Why does my 1993 Chevy TBI stall at idle?

Timing is steady and not jumping all over. It is a fuel issue. The only code that ever sets is a P044, lean exhaust, and the exhaust is really lean. We have swapped PCM/PROM with a same year Suburban, no change. Both vehicles run the same as this did using the other’s PCM.

What should fuel pressure be on 1993 Chevy TBI?

Verify there is 18-20 of fuel pressure when you dead head the fuel pump. If low, verify there is good power and ground to the fuel pump and that the fuel filter is clear. Also, make sure that the MAP sensor vacuum port in the throttle body is not restricted.

When to replace a Chevy c1500 throttle body unit?

AutoZone carries replacements to restore your confidence in your truck. Hitting the gas should open the valve in a throttle body unit for Chevy C1500. If there’s a clog or other defect, there isn’t enough air mixing with the fuel going into the combustion chamber, and flooding, stalling and poor fuel economy are the result.

What’s the fuel Gage on a 1993 Chevy truck?

Fuel gage never wavered at 12-13 psi. MAP around 2.9v when PW 2.8MS when truck seemed to be falling a little flat under brake torque. This thing is really close to getting a carburetor on it.

What’s the fuel pressure on a Chevy long tern?

Long tern fuel trim seems to hang aroun 162-65 on a hot engine, short term fuel trim starts at 128 and sometimes goes to around 134. Vacuum at 2500 in park is around 20inches. Ok.. Verify there is 18-20 of fuel pressure when you dead head the fuel pump.

Fuel gage never wavered at 12-13 psi. MAP around 2.9v when PW 2.8MS when truck seemed to be falling a little flat under brake torque. This thing is really close to getting a carburetor on it.

What causes hesitation and surging on Blazer 4.3L?

Fix Hesitation and surging on Blazer 4.3L If you have Hesitation and surging on Blazer 4.3L and it’s driving like a dog—poor acceleration, hesitation, or a surge and you suspect a fuel problem, you may be partially right.

Why is my Blazer 4.3L driving like a dog?

If you have Hesitation and surging on Blazer 4.3L and it’s driving like a dog—poor acceleration, hesitation, or a surge and you suspect a fuel problem, you may be partially right. But before you start replacing really expensive components like the fuel pump, try this: Disconnect the electrical connector to the MAF sensor and take it for a drive.

Why does my Chevy truck shake at idle?

While the truck is idling with 02 lean, a quick shot of carb spray in the throttle body will cause the 02 to go rich. And when the truck sometimes starts shaking at idle it will smooth out with carb spray. I jst don’t understand why the computer is not trying to richen the mixture up based on the 02 saying lean.

How to troubleshoot your TBI fuel injection system?

Troubleshooting your TBI Fuel Injection System Most of the problems encountered while installing your fuel injection system or after a time of operation are very simple. If your check engine light is on you more than likely have a hard fault meaning something is grounded out, unplugged, operating out of range or has gone bad. See

When does the 1990 c1500 TBI idle go away?

1990 C1500 TBI 5.7L Idle is surging when warm. Unplug the MAP Sensor and the problem goes away, I replaced the MAP 1990 C1500 TBI 5.7L Idle is surging..MAP Sensor..goes away..Autozone… 1990 C1500 TBI 5.7L Idle… 1990 C1500 TBI 5.7L Idle is surging when warm.

What should BLM be on 1990 c1500 TBI?

With engine running look at fuel integrator & block learn (fuel trim) they should be close to 128.If they are higher the computer is adding fuel.When the engine is warmed up the 0/2 should be bouncing back & forth over .500 mv. My BLM is 135, sorry I forgot to mention i replaced the 02 sensor.

What causes a Chevy TBI to run lean?

O2 sensor won’t have any effect when cold, its signal is ignored. Are you sure the rebuild is 100%? It wouldn’t hurt to run a compression check to be positive. High NoX can also indicate a lean condition, not necessarily a vacuum leak, but something else that could cause it to run lean.

How does the GM TBI fuel injection system work?

The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. Unlike a port fuel injection system, that sprays fuel into the intake manifold runner just above the intake valve, the injectors in this system spray fuel directly into the throttle body above the throttle plate.

Where is the idle plug on a GM TBI?

Plug the vacuum lines with golf tees or other suitable item. Remove plug over the idle screw located on the right front of the throttle body by using a hammer to drive a punch into the plug and then using the punch to pry the plug out of the throttle body.

Where does the vacuum leak come from on a TBI?

There are instances where the vacuum leak is coming from the adapter plate used to attach the throttle body to the manifold. If this is the case make sure that the seal is positive between the manifold and the adapter plate; also between the adapter plate and the throttle body.

Why is my Chevy Blazer stalling and stalling?

Check/clean EGR. This does have the newer style injection so could be fuel pump heats up and pressure drops – have to test at test port. Coil could be failing due to overheating due to ignition module never shutting off so always a low voltage to it.

Is there check engine light for intermittent stalling?

Many times, there will be no check engine light and no fault codes to give you a clue as to what might be causing the engine to stall. So the trick to diagnosing an intermittent stalling problem is to catch the vehicle when it’s acting up — and that rarely happens when you have the vehicle in your shop.

Why does my Chevy Blazer have no power?

No codes come up until after it happens then it comes up oxygen sensers port 1 and port 2. You can step on the gas and the engine just bogs it has absolutely no power . Put the car in neutral ( while still moving ) count to 3 and restart and have all the power you want. Tried Hi test gas , fuel additives, still happens!

What to do about idle problems on a TBI 454?

Loc: Twin Cities, Minnesota, U… If it just can’t slow down look for a vacuum leak like Richard said. Check to see if the EGR valve is stuck open a little. If it is unable of running below 800 RPM test the fuel pressure, especially if the idle sounds weak and unstable.

How many MV does a 1993 Chevy TBI have?

Even now it seems on the lean side, but will for a while have one 02 crosscount before the 20 second lean PCM clock expires throwing it into open loop. The 02 MV hot will frequently hang down around 56 MV to 156 MV and never cross over to rich for a long time.

How to remove Idle Stop cap from a GM TBI?

On a factory TBI unit the idle set screw will be capped from the factory so you cannot mess with it. But you just knew one day you would. Not all caps look like the one pictured but this is the one that is hardest to remove. The easiest way is to first grind the cap flush with the surface of the throttle body.

How does idle air control work in a GM TBI?

The air gap between the throttle body and the throttle plate is calibrated to allow enough air to pass by it for the engine to run at base idle speed. The IAC (Idle Air Control) valve utilizes the on-board computer to fine tune the idle speed according to engine conditions.

Why is vacuum plugged off on 1993 Chevy TBI?

EGR vacuum is plugged off because EGR diaphram has a leak. I pulled EGR to inspect days ago, and pintle spring has good tension holding valve completely closed, not leaking at all. I know the EGR will richen mixture a little on a hot engine, but that is not the problem.

What should fuel Gage reading be at idle?

The 02 reading starts out at idle a little biased lean, but switching, then as soon as into accelerator truck stays lean until open loop. 58-65 mv is normal when leans out. Fuel gage never wavered at 12-13 psi.

Why does my car stall after a few miles?

When a bad module is responsible for an intermittent stalling problem, the engine will usually cold start just fine and run OK for short distances, but stalls after driving more than a few miles or when driving at highway speeds (especially during hot weather). It’s as if somebody suddenly turned off the ignition.

Can a car stall with a bad throttle position sensor?

The engine can stall for no reason and without any warning. This happens when the TPS gives incorrect information to the ECM. The engine can stall at high speed, at low speed, or even at idle. A faulty throttle position sensor will not let your car accelerate normally. Though this doesn’t happen all the time.

Why does my Chevy Silverado stall and die?

The truck is, for lack of a better word, quite moody. It will occasionally start ok and run with no problems whatsoever – no stuttering or other problems, and then suddenly stall and die. It can be really hard to get it started after this has happened.

How often does my GMC Sierra stall at 15 mph?

When I go from 15 mph to a stop it will stall about 50% of the time. The other times it will recover after the tach drops to almost “0”. I have a 2001 Sierra 1500 with the 5.3 V8.

How long does it take for GM throttle body to relearn?

If you don’t do a relearn procedure, the PCM will “hunt” for a new baseline idle. It will eventually learn it on its own, but it may take over a week of driving, during which time you will experience high and low idle speeds and possibly rough idle. 1) Start the engine and let it idle in park for 3 minutes.

What causes stalling on a 1990 Chevy k1500?

So far it has a new distributor (for an unrelated problem), idle valve, throttle position sensor, knock sensor, temperature sensor, fuel filter, plugs & wires. The idle valve and tpi both tested bad, and replacing them helped on general driveability but didn’t affect the stalling.