1994 GMC Jimmy 1994 GMC Jimmy wont stay running

Tiny
FULLSKULL101
  • MEMBER
  • 1994 GMC JIMMY
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 171,000 MILES
Hi, my name is steve, I have a 94 gmc jimmy sle with a 4.3L vortec 'w'engine. I'm currently having a problem with keeping the truck running, every time I step on the gas I lose complete power almost like im losing fuel pressure, so far the spider injector where replaced 10,000 miles ago, I have replaced the fuel pump, the fuel sending unit, the fuel filter, the fuel pressure regulator, the o2 sensor and still no luck, the truck had 2 engine codes, a code for the egr valve and a m.A.P. Code. I put the truck in the shop and the mechanic found 3 vacuum leaks in the truck, two in the mapping system and one from the egr, he repaired them which cleared the codes, and I know he didnt just wipe the codes from the computer because I disconnected the battery to make sure, so as of right now when I start the truck it idles fine for about five minutes, then if I step on the gas it completely dies and white smoke comes out of the exhaust, I have no engine codes and im at a loss, could anyone please help me out
Do you
have the same problem?
Yes
No
Friday, January 29th, 2010 AT 8:55 PM

6 Replies

Tiny
RASMATAZ
  • MEMBER
Hi fullskull101, Welcome to 2carpros and TY for the donation

I strongly recommend you verify the fuel pressure if its 55-61psi, if okay test the TPS and KS
Was this
answer
helpful?
Yes
No
Saturday, January 30th, 2010 AT 12:48 AM
Tiny
FULLSKULL101
  • MEMBER
Ok but if it was the throttle position sensor or the knock sensor wouldn't I have an engine code?
Was this
answer
helpful?
Yes
No
Saturday, January 30th, 2010 AT 8:43 AM
Tiny
RASMATAZ
  • MEMBER
The CEL should popped up, at times this light don't come On at all to indicate a problem within the engine management system which there actually is-The TPS takes the place of the accelerator pump on a carb and the KS for vacuum advance-it retards the ignition timing when the engine is pinging/detonating
Was this
answer
helpful?
Yes
No
Saturday, January 30th, 2010 AT 3:22 PM
Tiny
FULLSKULL101
  • MEMBER
Ok, so now thers a brand new tps and ks, and still no change, there is no engine codes, is anyone else able to help me with this? I've check the fuel pressure, I've checked the ignition, its getting spark, it idles fine, even when I put slight pressure on the gas pedal, but too much pressure and it dies
Was this
answer
helpful?
Yes
No
Sunday, January 31st, 2010 AT 3:32 PM
Tiny
RASMATAZ
  • MEMBER
Check the ignition timing-also test the TPS reference and signal voltages also the MAP sensor.
Was this
answer
helpful?
Yes
No
Sunday, January 31st, 2010 AT 3:47 PM
Tiny
SCOTTY DEE
  • MEMBER
Are any of the spark plugs water fouled? Is the coolant level up to full? You mentioned it dies and WHITE (indicative of water/coolant) smoke comes out the tail pipe. With that clue I gotta ask about the plugs.

Many times engine mechanical gets overlooked in the equation and techs have a tendancy to go directly to powertrain management. However, reading the spark plugs would be part of it.
Was this
answer
helpful?
Yes
No
Sunday, January 31st, 2010 AT 4:03 PM

Please login or register to post a reply.

Recommended Guides