Do I need a new brain?
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From: Denver and San Francisco
Do I need a new brain?
I have a rich condition. I passed emissions July 2nd 2004 (with
HC GPM reading of 1.06 with Colorado limits of 3.0
CO GPM reading of 8.13 20.0
CO2 GMP of 555.88 no limit shown
NOx of of 1.91 6.0
The car is an '87 5 sp with a 100k miles, valve job done done 3K ago, new plugs, caps, rotors. The car puffs a little smoke at start up. Starts great when cold. Turn key starts. On warm starts it may take a couple of revolutions to start and it feels a little loaded up?
Looks like when the fuel brain goes the cars tend to run rich? Rich are you reading this? Is this true?
Any suggestions that I should look into first?
HC GPM reading of 1.06 with Colorado limits of 3.0
CO GPM reading of 8.13 20.0
CO2 GMP of 555.88 no limit shown
NOx of of 1.91 6.0
The car is an '87 5 sp with a 100k miles, valve job done done 3K ago, new plugs, caps, rotors. The car puffs a little smoke at start up. Starts great when cold. Turn key starts. On warm starts it may take a couple of revolutions to start and it feels a little loaded up?
Looks like when the fuel brain goes the cars tend to run rich? Rich are you reading this? Is this true?
Any suggestions that I should look into first?
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From: Gone. On the Open Road
Temp Sensor (aka NTC II sensor, temp sensor II). Check both circuits. When this sensor fails it can result in symptoms you describe; it tells the computer that is is -20 degrees outside, computer richens the mixture. It's on the passenger side of the water crossover bridge.
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From: AZ
Originally Posted by Scotts87928
I have a rich condition. I passed emissions July 2nd 2004 (with
HC GPM reading of 1.06 with Colorado limits of 3.0
CO GPM reading of 8.13 20.0
CO2 GMP of 555.88 no limit shown
NOx of of 1.91 6.0
The car is an '87 5 sp with a 100k miles, valve job done done 3K ago, new plugs, caps, rotors. The car puffs a little smoke at start up. Starts great when cold. Turn key starts. On warm starts it may take a couple of revolutions to start and it feels a little loaded up?
Looks like when the fuel brain goes the cars tend to run rich? Rich are you reading this? Is this true?
Any suggestions that I should look into first?
HC GPM reading of 1.06 with Colorado limits of 3.0
CO GPM reading of 8.13 20.0
CO2 GMP of 555.88 no limit shown
NOx of of 1.91 6.0
The car is an '87 5 sp with a 100k miles, valve job done done 3K ago, new plugs, caps, rotors. The car puffs a little smoke at start up. Starts great when cold. Turn key starts. On warm starts it may take a couple of revolutions to start and it feels a little loaded up?
Looks like when the fuel brain goes the cars tend to run rich? Rich are you reading this? Is this true?
Any suggestions that I should look into first?
Yes, running rich, clicking injectors when the ignition is on but the engine isn't running, bad idle speed regulation, and stalling at inoppertune times are all symptoms of a dieing LH.
Things to check first.
- fuel pressure regulator, pull the vacuum line and see if fuel drips out. If yes, that must be replaced.
- get the engine a little warm, turn off. Remove the connector from the MAF, start up. If it runs better then the MAF is suspect.
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Joined: Dec 2004
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From: Denver and San Francisco
Thanks all. I'm on my way out to the grarage now. I also need to replace the fuel filter since it has been quite awhile and it was on my list of to dos. But I don't have a check valve. I did replace one on my '81.
Then, I will check plugs to see if they are all similiar. I think the wires are good based on the dark garage and a misting spray bottle exercise. No archs at all.
Brian, wouldn't the fuel check valve make it start a little slow since the fuel would have to be pumped back up to the fuel rails on cold start. On warm start even after 15 seconds the car starts a little slower and sounds/feels like a flooded condition.
Dave, do I just put an ohm meter on the temp sensor? You mention 2 circuits? I will look at the book this evening.
Rich, I will try the vacuum line off the pressure regulator, and the MAF connection suggestions.
Will let you know what I find.
Thanks
Scott
'87 Gemball 5sp Red/Black
Then, I will check plugs to see if they are all similiar. I think the wires are good based on the dark garage and a misting spray bottle exercise. No archs at all.
Brian, wouldn't the fuel check valve make it start a little slow since the fuel would have to be pumped back up to the fuel rails on cold start. On warm start even after 15 seconds the car starts a little slower and sounds/feels like a flooded condition.
Dave, do I just put an ohm meter on the temp sensor? You mention 2 circuits? I will look at the book this evening.
Rich, I will try the vacuum line off the pressure regulator, and the MAF connection suggestions.
Will let you know what I find.
Thanks
Scott
'87 Gemball 5sp Red/Black
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Thread Starter
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From: Denver and San Francisco
I went through several steps:
1. Went to change the fuel filter and I changed it and the checkc valve last year - I thought it was on the '88 that I did that. Need to keep better records.
2. Checked the plugs and 5, 6, 7 are good may check the others today
3. Found out my flappy is stuck. I can turn it with a needle nose but if I let it snap back closed it is sticky again. I think it is my butterfly sticking against the walls of the intake. Maybe I have the spring too tight (I had the intake off in 04 when I had the heads redone). The solenoid works with 12 volts at start up.
4. Warmed the car up and pulled the connection to the MAF and it starts the same but wouldn't idle properly. So I don't think it is the MAF or the brain?
5. The fuel pressure regulator is not leaking when I pull the vacuum hose off. But I did it with the car off. Should I do it with the car running?
6. I do have a vacuum leak in the HVAC.
6. Does anyone know what the vacuum should be at idle?
7. Can I isolate the motor by pulling the small black vacuum line off the brake booster (the one that goes to the check valve) and plugging the hole in the larger line going to the brake booster?
8. Today I will check the temp sensor circuits
The car runs fine other than a little black smoke at warm start and not starting immediately, and the flappy not working which is why Ralph's '88 5 sp has me consistently by 3 or 4 car lengths from 40 to 90 and we are dead even out of the hole until the upper RPM range.
1. Went to change the fuel filter and I changed it and the checkc valve last year - I thought it was on the '88 that I did that. Need to keep better records.
2. Checked the plugs and 5, 6, 7 are good may check the others today
3. Found out my flappy is stuck. I can turn it with a needle nose but if I let it snap back closed it is sticky again. I think it is my butterfly sticking against the walls of the intake. Maybe I have the spring too tight (I had the intake off in 04 when I had the heads redone). The solenoid works with 12 volts at start up.
4. Warmed the car up and pulled the connection to the MAF and it starts the same but wouldn't idle properly. So I don't think it is the MAF or the brain?
5. The fuel pressure regulator is not leaking when I pull the vacuum hose off. But I did it with the car off. Should I do it with the car running?
6. I do have a vacuum leak in the HVAC.
6. Does anyone know what the vacuum should be at idle?
7. Can I isolate the motor by pulling the small black vacuum line off the brake booster (the one that goes to the check valve) and plugging the hole in the larger line going to the brake booster?
8. Today I will check the temp sensor circuits
The car runs fine other than a little black smoke at warm start and not starting immediately, and the flappy not working which is why Ralph's '88 5 sp has me consistently by 3 or 4 car lengths from 40 to 90 and we are dead even out of the hole until the upper RPM range.
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Joe Kucinski
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Joined: Feb 2002
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From: Cambridge England
If you have a vac leak then the fuel pressure at idle will be higher than it should be. So at cold start, in the minute or so before the O2 loop is active, the mixture could be too rich at idle.
If there is a temp 2 open or short circuit, the LH will detect this, and reverts to "hot" fuelling" .So this will affect cold starts.
If there is a temp 2 open or short circuit, the LH will detect this, and reverts to "hot" fuelling" .So this will affect cold starts.
