ahankins32984

Ok so I have a 86 Z28 with the 305 TPI once she heats up so loses power and has thrown codes 33, 43, and 44 so my mechanic believes its a vacum leak but he also thinks its a bad injector so my question is what do these codes mean so I can start there and fix them first and go from there

ahankins32984

I have replaced these parts trying to fix the power issue :
Plugs and wires, cat, timing chain, pick up, ignition coil, ignition control module, cap, rotor, timing is set at 6 degrees fuel pump, TPS, fuel filter, basically a full tune up minus the injectors

Tuned Performance

iTrader: (92)

http://www.gnttype.org/maint/malf.html

sounds like a possible maf !!

vetteoz

iTrader: (13)

First thing you should have done before spending $$$ was to pull the codes

You won the jackpot.
Are showing problems with MAF , spark control and O2 sensor

Note code 43
"Loss of the ESC signal to the ECM will cause the ECM to constantly retard the timing to its maximum. This results in sluggish performance"

ahankins32984

She didn't throw codes until after all the parts were replaced so I couldn't pull the codes until they were thrown so being that I replaced the MAFS and the O2 sensor and she is still running bad what should be replaced next?

myzblubyu

Amber brought me her ’86 Z28 about 3 weeks ago. When she dropped the car off it would barely run and idled poorly. After pulling codes and completing a complete diagnosis I found the following. Fuel pressure wasn’t stable and bounced around from 35-45 lbs. The intake manifold was leaking oil and antifreeze, thermostat gasket was leaking, runner bolts were loose and not torqued, runner gaskets to plenum were on wrong sides, TPS was out of range, a couple of wiring issues, throttle body bushings were shot, cracked leaking vacuum lines, and a leaking heater core. Basically the past mechanics that she paid to work on this car needs to find a new career. We are a home schooling family and my two oldest sons, 15 and 16, are getting to be pretty good mechanics so they got the task of getting it back on the road. First they removed the plenum, runners, fuel rail, injectors, distributor, and intake manifold. The injectors ohmed at 16.5 each but one of the injectors was not like the others. It was a ½ inch shorter and was not GM; we replaced it with a factory 19# injector. The injectors were cleaned, rebuilt and installed back on the rail with a new pressure regulator (the old one was worn out and the spring compressed with very little pressure). They completely cleaned all parts and installed them correctly, torqued all bolts to specification. Adjusted TPS to .54 volts, reset IAC, replaced new; O2 sensor, knock sensor and temperature sensor. They put in a new heater core, topped off the coolant and set the timing to 6 deg. btdc. The car would not stabilize while idling and all gauges were bouncing. I checked the ground wires on the back of the passenger head, the nut was almost off of the bolt and all the wires were loose. Removed the nut and cleaned years of grime and gunk off of all the wire ends and the block. Reattached all the wires tightened the nut, grounds were now good. The car ran but idled high, around 1500 rpm. As soon as the ECM went in closed loop mode a code 44 was stored, the car would run as if it was in a limp mode and fuel pressure would drop off. We put the car on a computer and it was one of two problems, bad ground or partial ECM failure. They replaced the ECM and the car ran great for about 20-30 minutes then it fell flat on its face. They removed the fuel filter and it was stopped up with black sludge. The fuel filter was replaced and the car ran very good for about 2 hours and then the filter clogged back up. So tomorrow they will drain the tank and hopefully get all of the gunk and rust out. If it was mine I would put a nice used tank or a new one in with a new fuel pump and strainer. She doesn’t have the funds for that, so hopefully, all of the gunk can be syphoned out. A lesson learned from all of this is don’t buy a car that has been sitting for years, don’t run, and needs a lot of work to make it road worthy (also called a parts car). Furthermore, unless you have the tools and the knowledge to do most, if not all, of the repairs you need to pass on this type of car and get something that is more dependable. Please also read before purchasing a third gen. https://www.thirdgen.org/forums/history-restoration/512521-before-asking-what-my.html
Peace

amlv20

good job man!!

myzblubyu

My sons get all the credit... They are my crew....

myzblubyu

What was inside the fuel filter....

amlv20

they are some lucky kids, i always wished my dad was a mechanic. i've had to learn and pick up everything i know now and still learning. some day i will past it down to how ever many kids i have.

what was in the tank? is it delaminating?

myzblubyu

I will find out Wed., my boys removed the new fuel filter and it was clean. The fuel pressure before the filter was 30 psi... The strainer is cloggged... The tank has to be dropped, cleaned, new fuel pump and strainer. The only problem is that the exhaust shop welded the muffler to the inlet side and the pipe before and after the cat. I will have to cut the pipe and weld it back on. It's a shame that my kids does better work than ASE certified mechanics...

ahankins32984

I agree and I plan on paying them extra for all the work as well thanks again!!!!!

amlv20

man i hate when they make dumb welds like that......ASE...ha! whats that??
lol just kidding, it is a shame ase's are just paper tests any hack who studies the tests can get certified.i choose not to get my ase's i'll let my work show how good i am not a piece of paper,they dont care at work anyways as long as i have my ford certs.

myzblubyu

My sons will refuse to take anything extra, they did it to help you out. This is all part of their education, it's called Automotive Technology... Some people pay for the type of training they get weekly. I just wished I could do the fuel pump for you, the exhaust blocks that... LOL They also want to give you a short class for future tune ups. When it's ready for pick-up plan on staying an extra hour or so. Now my boys gets to start on removing the motor out of my Buick Regal and put it in my '72 Datsun 240z with a T56 and a C4 rear differential....

Don Christensen

Gentlemen,

I have found that the easiest way to remove the gas tank is to just go ahead and cut the filler neck.

Merry Christmas to all

myzblubyu

For the update... We looked inside the gas tank with a camera and it was full of the brownish/black goo. We ordered a new tank and installed with a new pump and she's running great. After dropping the tank we found out that someone in the past cut out a hole above the fuel tank. This was done to swap fuel pumps quickly. I would never do this to one of my cars, but I do know plenty of TPI cars that had this done. Another third gen back on the road...

thatdavidkid

Thanks for actually posting a fix in a tech thread, this sounds very similar to my car, I'm going to check fuel pressure tonight, I've got the same code and a trusted friend put a new engine, fuel pump, and filter and pcm in my car right before I bought it but it sat for around 5 years before that.

ahankins32984

She is definitely running strong now thanks to myzblubyu and her friend!!!!!!!!