TPI Hard Start, Fault 45, Misfire, ECU, Injector Issues I've had and want to share
12-13-2015, 09:44 PM
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Car: 1989 Pontiac Firebird Formula
Engine: 355 TPI
Transmission: T-5
Axle/Gears: 3.45
TPI Hard Start, Fault 45, Misfire, ECU, Injector Issues I've had and want to share
Hey guys,
Not looking for help just want to share some helpful technical issues I've had with my 89 Firebird Formula TPI. Originally it was a 305 TPI car. I put a 355 TPI in it (To see all the mods see my profile). The Engine Harness and ECM is identical (The PROM is not) . I physically built the motor, but for all people wondering about harness's and manifold parts its mostly interchangeable. Earlier models did have a cold star injector but i ruled that out today with my ECM issues.
Yesterday I was driving my car and stopped at a restaurant. I came out and my car ran like absolute crap. Skipping. Barely starting and running extremely rich. My quick thought was MAF sensor cause its common and a sensor used during open loop operation. However my scanner wouldnt talk to the car. A few weeks earlier it would talk to the car, but intermittently. Initially I just assumed the scanner was junk cause I hadn't used it in forever. Anyways, after checking over all the car. Having perfect TPS 0.54 volts signal and 4.80 at WOT, a fairly new distributor as well as all new plugs and hand made wires, and AC Delco Ignition Module (which is another story I'll explain (I 99% knew these components weren't the problem.)I alo verified after it running for a few minutes the coolant temp sensor was around 1000 ohms. in spec based on temperature (I've had one go and it will cause a rich running condition and -38 degrees on a scan tool) After running the car long enough to finally sputter its way to closed loop the car would through a Fault 45 - Rich 02 sensor condition which was pretty damn obvious, I knew not to chase the 02 as the reason cause its not used during Open Loop Operation. I checked everything out and even had solid 45 PSI of fuel and recently all 8 reman injectors had been installed.... without the scanner working I tried a test MAF cause of all the issues I read about and it being a Open Loop used sensor, but the car ran the same. I was thinking it could possibly be it cause the car in recent weeks threw a few Fault 33, but after pinpointing a good TPS base setting and Throttle plate angle for a not stock car it finally went away with a few trial and error testing.
Anyways my friend not only had a GM Tech 1 scanner, but also had his ECU from his 87 Formula 350. Even though my 89 has VATS it has nothing to do with the ECU (90-92 are speed density and the ESC Spark module is internal so it won't work) the ECU part numbers are the same 305 or 350 car. His Prom was built for a 350 with 24lb aftermarket injectors. My car has 19lb even with all the work done to it cause I was on a budget and built it with the 305 injectors. Both chips will run the car for test module concerns, I confirmed it today, but I ran his ECU with my Prom chip and it fired up instantly. Not only that both my scanner and his Tech 1 would scan the car and live data with no issues. My scanner was intermittently working on the car so I think my computer was losing its brain over time. I was reading that the ECU's have a Back-Up Mode a fail safe mode to get you home or off the road in an emergency. I'm guessing thats what happened to the ECU... Happily the ECU is cheap from Autozone $80 bucks
So if you have a car that runs , but doesn't scan with all the faults and sensors reading if you unplug them with the blink code... and running rich and with no clue how to idle or skipping with a Fault 45 only I suggest checking your ECM.
Earlier I mentioned a "AC DELCO" Ignition module. I had one in my car for years and it was fine. Recently after the car had sat for 7 Years. It was randomly dying out of nowhere even while doing 50 MPH with a standard shift car (was actually the injectors) . I bought a aftermarket BWD (Borg Warner) Ignition Control Module. After the module got hot in the summer time a few car rides. The car would Randomly Die loosing Tach Signal while driving and sometimes with the engine off the fuel injectors would pulse on their own.... Strange, but yes putting a AC Delco device in solved the issue for months until my ECU just went.
When I first built the car it would start fine when Cold, but when Hot didn't want to start worth of ****. Its a 355 TPI with 2.02 Angle plug heads and some work with 10.5:1 compression. not much more than factory but I though maybe with the bigger motor the 305 starters weren't strong enough (I would break the nose cones off the stock aluminum smaller manual trans starters)... Being it only happened hot I thought it was some weird heat soak condition. Years later since I'm older, more wise, and have more money I ohm tested the injectors cause of the random stalling and found not only were the injectors not the 12 ohm specification cause some were only 8 ohms, but a few of them would ohm out to the intake base and short through the coil winding (which is supposed to be self contained and through the casing of the injectors.) The reman injectors I put in are plastic bodies so they won't short through the housings anymore. So long story short. the short circuit was shorting the ECM driver and shutting down the module or popping the inline fuse link near the battery. I had since installed circuit breakers for future issues to not be stranded.
After changing the injectors the "Heat Soak" starting issues was resolved. The car idles a lot better. So I killed multiple issues with the injector change.
I've always came to Thirdgen.org for questions even when diagnosing my ECU this weekend and after owning my car 14 years and having weird various tough to pinpoint problems I wanted to share them with you guys.
DCoull819
Not looking for help just want to share some helpful technical issues I've had with my 89 Firebird Formula TPI. Originally it was a 305 TPI car. I put a 355 TPI in it (To see all the mods see my profile). The Engine Harness and ECM is identical (The PROM is not) . I physically built the motor, but for all people wondering about harness's and manifold parts its mostly interchangeable. Earlier models did have a cold star injector but i ruled that out today with my ECM issues.
Yesterday I was driving my car and stopped at a restaurant. I came out and my car ran like absolute crap. Skipping. Barely starting and running extremely rich. My quick thought was MAF sensor cause its common and a sensor used during open loop operation. However my scanner wouldnt talk to the car. A few weeks earlier it would talk to the car, but intermittently. Initially I just assumed the scanner was junk cause I hadn't used it in forever. Anyways, after checking over all the car. Having perfect TPS 0.54 volts signal and 4.80 at WOT, a fairly new distributor as well as all new plugs and hand made wires, and AC Delco Ignition Module (which is another story I'll explain (I 99% knew these components weren't the problem.)I alo verified after it running for a few minutes the coolant temp sensor was around 1000 ohms. in spec based on temperature (I've had one go and it will cause a rich running condition and -38 degrees on a scan tool) After running the car long enough to finally sputter its way to closed loop the car would through a Fault 45 - Rich 02 sensor condition which was pretty damn obvious, I knew not to chase the 02 as the reason cause its not used during Open Loop Operation. I checked everything out and even had solid 45 PSI of fuel and recently all 8 reman injectors had been installed.... without the scanner working I tried a test MAF cause of all the issues I read about and it being a Open Loop used sensor, but the car ran the same. I was thinking it could possibly be it cause the car in recent weeks threw a few Fault 33, but after pinpointing a good TPS base setting and Throttle plate angle for a not stock car it finally went away with a few trial and error testing.
Anyways my friend not only had a GM Tech 1 scanner, but also had his ECU from his 87 Formula 350. Even though my 89 has VATS it has nothing to do with the ECU (90-92 are speed density and the ESC Spark module is internal so it won't work) the ECU part numbers are the same 305 or 350 car. His Prom was built for a 350 with 24lb aftermarket injectors. My car has 19lb even with all the work done to it cause I was on a budget and built it with the 305 injectors. Both chips will run the car for test module concerns, I confirmed it today, but I ran his ECU with my Prom chip and it fired up instantly. Not only that both my scanner and his Tech 1 would scan the car and live data with no issues. My scanner was intermittently working on the car so I think my computer was losing its brain over time. I was reading that the ECU's have a Back-Up Mode a fail safe mode to get you home or off the road in an emergency. I'm guessing thats what happened to the ECU... Happily the ECU is cheap from Autozone $80 bucks
So if you have a car that runs , but doesn't scan with all the faults and sensors reading if you unplug them with the blink code... and running rich and with no clue how to idle or skipping with a Fault 45 only I suggest checking your ECM.
Earlier I mentioned a "AC DELCO" Ignition module. I had one in my car for years and it was fine. Recently after the car had sat for 7 Years. It was randomly dying out of nowhere even while doing 50 MPH with a standard shift car (was actually the injectors) . I bought a aftermarket BWD (Borg Warner) Ignition Control Module. After the module got hot in the summer time a few car rides. The car would Randomly Die loosing Tach Signal while driving and sometimes with the engine off the fuel injectors would pulse on their own.... Strange, but yes putting a AC Delco device in solved the issue for months until my ECU just went.
When I first built the car it would start fine when Cold, but when Hot didn't want to start worth of ****. Its a 355 TPI with 2.02 Angle plug heads and some work with 10.5:1 compression. not much more than factory but I though maybe with the bigger motor the 305 starters weren't strong enough (I would break the nose cones off the stock aluminum smaller manual trans starters)... Being it only happened hot I thought it was some weird heat soak condition. Years later since I'm older, more wise, and have more money I ohm tested the injectors cause of the random stalling and found not only were the injectors not the 12 ohm specification cause some were only 8 ohms, but a few of them would ohm out to the intake base and short through the coil winding (which is supposed to be self contained and through the casing of the injectors.) The reman injectors I put in are plastic bodies so they won't short through the housings anymore. So long story short. the short circuit was shorting the ECM driver and shutting down the module or popping the inline fuse link near the battery. I had since installed circuit breakers for future issues to not be stranded.
After changing the injectors the "Heat Soak" starting issues was resolved. The car idles a lot better. So I killed multiple issues with the injector change.
I've always came to Thirdgen.org for questions even when diagnosing my ECU this weekend and after owning my car 14 years and having weird various tough to pinpoint problems I wanted to share them with you guys.
DCoull819
12-14-2015, 08:57 AM
#2
