Can't get it running
#1
Can't get it running
Here's my story
Hey guys I'm hoping someone can help. I have a 97 Trans Am with only 60,000kms on it. Wen I was driving home last Friday afternoon after an hour drive it seemed to shift kind of weird between 1st and 2nd. I got home check the fluid and all was good. This was around 6 when I got home. I tried to start it to go out later around midnight and all it does is crank over won't start.
I went to start the car the next afternoon and it started. It didn't start right away the engine turns over a bit i much before it starts. I notice this in the past week almost like a carburetor car would. I thought this to be out of the Norm. I put a clear spark plug tester on it and I have spark. After about 3-4 starts it won't start again.
Later my buddy came over and we heard the fuel pump kick on the car started and ran nice. Great spark from the spark plug tester. Shut it off and started it again no problem. The fourth time wouldn't start again and the light in the spark plug tester wasn't very strong. I was guessing the ignition control module. But I went to AutoZone and they tested it (5 times) and said it was good..
So far I believe it's getting gas and enough the battery is good and the ICM tested good.
It starts once in a while but won't stay running
I've changed the crank position sensor, fuel filter and the ignition control module and charged the battery.
I jumped a new coil so I know it's not that. The only other thing is the distributor???
I put a code reader in and no codes come up
Any help would be awesome
#2
Re: Can't get it running
have to test fuel pressure to rule that in/out
If FP is good than it is in ignition
testing cold ICM...not a real good way. Typically they fail when hot
If the coil & ICM are good, Opti is likely issue
If FP is good than it is in ignition
testing cold ICM...not a real good way. Typically they fail when hot
If the coil & ICM are good, Opti is likely issue
#3
Re: Can't get it running
I turned it in when I had the gas filter off and got a nice stream. So it does seem the fuel pump is working. I also hit the gas bleeding valve and seemed to spout far out pretty nice.
The ignition control module is brand new.
The ignition control module is brand new.
#5
Re: Can't get it running
You need to actually measure the fuel pressure with a test gauge.
To check the Opti, first, when the starter is cranking the engine, but it isn't starting, does the tach needle move up to 300 RPM or so? That would indicate the PCM is reading the cam position signal from the Opti. A more detailed check:
courtesy of Shoebox
4th Gen LT1 F-body Tech Articles
The crank position sensor has nothing to do with making the engine run. It is only there to check for misfires, as required by the OBD-2 protocol.
To check the Opti, first, when the starter is cranking the engine, but it isn't starting, does the tach needle move up to 300 RPM or so? That would indicate the PCM is reading the cam position signal from the Opti. A more detailed check:
courtesy of Shoebox
4th Gen LT1 F-body Tech Articles
The crank position sensor has nothing to do with making the engine run. It is only there to check for misfires, as required by the OBD-2 protocol.
#6
Re: Can't get it running
Thanks for the replies.
I don't have anything to check the fuel pressure so that's all I know about that. I'm trying to borrow one.
I'm fairly confident that the ignition control module is good being it's new and it's the same issue.
The tach doesn't move to 300 it just barely guess over 0 when I turn the car over.
I figured out after I replaced the crank position sensor that wasn't an issue. Buy seeing how that code came up why not.
I don't have anything to check the fuel pressure so that's all I know about that. I'm trying to borrow one.
I'm fairly confident that the ignition control module is good being it's new and it's the same issue.
The tach doesn't move to 300 it just barely guess over 0 when I turn the car over.
I figured out after I replaced the crank position sensor that wasn't an issue. Buy seeing how that code came up why not.
Last edited by zootzee; 08-13-2018 at 06:25 PM.
#8
Re: Can't get it running
Confusing.l. You indicated you put a code reader on it but none came up? But now you say you had a CKP sensor code. Which one (there are two)? The CKP code can be caused by bad data from the Opti cam position sensor, since the PCM is comparing crank data to cam data to detect misfires.
Any other codes you didn’t mention?
Any other codes you didn’t mention?
#10
Re: Can't get it running
Fuel pressure tested
Had the car running for about 5-10 minutes fuel pressure only got to 32 them died won't start again.
Checked the fuel relay it seemed warm on the bottom.
Let the car sit pressure when I turned on the key would only go to about 12 and won't start.
Had the car running for about 5-10 minutes fuel pressure only got to 32 them died won't start again.
Checked the fuel relay it seemed warm on the bottom.
Let the car sit pressure when I turned on the key would only go to about 12 and won't start.
#12
Re: Can't get it running
Those FP #'s are way low. Unless your fuel filter is severely clogged, your fuel pump or the wiring to it in tank are bad
Fuel filter is new. I'm going to try a relay that's only $20. If it's not that then I guess the pump? But it works sometimes then fails that's why I'm thinking relay?
Fuel filter is new. I'm going to try a relay that's only $20. If it's not that then I guess the pump? But it works sometimes then fails that's why I'm thinking relay?
#13
Re: Can't get it running
doubt it is relay. Just swap it with one next to it to see if FP improves
relay can be hot because pump is dying or wiring is failing adding a bunch of resistance to the circuit
you have to drop tank to replace fuel pump....or do the "cut a trap door" mod in the trunk
relay can be hot because pump is dying or wiring is failing adding a bunch of resistance to the circuit
you have to drop tank to replace fuel pump....or do the "cut a trap door" mod in the trunk
#14
Re: Can't get it running
If the pump runs for two seconds when you turn the key to “run” (not “start”) the relay is fine. Pump should prime to at least 40 PSI at shutoff, and pressure should not drop rapidly. You can test the pump by providing 12 volts to the fuel pump prime connector. This bypasses the security system and the relay.
courtesy of Shoebox:
http://shbox.com/1/fuel_pump_prime.jpg
With the engine idling, the pressure could be as low as 32 PSI. But you have to disconnect the vacuum line from the fuel pressure regulator. Pressure should increase, with 43.5 PSI being the design value, and GM specs accepting anything between 41 to 47 PSI. When you reconnect the vacuum line to the regulator, pressure should drop about 8 to 10 PSI below what you measured without the vacuum line connected.
courtesy of Shoebox:
http://shbox.com/1/fuel_pump_prime.jpg
With the engine idling, the pressure could be as low as 32 PSI. But you have to disconnect the vacuum line from the fuel pressure regulator. Pressure should increase, with 43.5 PSI being the design value, and GM specs accepting anything between 41 to 47 PSI. When you reconnect the vacuum line to the regulator, pressure should drop about 8 to 10 PSI below what you measured without the vacuum line connected.
#15
Re: Can't get it running
With the engine idling, the pressure could be as low as 32 PSI. But you have to disconnect the vacuum line from the fuel pressure regulator. Pressure should increase, with 43.5 PSI being the design value, and GM specs accepting anything between 41 to 47 PSI. When you reconnect the vacuum line to the regulator, pressure should drop about 8 to 10 PSI below what you measured without the vacuum line connected.
Ok when I hooked up the fuel gauge that's what I was getting 32. I took the vacuum line of the fuel pressure regulator and it when to 39-41.And when I reconnected it stopped back down
When I turn the car on the fuel pressure gauge doesn't move I had seen it go up to 20psi once I think.
But the car will only run for 5 minutes or less then won't start again until it suits for over an hour
Ok when I hooked up the fuel gauge that's what I was getting 32. I took the vacuum line of the fuel pressure regulator and it when to 39-41.And when I reconnected it stopped back down
When I turn the car on the fuel pressure gauge doesn't move I had seen it go up to 20psi once I think.
But the car will only run for 5 minutes or less then won't start again until it suits for over an hour