Car trouble.

Hi, my name is LB and i have a 99 Riviera supercharged and it is using twice the fuel it usually does and it seem that it is not getting enough fuel. When in park it idles great, but when you put it in drive and step on the gas it fall flat on its face. When on the hwy trying to pass and kick it down it wants to shut off. I have replaced the camshaft position sensor, EGR valve, cleaned the mass air flow and gave it a complete tune up and new fuel filter. If anyone has any answers for me it would be great. It's a great car just running a little rough when driving. PLEASE HELP!!!!!

clean the air idle control valve while your there.

LB,
How many miles on your car.?
Are you using any oil.?
Do you have a check engine light ON, If so what's the code(s) ?

Sounds like a failing fuel pump to me from the information provided.

my car has 134500, yes the check engine is on and the code keeps reading is the camshaft position sensor. I have put on 2 new ones and checked all the wiring. my next thing is replacing the fuel pump first thing in the morning. I have also replaced the air idle control valve.I love this car and dont want to get rid of it, but I can't afford to drop much more into it.

99SuperchargedRiv wrote:

my car has 134500, yes the check engine is on and the code keeps reading is the camshaft position sensor. I have put on 2 new ones and checked all the wiring. my next thing is replacing the fuel pump first thing in the morning. I have also replaced the air idle control valve.I love this car and dont want to get rid of it, but I can't afford to drop much more into it.

A bad coil pack could cause an issue similar to this too, especially considering the coil packs on these put out two different stages of power, the second being when you step on it....

Also the camshaft SES light could be an old code that just hasn't been dumped out of the computer yet...

Did you replace the ignition wires during the tune-up?

If the car is still telling you it's the camshaft position sensor, I think there is still a problem here, even if you replaced it. There's got to be a reason why it's throwing that code. Are there any other codes besides the CPS?

Check the wiring to the CPS, see if there's any exposed wiring around it. My ignition wires were routed incorrectly and that bled enough current to completely screw up the car.

Sometimes that code won't go away until a CASE Learn procedure has been performed.

I had the same problem as you did (p0341 code for me) and it turned out to be a wiring issue. My black Camshaft Position Sensor wire was sheared at the big connector by the trans dipstick


More info can be found in this thread....
https://rivperformance.editboard.com/series-ii-engine-transmission-f4/p0341-camshaft-position-sensor-cam-sensor-timing-chain-t4703-120.htm?highlight=p0341

Great Reply Matt. +

98riviera98 wrote:

Great Reply Matt. +

X2 --- It's always great to have pictures as well.

LB, do you know what the actual code you still have is.???

my code still reads p0341 so i am going to replace the coils and double check all the wiring possible. thank you all for all the helpful info and if you have anymore please send it to me

99SuperchargedRiv wrote:

my code still reads p0341 so i am going to replace the coils and double check all the wiring possible. thank you all for all the helpful info and if you have anymore please send it to me

You just brought me back to earth... We got hung up on ignition theory, and forgot that L67's story and photo of the wiring problem are the most likely solution to your problem.

99SuperchargedRiv wrote:

my code still reads p0341 so i am going to replace the coils and double check all the wiring possible. thank you all for all the helpful info and if you have anymore please send it to me

Before you replace the coils try checking the black Camshaft Position Sensor wire (location shown in table in P0341 thread) at the ICM for continuity between it and the PCM. If you get an infinite resistance reading then there is a break in the wire (possibly at the connector i posted before). I believe the PCM pin readouts are listed in the thread i posted earlier, and the map of pins for the big connector is in my FSM at home (I'm at school). I can tell you it is one of the corner ones right next to a yellow wire (MAF). Hopefully someone can maybe provide you with the pin map out of their FSM. If you dont feel like testing the wires right away, pull off the cover to the connector and try a quick visual inspection, mine was very obvious looking. Good luck!

99SuperchargedRiv wrote:

my car has 134500, yes the check engine is on and the code keeps reading is the camshaft position sensor. I have put on 2 new ones and checked all the wiring. my next thing is replacing the fuel pump first thing in the morning. I have also replaced the air idle control valve.I love this car and dont want to get rid of it, but I can't afford to drop much more into it.

Changing a expensive fuel pump without verifying the fuel pressure is out of spec is the worst thing you can do to your wallet !!!!!!!!!!

I need a fuel pump and would gladly pay postage for your "junk one" if you are randomly changing things.

PLEASE peruse the cam sensor code ,is this a new thing since the fuel consumption ? If you feel the urge go check the fuel pressure while in your bog mode before buying a new pump.

98inSFl wrote:

99SuperchargedRiv wrote:

my car has 134500, yes the check engine is on and the code keeps reading is the camshaft position sensor. I have put on 2 new ones and checked all the wiring. my next thing is replacing the fuel pump first thing in the morning. I have also replaced the air idle control valve.I love this car and dont want to get rid of it, but I can't afford to drop much more into it.

Changing a expensive fuel pump without verifying the fuel pressure is out of spec is the worst thing you can do to your wallet !!!!!!!!!!

I need a fuel pump and would gladly pay postage for your "junk one" if you are randomly changing things.

PLEASE peruse the cam sensor code ,is this a new thing since the fuel consumption ? If you feel the urge go check the fuel pressure while in your bog mode before buying a new pump.

Poor fuel economy is a result of Camshaft Position Sensor failure.

thanks for the info Matt. I will try everything you suggested before dropping any more money. THANKS AGAIN

Also I forgot to mention you can test from the ICM to the connector if that is easier for you. This diagram shows the black wire pass through the big connector (proper name is C101) on its way to the PCM.


Again like I said before most pertinent information is located in the other thread.

i checked all the wiring and they all look good. my next step is the coil pack and i will go from there, if anymore suggestions please feel free to give them to me. i am getting very frustrated.

Honest answer you do not want tho hear, bring it to someone that can diagnose it properly, in the long run you WILL save $$

I deal with this all day long, people guess and buy one of everything then when it aint working any better they show up at my door step and cry they dont have any $ left. By the time I am done they have spent 1/3 of what they had by doing it their self(after the fact math)

AND I put back half of the good used stuff from the trunk because GM used parts are usually better quality then the cheeeeepie junk from discount auto

You could have a hidden harness problem, a bad coil module, a bad PCM ,or other issue any of witch will throw a cam sensor code.

I will say it again ,A fuel pressure test, a computer scope/scan will cost less then buying random parts.

Ok you can most likely get a free rental on a fuel pressure gauge at the local parts store but the scan has to be done at a advanced shop, not a tire place.

99SuperchargedRiv wrote:

i checked all the wiring and they all look good. my next step is the coil pack and i will go from there, if anymore suggestions please feel free to give them to me. i am getting very frustrated.

Did you do a continuity test with an ohmmeter to verify or did you just base this conclusion off of a visual inspection? Sometimes cracks in the insulation/wiring are hard to see, especially if they occur deep in the wiring looms. A continuity test is an easy way to verify before you keep throwing money at the problem.

well i changed my mind on that because on my way back from the parts store she died 3 times and would not start the 3rd time so i bought a fuel pump and getting ready to replace it now

99SuperchargedRiv wrote:

well i changed my mind on that because on my way back from the parts store she died 3 times and would not start the 3rd time so i bought a fuel pump and getting ready to replace it now

P0341 can also cause starting problems, since technically there is a 1 in 6 chance that the motor will start. Good luck....

Comment to those reading this thread:

Back in the day when vehicle control and feedback systems were mostly mechanical, replacing parts when a problem arose was not a terrible strategy.

Nowadays when vehicle control and feedback systems depend so much on computers and the wiring that connects them, it is a vey bad strategy.

My wild guess is that someting was done or happened under the hood to break a wire from the cam sensor, rendering it inoperative. Sometimes the copper in the wire is brittle and breaks inside the insulation. Such a break is hard to find unless you are using an ohmmeter and a gentle touch.

Comment to L. B.

You are not going to like the price of the fuel pump module. Also, when you replace it be sure to get the o-ring and locking ring. You may need to go to the dealer to get them. They are not that pricey, but when you replace a fuel pump on the last generation G-body Riv they are almost always needed - fuel pump work is so infrequent that usually the locking ring has rusted into place and maybe rusted thru in places; sometines you also chew up the O-ring during the R&R. And also, when you get the old fuel pump out you may want to keep it - there is a repair kit for the pump available from ACDelco and the sending unit is available as well through some of the larger auto parts stores (to wit, NAPA and CarQuest last time I checked).

Hope this helps

Albertj