Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

1989 GMC van, TBI, stumbles at part throttle


  • Please log in to reply
1 reply to this topic

#1 MilesFox

MilesFox

    Catch this Fox!

  • Members
  • 10,180 posts
  • Madison/Milwaukee, WI

Posted 12 May 2012 - 06:38 AM

I have a free van from a retired painter. This van is a 1989 gmc/chevy '20' panel van 305 v8 automatic TBI.

this thing has only 88,000 mi, but has sat for the better part of 10 years.

Since we had it, the crack heads chopped out the cats, and now it has a cherry bomb and side pipe. She runs great on the highway, but at part throttle acceleration, especially on hills, she stumbles and backfires thru the TBI. I have to feather the pedal, or completely bury it to get her to move.

There is a lot of vacuum sucking noise, but i cannot find a leak or loose fitting. There is a broken nipple on what appears to be an EGR control solenoiid. This van has electronic ignition and coil packs. She has some original looking delco or autolite spark plugs.

I am wondering if the timing is off? it drives as if the vacuum advance isn't working, but it is load sensitive, and an electronic disty.

I am not familiar with these archaic american v8's as they are as foreign to me as a subaru engine is to any old-timer.

the van seems to run right until it is warmed up, although it idles a bit higher than it should. IT drives like it has a vacuum leak.

So, what is the GM TBI system sensitive to?

is there some kind of thermo vacuum switch that fails?

can an engine temp sensor throw it off, and where is it located.

there is an oxygen sensor present, as i have located it on the driver side manifold.

what are common problems and common fixes for this type of generic engine?

there is an oil leak on the back of the intake. that will be fun to fix. I want to smack the general for using a 30 year old engine in 1989. Wouldn't you smack FUJI if they were still slangin' ea82's in the '12 wrx?

#2 Subruise

Subruise

    Official Party Pooper

  • Members
  • 1,303 posts
  • pierce county

Posted 13 May 2012 - 01:46 PM

my old boss had one of those. make sure theres no cracks in stuff like the disty/cap. timing could be off and, iirc vacuum was kinda a pita on that thing. we did a bunch of work on it and it was still gutless. 305s, pfft. is your tbi/electrocarb doin its job?




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users