Tune up...
09-22-09, 02:14 PM
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Tune up...
What would you recommend i do for a thorough tune up? i was doing some research online and i found that the 88 rx7 is supposed to have around 146hp.. im not entirely sure that thats what my car is putting out. any ideas as to why? and how to fix it?
09-22-09, 03:34 PM
#2
spark plug wires
oil change in engine, transmission, and differential
change coolant
air filter
fuel filter
oil filter
injector cleaner or send them out to get professionally cleaned
you can also do a compression test to see how healthy your engine is.
I'm probably forgetting a few things, but that's a good start.
09-22-09, 04:11 PM
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Oh, well, I have been meaning to write this up anyway. Here it is... it should keep you busy for a while...
Major tune up, 1986-88 RX7 normally aspirated
Reference: Mazda Factory Service Manual (FSM) 1986-1988 RX7. Available online at http://www.teamfc3s.org/main/factory...ual/1986_1988/
Special tools:
Compression tester
Oxygen sensor socket, crow’s foot type
Multi-meter (voltage and resistance. Best to use old style with analog needle display when looking for resistance dropouts in the TPS and AFM)
Timing light
Fuel pressure test set
Mightyvac or similar hand-type vacuum pump and gage
1. Check compression. No sense tuning up an engine you are going to have to rebuild anyway. You can do this with a conventional compression tester by holding the release valve open while an accomplice cranks the engine (do this with the EGI fuse out so you do not introduce fuel during this operation.) You should observe three peaks on the gage in each cycle, each one at or above 85 psi.
2. Take a sample of your coolant to a radiator shop, and have it checked for the presence of exhaust gases. If the coolant seals are ruptured, same advice as in #1 above applies.
3. Check operation of the EGR valve per the FSM procedure, pg. 4A-82 . If you are going to have to replace and or eliminate it, the best time is when the UIM is off in the next step.
4. Remove the upper intake manifold (UIM). Pull all 4 fuel injectors, have them sent out and professionally cleaned. While you are waiting for them, check and if necessary replace the EGR valve; also remove, clean and reinstall the ground at the top of the engine, using carbon conductive grease. When the injectors come back, reinstall with new grommets.
5. Remove the spark plugs and replace with new, NGK, per FSM specs. Note that the leading and trailing plugs are different model numbers. These plugs are more expensive than many, but I am told they last forever…
6. Check and/or replace ignition harness.
7. Pull the oxygen sensor. Run the car with the sensor open. If it has noticeably more power, have your exhaust system checked for restrictions, i.e. clogged catalytic converters.
8. If the oxygen sensor has more than 30k miles on it, replace with new. ($20 with generic connector; $56 with OEM connector. I get the Bosch with the generic connector, and cut it off. I replace it with the OEM connector on the old O2 sensor, solder the wire and insulate the splice with heat shrink tubing.) You need a special socket; get the ‘crow’s foot’ type, as the socket type is not tall enough. $3 at Harbor Freight (HF).
9. Replace all the vacuum hoses with new. It’s cheap.
10. Check for vacuum leaks, and correct as necessary.
11. Listen to each of the fuel injectors with a stethoscope (HF, $3); you should hear normal operating sounds (clicking).
12. Check the fuel pressure. HF has a nice test set for $16. See the FSM for specs: check the pressure in all three test conditions: blocked (tests maximum pressure capability of the pump), in operation with the regulator running, and with the regulator disabled. See FSM, pg. 4A-66.
13. Pull trouble codes. The method is documented at this link: http://www.teamfc3s.org/info/article...odes/main.html
14. Correct any problems identified by the trouble codes. Reset the ECU by removing the negative battery terminal for at least 5 sec. Reconnect; check for codes again.
15. Check for closed loop operation. See the check in the FSM, pg. 4A-22, but make your own ($3) checker. Search this forum for my posts containing the words ‘green lamp checker’. See that you have the lamp on at idle and under acceleration; flashing during steady rpm cruise; and off during deceleration.
16. Check and if necessary adjust ignition timing. HF has a nice xenon timing light that works perfectly well for $16. There are separate timing marks on the pulley for the leading and trailing coils; check both.
17. Check spark advance: rev the engine while running the timing light, observe that the timing advances (the timing mark ‘moves’)
18. Adjust idle speed to 750 rpm. Adjusting screw is on the top of the UIM. Make sure you jumper the initial set connector first; see the FSM procedure, beginning on pg. 4A-77.
19. Check the resistance of the variable resistor, and adjust idle mixture of the max rpm point using the FSM procedure beginning on pg. 4A-77. Make sure to remove the jumper from the initial set connector when you are done!
20. Check the throttle position sensor for normal operation: no dropouts across its operating range. Max and min values per the FSM numbers.
21. Adjust the TPS for exactly 1k ohm at idle throttle. Some people recommend adjusting the TPS for exactly 1v output at idle throttle.
22. Check operation of the Air Control Valve per FSM, pg. 4A-42
23. Replace the air cleaner element
24. Check operation of the air flow meter and intake air temperature sensor per FSM pg. 4A-54. Make sure there are no dropouts (0 ohm points) across the range of operation of the AFM.
25. Check operation of the auxiliary port valves, also called the 5th and 6th port valves. These ports open under heavy throttle at rpms above 3800 rpm. They supposedly contribute about 25 hp at the top end; if they are not opening you will have significantly less power. If they are not closing, you will have a very rough idle. Put a dab of grease on each actuator shaft; go for a hard drive; inspect upon return. If the grease has been wiped up the shaft, the valves opened. If not, there is a problem. If so, see FSM pg. 4A-60 and -61 for testing. Note: these valves are opened by exhaust backpressure in the series 4 cars. If you have a low restriction exhaust, the valves may open late or not at all.
26. Check operation of the double throttle diaphragm. It should be open (fully clockwise) at operating temperature. Check that the diaphragm will hold 14” of vacuum; see FSM, pgs. 57-59. Some disable this system completely and take the throttle valves out to reduce restriction in the throttle body; search the forum for “throttle body mod”. There are also some on this forum that offer services to port and polish the throttle body.
27. Check operation of the boost sensor, FSM pg. 4A-73. I know your car does not have a turbo, and therefore no boost, but it uses this sensor anyway.
28. Check the water thermo sensor; FSM pg. 4A-46.
29. Verify all the voltages at the inputs and outputs of the ECU. See the table beginning on pg. 4A-30 of the FSM. The ECU is under the passenger’s toes. You will have to remove the right door sill plate, part of the door seal, the right kick panel, pull up part of the carpet, and remove 3 10 mm bolts holding the protective steel panel over the ECU. Carefully back probe each pin of the ECU connectors and compare the voltage there with those in the table. Do it for both conditions: ignition on but not running, and running at idle, with the car at operating temperature. Anything out of range suggests a problem that needs to be identified and corrected.
30. Some people also think it is good to improve the electrical grounds in the engine compartment. I have not seen any hard data that shows that this helps, and I have not done this with my car, but it can’t hurt either. The process is to disassemble each ground, clean it up with a wire brush, and or replace the connector with a new one, and reassemble using carbon conductive grease. The FSM will show you where each ground is located. Do not forget the two coils with igniters: they ground via their underside in direct contact with the car body. There is also a mod that was recommended in a service bulletin, which adds a ground wire from the boost sensor to one of the bolts on the thermostat cover. My car had this when I bought it, but I have never compared how it runs with it connected vs. disconnected. The grounding business is supposed to help with the ‘dreaded 3800 rpm hesitation’ that affects many of these cars, but I have found that precise adjustment of the TPS sensor to be most effective in eliminating that hesitation.
Major tune up, 1986-88 RX7 normally aspirated
Reference: Mazda Factory Service Manual (FSM) 1986-1988 RX7. Available online at http://www.teamfc3s.org/main/factory...ual/1986_1988/
Special tools:
Compression tester
Oxygen sensor socket, crow’s foot type
Multi-meter (voltage and resistance. Best to use old style with analog needle display when looking for resistance dropouts in the TPS and AFM)
Timing light
Fuel pressure test set
Mightyvac or similar hand-type vacuum pump and gage
1. Check compression. No sense tuning up an engine you are going to have to rebuild anyway. You can do this with a conventional compression tester by holding the release valve open while an accomplice cranks the engine (do this with the EGI fuse out so you do not introduce fuel during this operation.) You should observe three peaks on the gage in each cycle, each one at or above 85 psi.
2. Take a sample of your coolant to a radiator shop, and have it checked for the presence of exhaust gases. If the coolant seals are ruptured, same advice as in #1 above applies.
3. Check operation of the EGR valve per the FSM procedure, pg. 4A-82 . If you are going to have to replace and or eliminate it, the best time is when the UIM is off in the next step.
4. Remove the upper intake manifold (UIM). Pull all 4 fuel injectors, have them sent out and professionally cleaned. While you are waiting for them, check and if necessary replace the EGR valve; also remove, clean and reinstall the ground at the top of the engine, using carbon conductive grease. When the injectors come back, reinstall with new grommets.
5. Remove the spark plugs and replace with new, NGK, per FSM specs. Note that the leading and trailing plugs are different model numbers. These plugs are more expensive than many, but I am told they last forever…
6. Check and/or replace ignition harness.
7. Pull the oxygen sensor. Run the car with the sensor open. If it has noticeably more power, have your exhaust system checked for restrictions, i.e. clogged catalytic converters.
8. If the oxygen sensor has more than 30k miles on it, replace with new. ($20 with generic connector; $56 with OEM connector. I get the Bosch with the generic connector, and cut it off. I replace it with the OEM connector on the old O2 sensor, solder the wire and insulate the splice with heat shrink tubing.) You need a special socket; get the ‘crow’s foot’ type, as the socket type is not tall enough. $3 at Harbor Freight (HF).
9. Replace all the vacuum hoses with new. It’s cheap.
10. Check for vacuum leaks, and correct as necessary.
11. Listen to each of the fuel injectors with a stethoscope (HF, $3); you should hear normal operating sounds (clicking).
12. Check the fuel pressure. HF has a nice test set for $16. See the FSM for specs: check the pressure in all three test conditions: blocked (tests maximum pressure capability of the pump), in operation with the regulator running, and with the regulator disabled. See FSM, pg. 4A-66.
13. Pull trouble codes. The method is documented at this link: http://www.teamfc3s.org/info/article...odes/main.html
14. Correct any problems identified by the trouble codes. Reset the ECU by removing the negative battery terminal for at least 5 sec. Reconnect; check for codes again.
15. Check for closed loop operation. See the check in the FSM, pg. 4A-22, but make your own ($3) checker. Search this forum for my posts containing the words ‘green lamp checker’. See that you have the lamp on at idle and under acceleration; flashing during steady rpm cruise; and off during deceleration.
16. Check and if necessary adjust ignition timing. HF has a nice xenon timing light that works perfectly well for $16. There are separate timing marks on the pulley for the leading and trailing coils; check both.
17. Check spark advance: rev the engine while running the timing light, observe that the timing advances (the timing mark ‘moves’)
18. Adjust idle speed to 750 rpm. Adjusting screw is on the top of the UIM. Make sure you jumper the initial set connector first; see the FSM procedure, beginning on pg. 4A-77.
19. Check the resistance of the variable resistor, and adjust idle mixture of the max rpm point using the FSM procedure beginning on pg. 4A-77. Make sure to remove the jumper from the initial set connector when you are done!
20. Check the throttle position sensor for normal operation: no dropouts across its operating range. Max and min values per the FSM numbers.
21. Adjust the TPS for exactly 1k ohm at idle throttle. Some people recommend adjusting the TPS for exactly 1v output at idle throttle.
22. Check operation of the Air Control Valve per FSM, pg. 4A-42
23. Replace the air cleaner element
24. Check operation of the air flow meter and intake air temperature sensor per FSM pg. 4A-54. Make sure there are no dropouts (0 ohm points) across the range of operation of the AFM.
25. Check operation of the auxiliary port valves, also called the 5th and 6th port valves. These ports open under heavy throttle at rpms above 3800 rpm. They supposedly contribute about 25 hp at the top end; if they are not opening you will have significantly less power. If they are not closing, you will have a very rough idle. Put a dab of grease on each actuator shaft; go for a hard drive; inspect upon return. If the grease has been wiped up the shaft, the valves opened. If not, there is a problem. If so, see FSM pg. 4A-60 and -61 for testing. Note: these valves are opened by exhaust backpressure in the series 4 cars. If you have a low restriction exhaust, the valves may open late or not at all.
26. Check operation of the double throttle diaphragm. It should be open (fully clockwise) at operating temperature. Check that the diaphragm will hold 14” of vacuum; see FSM, pgs. 57-59. Some disable this system completely and take the throttle valves out to reduce restriction in the throttle body; search the forum for “throttle body mod”. There are also some on this forum that offer services to port and polish the throttle body.
27. Check operation of the boost sensor, FSM pg. 4A-73. I know your car does not have a turbo, and therefore no boost, but it uses this sensor anyway.
28. Check the water thermo sensor; FSM pg. 4A-46.
29. Verify all the voltages at the inputs and outputs of the ECU. See the table beginning on pg. 4A-30 of the FSM. The ECU is under the passenger’s toes. You will have to remove the right door sill plate, part of the door seal, the right kick panel, pull up part of the carpet, and remove 3 10 mm bolts holding the protective steel panel over the ECU. Carefully back probe each pin of the ECU connectors and compare the voltage there with those in the table. Do it for both conditions: ignition on but not running, and running at idle, with the car at operating temperature. Anything out of range suggests a problem that needs to be identified and corrected.
30. Some people also think it is good to improve the electrical grounds in the engine compartment. I have not seen any hard data that shows that this helps, and I have not done this with my car, but it can’t hurt either. The process is to disassemble each ground, clean it up with a wire brush, and or replace the connector with a new one, and reassemble using carbon conductive grease. The FSM will show you where each ground is located. Do not forget the two coils with igniters: they ground via their underside in direct contact with the car body. There is also a mod that was recommended in a service bulletin, which adds a ground wire from the boost sensor to one of the bolts on the thermostat cover. My car had this when I bought it, but I have never compared how it runs with it connected vs. disconnected. The grounding business is supposed to help with the ‘dreaded 3800 rpm hesitation’ that affects many of these cars, but I have found that precise adjustment of the TPS sensor to be most effective in eliminating that hesitation.
Last edited by calpatriot; 09-22-09 at 04:23 PM.
09-22-09, 04:23 PM
#4
You forgot to add the throttle must be at WOT(wide open throttle) while doing a compression test. If you dont then you will get lower comp numbers. Also the comp numbers will vary when the engine is cold or hot. Overall thats one hell of a write up you made calpatriot!
09-22-09, 04:27 PM
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You forgot to add the throttle must be at WOT(wide open throttle) while doing a compression test. If you dont then you will get lower comp numbers. Also the comp numbers will vary when the engine is cold or hot. Overall thats one hell of a write up you made calpatriot!
09-22-09, 08:34 PM
#6
Speed Safely...
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damn bro... that list is pretty extensive. any recommendations as to where to send my injectors? i found this place called WitchHunter Performance out of WA, heard anything good about them?
09-22-09, 09:38 PM
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I have only used witch Hunter for one car, one time so I can not comment on the quality of his work when compared to others.
The only gripe I have is that after he cleans your injectors he does not respray them. If you forget to do this, like I did, then your "fresh" injectors begin to show surface rust in 2 months
-Pat
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09-23-09, 03:23 PM
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09-25-09, 03:53 PM
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One of the mechanics at the shop down the street from where I live said that the 88 rx7 is only supposed to have 146hp if it was built in japan. If it was built in the US its only supposed to have like 120.... Really??
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