Lt1 guru needed
TECH Senior Member
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Joined: Oct 2006
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From: Decatur, TN (N-W of Athens)
I'm not taking sides, but I think he was pointing out that more often then not it's not going to be totally dead, it'll put out incorrect signals. So using a multimeter won't do the job since it'll show it's "alive" but that doesn't mean it's working right :\
Also, it's not alternating. Alternating would mean +/- zero, or what would be referred to as a sine wave. There are no sine waves happenin here. It's all digital square wave.
As I stated before, the only way to even POSSIBLY check an opti with a DVOM is to use the frequency scale, and then all it's going to tell you is the amount of times it's switching. It won't tell you how accurate it is, how clean the signal is, nothing. And the high res is happening so fast, you NEED a scope to see it.
Thread Starter
Teching In
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UPDATE: Shop said car starting and idling fine. NO codes, and no surging... Said only thing they found at all was the opti harness with long connector wasnt clipped in fully. Didnt explain how it magically started for tow driver being he didnt touch it to me, OR rev surging. Mechanic seemed to think it being loose could have explained surge(but he didnt even know my distributer was called optispark lol). So drove it home sure as hell flawless idle etc. So LT1 gremlins FTMFL
UPDATE: Shop said car starting and idling fine. NO codes, and no surging... Said only thing they found at all was the opti harness with long connector wasnt clipped in fully. Didnt explain how it magically started for tow driver being he didnt touch it to me, OR rev surging. Mechanic seemed to think it being loose could have explained surge(but he didnt even know my distributer was called optispark lol). So drove it home sure as hell flawless idle etc. So LT1 gremlins FTMFL
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OK, so sunday installed new opti.Took my time with it... Take for drive got about 2 miles had the whole hesitation/sputter under 2/2.5k.. Engine light pops on, then goes off, as give it more gas.Drive back home, look everything over and my engine light no longer on but low coolant on so check coolant, and bleed line was quite bit of air in there.So start it up coolant light on, drive some all is well...drive again about 80 90 miles worthe no problems.Driving to work today,go get gas, drive highway to work about 20 miles, get downtown all of a as going through light sputters under 2.5k.Check engine light comes on and stays on..Get into parking garage which was like half mile from that point park and turn off.Again low coolant light on but fluid levels fine and check engine light still on..Im going to read codes ASAP just would rather go buy part and fix it before drive home..Im pretty set on it being one of the following and just wanted some input..Either the TPS,MAP, or coolant temp sensor...After I started in garage to see if check engine stayed on this time and got out seemed like it smelled hell of rich so thinking might be MAP. TPS just seems logical but why would it be fine for almost 100 miles then act up etc. Coolant sensor just because damn coolant light seems to pop on when trouble occurs and I had just put csr ewp on.. Thoughts?
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My guess now is a faulty O2 sensor(s) since it seems as though it doesn't start acting up until the PCM goes into closed loop, but as stated a scan may confirm. If your SES light is on then you should have codes stored.
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When the TPS went bad in my my Z28 it would idle all the way up to 1500 RPM and the car ran like crap while driving you could tell the power was off. I scanned my own car with a laptop and ALDL Cable and found out it was the TPS sensor, but i changed the IAC Valve also.
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Well I have ADD when it comes to car issues.So good ol ' Herron called me we did some trouble shooting etc.. So on my break at work went out parking garage took off air intake,maf, inlet etc...Looked over everything AHAAAAA! Crack in cap of coolant temp sensor going into wp. So went to autozone got a new one ($12) came back put it on,started right up.Check engine light off..So pretty Fn happy camper..Thanks for input again though all
Well I have ADD when it comes to car issues.So good ol ' Herron called me we did some trouble shooting etc.. So on my break at work went out parking garage took off air intake,maf, inlet etc...Looked over everything AHAAAAA! Crack in cap of coolant temp sensor going into wp. So went to autozone got a new one ($12) came back put it on,started right up.Check engine light off..So pretty Fn happy camper..Thanks for input again though all
