2.8 Carbed problems

[shortygy]

Hey guys,

I have had my 1985 2.8 carbed Jimmy for approx 4 years but it has never been driven as I was redoing body work interior etc.

I have just started driving the truck as a daily driver as of 2 weeks ago. I sold my other daily (2001 VW GTI) so I think my expectations are high.

I am having problems with the truck having alot of hesitation at partial throttle feels like it cuts out once and a while etc. Sometimes it runs excellent and other times it runs very rough and inconsistant. Its usually best when its really warm and I have been driving it hard to get it hot.

The carbeurator is rebuilt new rotor, cap, wires, plugs (although they are like pregapped 4 point ones maybe no good for our older trucks?) Blocked EGR Vacuum lines redone. Timed etc.

Anything else I can check over to help it run better? Fuel pressure? 02 sensor or something?

Thanks,
Greg

[Tink]

Those plugs aren't bosch are they? I'd always stick to regular AC Delcos in any GM - especially the old carbed ones. Have you pulled one out to see how it looks?

Is it usually rougher cold? I'd also ditch as much of the emissions BS (that you can) - like the smog pump and all associated lines... On our 85 fullsize, we ditched over 75% of the vacuum lines on there and the smog pump. I think the only things left are the vacuum to the brake booster, the tranny and to the controls inside. We also got rid of the EGR and PCV... but that is up to you... we put a block off plate where the EGR is and put a push-in breather in where the PCV is.

[shortygy]

Yes the plugs are bosch platinum 4's I think... i put them in a few years back when I was younger and ignorant lol. I have not pulled one to check but I will do an oil change and change the plugs to normal ones tonight.

I replaced the EGR yesterday, but it is also disconnect so it is acting like a block plate (vacuum line is plugged)

Engine has a breather on the passenger side valve cover ( I think it was vented to the air cleaner possibly before?) I will try to add one to the other side as well.


And yes it does run worse when its cold... it stalled twice this morning on the way down the hill. How long do I need to let it warm up for? im use to newer fuel injected vehicle....

[Sparky2263]

Sounds like you have a choke problem. The choke vacuum break (pull-off) sounds like it's not adjusted properly on the cold start. Also sounds like the choke isn't fully opening when warm. Either that, or it's always open and you have an accelerator pump problem.

I don't know who rebuilt it, but if it wasn't an older guy who grew up on carbs, it's probably way off on the adjustments.

Very good carbs but in the wrong hands they become very bad carbs.

[shortygy]

Tonight I replaced a few things...

-spark plug wires as I noticed one was arcing off the coil
-plugs to autolites gapped 0.045
-removed pcv plugged line and put a breather on

-I also picked up a remaned distributor but have not installed it yet..


The guy that did the carb is a shop called Canadian Carbuerators. He really knows his ****. He rfound some vacuum leaks fixed those after the rebuild and he said the EGR was leaking so I replaced that but its not connecting just using it as a block off. He also mentioned the distributor was hanging up a bit by watching the timing climb when reving it it sticks at 1 spot and then jumps up. Not a smooth curve. That is why I picked up the Remaned Dist.

The truck is running a bit better after tonight but still has some hesitation kinda bogs and if I push the gas a bit more then boom accelerates back to normal.


I will try putting the Dist on tomorrow.

[shortygy]

ohh and by the way while changing the plugs I noticed cylinder 1 3 and I think 5 had some oil at the very top of the threads... Not sure how bad that is...

[T Man]

leaky valve cover, not a biggie. When the oil is on the electrodes...you have a problem

[shortygy]

Cool thanks for that (good news I guess lol) I was thinking blow by but at the same time didnt think so because it was on the top of the threads.

2 more things to add... When I replaced the EGR the other night I noticed in the square shaped port that there was a bit of green liquid inside. Looked like coolant possibly. Is Coolant supposed to be in there?

One last note... This morning I started the truck up approx 5 minutes before leaving to warm it up. Hoped in drove it down the hill ... wasnt running too too bad but still not spectacular, I went around a corner at the bottom of the hill.... rolling speed and it stalled out of nowhere? This stuff is starting to tick me off lol.

Should I attempt the Distributor tonight and if so any tips?

[Slacker1357]

If there is any other possibilities, it may be also your oil may need to be changed or need your engine flushed out and filled because its been sitting. also your fuel system, you may need a "3-step". fuel cleaner, (dont think you need the carb cleaned due to the rebuild), and the sparks could be a another possibility (yes I read all the statements above, still a chance)

[shortygy]

I changed the oil last night. I have run about 2 tanks of fuel through it now... not to sure about the fuel cleaner since I have already refreshed all the gas.