Team Chevelle banner
1 - 12 of 12 Posts

·
Premium Member
Joined
·
4,221 Posts
Discussion Starter · #1 ·
My cousin has a 1993 Suburban that has an idle problem. It will run for 30 seconds to 2 minutes, then die. The fuel pump is about a year old & the IAC was just replaced. I disconnected the vacuum line from the EGR valve & it made no difference. My cousin's wife says that it will run fine at speed, but it dies at idle (in neutral or in gear - makes no difference). What is the next thing to look at?? Throttle Position Sensor?? MAP Sensor?? Any input will be greatly appreciated. Thanks in advance.
 

·
Premium Member
Joined
·
4,510 Posts
My cousin has a 1993 Suburban that has an idle problem. It will run for 30 seconds to 2 minutes, then die. The fuel pump is about a year old & the IAC was just replaced. I disconnected the vacuum line from the EGR valve & it made no difference. My cousin's wife says that it will run fine at speed, but it dies at idle (in neutral or in gear - makes no difference). What is the next thing to look at?? Throttle Position Sensor?? MAP Sensor?? Any input will be greatly appreciated. Thanks in advance.
GM had lots of problems with Mass Air Flow sensors, I don't know if Suburbans had MAF sensors in 93. TPS sensor is also a potential cause. Any codes in the computer?
 

·
Premium Member
Joined
·
4,221 Posts
Discussion Starter · #3 ·
I have not checked for any codes (there is no light on). This engine only has a MAP sensor (TBI).
 

·
Registered
Joined
·
430 Posts
Wild guess, but tons of problems with coolant sensors. They'll fail open and the ecm will see a much colder temp then it should. This won't set a code either.
 

·
Registered
Joined
·
2,597 Posts
Oil pressure switch will cut it off also. IIRC
 

·
Premium Member
Joined
·
4,221 Posts
Discussion Starter · #8 ·
My cousin replaced the fuel filter within the past few months. The oil pressure gauge is reading in the normal range. The temp sensor is a possibility, because it seems as though the temp gauge takes forever to start reading anything. I am going to have the ignition module in the distributor checked, as I found out that they send both a low & a high rpm signal to the ECM. Thanks for your input. I will check out those other forums & see what I can find on this problem.
 

·
Registered
Joined
·
430 Posts
The temp sender for the gauge is seperate from the one for the ecm. Most likely the oil pressure is the same way, though some are combined.
 

·
Premium Member
Joined
·
486 Posts
Check plug wire from coil to cap for corrosion.Ive seen stupider stuff cause these problems.High resistance in that wire will freak out the ign module.
 

·
Registered
Joined
·
18,906 Posts
unplug the temp sender and see if that helps. check the wiring going to it to make sure the wires aren't frayed and making contact. i had that happen on my 84 T Type and it wouldrun great cold and then want to die after a couple of minutes. the insulation on the wires had shrunk back enough to allow it to short out.
it's the one in the intake manifold right next to the thermostat housing with 2 wires going to it- i think the wires are yellow and black.
 

·
Premium Member
Joined
·
4,221 Posts
Discussion Starter · #12 ·
One of the guys at the recommended truck forum hit it square on the head. The short rubber line that connects the fuel pump to the pressure line had split down the side, causing low fuel pressure. We went ahead & warrantied the pump, which comes with that rubber line & all is well now. Thanks for the guidance to the truck site.
 
1 - 12 of 12 Posts
Top