Starts, then stalls
07-23-03, 05:38 PM
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Starts, then stalls
Hi all,
I posted a thread a few days ago about not being able to start a freshly rebuilt Turbo II. Thanks for all of your suggestions. I have since been able to get the car to start by small amounts of oil (2 stroke) in the spark plug holes.
The problem is that it will start and rev to about 2000 RPM, then stall. It almost seems like it is running out of fuel in the engine. It dies more quickly if I try to rev the engine at all.
I have read several posts about this subject and I have a few ideas about what may be happening. Let me know if you think that I'm going in the wrong direction.
Possible causes:
1) Bad AFM - I haven't been able to test it with a multitester, but it seems to be OK. I have tried wedging the flapper door all the way open to keep the fuel pump running, but that gives it too much gas and it floods (stalls). I have made sure that the plug is very securly attached.
2) Vacum leak - This is the explanation that I'm leaning towards. All small hoses on the engine have been replaced and zip tied. Open nipples have been capped off. Injector gromets and o-rings are new. Intercooler lines are in good shape and tightly connected. The one problem that I have found it that the TID has a crack right at the mouth that goes on to the turbo. It has been repaired with duct tape, but it may still be leaking.
3) Leaky/Bad Injectors - The wiring harness is pretty chewed up and the injector plugs are in pretty bad shape. Maybe they are getting an inconsistant signal. They do seem to be firing because the engine will flood. Maybe one or both are leaking badly. The only way I can think of to test this is to pull the primary fuel rail, and try to start the car to see how much gas comes out. I'm a one man show at the moment, so I guess that I can put them in a jar so that I can go back and start the car. I'm assuming that I should pull the EGI Comp fuse so that I don't blow my self up.
Sorry for the long post, but I have been fighting with this car for so long and I'm starting to get a bit frustrated. The worst part is that I'm still not sure that the engine itself is OK. It sounds like it may only be running on one rotor. I'll just have to see what happens. Wish me luck and thanks for your support.
I posted a thread a few days ago about not being able to start a freshly rebuilt Turbo II. Thanks for all of your suggestions. I have since been able to get the car to start by small amounts of oil (2 stroke) in the spark plug holes.
The problem is that it will start and rev to about 2000 RPM, then stall. It almost seems like it is running out of fuel in the engine. It dies more quickly if I try to rev the engine at all.
I have read several posts about this subject and I have a few ideas about what may be happening. Let me know if you think that I'm going in the wrong direction.
Possible causes:
1) Bad AFM - I haven't been able to test it with a multitester, but it seems to be OK. I have tried wedging the flapper door all the way open to keep the fuel pump running, but that gives it too much gas and it floods (stalls). I have made sure that the plug is very securly attached.
2) Vacum leak - This is the explanation that I'm leaning towards. All small hoses on the engine have been replaced and zip tied. Open nipples have been capped off. Injector gromets and o-rings are new. Intercooler lines are in good shape and tightly connected. The one problem that I have found it that the TID has a crack right at the mouth that goes on to the turbo. It has been repaired with duct tape, but it may still be leaking.
3) Leaky/Bad Injectors - The wiring harness is pretty chewed up and the injector plugs are in pretty bad shape. Maybe they are getting an inconsistant signal. They do seem to be firing because the engine will flood. Maybe one or both are leaking badly. The only way I can think of to test this is to pull the primary fuel rail, and try to start the car to see how much gas comes out. I'm a one man show at the moment, so I guess that I can put them in a jar so that I can go back and start the car. I'm assuming that I should pull the EGI Comp fuse so that I don't blow my self up.
Sorry for the long post, but I have been fighting with this car for so long and I'm starting to get a bit frustrated. The worst part is that I'm still not sure that the engine itself is OK. It sounds like it may only be running on one rotor. I'll just have to see what happens. Wish me luck and thanks for your support.
07-23-03, 06:50 PM
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It is pretty common for people to mount the injectors into a jar and fire them for a set amount of time. Measure the amount of gas injected, and get a rough estimate of the gps of the fuel (grahms per second, or gallons per hour depending on how accurate you need it). You can also run the fuel pump with the injectors in a jar, check for leaky ones. Also check your fuel pressure using a T-fitting in line. Fuel pressure testers can be had for $30.
07-23-03, 09:16 PM
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I have a similar problem on a N/A I just rebuilt. It will start and idle, but it won't rev past idle, even when I press the gas. (YES the throttle cable is hooked up)
I narrowed it down to a bad ECU, AFM or TPS needing adjustment. The Factory service Manual (FSM) gives directions for how to measure the output of the fuel injectors. It also tells you how much fuel should come out after 15 seconds of running them into a jar. If you don't have a FSM, you can download one at www.fc3s.org
I was told that the AFM is difficult to test accurately, even though an OHMs meter can test continuity between the pins. You can get a used one for about $30.
As far as the ECU, that too is kinda difficult to test. I dont' know what year engine you have, but the S4 (86-88) RX-7s don't have a check engine light. Also, the ECU doesn't store trouble codes in a memory. So to get trouble codes, follow the directions on this web page. I did it, and its pretty simple to do. This page also has instructions for extracting codes from a S5 (89-92) RX-7. These later model cars were equiped with a check engine light.
http://home.rmci.net/panther/86_88ecu.htm
The TPS can be checked using the instructions found in the FSM or a Haynes manual.
Hope some of that was helpful.
I narrowed it down to a bad ECU, AFM or TPS needing adjustment. The Factory service Manual (FSM) gives directions for how to measure the output of the fuel injectors. It also tells you how much fuel should come out after 15 seconds of running them into a jar. If you don't have a FSM, you can download one at www.fc3s.org
I was told that the AFM is difficult to test accurately, even though an OHMs meter can test continuity between the pins. You can get a used one for about $30.
As far as the ECU, that too is kinda difficult to test. I dont' know what year engine you have, but the S4 (86-88) RX-7s don't have a check engine light. Also, the ECU doesn't store trouble codes in a memory. So to get trouble codes, follow the directions on this web page. I did it, and its pretty simple to do. This page also has instructions for extracting codes from a S5 (89-92) RX-7. These later model cars were equiped with a check engine light.
http://home.rmci.net/panther/86_88ecu.htm
The TPS can be checked using the instructions found in the FSM or a Haynes manual.
Hope some of that was helpful.
07-24-03, 01:54 AM
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***Update - It Runs!***
Hooray! 
She's finally running. It looks like the problem has to do with flooding and low compression. I have a fuel cut off switch on the inside of the car. I found that if I start the car (with the help of oil in the chambers) with the fuel pump turned off, it would rev to about 2000 RPM then die because it ran out of fuel. If I started the engine with the fuel pump on it would get to about 900 RPM then flood and die. What I did was start with the fuel pump off, let it get to about 1800 RPM, then switch the pump on. It would get down to about 1500 RPM and I would turn the pump off again to kick the Revs back up. I bounced it this way for about a minute or two, then it settled to 1500 RPM with the pump on and kept running.
I had to turn it off after about 10 minutes because it was leaking coolant from somewhere very badly and the engine was getting very very hot. I'm going to try to find the coolant leak before I start it again, but at least I know that it will run on its own.
Happy Happy Joy Joy. Time to celebrate
She's finally running. It looks like the problem has to do with flooding and low compression. I have a fuel cut off switch on the inside of the car. I found that if I start the car (with the help of oil in the chambers) with the fuel pump turned off, it would rev to about 2000 RPM then die because it ran out of fuel. If I started the engine with the fuel pump on it would get to about 900 RPM then flood and die. What I did was start with the fuel pump off, let it get to about 1800 RPM, then switch the pump on. It would get down to about 1500 RPM and I would turn the pump off again to kick the Revs back up. I bounced it this way for about a minute or two, then it settled to 1500 RPM with the pump on and kept running.
I had to turn it off after about 10 minutes because it was leaking coolant from somewhere very badly and the engine was getting very very hot. I'm going to try to find the coolant leak before I start it again, but at least I know that it will run on its own.
Happy Happy Joy Joy. Time to celebrate
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