Gmc jimmy 1998 starting problem?

Dave C

• 1050 Answers
• Posted on May 18, 2009

SOURCE: Emissions sensor fuel tank 2001 gmc jimmy

I don't think you have anything wrong, I just don't think you have completed the correct drive cycle yet. Some vehicles must be driven in a very specific way before all the monitors will set. Here is the drive cycle that Gm Recommends:

1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 122°F (50°C) and within 11°F (6°C) of the ambient air temperature at startup.
   Do not leave the key in prior to the cold start or the heated oxygen sensor diagnostic may not run.
   
2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire, and - if closed loop is achieved- Fuel Trim.
   
3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 55mph (88km/hr) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
   
4. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
   
5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
   
6. Accelerate. Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This will perform the same diagnostics as in step 3.
   
7. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
   
8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

mike loshbough

• 1011 Answers
• Posted on Mar 22, 2009

SOURCE: 2000 gmc jimmy wont start fuel pump comes on and cuts off...

the fuel pressure if leaking could cause this the regulator is located under the intake plenum but you should smell gas .if you dont then most likely the pump is bad ,the pump will come on for 2 seconds when the key is on then go off it will not stay on with just the key on only when you crank it will it .so have your fuel pressure checked with a gauge.

SOURCE: 2000 GMC Jimmy will not start

The oil presure switch does have some bearing on the problem but my suggestion is to change the coil. I had a the same problem with an astro van. I changed everything that you have described and it fixed the problem just for a little while and then all of a sudden did it again. I changed the coild and the cold start swithch and never had the problem again.

SOURCE: 2000 gmc jimmy wont start fuel pump comes on and cuts off...

When you hook the pressure test guage to shrader valve on fuel rail what it reads is what the pressure is from pump, around 60 p.s.i. all you need to do is hook up the guage and turn on key, you do not have to turn engine over, and if pump is good it will shoot up to 58 or 60 right now.

SOURCE: 1994 cadillace anti theft system

I just had this same problem with a '96 . do you have a vats key in your '94? you need to bypass the VATS system. read some of the blogs on this site and it will tell you how to do it. I fixed mine with a $2 resistor from radio shack.