palomo88ta

Hey guys I hope someone can help cause I'm runnin out of Ideas. I've got a pretty much stock 1988 T/A with the LB9 305 TPI, 5 speed...only done minor mods (K&N air filters, flowmasters, hooker headers, thats about it) but anyhow it's always run strong but I had it parked in the garage for a month while I was out working away from home...came back started it up drove around the block just cause I missed it, worked fine parked it. Next day I started it up and it stalled burped died within 10 secs...I tried to start it and keep it on with no luck at all. I checked the air going in...sucking strong so I figured gas problem...did the little stuff new fuel filter needed that....and miracle it ran better!!! still would die if I left it idling long enough. And it idles very erraticly and eventually stalls...when I step on the throttle the engine stalls or bogs rather than accelerates...under any load it pops and chugs and is basicaly unusable.
So frustrated I though about checking for codes....33, 34 indicated MAF High voltage and Low voltage...replaced the rather expensive MAF and relays...no change. Checked the wiring from the MAF to the ECM...wiring good. Checked for vaccum leaks everywhere found one bad gasket (throttle body) no biggie put a new one on....no more vaccum leaks that i could find. Put a jumer on the TPS...reads correct voltages on the meter...replaced the o2 sensor just for the heck of it but that was never really the problem anyway.
Reset the computer. Now I've got a 42 code or EST open or grounded. I don't know how to test this without just buying another one and putting it on but I've talked to numerous people who all have different Ideas about it. My car is missing...backfiring out of the intake...stalls if I give it gas but increases rpms for a few seconds when I take my foot off the gas!?!?!

Some suggestions I've had...
bad computer (has been replaced about a year ago)
bad or clogged catlytic converter (stock original as far as I know)
bad tps (the readings were ok )
bad timing chain?( no idea if this is even a possibility)
bad inner gasket in the intake manifold? (don't know)
clogged injectors (don't know how to check but have been using fuel injector cleaner in the gas regularly)
bad fuel pump?(how do I know...it's hard to check a lot of things cause the car doesn't stay running.)

And this all happened from one day to the next. Amazing. I am open to suggestions so if anyone can help I'm all ears.. Thanks alot...sorry for the long thing here but I wanted to try and accuratly describe the problem. Thanks again. I'll check back soon.

formula350_87

Code 42 - EST (electronic spark timing) suggests that there is a problem with ignition. I would check the following:
1. Fouled spark plugs;
2. Spark quality (should be blue in color). There are also spark testers that one can connect between the spark plug wire and the spark plug;
3. Battery voltage. Is it above 12V? What's the voltage at the distributor?
4. Check the timing with timing light under normal operation. Check it with EST disabled too. To disable it there should be a wire from distributor to the ECM. If it's OK with EST disable then it's the ECM to blame (after you check the 12V off course).

To check if you have fuel delivery problem you might connect fuel pressure gauge to the fuel rail. There should be a port in TPI system. Pressure should be above 42PSI for stock TPI.

Hope this helps.

RMK

I saw you replied to an old post of mine.

Get out your DVM and set it on a 20VAC scale. Test the alternator output voltage right at the terminal stud on the back of the alternator. If you can read more than 0.20VAC, you have a potential problem. Any AC voltage over that level can cause ground reference problems (noise) that can render input signals to the ECM useless.

If you do get over 0.2VAC try charging the battery, disconect the alternator and start the car. See if that makes any difference.

I had a code 33 develope last time I was out in the car, but it had been stumbline for months before that. If I still have the code when my tranny is swapped over I'll be doing the above.

palomo88ta

thanks folks...I will try all of the above today and get back to yall. I love this site man...gives a brotha hope when he's down..or at least something new to try. Get back at y'all later.

RednGold86Z

iTrader: (1)

Central California, eh. Central Coast?
I'm in SLO.
Code 42 will pop up if the EST bypass wire is disconnected. It's a brown and tan wire with a weatherpack connector over by the heater blower motor.
If the ignition module goes, that'll also likely cause that code too. I don't think fouled plugs can cause a code 42.
If you're close to SLO, I could try to help if you want.
Later,
Jeremy