will a bad brake booster cause a vehicle to not turn over

[moochisboss]

i got an 03 chevy trailblazer and recently got bad gas from the gas station and now it wont run i checked everything i could think of nut nothin seems to work

 

[jlee]

Could you be a bit more specific with what exactly it's doing, what you have checked so far, why you're asking about a brake booster, and how you know you got bad gas?

 

[Rifter]

Yes, a large enough vacuum leak in the booster can stop it from starting, it will still turn over, but may not start, or if it does start may idle at crazy high rpms.

 

[mindless1]

Turn over is a generic term that means the engine won't spin, indicating a bad starter, dead battery, or engine seized more often than any other issue.

Speculating bad brake booster reads like a random shot on the dark unless you have a specific reason to believe that's the problem.

What is "checked everything I could"?

What is the nothing that doesn't seem to work?

What are the exact symptoms?

How do you know the gas was bad?

Did you drain the tank and put good fuel in?

Do you even care at all if this gets fixed given the low motivation you had to supply all the relevant information? Heck you can't even bother to push the shift key to capitalize the runon sentence or put a period at the end. Should you really be driving on public roads?

Yes, a leaking vac line to, or failed diaphragm in your brake booster, can cause a too lean condition and prevent it starting, but usually it wouldn't. Usually it would just start (manage to fire) then die as it settles down to its idle speed and/or throw a lean OBDII code.

You can just take a cork (or plastic bag and rubber band, etc) and plug the intake port for the brake booster line, or if it's not dry rotted too much, pinch off the vac line with vice grips to take it out of the equation (this is less stressful on the hose if you put two scrap pieces of (larger) hose over the vice grip jaws so their teeth don't dig in), obviously then losing power assist for steering as long as there's no vac to it.

 

[EXCellR8]

Turn over is a generic term that means the engine won't spin, indicating a bad starter, dead battery, or engine seized more often than any other issue.

I've always considered cranking and 'turning over' to be separate things. For example "my engine cranks but will not turn over" meaning from being cranked by the starter to 'turning over' and using its own power.

Honestly though, I don't know which description is correct.

 

[mindless1]

Turning over is turning. Cranking is also turning. Firing is what comes next. Or doesn't.

 

[moochisboss]

Could you be a bit more specific with what exactly it's doing, what you have checked so far, why you're asking about a brake booster, and how you know you got bad gas?

Well I checked all the fuses and relays, drained the gas tank checked out the evap canister changed the fuel injectors tested the coil packs, checked the spark plugs. Now I did notice that one of the plugs has like a black soot has in it when I pulled it out. When it does actually turn over it idles terrible like very low and only get a slight better when I gently pump the gas pedal

 

[moochisboss]

Also it was running fine before

Turn over is a generic term that means the engine won't spin, indicating a bad starter, dead battery, or engine seized more often than any other issue.

Speculating bad brake booster reads like a random shot on the dark unless you have a specific reason to believe that's the problem.

What is "checked everything I could"?

What is the nothing that doesn't seem to work?

What are the exact symptoms?

How do you know the gas was bad?

Did you drain the tank and put good fuel in?

Do you even care at all if this gets fixed given the low motivation you had to supply all the relevant information? Heck you can't even bother to push the shift key to capitalize the runon sentence or put a period at the end. Should you really be driving on public roads?

Yes, a leaking vac line to, or failed diaphragm in your brake booster, can cause a too lean condition and prevent it starting, but usually it wouldn't. Usually it would just start (manage to fire) then die as it settles down to its idle speed and/or throw a lean OBDII code.

You can just take a cork (or plastic bag and rubber band, etc) and plug the intake port for the brake booster line, or if it's not dry rotted too much, pinch off the vac line with vice grips to take it out of the equation (this is less stressful on the hose if you put two scrap pieces of (larger) hose over the vice grip jaws so their teeth don't dig in), obviously then losing power assist for steering as long as there's no vac to it.

its not throwing codes and it does actually turn over but idles really low. Lopes bad if I’m using that word correctly. I did drain the tank out heet in it tested the coil packs and plugs and injectors. Changed the fuel filter and blew out the lines. Checked the relays and fuses (both boxes).

 

[mindless1]

If you're still convinced it was bad gas, then check fuel rail pressure next and if it's good, I would wonder if it's just a coincidence this happened after getting fuel.

Which engine? How many miles? At least one of them seems to have an idle air control valve. If yours does then check that. Check whether the throttle body is highly gunked up.

Does it now run pretty much the same as before you swapped and checked those parts, or bad in both cases but bad in different ways? Just trying to rule out a faulty part or mixing up spark plug wire locations, or some connector or vac line dislodged, etc.

It is an OBDII era vehicle, hook up a scan tool capable of live data. Look at the long term fuel trims and temperature sensor reading, but also any other parameters that look wrong. It really should be throwing codes if running that badly.

If it has a MAF sensor, clean that. If it has A/C turned on, turn that off. Check the air filter if you haven't already.

If all else fails it's time for a compression or lead down test of the cylinders in case you have a head (warp, crack, gasket, etc) problem, but first I'd check whether it's losing oil or coolant. I assume no major leaks are visible. You can also get a kit that checks for exhaust coming out the coolant tank.

 

[moochisboss]

It’s an 03 Chevy trailblazer straight 6 4.2 no visible leaks and lopes bad when it does turn over I’m thinking either the crankshaft position sensor or the camshaft position sensor but idk how to test either one cuz I’m by myself

 

[moochisboss]

Could you be a bit more specific with what exactly it's doing, what you have checked so far, why you're asking about a brake booster, and how you know you got bad gas?

I ask about the booster because of lack of vacuum and I’ve been having a lot of issues with the brakes lately, but when it does run it lopes really bad and I have to lightly pump the accelerator for it to barely run but then it kills

 

[mindless1]

You'll need a multimeter.

https://troubleshootmyvehicle.com/gm/4.2L/cmp-sensor-tests-1

https://axleaddict.com/auto-repair/How-to-Test-a-Crankshaft-Position-Sensor-Using-a-Multimeter

These sensors are only about $20 on rock auto, if you don't have a multimeter then you might consider just replacing them, but a scan tool to look at pending codes, live data that seems off, could save money by narrowing down the fix instead of shotgun repairing... and yet shotgunning $20 at a time is still a lot cheaper than having a mechanic bill for labor, then you know your 18 year old sensors are good for awhile too (as long as you get a major brand instead of generic chinese junk).

Again about the booster, just pull the hose off the manifold and plug that port. This takes it, and the hose to it, out of the equation. If it has a vac leak, the issue you would have is a much harder time pressing in your brake pedal. It won't make the pedal softer, or make any particular wheel act differently than if you just had pushed the pedal less since it's harder to press.

If you have a vac leak so bad that it's causing the engine to barely run, it will definitely show high long term fuel trims on a scan tool