1997 suburban won't start


suburman
08-15-2012, 08:11 PM
I have a 1997 suburban vortek 5.7 with 200k miles. Went on vacation for a week and when I got back it wouldn't start. Cranks strong, good spark at spark plug and coil wire. I can hear fuel pump humming when key is turned on. Fuel pump was replaced 2 years ago (4th time in 6 years) with GM OEM pump. New plug wires. Engine will almost start and then goes back to just spinning. I sprayed starter fluid (generously) in the air intake while cranking it and it didn't fire at all (despite good spark). I thought that would be a good test to see if it was getting fuel. Strong smell of raw gas after attempting to start it. I'm going to download trouble codes this weekend but any suggestions in the meantime are welcome. Thanks in advance.

j cAT
08-15-2012, 10:59 PM
I have a 1997 suburban vortek 5.7 with 200k miles. Went on vacation for a week and when I got back it wouldn't start. Cranks strong, good spark at spark plug and coil wire. I can hear fuel pump humming when key is turned on. Fuel pump was replaced 2 years ago (4th time in 6 years) with GM OEM pump. New plug wires. Engine will almost start and then goes back to just spinning. I sprayed starter fluid (generously) in the air intake while cranking it and it didn't fire at all (despite good spark). I thought that would be a good test to see if it was getting fuel. Strong smell of raw gas after attempting to start it. I'm going to download trouble codes this weekend but any suggestions in the meantime are welcome. Thanks in advance.


plenty of spark and fuel.

maybe too much fuel.

do the fuel pressure test proceedure. use guage look for leak down.

ECT can cause this also.

suburman
08-16-2012, 08:03 PM
thanks Jcat, too much fuel is a possibility based on the strong fuel smell after trying to crank it and the fact that starter fluid won't even fire it. I seem to recall a pressure requlator somewhere in the fuel system. Would that be a possible culprit? If I pull the fuse or relay to the fuel pump, and it fires momentarily, would that be a good test for high pressure? I may not be able to get access to a OBD II this weekend so I may be troubleshooting the old fashioned way (by pass everything that might be broke) and see what happens. thanks for the quick reply.

j cAT
08-17-2012, 07:01 AM
thanks Jcat, too much fuel is a possibility based on the strong fuel smell after trying to crank it and the fact that starter fluid won't even fire it. I seem to recall a pressure requlator somewhere in the fuel system. Would that be a possible culprit? If I pull the fuse or relay to the fuel pump, and it fires momentarily, would that be a good test for high pressure? I may not be able to get access to a OBD II this weekend so I may be troubleshooting the old fashioned way (by pass everything that might be broke) and see what happens. thanks for the quick reply.

scanner is good to indicate other failures that could cause this. with the fuel you will require a pressure guage. this then will with the proceedure being completed reveal any fuel issues.

another component that can cause this would be the ECT, this sensor/connector can go bad and report the wrong temp. like minus 40 deg f. this then would also cause excess fuel. 1997 is old and this is when these temp senders start to fail.

suburman
08-20-2012, 09:09 PM
I disconnected the ECT at the connector and did a resistance check and it seemed to check out. I left it unplugged and after a couple of attempts it started. I let it warm up and then restarted it several more times with no problem. Then I reconnected the ECT and it still started with no problem. The next day I tried and it wouldn't start again (ECT connected). I did an Acutron scan and got a P118 code but I'm not sure that wasn't from disconnecting the ECT the day before. I did a coolant temp "live data" check with the Acutron and the coolant temp was same as air temp (75 F) indicating the ECT is good. I'm going to do a fuel pressure check next. Anything else I should look for? Thanks, Scott

suburman
08-25-2012, 01:31 PM
Replaced ECT and no change. Engine seems to diesel for a few seconds when key is released from start to on with ECT connected but won't start. Had to disconnect ECT to get started and started after about 3 attempts. Starts with ECT connected after warm-up. Only OBDII code is P0118 (high ECT reading) probably due to disconnecting ECT. Fuel pressure test is 54psi at idle. Jumps to 60 when i hit the throttle then immediately drops back to 54 even if I hold at the higher RPM. Pressure increased slightly to 58psi after 5 minutes (probably due to 90F outside tem). Definitely no leakdown. Cranks with no problem after warm-up, even with ECT connected. Took a small gas sample during pressure test and saw no contamination. Any help is appreciated.

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