visit me @ http://toolsandtime.com Part 2. In this video i give an example of one way i go about trouble shooting a no start issue when i have limited resour…
Part 2. GM no start no fuel troubleshooting “Oil pressure switch”
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i have a 97 chev suburban with same issue just died replaced fuel pump 3 times but no diff they checked fuel pump the last time and it worked so i redid the wiring and still no power to fuel pump i tried checking the relays like u did but mine were different some odd reason opposite sides had power then the 1 u had in vid i tried same sides udid but mine didnt work tried opposite side and worked went by numbers like u did so not sure if my comp is gone or fuel pump oil pressure switch now lol
nice video man! very helpful! what if there is voltage on the wire going to the relay but not in the one going to oil pressure switch? i see on the diagram that they connect somewhere and if one has voltage the other should have voltage as well, or am i mistaking the diagram and they are separate wires coming from the pcm?
Great job breaking it down.I have a 94 gmc truck with same motor.Nopw I know what to look for if this happens.I have original pressure switch in my truck think I’m going to change it just to be safe. Thanks and great job.I’ve also been studying how to read wiring diagrams now.
Thanks for the tip on oil pressure switch causing my fuel problems. Been a month trying to figure out why no power under load. Put the switch in and now feels like a new vehicle. Thanks!!
Awesome video. Liked how you tested with air pressure and a regulator.
Ok we have changed the fuel pump and checked the relay in our 97 chevy venture the car will start after it sets for awhile but will only run for a few seconds. As it will start with starter fluid but no longer than a min before it dies. Please help. thank you
sadly my wife’s 98 suburban isn’t the only thing sufferning from this ailment, my 99 taho is starting to exhibit those same charicteristics also, that being the case I get to do this repair twice. not finding the part yet for very cheap though haven’t looked very far but the cheapest so far is $50.00 for that regulator
Good question, i should make a video response for this one. if i showed you first hand it will make more sense. say if the motor jumped time, Broken timing chain or belt depending or more extensive damage, you will hear a deference in the way the engine cranks, when in time you can hear the the starter working harder overcoming the compression from each cylinder… mechanical problem say a broken timing chain the starter would spin much faster less load, do to the cylinders without compression
Thank you, you may be correct, one thing to remember, if the relay is good that will over ride the oil switch and the vehicle will start even with no oil pressure, so yes if you do have a bad relay it will be very long crank times and my not start depending
would like to know what you’re listening for when you can tell there is compression, so no engine mechanical malfunction. please and thank you
very helpful! specially since my wife’s suburban with the same set up is doing a random no start thing. her’s is a little different issue but i think what you are doing here may have given me the answer i need to get hers going. haven’t checked the oil in hers and she NEVER does so it may just be low on oil now that might be why hers will only start when it’s warm out (assuming because the oil expands when it’s warm giving her enough pressure to start) it won’t start cold early in the morning
Man im trying, took a little break this week. put allot of time and effort in the channel and website this past year… im surprised you don’t get more hits man i been hooked spent a few hours last night checking out your vids, very impressed
MAN,u get 913 hits on your clips,u blow me out of the water PEEEACE
just wanted to add i mentioned this further down the comments,
some engines with excessive bearing clearances, worn oil pump, low bat. may not reach 3psi while cranking,
i can say, it did helped some. had a couple in the past with long cranking times that just needed a relay. very rare though
don’t have the vehicle any longer, i will be more than happy to perform this test when i get it in for the next service,
I agree should of performed that test as well for you guys guess i was a little sloppy on this one, i know for next time… wasn’t really trying to prove anything just going over some basic checks to determine if the system is working correctly. the comment you responded to was copied directly from Mitchell provided by GM. when i jumped the OP switch and the pump activated that was with the relay out. so yes in the perfect world as long as the contact close while cranking it will run,
Will, don’t you need to take the relay out and actually start the vehicle to prove that? You proved that to run, you don’t the need the relay but you have not shown that it can be started without the relay in place. Is there enough oil pressure during the cranking? The starter is only spinning at about 200 rpm, is that enough? All of my three vehicles, the oil light goes out once the vehicle starts and not before. If you still have the truck, please try that test.
I think that I would check the amp draw of the fuel pump. Having the relay and the OPS failed would make me ask why.
you know your stuff man … no code diagnose is quite hard. but you are a Pro man
thank you
😉 will do
this was performed on a 95 OBD-1 however no codes where present when i received the vehicle
lol bought most of my snap on tools on credit, still paying, the tool box alone would of been a nice used car altogether would of been a real nice down payment on a house lol
by the way were there any OBD2 CODES .. ?
hey man nice SNAP ON shirt … can you afford those tools ?
i almost had a heart attack looking at their prices man … steep man .. steep
you can keep all the videos about 98 gm trucks coming please :)
and your videos help a lot.
thank you. that would make sense to me to run on a oil pressure switch as the main to protect the engine 🙂 I had to change the intake gasket on my 98 gmc and I change my oil pressure switch the same time. nice to know for the future though. 🙂
Napa-permatex thread sealant w/Teflon i believe… i have a couple makes however i believe that’s what i used
thank you, glad i got it out to you. hope you found it helpful. your more than welcome
what brand thread compound is that you are using?
Great job! I was actually waiting for this test on that truck! Thank you for posting!
It saved a few from shoulder, however what would of maid more logical sense to me, they wanted to incorporate the oil switch. Why not use it to protect the engine like so.
use the relay until run signal and oil pressure was achieved, at that point drop out the relay, follow me? In that case if oil pressure was lost while running fuel pump would shut down as a protection for the engine,
However Gm simply just used it as a back up why they found that more important i really don’t have the answer
My first response on how the system was setup was from Mitchell provided by GM. that was their theory any how. Will it do just that depends. In some cases it may not obtain enough pressure while cranking example, low battery, bearing clearances and so on.
some engines with excessive bearing clearances, worn oil pump, low bat. may not reach 3psi while cranking,
i can say, it did helped some. had a couple in the past with long cranking times that just needed a relay. very rare though
thank you
thank you, your more than welcome
your welcome
thank you, that would make more logical sense, however GM was just using the pressure switch as a back up for the relay, so if relay failed as long as you had oil pressure the vehicle would still run. now if relay was bad, it would take real long cranking times to start if you could build pressure cranking to close the contacts that was their”theory”
if the pressure switch were to fail or you lost oil pressure as long as the relay is good it will still turn on the fuel pump. hope that helps
first off great video I learn something new. so if I understand you correctly if my truck loses oil pressure that will shut off the fuel pump?
Really Helpful Thanks
Actually, that does help. So, I’ll have to add the possibility of a failed fuel pump relay in the case of long crank start with a GM product. I wouldn’t have expected any start with a failed relay, so that might be a difficult diagnosis…. My oil pressure gauge doesn’t jump until a few seconds after starting, and without ignition (and only the starter pumping oil) it’s going to take longer.
Why is it so important for the vehicle to still start if the fuel pump relay dies?
also wanted to add, I agree, if I were to leave it be with just replacing the relay chances are it would be fine for many years, however in that rare case the relay were to fail again, as long as there is oil pressure the “back up” pressure switch will keep you in operation. what you will experiences is longer cranking times with a failed relay and an operational pressure switch due to the fact pressure needs to be obtained to close the contacts…
It’s simply just a backup, Hope that helps
Control module keeps relay energized if engine is cranking or running(control module is receiving reference pulses from ignition module) if no reference pulses, module turns off pump within 2 seconds as a back up system to relay, the oil pressure switch also activates the pump, normally open until oil pressure reaches about 4psi. if relay fails, oil pressure switch will back up, only when with pressure, cranking time will be longer if fuel pump don’t receive current until pressure is achieved
Nice job, Will! Last year a watched a vid by Scannerdanner, and I was hoping he would do what you did today. You might send him this as a video response to his video.
What puzzles me is, why did GM do this? What would happen if you had a bad oil pressure switch at that point? As far as I can tell, nothing, (grin)! An abrupt fuel relay failure would be very rare, and the worst that would happen is you would stall at speed, then coast to the side of the road…. What am I missing?
Great job / info, thank you for your time.
Nice job Will
I appreciate the compliment, your welcome
Muchas gracias amigo
great job will
keep up the good work amigo