limp mode?
07-11-17, 12:40 AM
#1
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limp mode?
I am trying to assist a friend get his fd running. We recently built an engine for it and deleted emissions stuff on it. Running stock ecu and harness. The car feels like its in limp mode. We checked codes and got codes 5 16 25 28 30 31 32 33 39 40 45 46 and 50. According to the fsm, none of these cause a limp mode or locked fuel/timing condition. We even got a brand new knock sensor to try and get rid of code 5 so it wont retard timing. The car runs great until about 20% throttle, then sputters and pops. We plugged the turbo solenoids into the harness to get rid of codes 43 and 44. Any help is appreciated.
07-11-17, 03:55 AM
#2
I'm not a tuner but doubt you'll ever get it running decently with that spumoni list of CEL's. You need a standalone ECU after deleting emissions. And I don't think there is a code 16. A guess is that it's 17 (O2 feedback), which may be your biggest issue.
07-11-17, 06:39 AM
#3
16 is EGR switch, CA models. Installation of 330 ohm resistors will get rid of the codes. Sounds like you guys took the TPS off and reinstalled it without preload.
RX7 FD and Series 5 Error Codes
RX7 FD and Series 5 Error Codes
07-11-17, 04:41 PM
#5
16 is EGR switch, CA models. Installation of 330 ohm resistors will get rid of the codes. Sounds like you guys took the TPS off and reinstalled it without preload.
RX7 FD and Series 5 Error Codes
RX7 FD and Series 5 Error Codes
I've also recently completed a rebuild and am getting 12 and 18, despite the TPS being connected. Are there contacts in the TPS that are supposed to make contact with corresponding prongs on the TB?
BTW, big thanks to you and Elaine for hooking me up with the additional hardware for the motor mounts!
07-11-17, 04:54 PM
#6
TPS has an internal spring, it needs to be installed with the connector side up and rolled counter clockwise to set up the preload. Then it needs to adjusted to spec at operating temp.
Last edited by Banzai-Racing; 07-11-17 at 05:20 PM.
07-11-17, 07:02 PM
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25, 45 and 46 will cause a limp home. if the ECU thinks it can't control boost or fuel it shuts you down.
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07-12-17, 01:37 AM
#8
Limping Prolonged
Reconnecting all the deleted solenoids certainly eliminated many of the codes, but we could never make the stock ecu happy with the mega delete exercise. Running an Apexi Power FC now (resorted back to parallel turbos).
TPS may show to be in spec, but could go out of spec once the engine is heated up (as compared to warmed up). Probably best to buy a new TPS ($200) to eliminate concern. It seems a fragile piece playing a key role.(Likewise replace the O2 sensor ($50).)
OMP was coding off and on. I believe OMP failure triggers limp mode.
How old is the ECU? Would you trust a 20 year motherboard running anything?
Turned out part of our hesitation was a pinched o-ring in the fuel pump, that was likely there from the beginning of our rebuild, as replacing the fuel pump was the first thing I had done
.
Locally here we can get a "smoke test" done for $50. This could reveal a surprising amount of vacuum/boost/air leaks. Codes won't necessarily tell you about air leaks. Worthwhile to do a smoke test, both before and after you do any work on the air management systems.
The fuel pressure valve requires vacuum to remain in-operative. If no vacuum, it turns itself on and you get too much fuel. This was one of the leaks the smoke test revealed.
Stock ecu may be calibrated to make adjustments to the reading from the O2 sensor to allow for by-pass air from the ACV that enters the exhaust manifold after the combustion chamber but before the O2 sensor. It thinks that air is still there even after an acv/air pump delete.
TPS may show to be in spec, but could go out of spec once the engine is heated up (as compared to warmed up). Probably best to buy a new TPS ($200) to eliminate concern. It seems a fragile piece playing a key role.(Likewise replace the O2 sensor ($50).)
OMP was coding off and on. I believe OMP failure triggers limp mode.
How old is the ECU? Would you trust a 20 year motherboard running anything?
Turned out part of our hesitation was a pinched o-ring in the fuel pump, that was likely there from the beginning of our rebuild, as replacing the fuel pump was the first thing I had done
.Locally here we can get a "smoke test" done for $50. This could reveal a surprising amount of vacuum/boost/air leaks. Codes won't necessarily tell you about air leaks. Worthwhile to do a smoke test, both before and after you do any work on the air management systems.
The fuel pressure valve requires vacuum to remain in-operative. If no vacuum, it turns itself on and you get too much fuel. This was one of the leaks the smoke test revealed.
Stock ecu may be calibrated to make adjustments to the reading from the O2 sensor to allow for by-pass air from the ACV that enters the exhaust manifold after the combustion chamber but before the O2 sensor. It thinks that air is still there even after an acv/air pump delete.
Last edited by Redbul; 07-12-17 at 11:45 AM.
07-23-17, 05:27 PM
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So a quick update: we plugged all of the solenoids into the harness and they are just sitting under the intake for now. Limp mode is gone! Needed to get it running right to get some break in miles on it. Single turbo and standalone are coming next.