An easy one for ya, old timers.. ;)

[bovic]

An easy one for ya, old timers..

Here goes.. I have a 1985 Jimmy 4x4 2.8 liters.. Do I actually need all those silly vacuum hoses? Can I just rip 'em appart?


At times, last winter, the truck would just descelerate on the highway to a point that i'd be driving 30mph flat out! Man that scared me sometimes as big rigs would drive past me, trying to drive on the shoulder.. I did noticed a leak on the fuel pump this spring, could it be the source of intermittent underperf? Last time I used the truck was april, it died on me on a rather nice day.. I cranked it and nha, wouldn't fire.. Was alone, didn't had what it took to test the firing gears so I called CAA (Canada) and waited a bit, I retried it like 20 minutes after and it just started, though it did took like 10 seconds.. So I elected to take the truck back to my workplace where we have a shoping center type of parking.. The truck really scared me often last winter but i'm willing to give it another shot, I kept it, parked it, started it every other weeks and it always ran fine, today I went to the truck and drove it for a good 15 minutes, all fine, the truck is a mistery to me.. So I have alot of time before winter, i'd like to refresh the engine and replace a few parts that i haden't yet (the usual tune-up was allready done).. Question amongst others, can I get rid of the vacuum system?

[maxwedge]

That is not the problem, why would you think it was, these are emissions components that will not cause what you describe, watch the fuel filter in the carb inlet fitting, ever replaced? Leak of fuel around/at the pump, again, why hesitate to fix that?,

[bovic]

Originally Posted by maxwedge

That is not the problem, why would you think it was, these are emissions components that will not cause what you describe, watch the fuel filter in the carb inlet fitting, ever replaced? Leak of fuel around/at the pump, again, why hesitate to fix that?,

Agreed, the filter was replaced during the fall tune-up.. And I just noticed the leak as I parked it in spring (it was intermittent i guess because I had that inspected during winter) but it did smell fuel now and then.. Do you think a weird fuel pump could be working but intermittently working half capacities in a snap the working fine again? It is of course the 1st thing i'll replace..

[maxwedge]

Originally Posted by bovic

Agreed, the filter was replaced during the fall tune-up.. And I just noticed the leak as I parked it in spring (it was intermittent i guess because I had that inspected during winter) but it did smell fuel now and then.. Do you think a weird fuel pump could be working but intermittently working half capacities in a snap the working fine again? It is of course the 1st thing i'll replace..

Not usually, the pump would just fail or be weak, the next time it won't start or dies see if there is gas in the carb and you have spark.

[blazes9395]

The 85's were carburated 2.8's. My grandfather had one way back, and wow, they were sloooowwww pokes - but quite dependable. Also, its a mechanical fuel pump. If its the original carb on there, take it off, get it rebuilt/replaced. Over time, carbs get dirty and sticky, and since you had it sitting, it gets even worse. It sounds like its not getting enough gas, or it could be the opposite its getting too much gas and bogging down. If you have good fuel pressure, and the ignition system is alright, then I would really be looking closely at that old carb.

Also, it wouldn't hurt to make sure the EGR system is working properly too.

[bovic]

Thanks for these answers.. I'm retuning it for winter and a weird thing, I noticed.. On the front of a head, I see bubles where the water pump or a bracket (IIRC) bolts! And there's some prestone here and there on the engine in that area.. This baby's tired i'd say.. Another thing, when I start the engine, oil pressure is fine, after like 5 minutes it drops to 0 and never gets back up anywhere even when giving gas.. This is becoming a weird engine indeed.. I'm scared

[maxwedge]

Get a mechanical gage on the engine, screws in where the oil pressure sending unit is and check the actual pressure, if it confirms 0, there are internal problems.

[bovic]

Well, I tought of something regarding power loss, in the morning, the 1st time that I apply the brake pedal the truck would slid on the rear right with the wheel locking.. What if, while driving, that rear brake is sticking and starts to heat up and expand.. It's hard to drive fast with a rear brake sticking.. Just a tought.. And regarding that oil pressure, I bought a new sensor and i'm yet to install it.. I'm also thinking of simply replacing the engine for a 3.8..

Here are some pics of the 4x4..:


























I'll do the body work on the rear next week, only the rear needs fixing, the rest is mint.. Actually there were no holes, I punched em myself to see how bad it was