I have a 1989, that I have changed out the MAF and power & burnoff relay at the same time. Still get a code on the OEM1 that flashes #33 which according to chilton stands for (Manifold Absolute Pressure sensor-signal voltage out of range,high or Mass Air Flow sensor-signalvoltageout of range,probaly high)
As far as i'm told this car dosn't have a "MAP"
The car at some times runs great and then at the next stop light starts off bogging,then runs good.On and off. Any Ideas ?????

 

Not sure about a 89 but a 86 code 33 relates to the MAF. You will need a FSM or maybe someone can post the troublshooting diagram. This will take you through the step on finding what the problem is since you replaced the 3 sensor. My guess is a bad connection to the sensors, faulty wiring somewhere, or possible faulty new sensor(s).

 

For once, a factual, "I was told". Yes, your car does not have a MAP sensor. Now what it needs is a FSM, so you can follow the trouble shooting charts (that the Chilton's doesn't have) and track down and fix the cause of the problem, rather than to continue to throw parts and money at it. The Helm's manual isn't cheap, but I'll bet it isn't any more than you wasted on the MAF you didn't need.

RACE ON!!!

 

Strangely enough, the 1989 had both a MAP and MAF... odd...

I donno how long that lasted, tho.

 

Did you clear the code after you replaced the MAF and the relays? Disconnect the negative terminal on the battery and let it sit for five minutes, then reconnect it and start the car. If the SES light comes on, check the code again. It might be different.

Also, regardless, you want to clean and reset your IAC valve.

Now, who manufactured the replacement MAF? (I had problems with a GP Sorenson rebuilt unit).

 

Very good point. If you haven't disconnected the battery or taken the ECM fuse out this would be a good time to reset the codes. Could be that the code still exist after fixing the problem and just needs to have the memory cleared. I had just taken for granted that this had already been done.

 

At least in the 87 FSMs if you read the second paragraph on code 33 you'd find the lowly fuel pump relay also plays a factor here..and can be the cause of this and another code. The FSMs or Helms would also have you checking, cleaning ect. for connections on the MAF, ECM and all circuits involved.

 

Yes I cleared the codes by disconnect the battery started clean with code 12 then after a hour run and two engine lightss saying service now 33 popped up

 

just pulled EGR and cleaned it same issue still

 

As CFI and Rick stated the FSM (factory service manual) for your year vette would make it a snap to find and fix the problem. Perhaps someone with one will chim in. Going by my 86 or 95 FSM might not be what you need.

 

Really odd... ! In the same car? Have you got documentation for that? I show a 1989 with a VIN code "8" (L98 engine) using a MAF. The 1989 with VIN code "J" (LT5 engine) uses a MAP. But I don't see either engine using both. "Are you testing me?"

RACE ON!!!

 

no, there is something in the back of my head that tells me they have both. And yes, it is odd.

I will have to check my reference material... but I am at work, so I don't have it in front of me.

 

It is pretty irresponsible to make such an bold post like that with no greater conviction, than:
It's been a day. Can you back that up or are you hoping it will go away, as usual?

RACE ON!!!

 

Paging Mr. Information... Bogus Information.

Times a-wastin'. Can you back up your statement...or what?

RACE ON!!!

 

actually, I lost track of the thread.

I checked the book, "Corvette Fuel Injection and Electronic Ignition, 1982-2001."

I was incorrect.

What it was, tho, apparently, there is a feed in the ECM for some years that has both ID'd, but only use one or other... that's the best I can figure.

 

At least you were hoping to. Once again, you engaged the mouth (keyboard) before putting the brain into gear, and posted nonsense for the less informed to soak up and regurgitate, as fact, at will.

RACE ON!!!

 

but it would be cool to have a combined MAP/MAF engine which would utilize the MAF during initial acceleration, then switch to the rearward MAP sensor to avoid AFR turbo lag....

Yeah...long week....

 

It would be cool to have wings and to be able to fly, too. But Bogus Infomation posting it it, ain't gonna make it true.

RACE ON!!!

 

I put it with a caveat...

What you keep missing, dude, is that these things bring out discussion.

Discussion is good.

Remember that.

This place is not full of absolutes... it would be nice, but it just ain't the way it is.

I am sorry if I can't remember everything 100% perfectly, or, have my library with me at all times.

*** EDIT ***

I found where I made my mistake... it was a memory caused by incomplete information. I found where I saw the info - within the damnedable Haynes manual. It has a chart that shows the MAP and MAF within the engine compartment... where 1989 came from, I donno... cause the MAP started in 1991.

Next time, I shall read farther...

 

Caveat? What caveat?I admit, you usually DO try to leave yourself an out for your fictitious statements. Why post what you don't know, in the first place? There is no need to try to remember an "OUT" if you are confident in your knowledge.

Now that is the most ridiculous excuse for a totally false post I have ever seen. Why talk about (discuss) what never was? The MAP/MAF equipped C4 was never built. That is a discussion for the twilight zone, or Mother Goose, forum. Besides it wasn't brought as a topic of discussion. You presented it as fact, with no room for discussion, and for others to repeat.

Remember this. Your steadily, increasingly, wrong, incorrect, fairy tale, nonfactual, fictional, posts have the ability to taint the knowledge base of the of the young, the impressionable and those anxious to soak up bits of info, and don't have the power to separate your nonsense from the truth. Info, right or wrong is "parroted" and spread. Do you want this forum to gain a "full of baloney" reputation? "Wadda mean that's not the way it works. I read it on the Corvette Forum, and it was posted by a long time member.

Tech questions scream out for absolutes. This place will never be perfect, but it will have a hard time improving, if people with the conviction of, "no, there is something in the back of my head" keep posting hallucinations as fact. Use your "I will have to check my reference material... ", line AFTER you check your reference material.


Fine, if you can't remember or carry your library with you at all times. But if you aren't sure, don't lead the forum astray. You also don't HAVE to post.

Perfect! You are the victim of what you are guilty of doing lately. Taking false or not fully explained information and "parroting" it so others could do the same and perpetuate, hell, start, a whole new fresh falsehood.

It's time to take some responsibility for what you post.

RACE ON!!!