V-6 w/MPFI Stumbls&Stalls - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

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post #1 of 6 (permalink) Old Jan 30th, 02, 07:45 PM Thread Starter
Join Date: Aug 2001
Location: Sacramento, CA
Posts: 11

Hey guy's I am turning to you for help on this one. My sister in-law has an '88 Camaro with a 2.8litre Multi Port FI engine. She took it to a garage for a diagnostic check because it will stumble and then stall when she tries to accelerate. They told her that she needs to have the injectors cleaned and it would be a good idea to change the fuel filter. I think I can handle the filter if I can locate the fuel pump fuse, but I have no experience with this type of injection system. What all is involved in the cleaning procedure? Does it require any special tools? She is on a budget and I'd like to help her if I can. Thanks in advance for any help you can give.

Phill V.
'79 Camaro mild 355 ci
Daily driver
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post #2 of 6 (permalink) Old Jan 30th, 02, 11:24 PM
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I have a 90 camaro with the 3.1 w/multi port fuel injection and all I did to clean things up was run a good can of fuel injector cleaner in the gas tank. Also it helps to run the good gas once in a while. The fuel filter is easy. It's located on the drivers side, right by the front of the rear wheel. Make sure you take of the gas cap or when you loosen the fuel lines, gas will come out a flyin. You may also want to try the TPS switch, (throttle position switch). It's located on the throttle body, passenger side. It's a little black switch with three wires. Mine went bad and caused all sorts of stumbles when I went tp pull out. I have since then, changed the filter, air and fuel, run good gas and a can of cleaner every once in a while and changed out the TPS switch and now I have no troubles. If your worried about the cost, the switch was under 20.00, the filter was 10.00, and cleaner isn't that much.
Godd luck,

[This message has been edited by bruce69camaro (edited 01-31-2002).]
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post #3 of 6 (permalink) Old Jan 30th, 02, 11:29 PM
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Join Date: Sep 2000
Location: Va Beach VA
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I'll take a shot at this,

The best way I know of fuel cleaning, and since it has MPFI, have the shop substitute a fuel cleaner set-up in place of fuel line from/to the tank. The engine runs from the charged can of fuel cleaner and cleans the injectors and even cleans some carbon from the combustion chamber. However, if the engine runs well, I'd think twice about injector cleaning, try a couple cans of cleaner from the shelf and pour into the tank.

Fuel filter you can do, find the filter and swap out.

I would check a couple more items first, does it idle well, cold fast idle and hot idle?
Hopefully, it does by reading your post. Get a DVM, and measure the resistance of the Throttle Position Sensor, as you rotate the throttle from idle to WOT, the reading in ohms should be a smooth transition, no jumps or holes. The other check would be the Manifold Absolute Pressure sensor, engine running, same check here, put the DVM across the two wires going to ECM, engine running, and give some throttle, transition of voltage should be smooth. You can substitiute a vacuum hand pump to check the same, ign on , to read DC volts.

I hope these help, maybe some more good suggestions from others will be helpful,

Everett 68/350/PG/11.90/115mph
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post #4 of 6 (permalink) Old Feb 1st, 02, 10:54 AM Thread Starter
Join Date: Aug 2001
Location: Sacramento, CA
Posts: 11

Thanks for the ideas and tips. I will let you know how it goes. I'm in the Air Force, so my work schedule is not allowing me much time to work on this car. My sister in-law went ahead and bought the throttle position switch after I showed her your post's. I read the installation instructions and it sounds like an afternoon project. She also put the 'ol "Engine Rebuild in a Can" (fuel injector cleaner) in the gas tank. I look forward to getting the time to fix this problem so I can maintain my reputation as the family car god.
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post #5 of 6 (permalink) Old Feb 9th, 02, 08:15 AM Thread Starter
Join Date: Aug 2001
Location: Sacramento, CA
Posts: 11

I replaced the throttle position sensor and it is still stalling. Has a strong smell of fuel. I'm not around much to work on this car and would like to see if anyone can recomend a reputable shop in Sacramento, CA that my sister in law can take this to. Fuel injection is not my area of expertise and I hate to just throw parts at a problem until it gets fixed.
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post #6 of 6 (permalink) Old Feb 9th, 02, 08:56 AM
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Join Date: May 2001
Location: Houston, Texas
Posts: 4,491

It's possible the fuel regulator is bad.
One quick check would be to pull the vacuum hose off the regulator and check for fuel
in the hose.

I've seen them so bad that raw fuel is pulled into the plenum/throttle body.
This could be your gas smell. It is not safe to drive like this.

Don~ ZZ430DropTop
70 RS/Z28
67 RS/SS Convertible, 70 RS/Z28
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