90 BII Engine trouble

Shran · Nov 3, 2010

Run a compression test. Also unplug your MAP sensor and see if it runs any differently. Let us know what the results of these are.

uscg10 · Nov 5, 2010

unplugged the map sensor and it did idle a little smoother but still has a miss. Also unplugged the throttle positioning sensor and idle air control and all of them make it run smoother. But just can't find what is causing the miss and it gets worse as it heats up

Shran · Nov 5, 2010

Uhh... huh. Unplugging the MAP sensor should make it run significantly worse. Interesting. Do the compression test.

uscg10 · Nov 7, 2010

well got tired of taking it to the shop so bought a code reader and got 3 codes. the map sensor, ect, and the tp bad. tried to do a timing check with the reader but all it would do was start the test then cut the truck off. any ideas. do i just start replacing all the sensors and computer or just the ones that are bad. so tired of spending my weekends working on this.

gribly · Nov 7, 2010

If you ran the vehicle with those sensors unplugged and then did not clear the computer before scanning the codes, they're sure to show up as bad. Plug all your sensors back in, take the negative terminal off the battery, and let it sit for an hour. Put the terminal back on, run it, and then check the codes.

adsm08 · Nov 7, 2010

Shran said:
Uhh... huh. Unplugging the MAP sensor should make it run significantly worse. Interesting. Do the compression test.

Unplugging the MAP should kill the engine.

If you ran your test with the engine below operating temp, then the ETC code should be ignored.

As for the rest of it, Shran is right, compression tests, both wet and dry, should be done, codes should all be cleared out, and then the self test should be re-run at operating temp.

uscg10 · Nov 7, 2010

had already reset the computer by unpluging the neg. power cable for 2 days. did the test with the truck warmed up. now for somemore problems to add let the truck run for about 30 minutes and whatelse could happen but the radiator busted all the way down the side. it has just been one of those weeks. where to go from here. :icon_confused:

adsm08 · Nov 7, 2010

5.0 swap?

uscg10 · Nov 7, 2010

maybe some type of swap or something. right now thinking about making it a good bream bed :icon_rofl:

adsm08 · Nov 7, 2010

a what now?

uscg10 · Nov 7, 2010

bream a type of fish or a crappie bed /shelter

voodoochylde · Nov 7, 2010

I feel your pain. I've been chasing a miss for a while now (as in, since I got the crummy thing). I'd replaced the O2 sensor, throttle position sensor, engine coolant temperature sensor, plugs, wires, dizzy cap and rotor, oil change, air filter change, throttle body cleaning.

I had borrowed a timing light to check base timing, started it up and let it sit for about 10 minutes, came back out and :O coolant is dripping from the bottom of the radiator.

Thank god my Impreza isn't having trouble right now.

You're not alone (though I kinda wish you were lol) Good luck!

90 BII Engine trouble

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