Wont Start Diagnostics - Cranks But Won't Start

hey welcome back to the car doctor studios thanks for stopping by Pete the likes and subscriptions to our channel anyway I hope this video is helpful I'm going to go through some common tips and tricks for best practices on no start scenarios this particular vehicle is a Chevy truck the 5:3 actually this is a 5 7 this is a 2000 k 2500 4 by pickup with the 5 7 vortex so this is the older school system with that flat distributor cap in the back of the motor does not have the individual coil packs or anything and it has the old old-school CIS injection system came in for an issue where it cranks but doesn't start so I thought this would be a good opportunity to talk about some of the common problems and your best practices for diagnosing those issues and getting it back on the road so first order of business with as with any no start issue through the three things the three big hits the fuel spark and compression so basically first thing I've done here is crank it over sounds like it's got good compression if you've listened to these enough you can pretty much identify a motor with no compression they're going to kind of sing over like a like a Toyota with the blown timing belt or Subaru four-banger with the timing belt slip and it just goes ending anything any so that's not the case here it's obviously got some compression and I'm going to assume that the compression is good at this point so we can move on to the other common issues I would say on this particular rig all the way through the from the late 90s to mid 2000s most common issue affecting these as a no start scenario is going to be the fuel pump and in this case we actually threw a pump module the ACDelco part actually the delphi part excuse me approximately a year ago so I'm highly doubtful it's going to be a fuel pump issue and also when we energize the key I can hear the fuel pump running and it registers as having fuel in the tank a couple things here this one has the Schrader valve in the back the left side of the motor just down over here little black plastic cap so I remove that after energizing the fuel pump basically turning the key on letting it sit for a few seconds turn it off and then I just depress the Schrader valve you want to make sure you don't get fuel sprayed in your face but if it's developing some pressure I think it's probably safe to say that your pumps good the circuit to the pump is good you know it can be especially on the CIS models it will not squirt the injectors if it doesn't have enough pressure which is somewhere around 50 not sure exactly but I think it's 55 running pressure and if you have a low pressure scenario like 2530 pounds it's not enough to fire these injectors so that's something to think about especially with this particular truck but not the case here so if you don't have a fuel pressure gauge like I say and you can kind of depress the Schrader valve you should get some fuel out of there in worst-case scenario and you had a can of starting fluid just throw a little bit of squirt a little starting fluid in that in the air intake then if it fires you know it's a fuel supply issue could still be a problem with the pump clogged filter even injectors not getting a signal so you may have to do some additional diagnosis on that side but not the case here I've already confirmed that it is getting fuel pressure and we're going to move on to the spark side one handy tool I have which I suggest they're relatively inexpensive I think you can get these for less than 20 bucks off the amazon's basically a spark tester that will go one end will adapt to the spark plug wire and the other one will slip on the spark plug itself and right in this glass area here it'll show the spark being delivered on the secondary side of the ignition circuit pretty cool little deal so I'm going to slip this on to the number one plug over here on the driver's side and get someone to crank it while I observe for spark so I basically remove the number one wire and I install my tool onto the plug in hook that up to the wire and now as we crank all observed for spark here go ahead and crank it okay no spark there so what we'll do now is move over to the coil side I'm going to check it for spark here on this vehicle the coil is external to the distributor and it's located right here on the right rear side of the motor disconnect the wire from the distributor I'm just going to route it over here next to a ground and see if we get spark out of this end all right go ahead and crank it we're getting great spark out of the coil so basically seeing that we have spark and it's coming out of the coil but not being distributed out of the distributor I'm going to assume that this is a bad distributor cap and rotor here's the cap and rotor on this this rig whenever replacing these I recommend you go with the quality cap and rotor definitely used to be that you'd only want to use GM parts on this particular ignition system and I would recommend it if if you're not worried about the cost the GM part is going to be probably the best option for you however I've had great success with these bwd parts and I'm going with the premium cap and rotors so some engineer decided in this case that it would be best to get a distributor cap like this so that all the wires would be routed out of the side in this fashion it doesn't even go by the firing order here they're just it puts out either the right or left bank right out of the side in numerical order and it just makes a routing better but it presents some problems because that secondary voltage is having to travel through these circuits in the cap and they're prone to failure inside the cap by moisture and crossover shorting as these parts where the rotor wears or the the rotator button or any of these contacts where they're prone to burning across creating a misfire issue or in this case I'm assuming it's going to create a no spark situation no spark at all so we're going to pull the old cap and rotor off and inspect them and basically and in this case it's going to call for what is this a t20 and a t15 Torx drivers to get them off and I'm also going to pull this up pull this air intake off of here to allow me to get access back to the distributor cap and you just got to kind of crawl up under the hood here and get it back to access it but that allows you plenty of room there and you could even number your your wires but they're pretty easy to identify which cylinder they go to they're numbered here usually along the cap so that'll make it easier and we'll pull that thing off and take a look at well I got the tap and rotor off and we found the problem so this part of the rotor the contact portion that sticks in there is completely fallen off and actually one of these screws was fallen off as well so this thing was probably just oscillating around in there and that's not going to cut it rest of the cap looks decent but we're going to replace it so I think we found your problem sir get this guy fixed up yeah be sure you get all your parts out of there in this case there's a small tab where the button of the rotor sets that also is down in there that I thought I would go look for so I got that basically this part here and then this had fallen off too so another thing that reminds me is a customer said that it made a funny noise and then it quit and when this came off it was probably starting to squeal and and make some noise coming out of the distributor before it crapped out so also you pay attention where this is pointing where it's oriented that will help you on reinstallation only goes on one way but you could waste a lot of time trying to put it on backwards and then be some replacement screws take care on replacing the the two larger screws that go in the cap and a lot of these distributors are plastic bodied and those screws actually thread into a plastic distributor housing and you don't want to strip those out and have to worry about that so throw this back on okay well reinstall the air condor intake air duct we'll see if this thing cranks up nice well this thing looks like a success ah it turned out pretty good so you know just some things to think about and you know I probably missed some things and if you can think of something great that will be helpful then go ahead and comment down at the video I'm not going to pretend to be oh you know like I don't still have stuff I can learn and appreciate your involvement as a community we can help each other out this could be a great video for us to build each other's knowledge base and probably think of some things that I missed especially common just too generic no start issues and the stuff we can deal with you know it's different for different makes and models of course different different ignition systems different fuel systems and there's a lot we learned over the years but this one definitely old school and nothing surprising here so I hope this video helps again I appreciate you watching and I will catch you next time have a good one

Channel: The Car Doctor

Views: 1,476,840

Keywords: Won't start diagnostics, Chevy truck won't start, Cranks but won't start, Chevy cranks but won't start, No spark, Diagnosis, How to, Diagnostics, No start, DIY, The Car Doctor Channel, Cranks but won't start diagnostics, No fuel pressure, Ford, Pickup, My car won't start, Why, Video

Id: Rpmt0FzaH9M

Length: 13min 25sec (805 seconds)

Published: Tue May 03 2016