Please help - failure to crank
- Thread starter Womack
- Start date
Welcome!
Do you have a voltmeter?
When you say you have "checked" did you use the meter?
When you say won't "turn over" can you tell us exactly what you see in terms of instrument panel and interior light behavior before and when you turn the ignition switch to START?
If the ignition switch is working and the fuses are OK, you should hear the starter relay click when you put the ignition switch to START. Does it?
Do you have a voltmeter?
When you say you have "checked" did you use the meter?
When you say won't "turn over" can you tell us exactly what you see in terms of instrument panel and interior light behavior before and when you turn the ignition switch to START?
If the ignition switch is working and the fuses are OK, you should hear the starter relay click when you put the ignition switch to START. Does it?
You jumped across the starter relay and the starter spins?!? And you can hear the relay click so we know the control side of the relay is OK?!?
Seriously, if you used your meter on the control wiring TO the starter you would have noticed the lack of voltage coming out of the relay, I predict.
I don't see how it can be anything other than front fuse #34. A 40A J-case fuse. Did you check ALL the fuses including the large J-case units?
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Seriously, if you used your meter on the control wiring TO the starter you would have noticed the lack of voltage coming out of the relay, I predict.
I don't see how it can be anything other than front fuse #34. A 40A J-case fuse. Did you check ALL the fuses including the large J-case units?
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Yes sir the starter does spin and your prediction is right low to no voltage at the wire!
I did check that fuse! I also checked to se if the PCM sees the crank request and grounds the bottom left terminal where the starter relay Is in the fuse block and it didn't ground it
I did check that fuse! I also checked to se if the PCM sees the crank request and grounds the bottom left terminal where the starter relay Is in the fuse block and it didn't ground it
Womack said:
It sounds like the starter is spinning but the solenoid for the starter is not fully extending or just doesnt have enough capacity to turn the engine. I would put some jumper cables on the battery and see if that extra oomph gets it to engage. Could be a worn out battery or the terminals are corroded.
Usually, if the starter does a clicking noise then that is a sign of a weak battery or bad battery connections. That happened to me on my old car. How old is your battery? I know you said you tested the battery, but how did you test it? With the meter or did you take it out and get it load tested? Autozone has a free battery load testing. Also make sure there is no corrosion buildup on the battery terminals or where the wires connect to the bolts. That happened to my boss's car and it wouldn't start until I cleaned it all off. He has to get new battery cables because his were messed up but at least he was able to start it so it didn't need towed.
I would jump it.
if you jump it and it cranks then there is a real good chance it is battery related.
If you jump it and it performs the same way then it is possible it is something other than the battery.
Cold weather is a killer to batteries.
Also keep in mind that a new part does not necessarily mean it is a good part.
if you jump it and it cranks then there is a real good chance it is battery related.
If you jump it and it performs the same way then it is possible it is something other than the battery.
Cold weather is a killer to batteries.
Also keep in mind that a new part does not necessarily mean it is a good part.
Womack said:
Should be the same voltage. Which leads me to believe you have some resistance/ corrosion at the battery bolt/ terminal interface as well. Corrosion hides very well in our side terminal configuration. You usually have to remove the bolts and then take off the red and black boots to clean the lug terminals. Its not just the bolt threads that need to be clean.
+1 for Sparky mentioning this.
New battery bolts at Autozone is $2.50 wire brush is .50 ... Cheap insurance.
You're not dumb, and neither are we. But accurate observations and appropriate experiments are called for.
Replacing the ignition switch and the starter could have been a total waste of money and effort, with a couple of well-designed experiments.
For more reading:
Replacing the ignition switch and the starter could have been a total waste of money and effort, with a couple of well-designed experiments.
For more reading:
Deffinetly didn't mean any disrespect! You have helped me with so many things on forums that you've answered for other people! I have the upmost respect for you roadie! Thanks to everyone for helping me! I'm gonna print out the manifesto! I see now that those parts were a waste of money and effort! I towed it to the shop and am now waiting for a diagnoses! Maybe it's something I can do my self! Thanks again everyone
But happens periodically and then fixes itself. It fixed itself for 6 months but its back! Spent nearly $1000 between parts replacement, dealer repair and inde repair. Changed starter (new AC Delco unit), new battery, new ignition switch, new underhood fuse panel (thanks dealer!), new relays. Still cannot figure it out. TB starts and runs fine, then cannot start again. Leave it overnight (or 2) then starts up fine with no codes. I'm not that saavy with electrical diagnosis so kind of plodding along - I have a meter and shop manual with schematics but it seems to be some short or bad ground somewhere and would appreciate if anyone could give me advice where to start considering what I've done already.
thanks much
thanks much
The professionals you paid to do all that parts swapping had access to the same stuff, plus experience, and they failed to find the true root cause (assuming there was only one root cause.)oceancon said:
Didn't the dealer guarantee you an accurate diagnosis before you allowed them to replace things?
The only way to find the root cause is to catch it in the act of failing, and RIGHT AWAY before it fixes itself, check everything you can in the path of controlling the starter relay. Assuming the relay doesn't click (that should be trivial to listen for), then look backwards on the control path, which will lead you to the BCM. Many things could convince the BCM that it isn't time to try to start the engine. Security issues (do you have ANY aftermarket electronics like a remote start installed?) or especially a faulty PARK/NEUTRAL switch on the transmission could suppress starting. Have you ever fiddled with the shift lever when it doesn't start and see if it behaves differently? Did the dealer ever catch it in the act and suspect this switch?
Thanks for your kind reply. The dealer did not guarantee the diagnosis so I did not let him replace the fuse panel (new one was $800). I bought aftermarket and replaced it myself. It worked for 6 months and thought the problem solved up until a few weeks ago. And yes I need the truck in a no start condition to diagnose but when it happens I cant get anyone there. Last guy that came pulled some codes 1041 and 1026 (had a GM scanner) but could not find any history of hard SES codes. Another guy's scanner showed a "loss of communication with the PCM" in the past but we could not duplicate (truck was in a start condition unfortunately). I know when I pull the starter relay, it seems to duplicate the situation. But that relay was replaced. I am truly perplexed how the issue could "fix" itself for so long and then reappear. I'm starting to lean to the BCM but I think when electrical components start to go, they just keep on getting worse. So I dont think a component is failing but wiring. Each"fix" I believe is coincidence as the problem comes back.
thanks again for replies. I hope to offer solutions to other folks problems in the future because I'm pretty handy with cars but this has got me big time! Also own a nice 2005 Acura TL.
thanks again for replies. I hope to offer solutions to other folks problems in the future because I'm pretty handy with cars but this has got me big time! Also own a nice 2005 Acura TL.
oceancon said:
Sounds like you and I have the same problem, basically. When it "no start"s on you - does the gas gauge read empty regardless of fuel level? Does your fuel pump pump? Can you get it to start by pulling and reinserting fuses #10 and #28 underhood? If so, your fix is probably the same as mine (although I haven't done mine, yet - haven't had time, will this weekend, though). Disconnect battery, remove all three PCM connectors, flush connectors on PCM and on harnesses with Electronics cleaner and let dry or blow dry with compressed air. Apply thin coat of WD40 and reconnect. Check battery terminals (clean if necessary) and reconnect (apply appropriate grease and tighten properly). Turn key to on and wait 90 seconds (actuators - don't want to kill those) then turn off. Now start the car.
I believe my problem (and yours by the sounds of it) is a bad connection at the PCM. I'm not sure what signal isn't getting to it, but it won't power the fuel gauge and pump circuit for whatever reason. As such, it also wont' command the starter to turn over. If a 10/28 fuse pull gets the car to start, that's your problem.
Roadie, feel free to chime in on your thoughts on the validity of what I've just written.
[edit] Just reread the entire thread, probably a bit of a hijack on my part replying to oceancon, sorry about that. [/edit]
TequilaWarrio, sorry to hear you have this issue too!
I'm not sure what the fuel gage reads or if the fuel pump is on when its in the no start condition (right now its starting) but I will check that when it happens. I also don't know about the nos. 10 and 28 fuse situation as I did change the entire under hood fuse panel (coincidentally that was one of the 'fixes' that worked for a short time). Had a weird experience last week on a long drive north and the "service 4WD light came on'. The truck would not go into 4wd or AWD. After getting home and trying to start it the next day (it did not start and then started -grrr), the light went off and it goes into 4WD again! I don't know if this relates to the BCM. Like I said to roadie is that I feel that when electrical components start to go, they eventually go, not get better. My thinking is the problem I (we?) seem to have correlates to a bad connection/bad ground somewhere.
Your idea of bad PCM connections is worth a shot. BTW I have the 5.3L V8 and if you have that you know how difficult it is to work in the engine compartment looking for bad connections, grounds etc.
thanks
Joe
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yeah, good idea. Thanks for that info
I'm not sure what the fuel gage reads or if the fuel pump is on when its in the no start condition (right now its starting) but I will check that when it happens. I also don't know about the nos. 10 and 28 fuse situation as I did change the entire under hood fuse panel (coincidentally that was one of the 'fixes' that worked for a short time). Had a weird experience last week on a long drive north and the "service 4WD light came on'. The truck would not go into 4wd or AWD. After getting home and trying to start it the next day (it did not start and then started -grrr), the light went off and it goes into 4WD again! I don't know if this relates to the BCM. Like I said to roadie is that I feel that when electrical components start to go, they eventually go, not get better. My thinking is the problem I (we?) seem to have correlates to a bad connection/bad ground somewhere. Your idea of bad PCM connections is worth a shot. BTW I have the 5.3L V8 and if you have that you know how difficult it is to work in the engine compartment looking for bad connections, grounds etc.
thanks
Joe
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CaptainXL said:
yeah, good idea. Thanks for that info
Womack said:
did you ever figure anything out with your truck go figure im floating in same boat you were in
shawnd450r said:
Yes. Sorry I didn't post an update in this thread.
The complete saga is here in this thread: http://gmtnation.com/f23/intermittent-starting-problem-all-but-gas-gauge-works-no-fuel-pump-no-crank-5999/
[caution, spoilers ahead]
I'll save you 10 minutes of reading: It was a loose fuse and I'm stupid - that'll be $75 please(sorry, gotta recoup my costs somewhere).
The slightly longer version: I checked every fuse for being bad, I didn't check to see that every fuse was securely seated and that the slots were tight. That was the problem, the slot for one of the PCM fuses was a little loose. So I now slightly twist the fuse blades before inserting the fuse into this particular slot (only changed it once). To see if it's the same issue as me: remove your under hood fuse box cover and wiggle each fuse, if the car sputters or dies while wiggling a fuse - bingo. When I say wiggle, I mean wiggle GENTLY - they aren't toggle switches that need flipped back and forth. If/when you find the offending fuse - use a pair of needle nose pliers and slightly twist the legs on the fuse, just a few degrees will do nicely.
Good luck.
I sure wish it was that easy for me I've struggled for days checked fuses good except no power to relay or crank fuse so traced back to ignition swapped out switch and tumbler and no go, got battery tested good and only thing I haven't checked is neutral safety switch and I don't believe I'm getting power to start other than one post