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| daddue11 | Gas problem I think. | ||
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Senior Guru
 
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Hello gurus,I've mentioned this before in another thread months ago.It's the Only thing left for me to fix on my 84 coupe.
It's not a big pain in the arse,just annoying. Maybe y'all can help. Problem = Every now and then and only when the car is cold it will crank about six times and when it starts it won't go above just idle for about 30 seconds,not rough idle and when it does this, it smokes and smells of gasoline bad,once the temp reaches apr.128 degrees then it'll quit smoking and run smooth as silk.  This only happens about once every 15 times that it's started,but when it does it's very embarassing and there is always some Idiot that asks "Does it always smoke like that?" and adds something like the rings are wore out, it needs rebuilt.  In another post a fellow guru suggest that it sounds like a sticky injector or injectors,but,the 84s have the throttle body injection. No warning light comes on when it does this and it doesn't show anything when I read the codes either. I've had the oxygen censors replaced about 4 months ago because the code said they were bad,after that it ran smooth as silk until that one very seldom time that it wants to act a little giddy till it warms up.  I drive my care usually once or twice a week for about 75 to 100 mi. and it stays in the garage the rest of the time. Thanks for all of y'alls help,I couldn't have done it without your help daddue11. |
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Posted on: 2007/12/4 16:11
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Aint no amount of gold in any ole mine,that would be enough to take away this car of mine.-beach boys |
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| Alcee1 | RE:Gas problem I think. | ||
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Guru Emeritus
 
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Ok, lets see if i can make sense when i say this. There is a sensor on the motor that tells the computer when the engine is hot or cold, this directly affects the way the engine runs, i'm not sure but it sounds to me if that sensor is bad and the computer thinks the engine is hot when it's actually cold thus the smoking, and when the engine gets to a hotter temp then it starts to act right. does it idle high at start up like it should??? again i'm not sure if this is your issue but i had a simular problem and that was my problem. hope this helps.
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Posted on: 2007/12/4 19:18
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Edlebrock Heads, 2030 cam, X-ram w/EGR, 1.6 R/R, Bored TB´s, AFPR, Pro-built Tranny, Vigilantly 2600, Transgo, Dana 44 3.54, Hardened Pushrods & Head Bolts, Custom performance chip, K&N, Double roller timing chain, Aluminum radiator & flex hose, MS |
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| daddue11 | RE:Gas problem I think. | ||
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Senior Guru
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Quote:
Ok, lets see if i can make sense when i say this. There is a sensor on the motor that tells the computer when the engine is hot or cold, this directly affects the way the engine runs, i'm not sure but it sounds to me if that sensor is bad and the computer thinks the engine is hot when it's actually cold thus the smoking, and when the engine gets to a hotter temp then it starts to act right. does it idle high at start up like it should??? again i'm not sure if this is your issue but i had a simular problem and that was my problem. hope this helps. To answer"Does it idle high at start up like it should?" No, not when the smoking occurs,It idles smooth but very low speed,aproximately 600 rpm,and it runs at 1100 rpm at startup when it's acting normal. I'll look in the manual for the type of censor.and see if that might be the problem. It sure does sound like it could be the prob. It seems so minor but a pita at the same time. thanks for the analasis Alcee  |
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Posted on: 2007/12/4 22:25
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Aint no amount of gold in any ole mine,that would be enough to take away this car of mine.-beach boys |
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| Alcee1 | RE:Gas problem I think. | ||
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Guru Emeritus
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I think it's called the coolant temperature sensor and it's located in the front of the motor. you can replace it to see if that's the problem (don't cost much) but you may have to get what they call a coolant temperature sensor update kit because you may not be able to find the OEM part.
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Posted on: 2007/12/4 22:57
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Edlebrock Heads, 2030 cam, X-ram w/EGR, 1.6 R/R, Bored TB´s, AFPR, Pro-built Tranny, Vigilantly 2600, Transgo, Dana 44 3.54, Hardened Pushrods & Head Bolts, Custom performance chip, K&N, Double roller timing chain, Aluminum radiator & flex hose, MS |
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| CasetheCorvetteman | RE:Gas problem I think. | ||
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Elite Guru
 
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First off, and this isnt the problem solving line, this is just for your personal info and future reference. Your 84 has only 1 O2 sensor, and there is no DTC that can tell you dirrectly that it has failed. The related DTCs will simply point in that dirrection and indicate the problem is related.
2ndly, as Alcee1 said the CTS at the front is quite likely the cause, but you can test this sensor and see what it is saying. Info for that will be in the GM service manual |
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Posted on: 2007/12/5 1:54
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| daddue11 | RE:Gas problem I think. | ||
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Senior Guru
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Thanks Case,I didn't know that there is only one censor in an 84,
I just know that the check engine light kept coming on and when I put the code reader on,it was flashing the numbers for 02 censor. When I took it to the mechanic he told me that it had 4 censors and he had to replace 2 of them and that he cleaned the TB. I do not take it there anymore because they screwed up my wifes Caddy for 2000.00 and ruined the heater consol. I have since semi learned to use the manual to locate and fix problems on my own. I still like to ask you all because I know that I can trust you to point me in the general directions. I'm not lazy,I'm just beginning to learn this stuff because I don't want to be at the mercy of the rip off mechies any more. And I appreciate this forum very dearly. Thanks. |
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Posted on: 2007/12/5 3:47
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Aint no amount of gold in any ole mine,that would be enough to take away this car of mine.-beach boys |
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| bogus | RE:Gas problem I think. | ||
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Grand Imperial Pooh-Bah
 
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two? damn, that tech was either a crook or a moron. Whichever, you are better off without him.
I like the temp sensor, it's on the front of the manifold, IIRC. I had one go bad on my 92 and it caused all sorts of havoc... next time you have the problem, see what the temp gauge is saying. That sensor feeds the dash, IIRC. |
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Posted on: 2007/12/5 5:50
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| CasetheCorvetteman | RE:Gas problem I think. | ||
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Elite Guru
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Give me his phone number mate, i want to give him a call and ask him how much he knows about 84 Corvettes..... He gave you a bum steer.
The first Corvette to have 2 O2s is the 92, the first to have 3 was the 94, and the first to have 4 of them is the 96. Any Corvette 91 or earlier only has 1 (excluding some export early 84s which ran on leaded fuel and had no O2 sensor, lead poisons the sensor) No Bogus, i think the sensor in the head feeds the dash mate, and the one in the other head turns on the fan. Im not certain on that, but im pretty sure. The one in the front of the manifold is indeed the one that feeds the ECM in order to control various managment functions of the engine. |
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Posted on: 2007/12/5 8:45
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| bogus | RE:Gas problem I think. | ||
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Grand Imperial Pooh-Bah
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I will need to check my 84 service manual to be 100% sure.
However, the 1994 vettes were considered ODB1.5... they had ODBI functions, but with an ODBII connector. With that said, they had only 2 O2s. In 1995, GM added the 2nd pair of O2s, but they were dummy's and didn't function. The PCM didn't have a code for them. In 1996, yes, the ODBII kicked in. |
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Posted on: 2007/12/5 15:40
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| daddue11 | RE:Gas problem I think. | ||
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Senior Guru
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Hey thanks guys,that would be kinda like the old carbed rigs having an auto choke that was stuck open or closed.
Except this is run by a computer.Kinda neat I'll check the censor over the weekend. I found it in the manual once I knew what to look for,Thanks again guys. |
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Posted on: 2007/12/5 20:48
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Aint no amount of gold in any ole mine,that would be enough to take away this car of mine.-beach boys |
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| CasetheCorvetteman | RE:Gas problem I think. | ||
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Elite Guru
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Quote:
Bogus, most of that is wrong. 94s and 95s are basically exactly the same. No question about it, and both of them have [color=red]3[/color:65d40c4883] factory fitted heated O2s. The primary O2s on 94/95 did as they did in 93 and previous. The secondary O2 fitted to the right bank after the cat converter DOES funtion, its related to the emissions system and simply monitors the function of the cat converter. They were totally OBD1, completely controlled by OBD1. The OBD2 codes WONT set the MIL on the dash, and they wont set SYS, they wont alert they driver in any way at all if they set. The only way youll know if they set is by seeing them on a scan tool of some kind (like a TECH 1 or TECH 2) The PCM does indeed have a code for the secondary O2 sensor fitted to 94/95 Corvettes. Ofcourse it has a code for them. Its also got a diagnostic procedure for it in the GM Service manual. It wont affect the engine management, and it wont set the MIL, but it WILL set a DTC if there is a problem with the secondary O2 sensor. You should know all too well youre lucky to even get what you pay for with GM, and there is no way in the pit of haydes GM will ever give you anything for nothing, and no way are they ever going to fit 44,072 heated O2 sensors to a line of vehicle over 2 full model years that doesnt use them for something. |
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Posted on: 2007/12/6 6:31
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| bogus | RE:Gas problem I think. | ||
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Grand Imperial Pooh-Bah
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news to me.
the 94/95 rear O2s were, as I understood them to be, were dummy's. |
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Posted on: 2007/12/6 6:41
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| CasetheCorvetteman | RE:Gas problem I think. | ||
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Elite Guru
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Negative mate, as i said, and have a think about it, why on earth would GM install 44,072 heated O2 sensors that are not used? They wouldnt. It would be the same as getting 44,072 perfectly good brand new heated O2 sensors and throwing them in the bin. No vehicle manufacturer is that stupid.
Ive got a 94, and i know for a fact the secondary O2 in the right bank is NOT a dummy. Whoever told you they are is the dummy, and wrong. It may have no influence on the engine managment, but that certainly doesnt mean it does nothing. |
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Posted on: 2007/12/7 7:39
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| bogus | RE:Gas problem I think. | ||
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Grand Imperial Pooh-Bah
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I am not disagreeing with you, I am just shocked!
I checked that Fuel Injection book by Charlie Probst, and duh, there it is! |
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Posted on: 2007/12/7 15:39
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| CasetheCorvetteman | RE:Gas problem I think. | ||
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Elite Guru
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Well there ya go, we're laughin our bloody heads off eh??
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Posted on: 2007/12/7 19:45
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| CFI-EFI | RE:Gas problem I think. | ||
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Senior Guru
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Quote:
Give me his phone number mate, i want to give him a call and ask him how much he knows about 84 Corvettes..... Quote: (excluding some export early 84s which ran on leaded fuel and had no O2 sensor, lead poisons the sensor) Quote: No Bogus, i think the sensor in the head feeds the dash mate, and the one in the other head turns on the fan. Im not certain on that, but im pretty sure. Quote: The one in the front of the manifold is indeed the one that feeds the ECM in order to control various managment functions of the engine. There is info in the FSM that will guide you to testing the ECT sensor. Just because it is a Crossfire with throttle bodies, it DOES indeed have injectors that CAN leak. Try starting the engine with the throttle wide open. That puts the ECM into the "clear flood mode", where it will shut off the fuel while cranking. If you have leaky injectors, flooding the engine, this can help. Also, keep a fuel pressure gauge handy. Possibly the fuel pump relay is bad which will eliminate the 2 second priming period and increase the cranking time while the oil pressure builds. RACE ON!!! |
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Posted on: 2007/12/8 2:20
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| CasetheCorvetteman | RE:Gas problem I think. | ||
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Elite Guru
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Quote: Thanks mate I wasnt too sure which was which of the left and right head sensors.Quote: Quote: No not the ones sold in the US, some of the models made for export (to where im not sure) were built with leaded fuel capability. No idea how many were made, how youd find out the info, or anything else like that, but im not refering to the US sold models, only exports. I read that in a black book years ago, but ive read it somewhere else too. |
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Posted on: 2007/12/8 6:55
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