86__TA

Hi all. My cars coming along, and I''m down to my final serious problem (hopefully), Before I start I have a 86 Trans Am 305 TPI. The only problem left is when I accelerate it bogs down, I have a video of it running as well I will link to this thread.
Also my check engine light does not come on, but i checked the obd1 anyways and code 42 came up. Code 42 is the distributor, distributor timing, ICM; and related things. I did a quick search and I didnt find any issues people were having that correlated my issues together. Anyways, any help would be appreciated, also of note: I had the battery disconnected, so if it is a sensor like the MAF or O2, would I need to perform a drive cycle on this car to get a reading?

midias

What is the history on the car?
Did you just buy it?
Did you check the timing?
How old is the distributor / ICM in the distributor?

86__TA

I bought the car last year, but I haven't had it on the road yet, I put a new interior in it over the winter and early spring. New cap and rotor as of a few years a go but it hasn't been driven on the road since. The car has 46,000 original miles. I haven't checked the timing I'm planning on doing that tonight.

midias

If the car has not been driven sense a new cap and rotor was installed and you have a code pointing to the distributor then check that first. See if the firing order is correct.

Second make sure the timing is correct.

BadSS

As indicated - double check the wiring/firing order first. If that's OK, double check all your grounds, make sure the connector on tan wire you unplug to set the timing is good and making a good connection – also look to see if there’s any damage to that wire (potential short or stretched and broken inside – remove the wire loom to be sure). Check to make sure your TPS is good and sweeps properly/smoothly. Check to make sure your IAC is good. If you or you think anyone may have been inside the ECM (very likely as old as the cars are), pull the cover and double check the eprom is seated properly and the wiring harness looks well seated.

The majority of the time I’ve found that the minimal idle speed, TPS, IAC, and base timing are out of whack when you get a Code 42. Below is a really good link to making sure you get all these “in phase” so to speak. I do the steps as indicated in the link, but I do a “rinse and repeat” on the initial steps until I there is no change in the idle speed or timing. Meaning, if you have to increase the idle speed, you have to adjust the timing again. If you have to adjust the timing, you have to adjust the idle speed. If you’re TPS voltage is low and you increase it, the idle speed may increase, and so on. So,, keep going through those procedures until there’s no need to adjust or change anything. Also, while I’m there, I make sure I adjust the TPS to give as high an open voltage as possible with at least a .56V closed TPS setting. You’ll hear as long as it’s over 4.25V open “you’re good”, but they always seem to run better to me when I get the open voltage to as close to 5V as possible.

http://garage.grumpysperformance.com...s-and-iac.168/

If it’s better but still not acting right, then I’d pull the throttle body and clean it and service the IAC as indicated in the link below.

http://garage.grumpysperformance.com...tle-body.3145/

Hope that helps.