Chevy engine problems

[runeight]

fuel pump.

+1

fuel pumps do two things usually..

works..

don't work..

You might check that inline fuel filter. Supposed to be changed once a year. I bought my 94 S-10 Blazer from my step father. Ever change it Dad? Not that I'm aware. That thing must have weighed a pound!

hogger...

 

[nitrousjunkie]

Check the fuel pressure,youre gonna have to have it scanned to be sure,if it has multiple codes,fix the first one first,clear the codes then drive it.

 

[06BUSA]

have you changed the exhaust??

Prolly an o2 sensor gone bad

Does the truck run rich?

O2 sensor. Good chance this is the prob. Not sure if you have 1 or 2. My Silverado has one for the left bank and another for the right. Only one needs to take a dump.

 

[Professor]

fuel pump.

+1

fuel pumps do two things usually..

works..

don't work..

You might check that inline fuel filter. Supposed to be changed once a year. I bought my 94 S-10 Blazer from my step father. Ever change it Dad? Not that I'm aware. That thing must have weighed a pound!

hogger...

I'm thinking the fuel pump as well. It is not really a work/don't work type of device in the later model stuff. You can get symptoms like this when they fail. It is common for them to not develop enough pressure/volume to go much past idle. Also be prepared, as the price on these late model pumps are up there in the $250-$300 for the pump alone (not retail either).. Regular replacement of the fuel filter and not running the tank below the 1/8 mark will help them last longer.

 

[DrBoom]

fuel pump.

+1

fuel pumps do two things usually..

works..

don't work..

You might check that inline fuel filter. Supposed to be changed once a year. I bought my 94 S-10 Blazer from my step father. Ever change it Dad? Not that I'm aware. That thing must have weighed a pound!

hogger...

I'm thinking the fuel pump as well. It is not really a work/don't work type of device in the later model stuff. You can get symptoms like this when they fail. It is common for them to not develop enough pressure/volume to go much past idle. Also be prepared, as the price on these late model pumps are up there in the $250-$300 for the pump alone (not retail either).. Regular replacement of the fuel filter and not running the tank below the 1/8 mark will help them last longer.

yeah I tried the fuel filter, and it ran great for a day, I'm going to get a fuel pump this morning, my buddy with the analyzer is gone for the weekend. we'll see if that takes care of it. Yeah and the fun of it it looks like there are four o2 sensor on this damn thing 2 before and 2 after the cats.

 

[DrBoom]

i.m thinking the pump strainers could be dirty too.

 

[Sloto200]

The Autozones in my area will pull your code for free but wont reset it. Worth a shot to give them a call and see if they can pull your code for you instead of going to a garage and paying alot of money for 2 mins of work.

 

[StuckInBaghdad]

my best guess would be either a bad o2 or catalitic converter.

either would cause the ecu to over compensate fuel when it doesnt need when accelerating it which makes it runs like shib and get bad gas milage.

cant explain the fan unless the truck is running hot.

+1

 

[SpeedAdict]

Was your fuel filter dirty when you pulled it?
If it was it might have clogged your injectors or gummed up your carb floats which ever you got. I had that same problem with a 454 a couple years back and it was a wierd fuel filter getting stuck . Pulled the filter and it ran great. Just had to put a different in line filter in and it was cool after that.
I wouldn't think it was a spark problem just cause it is RPM driven but check your plugs and wires anyway.
I think it sounds more like a fuel problem than an O2 sensor. Just my thought though

 

[runeight]

Was your fuel filter dirty when you pulled it?
If it was it might have clogged your injectors or gummed up your carb floats which ever you got. I had that same problem with a 454 a couple years back and it was a wierd fuel filter getting stuck . Pulled the filter and it ran great. Just had to put a different in line filter in and it was cool after that.
I wouldn't think it was a spark problem just cause it is RPM driven but check your plugs and wires anyway.
I think it sounds more like a fuel problem than an O2 sensor. Just my thought though

ageed..those EGT deals have a small orrfic in them that gets plugged up. Have heard of guys welding the orfice closed.

I wish I could think of the name on that part? It reburns excess fuel from the engine.

hogger...

 

[300Busa]

my best guess would be either a bad o2 or catalitic converter.

either would cause the ecu to over compensate fuel when it doesnt need when accelerating it which makes it runs like shib and get bad gas milage.

cant explain the fan unless the truck is running hot.

or injectiors, spark plugs, or bad gas.

 

[busahaya]

I would have to say the ignition system, I'm alil outdated but newer vehicles come with distributorless ignition, correct?

 

[Projekt]

Get a Haynes or Chilton's manual it will give you a good set of steps to follow for troubleshooting the issue.
Sounds like a variety of causes could result in this problem.
1. Fuel delivery system or blockage (filter, pump[ however these tend to fail completely and not partially], regulator somehow allowing only partial pressurization, injectors [could be clogged but I doubt it].
2. Ignition system failure... (if your tahoe has coil on plug this is unlikely but could be caused by a voltage limiting condition) If you have a distributor then pull a plug and cable to ground the plug on the block and look at the spark. It should be blue/white, if yellow this could be the problem.
3. Exhaust system blockage (the catalyst could have been plugged up) hence a capacity to run properly at low rpms but unable to accelerate when in high demand driving. (this also could explain your fan noise due to heat buildup and therefore constant viscous clutch lockup) It might be time to change your fan clutch anyway.
4. Computer (sensor) problems could be causing power loss.. If your knock sensor is going haywire the ECU could be retarding timing so much that you just slow down because it thinks you are pre-detonating. Possible that the fan noise (due to a bad clutch) is being interpreted as knock and leading to timing retard but that is a remote possibility.
5. Try to google a GM truck forum as you may be able to find someone with the exact problem has already discussed the issue with the forum.

 

[Projekt]

By the way when O2 sensors fail, you just get bad gas mileage as the engine always runs in open loop (warm-up) mode. Typically they will not have a noticeable effect on your driveability.

 

[Batman#1]

It sounds like the fuel pump to me also, try e-bay if you have not bought it yet. I got mine, the full unit for $125 there. I have a 96 tahoe and mine just whent out at 100,000 miles

 

[onerabidshark]

could be any of mentioned above catalytic covertor stopped up, 02 sensor bad, Fuel injected right? could be fuel pump getting weak or injectors going bad, electronic ignition could be going bad, get it plugged in most auto parts stores will plug it in for free with a small hand held diagnostics computer

 

[06BUSA]

By the way when O2 sensors fail, you just get bad gas mileage as the engine always runs in open loop (warm-up) mode. Typically they will not have a noticeable effect on your driveability.

O2 went on my truck and one bank ran rich. Power was gone. I could accelerate but very slow only. A little more gas and it would dang near shutdown. I dont freak easy, but I thought my 03 Z-71 motor was done.

 

[Projekt]

By the way when O2 sensors fail, you just get bad gas mileage as the engine always runs in open loop (warm-up) mode. Typically they will not have a noticeable effect on your driveability.

O2 went on my truck and one bank ran rich. Power was gone. I could accelerate but very slow only. A little more gas and it would dang near shutdown. I dont freak easy, but I thought my 03 Z-71 motor was done.

Yeah good point... I was thinking more along the lines of a single O2 sensor equipped vehicle with an old (fouled, dirty) sensor. Your's sound right for a dual sensored vehicle with modern more complicated electronics.

 

[DrBoom]

took it to my buddy today and it pulled 3 codes. low on mass air flow sensor, low on bank 1 O2 sensor, low on bank 2 O2 sensor. He said that it might just need cleaned but may need ro replace it (125000 miles).
Low air reading , tries to compensate by cutting fuel to correct ratio. Makes sense. Which could cause the bad readings on the O2 sensors. Tried cleaning the mass flow with cleaner, worked for twenty minutes but started acting up again will have to replace it tomorrow. Will post how it does. Funny thing CarQuest $110., Checker $279.00 both remanufactured. 1 year warranties.

 

[unkleslapnutz]

catalytic covertor..my brother has a gmc pick up and when is cat got clogged it wouldnt go over like 20-30 mph...we gutted the cat and it ran like a scalded dog...you may be able to get o2 trickers and save a bit of cash.

And hogger I belive what you are talking about is the Exhaust gas recirculation (EGR)...