Just bought a 86 6.2 almost didn't get home

[spencergt66]

So I went and looked at this 1986 gmc 2500 4x4 with a 6 .2 looks all stock has dual flow masters was told it has a tranny issue seamed ok to me so I got it cheep (1200 bucks) about 3/4 of the way home it started getting slower and slower seamed to shift ok but just less and less power seams like the truck isn't getting fuel.

The old owner said he put an electric lift pump in it but I have no ideah what or where guess I'll have to start digging into it next seeker seams to run ok but no power he kept saying the tranny was the issue but it doesn't seam to pull at all no matter the gear

How much life can on expect out of the fuel system if taken care of?

 

[towcat]

my suggestion......
replace all fuel filters first. if it is still "stock" on one of the filters is a brick shaped unit on the passenger side of the firewall.
also, make sure the glass ball on the return side of the pump is not blocked.
if the return on the pump is not flowing, the pressure inside the pump will slowly shut off the fuel supply.

 

[spencergt66]

The supply pump has been replaced with an electric unit and a different water separator filter instead if the brick I need to go through and check the basics the longer drove it the worse it got when I took the off ramp the truck actually died it restarted no issue but still left a bad feeling in my gut

I don't like having 2 tanks twice the issues to trace down but this is the way things were done back then so ohwell I didn't know about the return fide I'll look at that when i get a chance this might be my issue but we shall see

Thanks for the input I'm new to the 6.2s I've had 3 6.5s with pretty good luck and some idi fords idk I just like the old mechanical stuff call me old school

 

[Kevin 007]

Don't give up on it! In my opinion they are quite superior to the 6.5, less stress on the motor without a turbo so usually they are more reliable and as long as it stays cool, the run and run and run.

My guess would be that lift pump. Get rid of it and put a new OEM pump back on, that is if he didn't ****** the fuel line plumbing when installing the new pump.

Or, disconnect the fuel line from the electric pump and turn the key on and see how much fuel its pumping. Thats a start. But I would still get rid of it regardless of how it works. The injection pump could also be bad of course but eliminate the things that support it, like the lift pump/filters etc.

I love the 6.2, I have had great luck with great economy with them. hope you have the same.

 

[lindstromjd]

What exactly did it start doing when you say it just seemed like it lost power? Rev up but not go anywhere? Or push the pedal to the floor and get no response and the engine kept slowing down? And what transmission is it? If it's an automatic, you could be losing it; once the fluid is nice and hot you notice it more when the clutches start slipping. Just a thought.

 

[spencergt66]

I think it may have multiple issues haven't had a chance to even look at it yet thoug. Going on the freeway it wouldn't get going more then 45 and seemed to be stalling at times if you down shift it didn't want to rev much and when it did the trans would just slip. It has a 350c.

When I pulled off the freeway it just died it restarted but with the lack of power and stuttering it has I wouldn't be surprised if the fuel system is shot as well as the tranny may be this weekend I'll have a free minuet

I like these old truck and plan to hang on to it any one know a good website for good fuel system components like pump and injectors

 

[lindstromjd]

dieselplace.com is a great resource for the old 6.2's and 6.5's

 

[spencergt66]

Looks like another forum I was looking for parts

 

[lindstromjd]

Looks like another forum I was looking for parts

It is another forum; just like this one is dedicated to IH diesels, deiselplace.com is dedicated to GM diesels. Those guys always have spares for whatever you'll need for your 6.2

 

[spencergt66]

Ok so I pulled the tranny out everyone wanted an arm plus leg for a standard OH. So i said screw it and took it apart my self not really finding anything bad few bushings worn the filter was put on way wrong pry mostly the cause of my problems. I also found everything in the valve body sticking so I got a new Ultra low stall HD torque converter coming and all new BandM internals. with Valve body and pump upgrade kits all for less then half of what anyone wanted for an OH using knock of parts

 

[spencergt66]

Got the tranny back in seams to work much better but I think the fuel system is shot. higher rpms the truck does not like and will studder and miss also has a little bit of white smoke I would say the pump and nozzles are done

 

[Black dawg]

are you sure the trans is not a th400? seems really wierd to have a th350 behind a 6.2

 

[spencergt66]

Yes it is a 400 the guy told me it was a 350C but he was pretty dumb the 400 works good with the ultra low tq converter I still need to check the vacuum at the modulator and the pump for that matter seams to be shifting late minor things. I'm looking for a pump And nozzles now to get the fuel system operating correctly and also a turbo

 

[spencergt66]

So just about everything in this truck as far as a fuel system is shot the filter is wrong (too small) the electric pump is also too small pulls a vacuum on the fuel system with the truck running and the pump is some what iffy what a mess

 

[spencergt66]

Got new injection pump and injectors installed now plumbing in new lift pump and turbo manifold does a 6.5 down pipe work for these trucks? looks like its going to be a tight fit in there