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Gearheadotaku
Gearheadotaku UltimaDork
4/22/19 9:06 p.m.

What ignition module are you using in the distributor? The TBI and TPI use different ones. The TBI will pull 4 degrees of timing at 3500prm while the TPI will not. The TPI then add 2 degrees at 4000rpm.

The GM module used to be marked with 048 for the TBI and 369 for TPI. Newer ones have no marks.  Search for D1943A to get the good one. I think this is mentioned on 3rd gen somewhere.

Just got one for my '91 TBI w/LT1 cam but haven't been able to get on the road for a proper test drive.

I am using a 3-wire o2  triggered when ever the key is on. Seems fine so far. Used a hot lead from the unused AIR system to power it up. My exhaust is the larger cast iron manifolds from the 305 G92 / 350 engine.

zordak
zordak Reader
4/23/19 9:52 a.m.

On the 91 TPI speed density ECUs the timing is controlled by the ECU. Knock sensor and distributor module all connect to the ECU and there is a setting in the chip for base timing, which on a stock TPI is 6 degrees advanced. The TBI are also speed density (MAP, MAT and TPS sensors and a table in the chip for VE and RPM). With a TBI system and a LT1 cam you will need either an after market controller or find someone to re-tune the stock chip to match the new VE/RPM of the new cam. Also ordered a new distributor for a TPI.

zordak
zordak Reader
5/27/19 1:14 p.m.

Hi all,

    Took the 'bird up to the property up north and on the way back she started slipping really bad in 4th gear. This means she sits until I can get a replacement. In the mean time I bought a cheap boat. I know there is no such thing as a cheap boat, all the repairs and upgrade will cost. At the moment I am still under $1000. If anyone is interested say so and I will start a post in the off topic section.

zordak
zordak Reader
5/27/19 1:29 p.m.

Confession time. I know I complain about not having money sometimes then mention I dropped a good sized chunk on something else. I do have a spending problem when I have spare cash. I do manage to save money for important stuff, insurance, taxes etc. But I get distracted by other shiny (actually rusty and need work)  things. This seems to get worse as I get older using the excuse "If I don't do it now then when? When I am sitting in the nursing home and can't?

GCrites80s
GCrites80s Reader
5/28/19 9:07 p.m.

Yeah it seems like people develop a complacency between 35-45 where they're like "I don't feel like doing anything to the car, it's fine" that they didn't have from 16-30. Then over 50 the alarm goes off.

zordak
zordak Reader
8/19/19 9:47 a.m.

Ok after fixing a few other vehicles and taking about 3 passes across the work bench and getting really honest about "do I really need to save this", I got the bird up in the air (jack stands high enough i can almost roll over underneath) I have the fluid drained out. of the tranny. A few other wife induced projects and the usual mess on the floor kind of used up all the ambition. I did get most of the trans fluid up but nee to go under there and clean up some more.

zordak
zordak Reader
9/9/19 10:05 a.m.

Ok 3 hours on Sunday got the trans out. Because of clearance issues I think I need to pull the distributor out to access the 2 top screws for re install.  Problem The wife wants a good looking car to run around in and this one needs paint and interior so we have been looking at other options. option #1 a decent C3 vette because I remember when these came out and thought they looked cool then and still do, also drove a 68 327 300hp 4 speed in 76 and 17 year old me was impressed as the only other performance car I had driven at the time was a 70 Trans Am 400 4 speed. option #2 buy a 4 gen Firebird in good condition, a convertible preferred but T tops would do. Although we test drove a 95 convertible yesterday and she thought something was wrong in the front end but I thought it was just body twist so we might end up in a T top car. This leads to If we keep it, definitely a rebuilt but if we are going to kick to the curb then a used one. So on hold again until a decision is made.

zordak
zordak Reader
9/23/19 9:29 a.m.

Pressed the big green easy button and ordered a rebuilt trans.  Looks like we will get a maaco paint job and then attend to the interior. I will let you know when the trans shows up. Hopefully I can get a few drives in before packing it in for the winter.

zordak
zordak Reader
10/8/19 9:35 a.m.

Trans showed up. Then I screwed up right away, thought I needed to drive out the speedo gear lock to remove the gear, broke said lock, ordered new one should be here this week. I made longer puller arms to help remove the gear. In case your wondering the new trans came with the wrong tail housing and no speedo gear. Apparently your supposed to transfer any items not matching the old trans. The tail housing are the same length but the new one came without the torque arm mount bosses. Of course other life problems are getting in the way, mold from leaky basement meant a day of tearing out drywall, trimming out some trees that had gotten out of hand. and dealing with a lump on a finger of my left hand. The last I need to go in for day surgery next week fri. Doc believes it is a growth caused by an old metal chip I failed to get out 6-8 months back. Anyway updates as works gets done.

AngryCorvair
AngryCorvair MegaDork
10/8/19 9:49 a.m.

i'm still reading.   love me some third gen.  get the hand fixed so you can get the firebird fixed!

zordak
zordak Reader
10/9/19 9:21 a.m.

well I might have time this weekend as the wife is going on a trip and needs time over the weekend to prepare. So if the clip shows up this week as promised I could get it in and running. Depends on getting the top screws in.

zordak
zordak Reader
10/10/19 9:16 a.m.

Clip showed up yesterday took a little time to finish swapping over parts and crating up the old trans.

zordak
zordak Reader
10/13/19 3:47 p.m.

OK First I double flared the coolant lines because I cut them to make it easier to remove the trans. I got the trans under the car then wrestled on to my low profile floor jack then on to the trans jack. This was a couple of hours. I then put in the dipstick tube and the 2 upper screws in the trans so I would not have to do it later. Once I got it up near position I found it was sitting at an angle to the engine. I found long 3/8" screw, got it in one side then cranked up the trans to line up the other holes. All the while making sure the torque converter was not sticking out to far. Right now I have 4 screws in and figured the exhaust is what is keeping the engine from tilting down far enough to get at the upper screws. At this point I decided I had enough fun for one day and will attack this again later when it is warmer. Highs in the 40s today supposed to be in the 60s next weekend so I'll see how I feel the day after my surgery.

zordak
zordak Reader
10/21/19 9:18 a.m.

Surgery went well but stuck with a splint on the finger. Something about the incision being on the joint and it will heal better/faster with the splint. Any way since it did not hurt after the local wore off I tore in to the 'bird. Disconnected the exhaust and got a little more access to the upper 2 screws. got the screws in. attached wiring connectors, TV cable and shifter. The rear mount and cross member was next with the drive shaft following that. re-connected every thing else and filled it with fluid. On the test drive the shifting is a little harsh if I romp on it (squeaked the tires from 1st to 2nd) but no slippage in third or fourth. I am pleased with the trans. I will get it cleaned up (last trip was up north when the pine trees were pollenating all over the place) and drive it as much as I can until the snow flies. 

zordak
zordak Reader
11/10/19 3:13 p.m.

Ok this is the last update went out and bought another car and need to let the Firebird go. Thank you for reading.

zordak
zordak Reader
3/1/20 3:51 p.m.

O.K. Probably not selling. My air compressor died a week or so before the vacation. I went out and bought a Harbor Freight one that had the best cfm at 90 psi. I wired in a new outlet for as it draws 14 amps. While doing this I noticed trans fluid under the vette. Damn. I check the trans fluid level on the vette and it is ok. Since the Firebird was parked there until just after the vette arrived I looked under the Firebird. Damn again more trans fluid there. O.k. I just swapped the trans so I could have left something loose. Jack it up, crawl under and look around looks like the pan gasket is leaking. Grab socket and ratchet and check the pan screws, bingo, snug but not tight. go around and tighten them all up, refill with about 3 pints of fluid to get the level up and I am hoping this cures the leak. Because the wife complained about smelling exhaust I checked it and found no leaks, must have been from another car nearby when we were out for a drive. I did take the 'bird out for a test drive after the tighten and fill and was rewarded with a nice responsive car with firm shifts. Next I will probably re work the cruise mount to get the cruise working.

zordak
zordak Reader
3/9/20 9:47 a.m.

Well I did not get to the cruise control. Spent some money and got a set of 8mm plug wires from Summit racing. In the course of putting these on I found the #4 wire got burned a little.  I also wrestled with the front alignment. It had a large dead spot when trying to go straight and the steering wheel was turned a little to the left. After checking with a tape measure I confirmed it had around 1/4" toe out. 1 turn on the right tie rod got the toe closer, not perfect but closer. I then took it out for an extended test drive with the computer hooked up to check the A/F mix. The rough alignment still needs a little work but is much better. However I still have out put from the O2 sensor that looks like a saw. Running way rich then drops to really lean then back. Due to problems with my laptop's USB ports I did not get the data recorded like I wanted, but seeing as I am on the 3rd O2 sensor and have run wires direct from the sensor to the ECU and now I know that the all the plugs are firing properly I am feeling that the budget priced injectors do not work well in this application. I think they cannot handle a small pulse width which would explain why it starts hard when warm. So I need to spend some serious bucks to fix this.

zordak
zordak Reader
3/16/20 9:13 a.m.

I should have new injectors today or tomorrow. Bigger problem, I was running to the hardware store and it died at the stop light nearest to the house(4 blocks) After getting it pushed to the side of the road(A big thanks to the people who stopped and helped with that) I got friends and family to get it pushed back to the house. I checked of fuel pressure and it was ok. I hooked up the timing light and reasonably sure no spark. I checked for power at the coil and had 12VDC. I believe the ingnition module went bad. I am going to try a new one.

zordak
zordak Reader
3/17/20 9:18 a.m.

1 new ignition control module later and it runs again. yayyyyyy!!!!.  New injectors due wed.

GCrites80s
GCrites80s Reader
3/17/20 5:50 p.m.

Did the ign. module help the car run any better or just make spark return?

zordak
zordak Reader
3/18/20 9:37 a.m.

Haven't had the chance to drive it yet, I just fired it up to make sure it was the problem.

zordak
zordak Reader
3/20/20 9:14 a.m.

I hooked the computer up to see if it ran much different with the new module.  I did not get the saw tooth O2 output at idle but at around 1400rpm it showed up big time. I also took the time to watch injector pulse and it was jumping up and down a lot. My guess is the minimum pulse width of the injectors is to large to make the engine run right at low rpm, at higher rpm they probably work just fine. Unfortunately this is more of a road car and not a track car so I will swap the injectors for the stock ones I just sourced from Rockauto.

zordak
zordak Reader
3/28/20 11:41 a.m.

O.K. Time to swap injectors. Where to start?. O.k. I will need to pull the alternator so disconnect the battery. Now what? Throttle linkage, since I plan to just remove the throttle body from the plenum so I don't have to crack the cooling system and the bracket is attached to the plenum thats good. Now remove the air intake. Alternator, remove belt, disconnect battery lead, remove the 2 screws and oh yeah the other connector. Throtle body next remove the 4 screws and yes!!! no coolant passages to the plenum. Disconnect the fuel lines and remove the screw in front that holds the fuel rail on. O.K. plenum screws, cool it just came off considering it was a pain to get on when I thightened the tubes it was a pain to get the plenum in place. Now maybe I can get the fuel rail out without removing th tubes. I can get it high enough in front to get at the injectors but I think it would be better to remove the tubes and do the swap on the bench. Good time to take a break. By the time I clean up and write ths up on the builds forum it wiil be lunch time.

zordak
zordak Reader
3/28/20 4:55 p.m.

Part 2.  Remove the right side tubes, try to remove fuel rail, no go, EGR valve in the way, remove it. Fuel rail out replace injectors, install fuel rail. Put EGR, right side tubes and plenum on. Try to hook up fuel lines backward, waste 10 minutes. Thank God for different size connectors. Put alternator in, hook up battery, and check for leaks. Hook up everything else. O.K. saying the Alan Shepard prayer(Dear lord don't let f**k up) I fire it up. No leaks seems to run fine. Connect computer run it til it gets to closed loop mode and....Damn still getting the saw tooth.  Slow down, everything is working properly, has to be software, but what? Check out very carefully the BLM, integrator and injector pulse width. BLM down to 108, well s**t that is the bottom end for it. Integrator drops to 82 and at that time the pulse width drops below 1.0ms and the O2 output drops to about 30mv. What does all this mean? I am starting to think the 1.6 ratio rockers caused the idle/low rpm vacuum to drop and the fuel pressure regulator is not pulling out enough pressure.The other is the regulator is bad and not pulling out pressure at all. I think I need to hook up the pressure gauge and see how much pressure I have at various engine vacuums. This is a learning moment I needed to carefully look at everything before jumping to conclusions. The cheap..I mean financially responsible Ebay injectors probably would work just fine with the correct fuel pressure.

zordak
zordak Reader
3/29/20 3:01 p.m.

Checked fuel pressure, 46lbs at key on, 40 lbs at idle. It seems the regulator is functioning properly. I tried adjusting the VE tables but it just takes a little longer to bottom out the pulse width. It seems the injectors cut off between .98 and .96 ms. I cannot find any thing to adjust in the BIN file to set a minimum pulse width. I realize it would just run rich but it would not bounce around. I need to reduce the pressure (new adjustable pressure regulator) I am also considering installing a resistor in the power lead to the injectors to reduce the voltage to them thus reducing the amount of fuel. The question is how much resistance.

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