1987 Vette - runs rough and rich, dies
Hi, I have a 1987 Vette. It is running very rich, blows black smoke rich, and when it begins to warm up it starts to run rough and acts like its loading up. When you give it some Rpm's it gets a miss and when returned to idle it dies. Now after letting it sit and coming back to mess with it, it smells of raw gas and is hard to crank, when it eventually does it sputters badly and dies. Almost like a car that has flooded. I replaced the coil, cap and rotor with a kit from DUI. It also has a new egr valve and IAC, and temp sensors aside from the MAT, along with new injectors. The throttle body and intake have all been taken apart and cleaned and had new gaskets installed. The TPS and fuel pressure checks out good and there is no fuel in the vacuum line to the fuel regulator. It is now giving code 45, witch suggests the next thing on the list to check is the o2 sensor. The only things that aren't new is the MAF, MAT, ECM, o2 sensor and TPS, plugs are new-ish, I've cleaned them, but they probably have been through the ringer now.... Thats all I can think of off hand. Any suggestions on what could be going on? Thanks.
Id adjust the TPS and IAC as a quick check, as its easily done and costs nothing, your running rich is obviously something related to a defective control sensor or defective part,
code 45 is a rich exhaust, you already know your running rich, fuel enters the cylinders from the injectors or a defective fuel pressure regulator, and the maf is the major control on fuel flow rates, test heat sensor.
Id start by verifying the injectors are not leaking, they may be new, but that does not mean they are functioning correctly,
Id test and if required replace the MAF and the relays behind the battery on the engine compartment firewall ,and the oxygen sensors as they are most likely trash at this point, you also did not mention the fuel pressure, if you turn on the key but not start the engine, the fuel pump should pressurize the fuel rail, to about 40 psi, it should remain pressurized for at least 6=7 minutes before slowly losing pressure, if it loses pressure the fuel is leaking at the injectors or fuel pressure regulator or the fuel pump, if its the fuel pump, it would not cause your issue, if you block off the fuel pressure return line and it still loses pressure you know its the injectors
youll need a fuel pressure gauge and multi meter
it helps if you have a spare fuel injector pig-tail for testing
having a NOID light injector harness tester wont hurt either
https://www.harborfreight.com/11-piece-noid-light-and-iac-tester-set-97959.html
on the TPI and LT1 efi and many other EFI intakes,
theres a shrader valve,
that can be easily accessed to check fuel rail pressure,
dealing in facts you verify is always preferable.
http://garage.grumpysperformance.co...oblem-sources-1987-corvette.15596/#post-93275
http://garage.grumpysperformance.co...lay-switch-locations-and-info.728/#post-93194
http://garage.grumpysperformance.co...your-c4-corvette-runs-badly.15212/#post-87228
http://garage.grumpysperformance.co...oven-facts-if-your-in-doubt.13051/#post-84890
http://garage.grumpysperformance.co...le-shooting-flow-chart-info.11536/#post-71845
http://garage.grumpysperformance.com/index.php?threads/adjusting-your-tps-and-iac.168/#post-82331
http://garage.grumpysperformance.co...blem-with-my-87-c-4-corvette.5055/#post-93889
http://garage.grumpysperformance.co...questions-can-be-found-here.12892/#post-67808
http://garage.grumpysperformance.co...anufactured-maf-bad-code-34.15752/#post-94278
http://garage.grumpysperformance.co...s-cause-a-bad-idle-in-drive.14203/#post-72114
Hi, I have a 1987 Vette. It is running very rich, blows black smoke rich, and when it begins to warm up it starts to run rough and acts like its loading up. When you give it some Rpm's it gets a miss and when returned to idle it dies. Now after letting it sit and coming back to mess with it, it smells of raw gas and is hard to crank, when it eventually does it sputters badly and dies. Almost like a car that has flooded. I replaced the coil, cap and rotor with a kit from DUI. It also has a new egr valve and IAC, and temp sensors aside from the MAT, along with new injectors. The throttle body and intake have all been taken apart and cleaned and had new gaskets installed. The TPS and fuel pressure checks out good and there is no fuel in the vacuum line to the fuel regulator. It is now giving code 45, witch suggests the next thing on the list to check is the o2 sensor. The only things that aren't new is the MAF, MAT, ECM, o2 sensor and TPS, plugs are new-ish, I've cleaned them, but they probably have been through the ringer now.... Thats all I can think of off hand. Any suggestions on what could be going on? Thanks.
Id adjust the TPS and IAC as a quick check, as its easily done and costs nothing, your running rich is obviously something related to a defective control sensor or defective part,
code 45 is a rich exhaust, you already know your running rich, fuel enters the cylinders from the injectors or a defective fuel pressure regulator, and the maf is the major control on fuel flow rates, test heat sensor.
Id start by verifying the injectors are not leaking, they may be new, but that does not mean they are functioning correctly,
Id test and if required replace the MAF and the relays behind the battery on the engine compartment firewall ,and the oxygen sensors as they are most likely trash at this point, you also did not mention the fuel pressure, if you turn on the key but not start the engine, the fuel pump should pressurize the fuel rail, to about 40 psi, it should remain pressurized for at least 6=7 minutes before slowly losing pressure, if it loses pressure the fuel is leaking at the injectors or fuel pressure regulator or the fuel pump, if its the fuel pump, it would not cause your issue, if you block off the fuel pressure return line and it still loses pressure you know its the injectors
youll need a fuel pressure gauge and multi meter
it helps if you have a spare fuel injector pig-tail for testing
having a NOID light injector harness tester wont hurt either
https://www.harborfreight.com/11-piece-noid-light-and-iac-tester-set-97959.html
on the TPI and LT1 efi and many other EFI intakes,
theres a shrader valve,
that can be easily accessed to check fuel rail pressure,
dealing in facts you verify is always preferable.
http://garage.grumpysperformance.co...oblem-sources-1987-corvette.15596/#post-93275
http://garage.grumpysperformance.co...lay-switch-locations-and-info.728/#post-93194
http://garage.grumpysperformance.co...your-c4-corvette-runs-badly.15212/#post-87228
http://garage.grumpysperformance.co...oven-facts-if-your-in-doubt.13051/#post-84890
http://garage.grumpysperformance.co...le-shooting-flow-chart-info.11536/#post-71845
http://garage.grumpysperformance.com/index.php?threads/adjusting-your-tps-and-iac.168/#post-82331
http://garage.grumpysperformance.co...blem-with-my-87-c-4-corvette.5055/#post-93889
http://garage.grumpysperformance.co...questions-can-be-found-here.12892/#post-67808
http://garage.grumpysperformance.co...anufactured-maf-bad-code-34.15752/#post-94278
http://garage.grumpysperformance.co...s-cause-a-bad-idle-in-drive.14203/#post-72114
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