Mechanics

454 BLACK SMOKE & FUEL EXHAUST. 4 SHOPS AND $1800 (NO LU

Chevrolet Truck

The truck is a

1989 Chevy 1 Ton dually crew cab
454 TBI dual fuel pumps (one doesn't work because of hole in tank for years now)
Mileage is way up there (Highway pulling trailers)

Over 2 years ago Replaced

Exhaust manifold gasket passenger side

Then replaced cat since is blew up in driveway while trying to start

3 weeks prior to making an appointment at a shop the truck after a 15 minute ride and then sitting at idle for about 10 minutes and sometimes less while loading it at shop it would start to run rough and sometimes shut off.
I would then be able to start it but it bogged down when I touched the gas. If I put it to the floor to keep it running it would bog, but if I feathered it the truck would try to stay running. If you let up on the pedal it would run but then try to die. Would actually have to get in the truck and put it in gear and push peadl to floor around complex to get it to clear up. This would take about 2 minutes and then would be fine for awhile. This episode lasted for about 3 weeks and only after a ride of maybe 15 minutes or more.

So this year took truck to shop since it was getting loud again due to driver side gasket on ehxaust manifold and loosing power (Not able to make it up a driveway & having trouble from acceleration pulling trailer)
The previous problem above dissapeared for no known reason with the bogging and stuff

Also before the shop trip the truck overheated without warning and everthing was rock hard.
Checked thermostat after we relieved pressure and the thermostat was open so then I remember the truck was overheated and the overflow bottle had no action of boil over.
I then replaced the cap and have not had a problem yet. I still get nervous when I see the temperature at 220 mark though and hoses get hard but no overheating

The shop found also a cracked exhaust manifold on driver side just above the o2 sensor so they replaced

the exhaust manifold with new one and took off my smog tubes and plugged one side and bent the ones over on the other side. (I did not authorize this, but they said the truck should run like a champ now)

gave the truck a complete tuneup

I received the truck back quieter, but with same problem of no power to go up a driveway or poor acceleration unless you stomp the pedal after rolling.
This trucks tires used to let loose, but not anymore and this was before the shop
They have no idea what it is so I took it to 3 other shops all with the same answer. We looked at it and don't know what to say except we will replace everything.

I then took it to a friend who has a trans shop and deals with drag cars as a hobby. He always has toys to play with for tools. He ran a test on it with machine with key on and off eninge not running and running for the test computer.

We got the codes 22 tps low voltage and 34 map sensor high vacuum.
He doesn't deal with TBS so he said to test every sensor with the test flowcharts.
I tested every wire with OHM meter tester and other and could not find bad grounds after opening harness and looking for broken or open wires and what not.

The truck just gets worse with black fuel smelling smoke that can clear a neighborhood of fuel smell

I tested every sensor and they all tested fine through tests and checked resistance on others including wires.

So I then replaced them just incase I missed something.

So I replaced the
-replaced fuel filter
-replaced TPS sensor
-replaced Map Sensor
-replaced egr vacuum solenoid
-tested the Egr valve itself (Stalled engine and holds vacuum)
-tested the AIC as test said with meter for resistance and ohms and it works because I actually can hear it move when frst turn key on
-replaced coolant temperature sensor
-had the cats ripped off for now incase they were acting up again (Straight muffler for now)
-Replaced the o2 sensor since they should have (Did not touch the end of sensor as told not to)
-checked firing order of wires just incase
-Looked under cap for curiosity
-tore the TBI apart and checked for leaks and crud or other while also checking the pressure regulator diaphram (Looked fine), and injector screens were clean and tbi port and other were clean and easy to blow through
-put new base gaskets on since the old ones hated any carb clean sprayed near them
-checked all vacuum hoses
-blew into fuel return line and it went into tank
-checked wiring again with eyes and meter for 2 days just incase again since engine overheated and melted harness cover to intake but was fine
-checked ecm for loose wiring since I drive down some bumpy roads all the time
-checked the oil/fuel pressure switch on block for bad wiring (My oil pressure guage always bounces around 60 psi May be bad but shouldn't affect truck right?

The truck now if you take the pcv valve out and the egr hose of the solenoid and tbi it likes to run a little better but not always (High idle though). It will smoke the tires if needed but not always it then just leads back up

Sometimes if you start the truck and put it in gear and try to move it will smoke the tires but only for a second until it loads up again

Almost like if I can catch the computer sleeping it will take a second to catch me and then flood me out

The truck still getting worse and sometimes lopes when driving at a certain speed of maybe 15 mph. Sounds like a competition cam, but will not do it always and goes away after you get going
Also
High idle after a 10 minute run, but when you shut it off and start it again it has low idle.

sometimes the idle will be so low when coming up to a light it sounds like it is off, and it used to be the opposite it wanted to put you through the light

Also if you are at a light and hit the gas quickly or while parking to manuvuer it willnow stall and give some nice fuel smelling exhaust after start up

I am at my witts end please help me since this truck is part of my lively hood

Forgot to mention: The truck runs fine once going with the slight black smoke unlees punched and then big burst of smoke. If you are driving and want to pass or accelerate it but off the light acceleration and idle are killing me here with the smoke and fuel.
Also when a trailer or load it takes off like a rubber band car slow until it picks up speed.

I don't think I left anything out that I may have tested, but lets say I have lived under the hood and under the truck and dash for the past 2 weeks.
Avatar
Dave Ott
July 4, 2007.




I have a few questions, Has youre motor had a compression test done on all piston cyl's. Could have a sticky exhaust valve on the cyl hd's, Also youre fuel pressure regulator is faulty, Also How about youre timing. Could be off some degree's, Also could have alot of play in youre timing chain. Also Have you checked all youre vaccum line hoses? ( Cracks & broken parts). Also is youre distributor firing properly too.
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Tiny
E40water12
Jul 4, 2007.
Compression check was fine from what was told to me.

I just checked the timing since they said they did. With timing connector unhooked (Tan/Black) the timing it say should be (before at 4degrees) it is actually at 5 at idle but was told this one degree wouldn't do it

Just changed the pressure regulator and it still does the same. They gave a smaller spring with the new kit not as tall will this affect anything?

Now they said the reason they did a tuneup was because the cap was cross firing now that you mention it. How would I tell if it is still crossfiring? I looked under it but didn't see much like specks or anything on cap or rotor. (Wierd marks)
I did notice the distributor base has alot of rust in there. Would that hurt any of the other electrical parts in there? (Module)

I just got done playing with it again and kicking the bumper Ha Ha

The truck is getting worse and actually has a loping sound when the pedal is depressed which used to only happen when driving around 15 mph
(Sounds like a drag car)
If I move the throttle slightly is will lope and as soon as I unhook the vacuum line fron egr valve it will stop.
I tested the egr valve because it will stall the engine when given vacuum with a hand pump

Could it now be fine, but that smaller spring they gave with the kit not right? It alsmost sound like it is starving a little now which makes no sense since it used to be drowning. It still smells like fuel a little and acts up

Tiny
Dave Ott
Jul 5, 2007.
How about this rust monster and melted wires


http://www.2carpros.com/forum/automotive_pictures/83376_truck_distributor_006_1.jpg


Tiny
Dave Ott
Jul 6, 2007.
Okay new distributor helped it run a little better still same smoke problem

Every sensor has been replaced now twice

New cap and rotor and wires with plugs again since the new wires were sparking all over at night, still same problem

Took truck to another shop for electrical testing nothing

Truck went to another shop and they took the intake off to check gaskets after checking for leaks (The exhaust ports were leaking into block with alot of carbon buildup)
Decided to take heads off and took to machine shop for rebuild and checked
Everything put back together (Top end rebuild) few mile later same issue with smoke and still getting worse with chugging

Had truck taken to friends shop to check valves for proper adjusting and timing everything was fine (You never know)

Replaced the ECM

Replaced 2 new fuel injectors and still has same issue

So now that everything possible has been done and looked at. Is there a sensor under the dash on this year vehicle that someone has missed?
There has to be a reason it wants to give more fuel than needed.

Fuel pressure was tested and pressure regulator was replaced also and return lines blown out to check for return

I have one tank that I do not use but I don't see how that would be a problem anywhere with the pump that isn't used

Any ideas because a carb is sounding pretty good right about now. This computer controlled stuff is ridiculous

Something has to be missed somewhere and everyone and every shop is scratching their heads

Tiny
Dave Ott
Aug 14, 2007.

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