93 chev.

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  #1  
Old 01-18-04, 10:38 AM
toivo
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93 chev.

my 93 chev. ck-1500, reg. cab, 4.3 litre, 4l60e trans. it will start and when i put it in gear, idle will drop and it dies. the last time it did it, i babied the throttle and got it going but was sluggish on pickup when i pressed on the gas. when i got home i scanned it and got a map sensor too high reading. plugs are good, wires are good, replaced coolant sensor some time back. air filter is good, ran injector cleaner through it, also put drygas in it. it has 177,000 miles on it, fuel pressure is 10 lbs. injectores seem to be spraying ok. oxygen senor is working fine. although mileage is down some. i replaced the base gasket on the tbi. it was leaking. this happened after that was replaced. the most constant sign is it dies when i shift it into gear. i cleaned the base of the tbi when i removed it. the egr seems to be working, it ran rough when i pushed it in manually when idling. if the knock sensor reads 5 when idling will this retard the timing and cause problems. sometimes reads as high as 16 going down the road.can you help with this one? thanks.
 
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Old 01-18-04, 02:03 PM
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Check to see if you have vacuum to the MAP sensor. That base gasket you put in could be wrong or in backwards and blocking an important vacuum supply.
 
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Old 01-19-04, 09:10 PM
toivo
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93 chev.

sorry it took so long to get back. i checked the vacuum to the map sensor and it was 18" rock solid. no movement at all. and now the truck runs ok but the mileage is way down. i am wondering if the injectors are worn. or the map sensor is just played out cause its old.
 
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Old 01-20-04, 04:01 AM
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That's the computer's job. It will compensate for any leakage or restriction in the fuel injecters until it reaches it's limits and then it will tell you by putting on the check engine light. If it's running good now and not setting the code anymore, either you fixed the problem or it is intermittant and will be back. If you have scanner capability, check your temperatures at the sensors and make sure they are reading correctly and the engine is fully getting up to correct temperature and going into closed loop. Make sure you hooked the map up to the correct vacuum source when you replaced that base gasket. you could have a map sensor starting to go bad but it will show up again if that is the case.
 
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Old 01-20-04, 02:53 PM
toivo
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93 chev.

desi, i read your post and went right outside and scanned the truck. i have an auto xray scanner and it doesn't incorporate the parameters as it scans. this is cold before it starts. idle air-145, coolant 38.3* degrees,battery voltage-11.9, tps-.058 volts,map sensor-4.78 volts,baro sensor-4.78 volts, integrator-128, block learn cell-16, block learn 123, injector pulse 56.6, air to fuel mix 6.6 to 1, now when i started it the map sensor went to 1.26, the air mix ratio went to 12.9 to 1, knock sensor read 4, injector pulse 5.6 milliseconds, it's cold so it is still in the open loop mode,battery 14.2 when running, the idle air moved to 45 steps so what does this info tell you? thanks, toivo
 
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Old 01-20-04, 04:39 PM
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Well, since your in upper michigan, your temp sensor seems correct. Everything else looks OK. Try this, start the engine and warm it up to operating temperature and in closed loop. Once it's hot, shut it off and disconnect the battery for a minute or two. Hook up your scanner, now reconnect the battery and start it up. Watch your block learn and integrator. You may have to wait for the timer to expire to go into closed loop again. They should start out around 128, now watch to see which direction they travel. If the numbers start dropping and continue to do so, then you may have a fuel injector leaking or something else making it rich. If it holds somewhere between 124 and 132 there's not any big problem with fuel leakage.
 
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