I've read a ton of crank no start posts and none are like mine. I have a 98 Tahoe with the 5.7. I drove it for about a year before out of nowhere it decided to not start. I did some research and checked the IDM, coil, fuel pressure, etc. it had spark and even if I put starter fluid down it's yap it still wouldn't fire off. The battery was starting to get drained so I put the trickle charger on it for a couple days. I went to start replacing ground wires and the thing fired right up. Drove it like that for over a month and then same thing. I went out and it wouldn't start. I tried to use my jumper pack but it didn't help and after cranking it would blink saying it was hooked up incorrectly... threw the trickle on it again and after two days I went out to push it out of the way of my jeep and again it fired right up. Seriously it turns over barely and fires off. I know I have fuel and spark and my air filter is new. Does the PCM need a certain voltage to work? Any ideas?
98Tahoe crank no start... sometimes
- Thread starter CaseyA
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
bsamole
Member
Any codes? My 99 Tahoe that I have owned since new has went through 3 Crank Case sensors in 24 years. Same symptoms as you describe.
No codes... Battery is 6 months old and Orielly's tested it and said it was good. They also said the alternator is good. No anti theft light on the dash.
I'll swap out the dist cap since I have it from the first time it didn't start. I didn't swap it because it started again and ran great. I also have the crank case sensor in case I need to swap that but I don't want to swap a bunch of things and not figure out what was actually wrong. I have my doubts about the alternator being good. It would make sense to me if the battery was drawn down just enough that it would crank like normal but didn't quite have enough for the computer to run. Might have to get it checked again.
I'll swap out the dist cap since I have it from the first time it didn't start. I didn't swap it because it started again and ran great. I also have the crank case sensor in case I need to swap that but I don't want to swap a bunch of things and not figure out what was actually wrong. I have my doubts about the alternator being good. It would make sense to me if the battery was drawn down just enough that it would crank like normal but didn't quite have enough for the computer to run. Might have to get it checked again.
More on the Minimum tool list- Spark tester, Fuel pressure guage preferably with long hose so you can stick it on windshield, Multimeter DVOM, Set up your scanner for Live Data, maybe 2 or three screens that you can run as needed. Don't wait for a failure to try to understand what "NORMAL" numbers are.
Bad batteries usually fail in 1st 6 months. How long will it sit not driven and still start? Usually a week to 10 days max without disconnecting battery. Good Luck!
Bad batteries usually fail in 1st 6 months. How long will it sit not driven and still start? Usually a week to 10 days max without disconnecting battery. Good Luck!
I have those tools. Thats how I was able to determine I have spark and fuel pressure at 55-57psi. I've run continuity with my multimeter to check grounds and voltage at the battery. What live data would be good to look at while its running? What about the data when it doesn't start? I haven't looked at my scanner other than to check for codes... Again, I've searched this forum and did most if not all of the test's that you guys have said to do in other posts, that's why I made my own.
I can get my battery checked again easily but it doesn't sit more than a day or two without starting. Also when it doesn't start the battery is able to crank the motor easily and doesn't seem to be drained at all. I crank on it pretty good, like it's my 7.3 powerstroke in the cold... haha I think I might let it sit for a week or two and see if it'll start. Then it it doesn't start, charge the battery again to see if that changes things.
Another thing I think is weird is that my jumper that does fine with my powerstroke didn't seem to help and also after cranking on it blinked that it was hooked up incorrectly.
This is will crank, no start condition. Thank you for your reply!
- Joined
- Aug 2, 2018
- Posts
- 10,348
- Reaction score
- 15,001
Welcome to the Forum from NH.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
You are already receiving clarifying questions from the knowledgeable folks on this Forum.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
You are already receiving clarifying questions from the knowledgeable folks on this Forum.
Your fuel pressure is low. Is that key on eng off? Running idle? Running highway steady state? My experience on this vintage is 60# min.
88-98 Service Manuals
Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...
www.gmt400.com
Last edited:
That was key on engine off. I'll have to check it now that it's running again.Your fuel pressure is low. Is that key on eng off? Running idle? Running highway steady state? My experience on this vintage is 60# min.
88-98 Service Manuals
Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...
I'll try again. When it doesn't start you say it turns over OK. If that is the case then why the jumper box and the battery charger? As someone related fuel pressure seems low.
When it won't start cycle the key off and on multiple times, not cranking just off and on, and listen to hear the fuel pump cycle. The after doing that try and start it. If it starts it is most likely the fuel pump.
As in my first response if it cranks but won't start turn the key off and then to the on position and watch the security light to be sure it shuts off.
When it won't start cycle the key off and on multiple times, not cranking just off and on, and listen to hear the fuel pump cycle. The after doing that try and start it. If it starts it is most likely the fuel pump.
As in my first response if it cranks but won't start turn the key off and then to the on position and watch the security light to be sure it shuts off.
If you've confirmed fuel pressure and theft system aren't culprits, look into the ignition system. When mine was doing this (years ago) I narrowed it down to the PCM or a component (don't recall the name) in the ignition system. Ended up selling it (with full disclosure of the history) before I was able to confirm what I did actually fixed the issue.
I let it sit a week and I have another no start situation. I haven't changed out any parts but I wanted to report that I checked the fuel pressure now that it's no start. With key on engine off its still 55-57psi but when cranking it goes to around 63psi.
Try key to run 2 seconds, OFF, repeat 2-3 times then START. Usually 2 cycles works. Once running, recheck fuel pressures including driving.
A weak fuel pump will not keep up on highway. Change fuel filters yearly at a minimum.
Sitting a week is the Max for these trucks 4 days normal. Due to battery drain. Some a little better some worse.
A weak fuel pump will not keep up on highway. Change fuel filters yearly at a minimum.
Sitting a week is the Max for these trucks 4 days normal. Due to battery drain. Some a little better some worse.
Just wanted to update everyone. I believe it was the distributor cap and moisture. Seems like it wouldn't start only after it rained and only would start after a week or more to dry out. I finally pulled the cap and rotor and they were very corroded. Replaced and it seems to be running great again. Wasn't a fuel issue... Thanks for the suggestions/help.
Set your scanner to monitor misfires, fuel trims, trans slip, and anything you see available. Watch it at steady state at various speeds. Say 35/45/55/65/75. Not knowing capabitities of your scanner.
Also start at the beginning and re-read the posts here. We can only suggest based on the info you provide. My next guess will be at speed your fuel trims will max out due to low fuel pressure.
Also start at the beginning and re-read the posts here. We can only suggest based on the info you provide. My next guess will be at speed your fuel trims will max out due to low fuel pressure.
Similar threads
