Have a 95 K1500 5.7 that just died suddenly on me last week, had to come home on flatbed. Tried turning it over a few times after i got home but didn't even want to start and a couple huge backfires outta the exhaust. Figured it was a fuel related issue so i replaced fpr with no luck. Did the fuel pump next along with a new filter. Relay was good but no luck starting. Spark was good and i verified i was getting fuel to tbi by cracking line loose at tbi and gas shot everywhere. To make the story short i replaced the oil pressure switch, cts, rebuilt tbi, new plugs and new ignition module still no luck. Now when i crank it over it wants to start with throttle at 75% but wont go just a loud backfire from exhaust. Pretty stuck here and don't want to keep throwing money at it. I forgot to mention at first i was getting a code 54 and 35. Checked iac with meter and it checked out fine. Any suggestions?

 

Do you have good OPERATING single or pair of fuel injectors for your throttle body injection, good spark plug wires, are spark plugs properly gaped? Did you check your starter and the wiring as well? Do you have lean fuel or a bad air/fuel mixture from the air intake side? As much as you can list is more to help eliminate any other possibilities.

 

Codes 35 and 54 which you should of had mention what are. Are listed as code 35
IDLE SPEED CONTROL (ISC) CIRCUIT, and Code 54 FUEL PUMP CIRCUIT (LOW VOLTAGE).

 

CODE 35
Trouble Code 35 indicates a problem with the Idle Speed Control (ISC) circuit. It will be set when the closed throttle engine speed is 200 RPM above or below the desired (commanded) idle speed for 50 seconds. Possible causes include:
1. Vacuum Leak (High Idle) - Also check for binding of throttle blade or linkage.
2. System too lean (High Air/Fuel Ratio) - The idle speed may be too high or too low. Check for low regulated fuel pressure, water in the fuel, or a restricted injector.
3. System too rich (Low Air/Fuel Ratio) - The idle speed will be too low. May exhibit black smoke in exhaust. Check for high fuel pressure, leaking or sticking injector.
4. Foreign material in throttle body.
5. Faulty IAC Valve electrical connections.
6. Faulty PCV valve.
7. Faulty IAC.
8. Faulty ECM.

CODE 54
Trouble Code 54 indicates a low voltage at the fuel pump. If the voltage at terminal "A20" is less than 4 volts for .4 seconds since the last reference pulse was received, the code will be set.
Possible causes include:
1. Faulty fuel pump relay.
2. Faulty connection at ECM.
3. Faulty oil pressure switch.
4. Faulty ECM.

 

Have you tried addressing either of the code issues as that may be where the problem lies there in. Welcomes

 

Had my son turn engine over as i watched spray pattern from injectors seemed to be ok but hard to see. I would think with all the cranking i have done on the engine that it would be flooded by now but when i pull the plugs only #3 and #6 cylinder has wet plugs and the rest are dry. Fuel seems to be puddling in bottom of intake manifold. Plug wires and cap are maybe 1.5 years old and i gapped and put new plugs in this week. How would the starter and or wiring have an adverse effect on this? Checked compression in one cylinder to make myself feel better it was at 160 psi. It seems like a lean condition ecspecially with the backfire outta the exhaust. Will check vacuum hoses again for leaks. Already tested iac with meter and that checked out per the manual. Fuel pump relay clicks when you turn the key and i have fuel coming out when you crank it so i would think that would be ok, besides i think the oil pressure switch takes over shortly after in which i have replaced that too. Can check ecm connection, where is ecm located on this truck? Behind glove box? I don't have means of checking fuel pressure but i suspect that maybe the culprit. When i rebuilt the tbi unit the pressure regulator i believe is an adjustable unit being that there is a small torx screw on the bottom of the bowl. Thankyou for suggestions anymore would be greatly appreciated.

 

The starter or that I just posted as general, I don't know how much people know on vehicles so I post general to more advance to help them along. Also when you say ECM/ECU that is something you would need a book on or can get offline off google images putting in your year and make and ECU or ECM remember though it might think your talking PCM with the E in front though. The ECM as far as I know from knowledge on working on a lot of vehicles is that it is usually always located under the dash and pushed up pretty hard where its hard to see. PCM usually always is under the hood. Also if your having flooding to cyinders 3 and 6 that makes me wonder if you have a cracked heads or the easier just a bad gasket failing just on that side. When I get back tonight I can write a little more on it but I have to run to get some stuff for my daughter. Sorry will try to get back and post more on this.