Poor Gas Performance
kcpete
07-06-2007, 06:28 AM
My 93, 3.1 has been using a lot of gas lately and also with my foot on the brake has a rough idle. I changed my plugs and wires over the weekend thinking this would be the fix, but still has same problem.
At times I can smell gas but never see any signs of it! During the past winter the van would really reap the smell of gas and not start. I would undo one set of injectors and then it would start. It was like it was dumping too much gas. But drives fine up and down the hiway. Can anyone lead me in a direction to help gas performance and idle?
At times I can smell gas but never see any signs of it! During the past winter the van would really reap the smell of gas and not start. I would undo one set of injectors and then it would start. It was like it was dumping too much gas. But drives fine up and down the hiway. Can anyone lead me in a direction to help gas performance and idle?
richter111
07-06-2007, 08:27 AM
This is my first Pontiac vehicle in a long time, but I have owned a lot of Ford products, and what you are describing, (in a ford product) usually meant that the fuel pressure regulator was shot. It may be wort looking at it, (I have no clue where it is) and smell if the gas is stronger around it. If so, it's a good chance it is shot.
RIc
RIc
aamirmali
07-06-2007, 09:42 AM
Check all your vaccum lines...especially the one going to the master cylinder.
LMP
07-08-2007, 08:50 PM
.... I would undo one set of injectors and then it would start. It was like it was dumping too much gas. But drives fine up and down the hiway.
It seems you have pinpointed the problem: there are 2 injectors in hte throttle body, and your description indicates one of them is blocked open...it happens.
Once warmed up, the computer senses the rich mixture and probably leans as much as it can....but at idle and cold, the computer is "open loop" and does not make any corrections.
It seems you have pinpointed the problem: there are 2 injectors in hte throttle body, and your description indicates one of them is blocked open...it happens.
Once warmed up, the computer senses the rich mixture and probably leans as much as it can....but at idle and cold, the computer is "open loop" and does not make any corrections.
kcpete
07-09-2007, 10:02 AM
The pressure regulator was replaced over the winter with a new kit. This weekend I spent hours looking and searching for vacuum leaks and check EGR. Nothing!
LMP, what do I need to do to determine and fix the injectors?
LMP, what do I need to do to determine and fix the injectors?
LMP
07-09-2007, 03:11 PM
try that
www.avigex.ca/xport/injectors31_1.jpg
www.avigex.ca/xport/injectors31_2.jpg
THe injectors are quite expensive....With air ducts removed, you can look at them when someone turns key to ON and check is flow looks larger from one and specially if one leaks after initial 2 sec prime burst. Another check is measureing fuel pressure ..rather low on the 3.1, around 12-14 psi, and see if pressure remains after initial prime. It might not stay at 12, but should not fall to 0...falling to 0 suggests injector blocked open.
ALso, as a '93, you can pull codes if CEL is ON.
www.avigex.ca/xport/readingcodes.jpg
www.avigex.ca/xport/codes31.jpj
www.avigex.ca/xport/injectors31_1.jpg
www.avigex.ca/xport/injectors31_2.jpg
THe injectors are quite expensive....With air ducts removed, you can look at them when someone turns key to ON and check is flow looks larger from one and specially if one leaks after initial 2 sec prime burst. Another check is measureing fuel pressure ..rather low on the 3.1, around 12-14 psi, and see if pressure remains after initial prime. It might not stay at 12, but should not fall to 0...falling to 0 suggests injector blocked open.
ALso, as a '93, you can pull codes if CEL is ON.
www.avigex.ca/xport/readingcodes.jpg
www.avigex.ca/xport/codes31.jpj
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