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1989 Suburban TBI issues? (350) Please Help!

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Old April 12th, 2014, 1:36 AM
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Default 1989 Suburban TBI issues? (350) Please Help!

First post, you guys have an awesome forum on here.

Trying to troubleshoot some issues with my '89 suburban.

It had been running really rough, cutting in and out. Found that it was one of the injectors connections was not strong and would short in and out. The truck had never thrown any codes. Fixed the issue. Now it does not sputter or run rough.

Now, after I fixed the injector, on start up it idles very high for 10 seconds, (regardless of engine temp) then goes to normal rpm and the SES light comes on. If you depress to WOT it will bog for a second and then rev normally, this happens under load and when in park/nuetral. It has never thrown codes before.

I have tried to read the codes using paper clip method but nothing comes up, sometimes the SES light will go off and it will run fine and then kick back on and do the same throttle bog, I pulled the 02 sensor and cleaned it, haven't gotten a new one though.

The motor only has 50,000 miles on it, a crate motor from the dealer we put in 10 years ago.

The TBI has been rebuilt within the last year, I am thinking because of the issue being off and on, that it is a short somewhere in the electrical or a sensor is clogged etc. I have found unplugging the TPS fixes the high idle at start up.

Also my brakes work very poorly ( I just put all new pads and shoes, bled and fluid, but they still do not depress like I would think they should, maybe I don't know though.) I am thinking it could all be vacuum related? Maybe a stuck EGR or Coolant temp sensor going out.

Looking to find someone with more knowledge than me.

Any tips, advice, or things to check are much appreciated.

Thank you in advanced,

Corey
Old May 7th, 2014, 5:56 PM
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ok first... your asking a lot of questions in one post

you need to know the code definition so finding out which one it is is priority. If it comes on then off it's a soft code. i.e. you're not gonna explode !!!

very high cold idle, check for a vacuum leak first, then check coolant temp sensor connections and sensor itself. unplugging the TPS is only adding to your misery so plug it back in

check for a vacuum leak first
get your codes read, any autoparts store does this for free
get your code definition
fix

cleaning an O2 sensor rarely helps unless you get it red hot

so your telling us it's very hard to push the brake pedal down ??? like no vacuum going to the brake vacuum booster ??? then I would check for a major vacuum leak first, then for carbon build up underneath the throttle body, then suspect a vacuum booster issue
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