I apologize ahead of time if this topic has already been covered. So I purchased my 86 truck two years ago with 140,xxx miles on it. The owner did not do any oil change on it since he's got it but he hardly drove it either. I believe he's the second owner. Anyhow, I was getting only about 130 +- miles on a tank of gas. I changed the spark plugs and wires and got 230 miles. I took it up to the forest to go camping and I found that the truck gets really hot and looses power going uphill. Now I have about 145,xxx +- miles on it and I am now having problems.

1. The truck sometimes dies coming out of third gear to neutral to stop. However it will not die if I downshift to 2nd then 1st gear then neutral before a stop.

2. The other problem is that some mornings when the truck is cold it will idle fine but when it heats up it will die. It will restart and if I gas it will run and not die until I encounter the 1st problem I mentioned above.

3. Now I get 130 miles on a tank.

4. Second gear sometimes hesitates at low rpm when engine is cold.

5. Sometimes feels like turbo does not kick.

6. Turbo light on dashboard comes on almost all the time at highway speeds. (don't know if this is normal)

I do not know anything about this motor and have no idea where to start to diagnose the problem. Please help anybody.

 

I'm not really familiar with the turbo trucks [wish I was lol] so I really can't advise but I edited your title so you should get some help sooner
I will say it sounds like you are having a fuel delivery problem either it's not getting enough at one point and then too much at another...
as for the turbo not making a diff. it might be a hose missing or the blow off valve stuck open/opening too soon we had that problem with a diesel truck at work... mechs. forgot to connect a hose and the turbo was dumping the air overboard instead of the intake...

Good luck
Welcome to the family

 

Thanks for the edit. I do hope I get some help.

 

Howdy ck.; When I bought my 86 turbo truck I had your # 1 problem, that baby will die at stops, untill I found out, that if i turned the a/c on, before got to the stop, the idle had the extra boost to keep the truck alive. maybe had some crap on the fuel lines, because the problem went away by itself, on about 6 weeks, try it, it may help you. Good luck.

 

you might PM Dirtco, link: he is building a turbo 4runner

he might be able to offer you some help...

 

Sounds most certainly like a boost leak. I would find a shop, and get them to do a smoke test on the intake system. If you have a leak in your intake somewhere, you'll run lean in vacuum, causing it to idle low, and die, and it'll run rich in boost, causing poor fuel economy, and hesitation. I would try taking the intake pipe off to the turbo, and spin the compressor wheel. See if it spins freely. It's possible that the centre section is coked with crap, causing it to not spin properly. If that's the case, some degreaser into the oil lines, and a good rinse afterwards can to wonders.

As for the turbo light being on all the time on the highway, I find that's pretty normal for anything over 65. I once was cruising into a head wind doing 70, with the pedal floored. haha.

Check you PCV valve, to make sure it's working properly. If it's leaking, it'll dump pressurized air right back into your intake, making the turbo really laggy, and the motor sluggish. Also take a close look at the AFM, and see if it looks like someone has opened it up, and glued it back shut. That's a sure sign someone has messed with the spring tension, making it run super rich, or super lean. Make sure your timing is properly set too.

Oh, and install a boost gauge, so you can make sure the turbo is working properly.

 

Thanks a lot guys. I'll have to try out those tips you all mentioned. However I have to figure out where everything is first. Not much of an engine guy. Appreciate all the advice.

 

Our trucks don't have blowoff valves as mentioned above unless an aftemarket one is installed. How hot is the outside temp when you have the overheating problems? the turbos compress the air which makes it hotter going into the engine and that can cause overheating rather quickly. Intercoolers can help with the temp and power gains. the air is more condensed so you have more oxygen molecules getting mixed in with the fuel.... The factory CT20 turbos are junk. The exhaust housings always crack at the wastegate. Good swaps include supra 7mgt ct 26's (thats what i got) or the t3/t4. As for the turbo light, it should come on anytime you start building boost. and definatly look for vacuum leaks everywhere.

 

It was about 50 degrees when it got really hot. It never overheated but it go really hot and started to loose power, mostly on up hills. Are the supra turbos the same size or do they need to be fitted?

 

Have u checked to see if your throwing any codes?

 

No I haven't checked yet. Would a regular obd2 reader work for checking it?

 

no...search for getting the codes, its a lot to type....these trucks are OBD1 so you have to do it a different way, I would reccommend getting a haynes manual, they have a lot of good information on little things!!

 

Check the EFI SYSTEM - DIAGNOSIS SYSTEM section of the fsm for pulling the codes:
http://www.ncttora.com/fsm/1985/1985FSM.pdf

You might want to pull the cat and see if it's clogged - sounds like it may be.

Probably not a bad idea to run a compression test either, if it never received any oil changes