89 Camaro RS - RPM problem

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  #1  
Old 03-07-03, 03:55 PM
waaland
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89 Camaro RS - RPM problem

Vehicle: 1989 Chevrolet Camaro RS, 305 ci. with TBI and automatic transmission.

Problem: When car is first started, will die if given ANY throttle. RPM will not go above 1500 - 1800. As the car warms will take a little throttle without stalling - rpms will reach 2500 - 3000 rpm. With accelorator in the same position enging will seem to pulsate between 3000 - 3500 rpm. As engine continues to warm, rpm will continue to go up (still pulsating) 3500 - 4000, then 4000 - 4500. At about 180 degrees engine will stop pulsating, rev fine and car is then runable but performance will deteriate again if engine begins to cool down.

Is this the symptom of a bad coolant temp sensor?
How about a bad coil?

I am also getting a code 44 on the check engine light when on the open highway. The book says O2 sensor is detecting a lean exhaust. O2 sensor was replaced 4 months ago.

Also - what would be the symptoms of a bad MAP sensor? Could this be causing the definate pulsating that I am getting?
 

Last edited by waaland; 03-07-03 at 04:21 PM.
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  #2  
Old 03-07-03, 04:57 PM
Joe_F
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Clean the throttle body and IAC passages/IAC pintle. Make sure there are no vacuum leaks at the throttle body. Spray a little carb cleaner around the TBI base. If the idle picks up, the gasket is bad or the TBI unit is loose.

Check for any vacuum leaks as well. Use the links and posts in my signature file for a guide.
 
  #3  
Old 03-07-03, 05:27 PM
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Check your fuel pressure,if low pressure or volume you will get a code 44 plus your other symptoms.
 
  #4  
Old 03-08-03, 08:25 AM
waaland
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Thanks for the tips.

Would a bad fuel filter be a possible cause for the engine code 44?

Also - Why would the engine temp directly effect a vaccume leak or fuel problem?
 
  #5  
Old 03-08-03, 08:31 AM
Joe_F
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A fuel filter is a maintenance, not failure, item. If it's been a while, change it.

Those vin E 305 engines are notorious for vacuum leaks which cause havoc. Checking for bad vacuum lines is cheaper than throwing parts at the problem.
 
  #6  
Old 03-08-03, 08:46 AM
waaland
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I asked about the fuel filter because I had a previous problem with it that was corrected by replacment.

I had gotten some bad gas (water in it) and needed to add several bottles of HEAT (alcohol) to eventuaal work out the water.

Care eventually began running ok again except for a few seconds after making a turn which was probably some water that had collected in pockets. When I changed the fuel filter there seemed to be some water in it. The car ran much better after the new filter. I was wondering if perhaps the new filter got messed up by the little bit of water that might still be there.

Also - what happened to the auto lookup page that used to be available? That was always a great resource.
 
  #7  
Old 03-08-03, 04:57 PM
waaland
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Checked as you described and found no vacuum leaks.

Where do I check the fuel pressure if I can get a guage from Auto Zone. I seem to have 2 fuel lines going into my TBI - one on each side at the rear of the TBI unit. Do I disconnect each one and check there? By the way, my pump is only 6 mos. old.

Saw you mention that this type of problem could be computer related. Is there anything that I can do to check/correct the computer?

Once again - could MAP sensor be the problem? That is one of the few sensors that I have not yet replaced.
 
  #8  
Old 03-09-03, 07:04 AM
Joe_F
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Work in order and don't jump around or you will easily spend more than this car is worth in parts!

Must check the fuel pressure. If the pump is not an AC Delco unit, that is probably part of the problem. Some aftermarket pumps are not of good quality.

The pressure gauge will have the proper adapters and instructions of which adapters to use to check pressure on your specific application.

Can't speculate about any other problems until the basics are ruled out first.
 
  #9  
Old 03-09-03, 08:38 AM
waaland
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Thanks Joe.

Do you know what the fuel pressure should read?
 
  #10  
Old 03-09-03, 10:16 AM
Joe_F
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The gauge set will come with pressure specs, but GM TBI is low....I think around 15 or so, but my memory fails me at the moment (that's what books are for..lol)
 
  #11  
Old 03-09-03, 10:27 AM
waaland
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Thanks Joe... heading to AZ now. I will let you know what I find.

I appreciate your help.
 
  #12  
Old 03-09-03, 04:10 PM
waaland
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The Autozone here doesn't have a pressure guage to rent so that was a bust.

I did notice that as long as my temp is 160 - 180 the car runs a lot better. I actually got up to 50 mph today. As soon as the temp goes below 160 the available rpm goes down and the engine wants to stall when I hit the gas. The lower the temp the slower I go. Does this indicate anything to you?
 
  #13  
Old 03-09-03, 07:25 PM
Joe_F
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No, still must verify the basics first.
 
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