S10 4.3l won't accelerate

[Dub11]

This thing has been handy with the torque lite app

 

[dall]

if the truck was in limp mode you could get it to rev to about 2 grand and it would be the temp and coolant sensor but your saying it wont rev up any and low pressure on fuel pump

 

[paragonbuilder]

Coolant temp sensor

Can't be much. I'll grab one. I can't imagine it would cause these symptoms, but weirder things have happened.

 

[Mastermind]

When the coolant temperature sensor is bad on my old truck it makes the idle too high, or too rich, etc.

 

[super3]

Weird thing is when I hit the accelerator pressure goes up a couple psi??? Is that normal?

Yes, it should. You are dropping vacum at the regulator to close it.

It should do the same at idle with the hose un hooked.

3 that I have worked on with that same issue were,
Fuel pump(yours shows an increase when you accelerate so I would rule that one out)
Coil
Ignition Module

 

[Motorhead]

The plug does look like its been running with the choke on for a while

 

[junkman]

I refer to the temp censor as the choke on a carb ,if it is bad the computer thinks the car is cold and dumps raw fuel ,it will blow black smoke out the exhaust normally when bad and be hard to keep running,they are cheap to buy so does not hurt to change it.

 

[Stihlbro]

Make sure the exhaust is not plugged up, easy way to tell is remove one of the 02 sensors closest to the engine. Leave it plugged up. Start the engine and see will accelerate.

Idles, bogs when touching the throttle, sparkplug sooted up. Symptoms of stopped up catalyst converters. Next is to find what caused it.

The coolant temp sensor for the egu would
have to be stuck in the below zero spec to enriched fuel up that much. If you decide to replace it, make sure you specify it's not for the gauge in dash.

 

[Dub11]

On the older tbi that I have the reluctor ring in the distributor was cracked. Would start idle soon as you took off die and restart. No cel i swear strangest thing. Off course it started this at 198000 miles

 

[paragonbuilder]

if the truck was in limp mode you could get it to rev to about 2 grand and it would be the temp and coolant sensor but your saying it wont rev up any and low pressure on fuel pump

Seems to me it would start to rev then stumble if it was fuel supply, but it's instant bog...
I just picked up intake air temp, coolant temp, cap, rotor, coil, and TPS. If those don't do it I'll pull the bed to get at the tank.

 

[paragonbuilder]

Yes, it should. You are dropping vacum at the regulator to close it.

It should do the same at idle with the hose un hooked.

3 that I have worked on with that same issue were,
Fuel pump(yours shows an increase when you accelerate so I would rule that one out)
Coil
Ignition Module

Ok good to know. I did the module a year ago, but who knows. I'll test it.

 

[Mark71gtx]

A lot of guys have already mentioned it. I will mention it again. Check the exhaust. I like what @Stihlbro said. Pull the O2 sensor and give it a whirl.

 

[jakethesnake]

I'm late to this ... Fuel pump or checked that ? Doubt it's an 02 sensor some should still run then. Either a severly stopped up fuel pump or the pump is leaving you. I'm no master mechanic and online diagnosis is tricky but that's my guess. Not enough fuel

 

[huskihl]

Fuel pressure specs are all over on these engines. 40 psi might be normal on one, where the next requires 70 or 80. Ime, if pressure is low, but close, you can baby the throttle and get them to go down the road, although with less power. 9 out of 10 fuel pump failures on chevys are a "no pressure at all" symptom. The pump won't even run. Especially during a cold weather snap.
This sounds more like a sensor issue of some sort. One that deals with throttle position or airflow. But I really don't know

 

[jakethesnake]

Pump is half assed working. Only reason I guess that. I used a gm pump in an outboard boy they were junk The man who put it in for me would fix this truck in half hour. I had many of the pumps fail on me and had one time it idled kept pressure up but after long durations died. Leave your guage on the truck and let it idle for longer. Eventually if it's the pump your numbers will slowly come down

 

[paragonbuilder]

A lot of guys have already mentioned it. I will mention it again. Check the exhaust. I like what @Stihlbro said. Pull the O2 sensor and give it a whirl.

It seems to be blowing out the tailpipe ok but I can pull the 02.

 

[jakethesnake]

Truck doesn't wanna idle now? I half assed skimmed through It is possible the pump is getting worse. Any check engine lights on? If no that would nearly eliminate senser issues. Doubt it's an 02 should get check engine with a code that say so. The exhaust plugging up would let you know with a slow loss of power usually

 

[jakethesnake]

I'll check back again as I'm curious and I'm not a certified mec. Is hate to pull the tank if unnecessary but I'm thinking that's where you'll find your issue A dying pump is hard to I'd because it wants to work good luck paragon hope you can sort it out on a short order

 

[paragonbuilder]

Truck doesn't wanna idle now? I half assed skimmed through It is possible the pump is getting worse. Any check engine lights on? If no that would nearly eliminate senser issues. Doubt it's an 02 should get check engine with a code that say so. The exhaust plugging up would let you know with a slow loss of power usually

Might be cuz I blocked off the egr? I ruined the gasket so I plugged it. Just picked up a gasket for it. See if that helps

 

[DELETED (Struggle)]

It'll never run right with plugs that fouled. If you drop below 60 psi then injectors may. Or spray properly causing it to foul plugs. Psi should raise up at least 5 psi or maybe re when you throttle it. Has it ever had an intake gasket replaced. If answer is no it needs to be replaced. They all go bad on the 4.3 and it can run lean from sucking on bottom side of intake


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