Hello, long time follower, first time poster.
I have an 89 b250 with a 318 tbi and a three speed trans.
We've been on the road for 7 months and have recently seen the Mpg's drop so we did some maintainence.
Air filter (was really dirty, like really) plugs and wires, and a new egr.
We also noticed a cracked rubber cap on the brake booster that must've been causing a small vacumme leak. We replaced it also.
The exhaust seems to be extremely hot. It's melting the hanger bushing near the muffler.
I also noticed black soot on the tail pipe and a bit of white smoke when cold starting it.
Lastly, when warm, it always takes two times cranking to fire up. (Ever since we owned it)
mother than that, it runs great. I'd really love some help here.
Weve never had the carb tuned or the timing checked, could that be the cause?
How about after the egr swap, was I supposed to reset the ecu?
Any help is appreciated. Money is tight so I can't be throwing parts at it.
Thanks in advance.

 

TBI, so, no carb to tune. It's all electronic.

When's the last time plugs/wires/cap/rotor were changed? (maintenance every 30K or so.....)

O2 sensors? They wear our over time, and won't necessarily set codes.

How many miles on it?

Sometimes, just changing the oil can increase your fuel mileage.

Welcome to DF!

 

Thanks for the reply.
Plugs and wires were done two days ago. Prior to that, they were replaced in April along with the cap and rotor.
O2 sensor was replaced in July. It has 174,000 kilometres. (Canadian, eh)
regukar oil changes have been done. I just finished one with the plugs and wires the other day.
How about the fuel pressure regulator? Or how about diagnostic procedure? Can I just get a smog done to see if it's running rich or lean? We're in San Diego so I see those places everywhere lol.
Thanks again.

 

Fuel pressure isn't easy to check on the TBI motors. No little valve to screw the gauge to. Need adapters and such.

Doing a smog check wouldn't hurt...... (not sure how much it costs...)

Is the CEL on? Getting any codes?

 

no cel but I haven't check for codes either.
I think I'll look around for a smog test I think.
It's weird hot hot the exhaust is getting. The floor over the muffler is pretty hot even.

 

Wonder if you cat is failing.......

 

So i just got back from the exhaust shop and he said the cat isn't clogged but he can hear a miss fire in the in the tail pipe as it makes a putt putt putt sorta sound that's very faint but somewhat obviously present.
He determined it was running either rich or lean with the amount of soot in the tail pipe he was leaning towards it being lean. He also noticed the high temp of the exhaust along with some discoloration of the new muffler (soot build up) and said its also an indicator that it's not burning correctly.
All that said and he doesn't do engine work so he refereed me to another guy that wants $150 off the bat to diagnose it... so i think im gonna schedule a smog tomorrow and see how it does then adjust the timing.

 

I also read this in another forum and the guy has the exact same year and drive train as I do. 89 5.2 TBI with three speed and 2:9:2 gears
The following text are his words:

****** I have been trying to post back about what happened but this board seems to keep kicking me off when i post. Lets see if this one goes through.

I fixed the problem a while back. I got my truck out of storage and replaced the fuel filter. That did nothing and the truck continued to run like it had about 10 horsepower. I got so fed up that I started tearing the air cleaner off the truck and pulled some vacuum lines off and once I had the air cleaner off I looked down the throttle body and what do you know? the right bore is bone dry! The fuel injector had stopped spraying.*******

Absolutely every single engine issue I have had since I owned this truck was caused by a faulty fuel injector. The severe pinging: lean spray on that injector. The stalling when cold: fuel injector not pumping enough fuel. The most recent drivability issues were also from this fuel injector because it was near death and simply not pumping enough fuel. The final straw was that it stopped altogether.

So long story short, I replaced both injectors and it has never run better.

 

'Tis fixed?

 

Not yet. I might bite the bullet and have a shop diagnose it.