OK guys,

I got all that carb stuff off and all the TPI re-installed on my '86 305. I got her running, albeit rough and stumble and I knew there would be issues. I figure my best bet is to get a reading and start working on the codes the ECM gives me.

Where do I find a scanner I can plug in to get started diagnosing the problems? What do I need, how much are they, and where do I find one, etc...?

Thanks

 

The one listed below is your BASIC scan too. You can also jump A and B ports in the ALDL and flash out the codes.

Actron/OBD I code scanner $29.99 Auto Zone


Code scanners retrieve OBD-1 data through a series of flashes. Retrieves engine trouble codes from the on-board diagnostics (OBD) computer for pre-1995 vehicles.
Retrieves ABS trouble codes from the on-board diagnostics (OBD) computer; trouble codes flash on dashboard check engine light
1994 & 1995 GM vehicles were equipped with several different engine computer systems.
Compatible with OBD I 1982-1993 domestic GM and Saturn vehicles
Includes user manual

 

I posted a link to a good low cost one (actually, a box of about a pound of em or something) here. https://www.thirdgen.org/forums/tech...de-reader.html They're pretty common, might not even have to buy one, might be able to borrow one from somebody.

 

Sofa.....you ALWAYS post the greatest. I am sooo happy that some people STILL have a sense of humor!!

 

Hey, if ya can't have some fun at it, why do it??

 

The only thing that lights up on my dash is the fasten seat belt light. Like I said, I gotta a lot of bugs need fixin'...

 

so you don't have a working CEL?

 

Buy acoupla boxes of 194s, pop the dash out, change every single bulb. Doesn't take 20 minutes. Sounds like you need it anyway so just do it.

 

I will add that to ever growing list..194's???

Forgive my ignorance Bob, what is a CEL and how do I know if it's working or not?

 

194's are the lightbulbs.. CEL is "Check Engine Light". C'mon, get wit the program! I am really kidding!

 

Hey, I'm new to these cars and there are so darn many acronyms to keep track of, TPS, IAC, MAF, MAP, CTS, ...It is scrambling my brain.

I'm sure it's trying to give me a CEL but it looks like I need bulbs..I imagine I can get them at any parts house..?

 

Its cool! I know. I've been around them for 30+ years and still throws me for a loop.
Yes, should be able to pick them up at Auto Parts store , or go to a electronics/Digikey/Mouser type place. I got a few at Advance Auto.

or if you REALLY want to, the dealer may/should/could have them.

 

I quoted these two sentences because I wonder if whomever put the carb on might have purposefully disabled the light ? The car is an 86 , I also wonder , is that early enough to still have had the separate CEL driver module ? I figure if the bulb is found to not be the problem you may want other things to check , and the presence of a driver module or not would be a good thing to know .

 

Nothing those people did will surprise me at this point. I mean who removes the temp sender and plugs the hole??


Anyway, I got in there and replaced the bulbs. I now have a CEL. When I turn the key on after jumping A&B I get what I assume is a code 12. One blink, then two quick blinks. The shop manual says it should flash this three times then flash any other codes stored. Except it just blinks code 12 over and over..?


I can't believe there aren't any codes in there. The car starts but idles poorly. I tried the IAC adjustment but couldn't get it to idle below 750 RPM's. Sounds great when I rev it but idle is brutal. Plus, once it's hot I have to hold the pedal to the floor it to get it re-started. Something ain't right and I can't believe there are no codes?? Ideas? Or am I doing something wrong?


Oh, and Sofa....the link to the paper clips.. Hilarious! got a good laugh out of that one...

 

It great that it was just the bulb , I was truly afraid they may have hacked the wiring to put the light out when it was carbed . Anyway , the repeating code 12 thing is normal if it's got no stored codes and of course not every failure always results in a code being set .

Now , I quoted part of your description because I want to mention that flooring the gas all the way while cranking the starter actually shuts the injectors off , Clear flood mode it's called . So it stands to reason that if you have a poor idle and need to floor it to start warm , it's highly likely you've got either a leaky fuel pressure regulator , or , leaky injector(s) . Have you done fuel pressure check , and fuel rail leakdown check ? If not , those should be your next two tests in the troubleshooting process .

 

If the fuel pressure regulator was leaking, would it be outside the unit, where it could be seen, or leaking into the engine? Not sure how to do a fuel pressure check and don't even know what a fuel rail leakdown check is or how to do it. How do I tell if the injectors are leaking?


Sorry guys but this is the first time I have ever bought a 30 year old car. Sure learning a lot but it's making me feel like a knucklehead...

 

If the regulator is leaking the vacuum line that connects between it and the plenum will have fuel in it. You'll need a fuel injection pressure tester and it hooks up to the schrader valve on the fuel rail near the pressure regulator.

 

Schrader valve being the nipple that resembles a tire valve and is used to relieve the fuel pressure? Is that something that can be rented or loaned from a parts store?

 

That's your guy. And yes they are typically rent-able.

 

Auto Zone here loans the tester out. So what should my fuel pressure be at idle? I do check it at idle right?

Will this tell me if I have leaky injectors?

 

FP should be around 42 - 45 psi idling with the vacuum line to the FPR disconnected; kinda 38ish with it hooked up.

 

If you prime the rail with the pump (engine off) and then pinch both pressure and return rubber lines the gauge should hold whatever fuel pressure was in there. If pressure drops, you have a leaky injector.