Should a mechanic be able to diagnose this problem without reproducing it?
Posted by quotidian_qt@reddit | askcarguys | View on Reddit | 62 comments
I have a 2000 Chevy S10 with 170k miles. About half the time I go to start it, it doesn't start on the first try but starts on the second or third try. It doesn't click, it just seems like not enough power is getting to the engine for it to turn over. I took it in yesterday and described it to the shop owner. So far it's started every time he tried it, so he isn't investigating further about what the problem is. He told me to just come pick it up.
I saw online the few things it might be. (I should add, I just replaced the battery because I assumed that might be the problem, so it's not that.) Isn't there a way to test those few things even when it's starting the first time? I don't understand why they can't just go off my description and diagnose from there. How is reproducing the problem even going to help that much? He's not charging me anything, so I don't think they even ran the codes. (Check engine light has been on for years.)
I'm frustrated because I have a trip next week from an airport an hour away and I'm worried it won't start at all after sitting that long. I wanted to get it fixed before then.
Equana@reddit
Let it sit overnight. When you get in the next day, turn the key to ON but not engage the starter, turn it OFF, then ON, then OFF several times. Each time you turn it ON you should hear the fuel pump moan a bit. After the 3rd 4th or 5th cycle, start the truck. If it starts right up, it is the fuel pump check valve letting the fuel pressure leak off. It isn't critical but it tells you the pump is on its way out.
wellvrsd@reddit
OP described a no crank problem and you are providing a crank no start solution.
Gunk_Olgidar@reddit
OP likely misstated "turn over" as start. Very common here.
quotidian_qt@reddit (OP)
They let it sit there overnight last night and it started on the first try this morning. I don't know if they tried anything other than just starting it.
So are you suggesting I try this at home and then just tell them I want the fuel pump replaced without them reproducing it?
Equana@reddit
Try it at home and decide if younwant.to spend the money for a fuel pump versus just cranking it a bit longer.
quotidian_qt@reddit (OP)
I was trying not to get stranded while whatever the problem is goes fully bad. But maybe that's just something you accept on a 26 year old truck.
Equana@reddit
It is.. Stuff just breaks.
If that fuel pump is original to the truck, it is a miracle. Delphi pumps don't usually last that long!
mor_and_mor@reddit
This is really good. The pumps are all only good for 100k before going out.
quotidian_qt@reddit (OP)
I wish I had records from the previous owner to know how long ago it was replaced. If they only last 100k, I'm probably not still on the original.
RemoteVersion838@reddit
You can't diagnose something you can't see. Same as with comptuers, the first step is always to reproduce the issue, then you can troubleshoot.
quotidian_qt@reddit (OP)
Why would it start the second or third time if it was the battery? Wouldn't it still not have enough power?
RemoteVersion838@reddit
The definition is pretty loose "not enough power is getting to the engine" so it could be cranking. A starter will often start to crank faster after you try it a couple of times. My comment was based on the fact that it works every time at the shop which I assume is on a warm engine or one that's been drive a few km to the shop.
Reejerey1@reddit
Verify the customers concern is step one of diag.
If the vehicle won’t do what you’re describing, it’s very hard to diagnose the exact cause. Also we learn very quickly that the average customer doesn’t know what they’re talking about and often doesn’t accurately describe the concern.
My car won’t start is a different complaint that my car won’t turn over, for example. Very different diagnostics for those two conditions that sound very similar to an average customer. Many times on things like this I’ll have the customer go and show me the issue, just so we are all on the same page.
quotidian_qt@reddit (OP)
I don't know what turning over means. When I try to start it, it makes noises like it is almost starting but not quite getting enough power, just short of actually starting. Which diagnosis should be next in that case?
Reejerey1@reddit
Exactly my point.
Does it sound like it normally does but just doesn’t actually start, or does it sound different than it normally does? The normal sound is the starter turning the engine, or the engine “turning over”
That’s a no start. If it doesn’t make the normal noises and just clicks, or doesn’t do anything, That means it doesn’t crank or doesn’t turn over.
The thing is, if it’s starting every time for your mechanic, he can’t diagnose a no start.
StupidAuthentication@reddit
Because if they can't duplicate the problem they can't confirm they have fixed it after having spent your money on parts and their time in labor to do work. If they can't confirm they have fixed it what happens when the same issue happens again next week because either your description lead then down the wrong path, or they made a diagnostic mistake? In that case you would be livid and would shit on their reputation, (auto shops live & die on their reputation) possibly file a small claims suit, etc. all because the two most important steps in diagnosing a problem were skipped.
Step 1: get the customer statement of what the issue is Step 2: confirm the issue Step 3: identify the problem Step 4: get approval for repair Step 5: perform repair Step 6: confirm the issue is resolved.
A shop that refuses to just throw parts at a car because they can't replicate the issue is typically a quality shop that doesn't skip steps to make a quick buck.
And your car likely has a dozen or more problems, so if they just start testing random things they are going to find things to sell you, but maybe not the resolution to the issue you have described.
Heavy_Gap_5047@reddit
I disagree, certainly on an issue like this, with this customer information. As the issue can only be a few things. The customer is best served by doing some diagnostics to inform a best guess and do the work. As long as it's done with a written agreement with the customer that it may not solve the issue. It sounds like the OP would accept a best guess.
quotidian_qt@reddit (OP)
Yeah kind of like how my battery was indeed bad so I replaced it and it didn't fix the problem.
Heavy_Gap_5047@reddit
On this particular issue, more or less yes. Without being able to confirm it's an educated guess informed by some diagnostics. It's possible it'd be wrong but unlikely.
ShoddyJuggernaut975@reddit
Gonna need more info than "doesn't start." When you turn the key, does it turn over and not start, or does it not even turn over?
I'd go in, ask them to demonstrate how they start it, and pay attention. Are they doing something different than what you usually do? Watch carefully.
For instance, they may be in the habit of making sure a car is in park before trying to start it. Something like that might point toward a bad nuetral/park safety switch that their simple check jostles into working.
Maybe they are in the habit of putting the key in, turning to run, waiting a couple of seconds, and then cranking. Maybe you jam the key in and go straight to cranking as fast as possible. Something like that might point toward a weak fuel pump; their waiting lets it build pressure, and your quick action ddoesn't
It could be something that stupidly simple as to why it starts for them and not you.
quotidian_qt@reddit (OP)
When I try to start it, it makes noises like it is almost starting but not quite getting enough power, just short of actually starting.
Carstuff392@reddit
Its got 170K on it and its 26 years old. It won't be money wasted to throw a starter on it. If you ask me that is likely your issue.
quotidian_qt@reddit (OP)
Couldn't the first two sentences also be true about a fuel pump?
NoPatience7817@reddit
Intermittent issues are difficult to diagnose. I had a similar issue with a 94 Caprice. I thought it was the battery. The issue persisted. So I replaced the starter. It’s been starting great ever since.
Tell the shop you want the starter replaced. That is strange they didn’t suggest replacing parts. It’s possible they didn’t want to be liable if they misdiagnosed it.
It could also be the starter relay or a bad wire.
quotidian_qt@reddit (OP)
I thought starters click when they're going bad?
NoPatience7817@reddit
Partially agree. Clicking is one symptom. A motor has brushes inside that connect to engage the starter. Those brushes wear out over time. Worn out brushes cause less electricity to flow. Therefore intermittent slow or no crank.
Again this could also be dirty connection, broken wires, or starter relay.
A proper diagnostic includes reproducing the issue. That’s why the shop won’t randomly replace parts. They will replace parts you ask them to replace though. Then if it doesn’t solve the starting issue, then it’s on you not them.
Ask them to replace your starter or do it yourself if you are able to.
quotidian_qt@reddit (OP)
I don't understand your response because you make it sound like the brushes are outside the starter and wouldn't get fixed if the starter was replaced.
NoPatience7817@reddit
The brushes are inside the starter motor and are included with a new starter motor. The brushes contact the commutator inside the starter to turn the motor.
Here’s a link to a visual if interested.
starter motor parts
quotidian_qt@reddit (OP)
OK thanks. That's helpful to see how many different parts of the starter could be going bad.
Odd_Activity_8380@reddit
If you want a educated guess then yes. Otherwise he needs to duplicate the problem. Otherwise its a guess
QuickCharisma15@reddit
Is this S10 a V6 or four cylinder?
quotidian_qt@reddit (OP)
It doesn't have much power so I assume it's four cylinders.
rac1283@reddit
Agree with the others - shop is right to avoid replacing parts if they can’t reproduce the issue. They can’t then say it’s fixed. That’s a more ethical way to run a shop than just firing parts at it.
Don’t know how many trouble codes you can get from a 90s era truck either, so that might be little help.
I’d want to know if they checked the fuel pressure. Sounds a bit like it could be the fuel pressure regulator or fuel pump.
quotidian_qt@reddit (OP)
They didn't test anything because it started every time they tried it.
Stock_Block2130@reddit
Or it could be the starter relay, not the starter itself. I don’t know that vehicle. The relay may be mounted on or near the starter or on a circuit board somewhere else.
quotidian_qt@reddit (OP)
Sigh, there are a surprisingly large number of things it could be!
wespellettieri@reddit
No, the entire system is very basic and archaic even by GM standards. Its a cheap truck.
And if your willing to go online to diagnose, you can repair it yourself. Its not rocket science.
Bulocoo@reddit
Did he ask you any others questions?
Did he do a capacity test on the battery?
For "weak" cranking and no other clues I would discuss with you changing the battery (depending on age and load test) & battery cables and telling you they won't hurt but may not help.
The next expensive part is a starter.
Car kwbers want an jnstant accurate fix on everything but these are systems.
I own classic cars and I rebuild by system. If the starter goes bad I change battery, cables, solenoid and anything in that system. My car us 50 years old. And after that the "system" should be good for another 20 at least.
quotidian_qt@reddit (OP)
He didn't ask me any other questions. I just replaced the battery because I assumed that's what it was and the old battery tested bad.
I thought starters click when they're going out?
More_Region_7475@reddit
I replaced my starter two weeks ago. It slow cranked for a week. Didn’t make a click. Try to take a video if you can
Bulocoo@reddit
You got it right about starters but the part that engages to the engine (bendix) can get worn/chipped - that would not cause low cranking though.
Very, very rarely you can have a starter bearing fail.
I am shicked the original mech did not even test the battery.
You done good. Bad shop.
quotidian_qt@reddit (OP)
I told him I just replaced the battery.
For the bendix part you mention, is that part of the starter and would get replaced if I replaced the starter, or is it a different part?
Bulocoo@reddit
Yes it's part of the starter. Technically it can be replaced separately but by the time the bendix fails it's time to do the whole starter.
It would be more likely a home hobbyist typ mechanic would spend the time to only change a bendix.
I am a home hobbyist and if my kid was to have a starter bendix issue I would change thenwhole starter - not much price difference there.
Lazy_Permission_654@reddit
This is the worst type of customer to have. The mechanic could have justified charging you for several random fixes instead of saying they don't know
Let the car sit in ACC mode for fifteen seconds prior to hitting the starter. That is a remedy for several possible issues
Kent89052@reddit
Solenoid, which is usually part of the starter and activates the starter motor. Most people just replace the starter. I've removed the starter and cleaned the contacts in the Solenoid.
quotidian_qt@reddit (OP)
That was one of the things listed in the AI answer but I didn't realize it was part of the starter. I thought it was a different part. So replacing the starter would fix it if that's the problem?
Kent89052@reddit
On most cars yes, but some cars have a separate relay or solenoid, which would be cheaper and easier to replace. Check rock auto and see what they offer for your car
Coryj100@reddit
Vehicle type and the model year. My guess is harness / connector issues. That’s the problem any shop is going to have unless it can be replicated it’s just going be a guess. Can’t recreate Can’t confirm repair I’d say the shop did you a solid by not going further and digging you in hole of diagnostic fees. However I’d definitely look into the PCM/ harness Connectors. Try starting and complete a wiggle test
Parking_Abalone_1232@reddit
In order for the mechanic to fix something it has to be broke.
It's really hard to fix something that isn't broke. Unless it's a CIWS mount. And then the maintenance philosophy is: if it's not broke, fix it til it is.
Intermittent problems are also hard to fix. Again, because you can't fix something that isn't broke.
Your mechanic needs to see the problem to figure out what it is. If you can reliably recreate the problem state, even if you don't know why, then you can provide the mechanic a place to start.
quotidian_qt@reddit (OP)
The problem is, it usually starts better after I've driven it, so if I can still drive it there, he's probably not going to be able to reproduce it, meaning I just have to wait until it stops starting at all and need to get it towed in.
Parking_Abalone_1232@reddit
Again, it's an intermittent problem. Really difficult to fix because you can't fix something that's not broken.
If the mechanic can't see it broke, anything they do is just guessing. Like others have said.
You might need to leave it at the shop for several days and have them try to start it daily over that time frame. That's assuming you can be without the vehicle that long and the shop has the space to keep it.
vortec350@reddit
Side post battery? Check under the rubber boots that encase the battery terminals for corrosion. It can look fine from the outside but underneath that rubber boot can be a pile of puss.
Ponklemoose@reddit
No. The best they could do is throw parts at it like you did with the battery (BTW: it was never going to be the battery), but that’s cheaper to DIY. A mechanic brings value by only replacing the broken bit, but can’t when it won’t act up.
But here is an easy test for you: next time it won’t start: without releasing the key wiggle the shifter. Sometimes the neutral safety switch that keeps it from starting in gear gets slightly out of adjustment.
Fancy_Chip_5620@reddit
Sounds like the starter, I remember my Tacoma did something similar with it's rebuilt starter
It would i guess short circuit sometimes, still turn the engine but take a shit ton of power doing it because it would pretty much kill the lights if they were on
Flip the ignition again and it would start like normal
DDrewit@reddit
I believe that yes he should be able to, but he’s doing you a favor by not. How many hours of labor do you want to pay for diagnostics?
ac5450@reddit
You need to see the problem happening in order to properly diagnose and fix it, then verify the repair fixed the condition. Otherwise you’re just firing the parts cannon at it with no guarantee of success.
seang86s@reddit
Having the problem reproducible goes a long way in diagnosing the problem. Without that, it's just a guessing game and replacing random parts will just rely on a hope and a prayer that it actually fixed it. Also the issue you have may in all likelihood not throw any error codes at all. For example, what if it's your ignition cylinder? The car just thinks you're not turning it or just have the wrong key in there. That wouldn't throw the check engine light.
He should read the codes tho just to see. But maybe he already did and whatever code it is has nothing to do with your problem.
You said he hasnt charged you. Why not just take it elsewhere?
llIIIlIllII@reddit
No
quotidian_qt@reddit (OP)
No it doesn't click.
right415@reddit
Unfortunately it's very difficult to diagnose and repair a problem if it does not rear its head. Some shops may be reluctant to perform repairs if they are uncertain if it will properly remedy the problem. Imagine if they sold you a starter, and then you had the same problem a week later?
You could say "I'd be happy to pay you for an hour or two of your time to go through the starting system and see if you see anything " knowing that they may "see" something and recommend repair without knowing full well if it will fix your problem. There is also a chance that they find the smoking gun. 🤷♂️
Sixgunfirefight@reddit
No. When it’s not happening, nothing is wrong.
Coryj100@reddit
No