hose goes to and if that is what is affecting the car. I should also mention that yesterday the car started sputtering on start up and continued to do the bouncing idle thing while coasting at slow speeds.

What i mainly want to know is what is the MAF sensor and where (if any) are there vacuum lines that run from it (I did not see any in my initial inspection; I will likely look at it more closely after work). And, is it possible the MAF is the source of the 3 latter problems in my original post + these new ones that surfaced yesterday (high idle, bouncing idle, SES, sputters on start up).

Dankhound: I suspect it is vats, and (This is for anyone with the same problem) everyone should be aware that I found in the firebird owners manual a possible solution to the intermittent start up. It says that if the "Security" light stays on but the car does not start, then there is either a problem with the key or the Ignition Lock cylinder. Thanks for the suggestion, I think that confirms the original problem. The really screwy thing is; now the "Security" light does not come on at all when the car decides to have a no start moments

Ahh well, I knew that GM's electronic systems were a little shady in the late 80's. I find it pretty amusing that a system that is supposed to make the car basically dead to anyone without a key, works better when its not working at all

Love the car though. Thanks all for your input.


Peace,
Lamp.

 

the MAF is the cylindrical thing in the air intake
the MAF power relay and burnoff relay are square/rectangle things on the driver side firewall

 

and yes, the MAF could be the cause of the latter 3 problems
if you are going to replace the MAF, replace the relays first (much cheaper)

 

Thanks RS92. The price for a MAF is pretty steep. Looks like I will make a trip to purchase the relays first.

 

Make sure your security light isnt burned out. It should come on when the key is turned on and then go out.

That hose could be the root of all your problems. There are no vacuum lines that go to the maf, just the large intake hose. Before you go out and buy anything try to find that vacuum leak and see if that takes care of your problems.

 

Dankhound, is there a way to test the MAF power relay and burnoff relay's to see if they are the problem?

 

Relays are pretty easy to check. If you apply 12v and ground to the smaller terminals you should get very low resistance (less than 1 ohm)on the larger terminals. Another thing to check is for 12v on the dark blu wire and the red wire with the engine running. While this is not as accurate as the above test it is a good indicator that both relays are functioning.

Before doing either of the above thou make sure you dont have any vacuum leaks as they can cause you maf to read inacuratly.