Guys, my 86 Z28 with a 305 TPI I just got has 3 different codes it's cylcling through. It's running pretty rough. I'm stumped as to what to look for first. Here's the codes it's giving me.

1-54
2-22
3-44

I know what all these codes refer too, but just don't know what to think. If I unplug the ECM to clear the codes, and then hook it back up and start it, wait for the check engine light to come on, it will give me say code 54. Then, I'll unplug it again to clear, start it back up, and get say the code 44. Code 22 will also come up sometimes. Now this car was sitting for about 6 years in a garage, which I believe cause the body is in good shape. No major rust. Even the paint is fair except for the nose wich is faded. With the ECM acting like this, I'm really starting to wonder if the ECM is whacked out?

ALSO! If i try and hook up a tech 1, it never gets the data. I checked the pins at the ALDL and they are all straight, and clean.

I don't want to be throwing all these parts at it cause money is tight right now.

Here's the questions I need help with.
1-What relay on the firewall is the fuel pump relay?
2-Those with more experience, do you think this is a whacked out ECM?
3-What wires, or connections should I be checking for fuel pump voltage?
4-Can this be a bad fuel pump? When I did a FP test, it stayed around 40psi at idle, and would jump to close to 50psi when given throttle.
5-Could someone point me to a wiring diagram for the fuel pump relay/fuel pump wiring.
I know this is alot to ask, but someone please take the time and help me out, I finally got a Tuned Port z28 with T-Tops and am dying to drive it in the nice weather! ANY SUGGESTIONS ARE WELCOME! THANK YOU!

 

well i'll try my best on some of these ?s. 1. condeming an ecm is a last resort, as they do go once in while but generally are pretty bulletproof. i do stress generally. 2. it seems you have hard codes, which means if you disconnect the batt and the light comes right back on those codes are legit and causing a problem. what you need is to get a diagnostic manual with a flow chart for your codes first. follow it and you'l find your problems. there are many thngs to cause problems like this like bad connections either to the ecm or the circuits that ar throwing these codes. corrosion in wires to the circuits witch have thes codes. etc. All i'm saying is trace your problem from what the code tells you. and if the codes are false look to the ecm last.

 

Your fuel pressure is a little high, but not high enough to cause any problems and its certainly not evidence of a bad fuel pump. Your fuel pressure is regulated by vaccuum through the fuel pressure regulator(amazingly enough) So this wouldn't be a part of your fuel pump circuit. I've encountered a few bad fuel pumps in my day and what happens is your car will run fairly normal at idle, but it will studder severely and sometimes backfire when you apply throttle. The greater the throttle change, the more studdering. Your fuel pressure will be around 30-35 psi at idle but then will DROP at higher throttle.

As for the code 22, the TPS is pretty easy to check. Take a (preferably digital) multimeter and insert the leads into the back of the TPS plug where the top 2 wires meet the plug. I believe red goes into the top and black into the middle, but I may have it backwards. Check thirdgen.org's tech articles for the full procedure and details. Make sure the ignition is in the on position, but the engine is not running. The voltage should read somewhere around .55 volts at idle. Move the TPS lever slowly towards WOT. The voltage should steadily increase to around 4.00 at WOT. If it sticks/jumps/decreases while you are increasing throttle, then the TPS is your problem.

For the lean exhaust code, either the TPS or low fuel pressure can cause it. Check those first. Also, I would change the O2 sensor because its only like $20 and its one of those things that steadily goes bad over the years.

Hope this helps

 

OK, I checked the tps volatage, and got it set. however., the car will not start up and stay running on its own. just coughs and sputters and dies out. one thing i noticed is it has no effect on weather or not i disconnect the mas airflow sensor. will this car not run at all with it disconnected? how can i test the mass airflow sensor? just by tapping on it and watching for a change in idle. im at a loss. been checking everything from the relays to connectors. GRRRRR!!!!!

 

The car should run with the MAF disconnected. Thats probably not your problem. How do you know the fuel pressure is fine if you can't keep the vehicle started? With the bad fuel circuit and lean exhaust codes, bad fuel pressure from a bad pump or wiring seems to be the most likely explanation. I believe you asked where the fuel pump relay was. Its on the firewall drivers side.

 

i had an ecm go bad on a 88 tpi vette and it threw a code for electronic spark controller. it would run ok when the check engine light was off, but once it came on it ran like complete crap and had no power. it would stay running however. replaced the ecm out of a 89 iroc i also had and the problem went away. so i just bought a new ecm and all was good. you might want to try to swap with a known good one to see if it helps at all before you buy one. make sure the wires in your MAF are not broken. but your also throwing no MAF codes so im not sure that would be it. never hurts to check though. replace the o2 sensor like said before. the only thing pointing to bad ecm is you couldnt get any data from the ecm. make sure that you have it in diagnostic mode and try again.

 

Ok, great news guys, I got the car running smooth and on all 8 cylinders. I got a wiring diagram and checked several connections, and the fuel pump relay wiring. They both had not so impressive connections. Corrosion city. Cleaned em all up. I also ran top engine cleaner threw it after I siphoned out all the old gas and filled it with fresh fuel. Also, cleaned the fuel injectors. (Working at a dealership has it's advantages. ) Tried to start it, and it wouldnt stay running. Set TPS voltage it was ok right on the money at .54 volts at idle and 4.xx at full throttle. The car smelled rich as can be, so I gave it one last ditch effort, and pulled the spark plugs I could get too, and sure enough, it was flooded. I cleaned the plugs, checked the gap, unhooked the injectors, cranked the engine to spit out all the fuel, and reinstalled the plugs. This time it started up! I then checked the timing, and was ticked off that it was so far out in Egypt it wasn't even funny. I shoulda known better and checked the timing earlier. Set the timing to 6 Degrees BTC, and she started running like a raped ape!! Thanks guys for all your help!

 

AWESOME JON!!!!!!!!!!!!!!!!11!!1 I hope you like it!
BTW.. how does it compare to your old carb'd 305?

 

hey guys mine has pretty similar prob heres my post oHad the camaro (86 5.o v8 AUTO) out a few weeks ago for a bit rip,which it hadn't had for literally a year or so!! all was fine till heading home and the srvice eng light flickered, as it did the engine seemed 2 choke/lose power and it felt like it wanted 2 die, this was at about 10mph, then it cut out, started up 1st time and got me home which was less than a mile away thankfully, kind of kangarood all way home with light flashing intermittantly.
did a error code check following night after leaving it to sit and showed up no codes and ran fine the other 2 times i had it out, however i took it out yesterday and gave it one boot on the way home an it started it's crap again, i pulled over an turned it off for a few mins but was still same all way home, then when got in would'nt hold a rev, ...was a bit spluttery, would say a misfire but is kinda hard to tell? too me anyway, cuts out if not on the gas, ok ive now had it up 2 a tuning clinic and it went haywire on the diagnostics they think it cud be the ECM or a break in the wires to the ECM ive also been told it cud be vacume leak, MAF sensor Coolant temp sensor, oil pump!? i must add tho, its completely intermittant, always runs perfect cold then once it starts to heat the SES light will flicker then it revs its self then drops and runs lumpy then randomly revs again, altho on way home from tunic clinic trip aprrox 15 miles it ran terrible till i got onto bypass(high way over there ) and then ran perfect all way till i got to my street?? i so dont know where to begin, any suggestions wud be appreciated, thanxn some sight any help wud be ace altho i think i may get timing check(how is this done)

 

p.s it Had been driven in over a year! just not very hard its my 2nd car so dont do alot of miles x