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Discussion Starter #1
1991 5sfe. this is what happens, i try starting the car and it likes to sputter and backfire alot. it will only stay running when if i keep my foot in the pedal. then after a little bit of that going on it will "catch" and rev up and run normally for a while. sometimes it will run great all day and even start up great! but then other times it will want to die when i am going down the road (drop about 1000 rpm and start backfiring again). problem doesnt happen all the time which makes it hard to figure out. with the code being a 51, what could it be?? its my only vehicle so any help would be great. thanks! Oh and i also put a timing light on it and when it messed up the light stopped blinking but the engine was still trying to run....
 

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.. thats a weird code.



im betting you have either an unplugged/very misadjusted TPS sensor, or a bad wiring harness.
 

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TomsMR2 said:
.. thats a weird code.



im betting you have either an unplugged/very misadjusted TPS sensor, or a bad wiring harness.
That's exactly what I said! It's a very odd code.
 

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I got a TPS for about $50 from Toyota. Keep in mind that I get a discount through my company...I believe list is about $60-65.

89452-22010 - Manual Trans

89452-12040 - Auto Trans (hopefully this is not you....list is $95)

However:

1. Loosen the two set screws that secure the TPS to the throttle housing. (DO NOT REMOVE THE SCREWS)

2. Connect an Ohmmeter to terminals IDL and E2 of the TPS after removing the connector.

3. Insert a 0.028 in. (0.70 mm) feeler gauge between the throttle stop screw and stop lever.

4. Rotate the TPS counter-clockwise and slowly back clockwise until the Ohmmeter just looses continuity, (infinite ohms).

5. Secure the TPS with the two set screws.

6. Remove the feeler gauge and recheck TPS setting.

7. There should be continuity with a 0.020 in. (0.50 mm) feeler gauge inserted in the stop. There should be NO continuity with a 0.035 in. (0.90 mm) feeler gauge inserted in the stop.

8. Remove the Ohmmeter and reconnect the TPS connector.

w/ AUTOMATIC TRANSMISSION:

1. Loosen the two set screws that secure the TPS to the throttle housing. (DO NOT REMOVE THE SCREWS)

2. Connect an Ohmmeter to terminals IDL and E2 of the TPS after removing the connector.

3. Insert a 0.024 in. (0.60 mm) feeler gauge between the throttle stop screw and stop lever.

4. Rotate the TPS counter-clockwise and slowly back clockwise until the Ohmmeter just looses continuity, (infinite ohms).

5. Secure the TPS with the two set screws.

6. Remove the feeler gauge and recheck TPS setting.

7. There should be continuity with a 0.020 in. (0.50 mm) feeler gauge inserted in the stop. There should be NO continuity with a 0.028 in. (0.70 mm) feeler gauge inserted in the stop.

8. Remove the Ohmmeter and reconnect the TPS connector.
 

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hey what code reader did you use i cant find any for my 92 N/A
they all tell me that they dont make code readers for 1992 .....only 1997+
 

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Discussion Starter #8
i found a tp sensor for a little over $50 at a parts store. bad news is that i dont have a DVOM, it was stolen. And i've never messed with the tp sensor since i've had the car so i'm pretty sure its the sensor. do new tp sensors come pre-calibrated so all i would have to do is center it up and screw it on??
 

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Discussion Starter #10
well i finally figured it out. it was the ignition coil!! i am happy that i know now but am pissed because the computer sent me in the wrong direction. reason it did is because the middle pin on the tp sensor goes to the ecu as a signal wire....that same wire splices off unto other parts of the engine harness into other plugs, (like the ignition coil plug) which is why the computer told me it was a short in the tp circuit. well at least thats what i think is the reason why. i plan on picking up a new one tomorrow and getting it up and running again. thanks guys....Peace!!
 

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mr2project_5sfe said:
well i finally figured it out. it was the ignition coil!! i am happy that i know now but am pissed because the computer sent me in the wrong direction. reason it did is because the middle pin on the tp sensor goes to the ecu as a signal wire....that same wire splices off unto other parts of the engine harness into other plugs, (like the ignition coil plug) which is why the computer told me it was a short in the tp circuit. well at least thats what i think is the reason why. i plan on picking up a new one tomorrow and getting it up and running again. thanks guys....Peace!!
Ah, all the reason why OBDI was overhauled and made into OBDII. Well, hope everything works out so you can get to driving your 2 again.
 

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Great Nick! See should have just went with me and my gut initially when I said it was your coil! ;) It had all the symptoms of the coil but the code 51 was just making us second guess! Sucks that you pulled the engine harness but it good though because it's how you finally figured out that it was the coil for sure! Told you it was something simple! :thumbup
 

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Discussion Starter #13
bad news!!! its not just the ignition coil, but also the ignition control module!! :( i am really depressed right now because i have absolutely NO money!!! this sucks! and there is a grey plug that is right next to the ignition coil....what is it for?? hope its nothing important because i lost it. i hate this whole situation.
 

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^It's not a big deal. :) Search on here for some one that has them used. Give PA autoracing a buzz and see if you can get some from him. Or I can.
 

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Discussion Starter #15
now i am really starting to wonder if it was the distributor connector, cause when i would move the distributor to advance or retard the timeing it seems to want to run more often. would the engine run the same way without it disconnected??? but this doesnt explain why i have a code 51!!! this is really starting to make me upset.
 

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thats your code 51 then, the dist sends those signals.

always ignore cel codes if you know you have an existing problem.
 

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Discussion Starter #20
well i checked the tp sensor and i have five volts going to it so thats good. but when i would open the throttle, it would stay at five volts then cut instantly to 0 volts. isnt it supposed to slowly go down to 0 volts. like an analog signal? well, I'll get the new connector first and let you guys know if that fixes the problem.
 
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