Hello and thank you very much for reading about my problem. I don't have a lot of experience with repairing cars, but I am eager to learn and become better at it. Please correct me if I'm using the wrong terminology or have obviously misunderstood something. I'm trying to teach my self and any kind of help and tips would be much appreciated.

About the car:
1991 S-10 Blazer, 4.3l TBI, automatic transmission, 4x4

The car has been sitting for one year and has 230k on it. It was donated to a nonprofit I am affiliated with. A few weeks ago I started trying to revive the car as an opportunity to get practical experience at repairing cars.

Ok, here's my current situation:

CEL comes and stays on when ignition is turned on. CEL turns and stays off after I start the engine.

Error Codes: none, ODB scanner tells me there are no error codes in the vehicles computer memory.

Symptoms: sudden loss of power and stalling when accelerating or changing gears, rough idling and stalling when cold.

The car runs, but to accelerate and change gears I have to feather the the throttle. Any normal motion to accelerate will have RPM drop, engine lose power and eventually stall - if I don't catch it by feathering the pedal again.

When cold, it takes several attempts to start the engine and sometimes it stalls out immediately after starting. I have to keep tipping the throttle to keep it from stalling when starting cold. After running for a few minutes it starts seamlessly.

Idle seems fine some times, other times RPMs decrease steadily. Some times it will stall right there, some times it will rev back up on it's own. After driving the car around the block, idling is pretty solid in park, but switching into D or R from P while idling will stall engine - if I don't feather throttle while doing so.

The car can pickup significant speed as long as I keep working the pedal and even push it's self up a steep hill.

Work I have done so far: replaced fuel filter, coolant temperature sensor, MAP sensor and TPS sensor. I also replaced a piece of vacuum hose that seemed brittle around the junctions. Fluids have been done right before it sat for a year.

Additional Information: temperatures out here are around 15F-30F . Just as an environmental factor to consider. The battery is not doing so well either. Sometimes I use a 200A battery charger to help start the car. The car will be idling fine while the charger is connected, but when I remove the clamps while the engine is running, it will stall. What's up with that?

If you have any insights into any of these issues, please do share! I'm more than happy to answer any questions you might have too.

Anyway, thank you for reading through this.

 

I would say a few things...

1. The lack of power could be a big problem, maybe the alternator is not charging. Needs to be checked.

2. The CEL being on during ignition on engine off is a good thing, it tells your fuel pump is priming the system, but, that does not verify your getting enough fuel pressure, needs to be between 9 and 13 psi for TBi. Also, when you disconnect the charger the system could be losing power, including your fuel pump, which therefore calls for a lean fuel/air mix situation.

I would suggest opening the air cleaner and verifying that your spraying fuel out both injectors while the engine is running, to ensure one of them is not clogged.

Vacuum lines would cause the idle to rise when broken, but also, the MAP sensor line has to be connected properly for the computer to run correctly.

Pulling the spark plugs, and checking the gap and also for buildup would be recommended.

Thats about all I can think of.

 

Just another thing to inspect I think. The distributer cap and the rotor. If these are worn, you engine will run rough, have no power to speak of, and will make it bog down like crazy as you give it the gas...just my 2 cents worth.

Wade

 

Thanks a bunch! Those are some good leads to look into. I'll let you know how it's going!

 

ruralite85 did you discover what the cause of your issues were? My 97 is having similar problems and I am wondering where to look next. Thanks!

 

Yeah bro, pull off that air filter housing and have a look at the injectors to see if they are spraying while someone else trys to start it. It wont look like fuel, but more like the horizon on a hot day - you know how its all vapor like from the heat? thats how the injectors should look when they are firing. If its dripping, or no vapors at all behind one, then you have a problem there and should check for crappy connections and leaks.

Lifting off that ditributor cap and having a look inside would be good too. You want all those 7 little **** to have no corrosion built up on them. If they have some, you can sand/scrape it off, but a new cap and rotor is like twenty bucks. As for the rotor thats under the cap, it lifts off, and also should not look scorched or have crud on it. Pop the plugs out and have a look at them, you can google for what they should/shouldnt look like, and take note of which cyl you took them from. Its easiest to mark all the stuff you unplug to make sure you get them back in the right order. Its easy to muck up the firing order of 3 and 4 if you dont pay attention.

You can do the backyard fix which is clean up the old plugs and ignition parts for free, which just may cure your problem. But plugs can be had for about 5 bucks each, and the cap and rotor for about 20 or 30. As for the battery, you can check for used batteries for around fifty bucks, but a decent new one with a warrantys gonna be about 120. You said its a donated car, it depends on what your intentions are with it. If you are going to donate it to someone who needs a car, then you could spend the money on it and make sure they get something reliable. If you are going to keep it for yourself, cool! Blazers are awesome and you came to the right place for a hand on reviving it. Dont forget that we also like pics here if you want some help with stuff.

 

I ended up doing pretty much everything oshofly said even before I read his post. I also cleaned out the TB, cleaned the IAC valve, ran a can of sea foam through the tank, replaced a bunch of leaky vacuum hoses. After all this work, the engine runs pretty well at idle and the injectors have good spray patterns - but under load the engine is not getting enough fuel. I haven't been able to measure fuel pressure yet, GM TB engines seem to need an extra inline adapter; they don't have a fuel pressure testport.

My blazer has been sitting for over a year and had old fuel in the tank before I started working on it, so my guess is that there might be residue buildup and stuff that is restricting fuel flow out of the tank. Or maybe the fuel pump itself is on its way out. Right now I don't have time to work on the truck, but I'll let you know as soon as I figure it out!

Thanks for y'alls help!

 

a piece of advice dont over look the coil easiest way is take off the spark plug wire (WEAR GLOVES) shove a screwdriver in the part that connects to the spark plug put it about and inch above grounded metal and have someone start the truck if its not a good bright spark u need a new one

 

I should have listened to your guy's advice. I was having stumbling issues and it ended up being corrosion on the rotor and cap. Didn't think they would have been my issue since they were changed about 9 months ago. Now I know in the future to not over look the distributor as a possible issue even if it is newer.