Guest Yesman Posted October 13, 2011 Share Posted October 13, 2011 Hi, i've got an serious problem with my Supra. Its an Non turbo mkiv 1993 model facts: No power above 2000 rpm Lot of smoke on idling, going flat out or even revving when the car is in neutral. The strange thing is, at 4000 rpm the engine won't rev higher. It is like the rev limiter is replaced from 7000 rpm to 4000. Big fuel consumption Because its harder to explain in english than in dutch i made a video: [video=youtube;_qLM-1mKiw8]http://www.youtube.com/watch?v=_qLM-1mKiw8 Quote Link to comment Share on other sites More sharing options...
Scooter Posted October 13, 2011 Share Posted October 13, 2011 trying to find old threads with the same problems. This one ended up being a ECU problem (is there anyone you can try a swap with?) http://www.mkivsupra.net/vbb/showthread.php?209003-Miss-fire-and-No-power!&highlight=overfueling It may not be this just trying to narrow down the things is might be..... Quote Link to comment Share on other sites More sharing options...
jonc Posted October 14, 2011 Share Posted October 14, 2011 Just a stab to try and help, 1.Are there any fault codes stored in the computer. 2.Poor performance and bad combustion mixture (black smoke!) can be symptons of a defective air flow meter. 3.My inital reaction when I saw your video was a defective throttle body as you are limited on RPM and losing power. 3. E-mail Chris Wilson he may have some ideas. Hope this helps a bit:) Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted October 14, 2011 Share Posted October 14, 2011 Chris (God of all things Supra) Wilson will be along shortly to use his powers and tell you what the problem is. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 14, 2011 Share Posted October 14, 2011 Has it any modifications except for the big exhaust? Have you checked to see if any fault codes are stored? If there are disconnect the battery for a few minutes, re connect, take for a short run and see what fresh ones are stored. It will be electrical unless the air filter or trunking from it to the engine is collapsing, which would mean none stock stuff fitted, or the fuel pressure regulator / fuel return line to the tank is faulty.. Are you good with electrical test gear? Did it used to run fine? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 14, 2011 Share Posted October 14, 2011 (edited) OK, I was a bit rushed before, I'll have a stab at this now. Has the engine been washed off, or got wet? If I have to make one diagnosis with just the video to go on I would say it's a throttle position sensor fault, especially if it has got wet. If has been moved or come loose this could also cause the problem. Assuming it's not loose take the connector off the TPS at the throttle body and blow out the connector and the socket with dry air, use WD40 or contact cleaner on plug and socket contacts. Refit and report back. Good luck. If you have a digital voltmeter have the ignition on, engine NOT running, and measure the voltage across the signal pin and ground pin of the TPS as the throttle is slowly opened. It should rise from about 1 volt shut to about 4.7 volts fully open, with no drop outs or sudden spikes. If it's not a problem with the TPS it may be an issue with the plumbing to, the wiring to, or the actual MAP sensor itself. I'd be surprised if it were not one of these two things. Have you fiddled with anything, or removed and refitted anything? Has it got a "fuel cut defender" fitted? Edited October 14, 2011 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest Yesman Posted October 14, 2011 Share Posted October 14, 2011 OK, I was a bit rushed before, I'll have a stab at this now. Has the engine been washed off, or got wet? If I have to make one diagnosis with just the video to go on I would say it's a throttle position sensor fault, especially if it has got wet. If has been moved or come loose this could also cause the problem. Assuming it's not loose take the connector off the TPS at the throttle body and blow out the connector and the socket with dry air, use WD40 or contact cleaner on plug and socket contacts. Refit and report back. Good luck. If you have a digital voltmeter have the ignition on, engine NOT running, and measure the voltage across the signal pin and ground pin of the TPS as the throttle is slowly opened. It should rise from about 1 volt shut to about 4.7 volts fully open, with no drop outs or sudden spikes. If it's not a problem with the TPS it may be an issue with the plumbing to, the wiring to, or the actual MAP sensor itself. I'd be surprised if it were not one of these two things. Have you fiddled with anything, or removed and refitted anything? Has it got a "fuel cut defender" fitted? I'm sorry for my crapy english, i do my best to explain it in the right detail. Hi chris, thank for your support. It only has an large end muffler and a short air intake. However, i searched to find my MAP sensor. They taken of the connector and put the loose wire's into the 3 pins . Then they taped the wires to the sensor so they wouldn't fall of. When i removed the tape, the wire's came loose so i lost the exact order to fit them on again. Now it is constantly going in emergency running mode or the engine stalls. I've tried to test the sensor, putting + and - on the pins and my multi tester( VOM) on the middle ( signal) pin. When testing it with an vacuumtester it didn't change any voltage. I think my MAP sensor died... Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 15, 2011 Share Posted October 15, 2011 OK, just seen it's a none turbo. The MAP sensor is just used to switch over the plenum volume flap on the N/A, so it won't be that, sorry. It's much more likely to be the TPS sensor on the throttle body. Do you need a photo of where it is? With the "short air intake" where have you put the inlet air temp probe that would normally go into the stock air filter box? Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted October 15, 2011 Share Posted October 15, 2011 Definitely a tps problem imo, mine did this when the tps was set incorrectly! Quote Link to comment Share on other sites More sharing options...
Guest Yesman Posted November 12, 2011 Share Posted November 12, 2011 trying to find old threads with the same problems. This one ended up being a ECU problem (is there anyone you can try a swap with?) http://www.mkivsupra.net/vbb/showthread.php?209003-Miss-fire-and-No-power!&highlight=overfueling It may not be this just trying to narrow down the things is might be..... You where right, it was the ECU. I've replaced it, it suddenly kept running and rides like hell! Switched back to the old one, directly into emergency running! Thanks for the support! Quote Link to comment Share on other sites More sharing options...
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