89 Corvette ( The saga continues ) and thank god the saga is almost over

Nov 24, 2016
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#1
So as some of you know I bought an 89 corvette beginning of last spring. The car is in very decent condition but as with any vette thats been sitting in a garage for 10 years and basically undriven, things will arise that need attention. and they arose very quickly. the first was the stupid key cylinder got stuck in the run position as some of you have read about in my other thread. that was resolved. did it all by myself with a ton of swearing and heavy research on how to dismantle half a steering column.

the next issue was smoke pouring out from under the car. turned out it was just a rear transmition seal that had dried out from sitting around for so long. That was fixed as well so no more leaking going on. all is good.

now its onto the idle surge. the last issue left that effects the car running properly. The engine light is on and its reading the dreaded code 36. "mass airflow burnoff relay issue." so the tech that i had look at it last fall disconnected the mass airflow sensor and it fixed the issue just enough that it will drive without major things going on. but it can get scary sitting at a red light if the vette doesnt feel like being nice to me.

so anyways, its time to adress this issue and see if i can solve this myself by trouble shooting, snooping through the engine and getting feedback from you guys. its worked before. and it will work again.

i will also be posting videos in this thread so everyone can see the progress thats going on.

now, ive already done a bunch of research but i think the most logical place to start is by inspecting the burnoff relay connections and wires going to the MAF before i start buying new relays.

what say you all?
 

Black 03 Z06

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#2
Steve if there was an award for preserving it would be hanging on the wall in your garage.

Good luck getting this sorted out, you will eventually become our C4 go to guy.:thumbs:
 

ddgermann

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#3
Sounds like a logical place to start Steve.
Yes get that thing running smoothly so you can join Ziggy and I + interested others on a cruise.
 
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Steve Fontaine
Nov 24, 2016
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#4
So im noticing 2 things going on here with the MAF disconnected.

1- when the weather is cooler, the vette runs perfectly fine. no drop in battery voltage at all and no rough idle surge.
2- when the weather gets up to about 20+ degrees and sitting in the sun, the idle runs rough almost instantly and the battery voltage starts to drop insane fast at the same time.

the battery always looses voltage when the vette idles rough. and its always when its hot out. in the cooler mornings.... nothing. runs like a dream.

im trying to wrap my head around whats going on here. I know the MAF burnoff relay needs changing. and i also know the battery is probably near death. but the fact that the MAF is disconnected completely and this is happening has me sort of stumped.

i know hot summer weather is the culprit for killing batteries. the guy who i bought the vette from only charged it in spring and literally put on only 500km a year for 10 years he had it. The battery will also die if i do not drive it for a week. so i know that needs changing. ive read that a dying battery can also cause the idle to run rough as the battery is drawing more power from the altenator trying to charge itself and leaving no juice left for anything else. so im wondering if thats the first part of this issue.

lastly ive also noticed that the accelerator will hesitate if i take my foot off while driving and then tap it again. but only at random times.

thoughts?
 
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ddgermann

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#5
Maybe trade in.

I hear there might be a smoking good deal on a slightly used/bent blue ZR1 Indy pace car coming up very soon.

Kidding.

On your C4 does your battery not need to be on the maintainer when not started for a week? The C7s and 6s for sure need it to keep the battery up to charge due to the computers drawing constantly. If not plugged in the battery will die in a week.

Not sure about the charging and idle. If the car is running it should be charging period I would think.
 
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Steve Fontaine
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#6
dont know about keeping it charging but its the voltage dropping as soon as idle is rough that has me stumped
 

Keith Tedford

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#7
With our 2005 C6, instructions are to put the six speed in park and put on the emergency brake. I've never had a problem with a dead battery. The Delco battery was new in the spring of 2012, so its not like the battery is new by any means. I don't know if this applies to other years or not.
 

Jeremiad

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#8
It sounds like an electrical issue to me. I think your plan to replace the battery is a logical first step, but I would also suggest replacing your battery wires while you are at it, including the ground side. Battery cables definitely corrode over the years, and they take a lot of abuse on those occassional starts. A bad ground cable doesn't flow like it should and causes resistance (bad flow), and noticeable heat. When your car is running badly, try grasping each battery cable and see how hot they are, but be careful, a bad ground cable can get hot enough to hurt.
 
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Steve Fontaine
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#9
well we have a starting point. i had a van once that needed a boost almost everytime you tried to start it. turned out it was dirty connections.

i will also change out the battery since i know its overdue anyways.

videos may be a while since my editing computer just literally died on me an hour ago.
 

seppi

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#10
So as some of you know I bought an 89 corvette beginning of last spring. The car is in very decent condition but as with any vette thats been sitting in a garage for 10 years and basically undriven, things will arise that need attention. and they arose very quickly. the first was the stupid key cylinder got stuck in the run position as some of you have read about in my other thread. that was resolved. did it all by myself with a ton of swearing and heavy research on how to dismantle half a steering column.

the next issue was smoke pouring out from under the car. turned out it was just a rear transmition seal that had dried out from sitting around for so long. That was fixed as well so no more leaking going on. all is good.

now its onto the idle surge. the last issue left that effects the car running properly. The engine light is on and its reading the dreaded code 36. "mass airflow burnoff relay issue." so the tech that i had look at it last fall disconnected the mass airflow sensor and it fixed the issue just enough that it will drive without major things going on. but it can get scary sitting at a red light if the vette doesnt feel like being nice to me.

so anyways, its time to adress this issue and see if i can solve this myself by trouble shooting, snooping through the engine and getting feedback from you guys. its worked before. and it will work again.

i will also be posting videos in this thread so everyone can see the progress thats going on.

now, ive already done a bunch of research but i think the most logical place to start is by inspecting the burnoff relay connections and wires going to the MAF before i start buying new relays.

what say you all?
Most relays under the hood are the same. Swap one out and check.
 
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Steve Fontaine
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#11
wait how would that work if you remove the another relay. then that relay wont work
 
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Steve Fontaine
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#12
are there any good sources for parts in canada. i went to a few sites and one wants $800+ for a mass airflow sensor and one in the states has it for $189.... am i missing something? these things average $200 on ebay
 
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Steve Fontaine
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#13
a video i found that went deeper than i hope to go myself. it may help anyone who has this issue. still working on mine.

 

ddgermann

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#14
are there any good sources for parts in canada. i went to a few sites and one wants $800+ for a mass airflow sensor and one in the states has it for $189.... am i missing something? these things average $200 on ebay
I’m looking for the same thing. There are a few out east but some have very little in stock and you end up waiting for import anyway.
Let me know if you find a great place. I’ll do the same.
 

AceCole

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#15
mine wasn't throwing a code, but it behaved similar to yours-idle issues when hot out, and no issues when cold out. for me it was the ignition coil. The paste was cracked and the coil gets really hot on top of that distributor, caused it to draw extra voltage and not make a good spark = enough idle. for $60 at Canadian Tire, might be worth a shot. its usually the simple things... like the PCV hose in that video lol.

Good luck with the hunt!
 

Jeremiad

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#17
Have you replaced that battery and the cables yet?

Ignition stuff is the next direction I would be suggesting, like the coil as mentioned above, distributor cap, rotor, and wires.

But it is important to do one step at a time and see if there are differences. You can replace the entire ignition system, but if the battery ground cable is pooched, it won't make a lick of difference.
 
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Steve Fontaine
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#18
I have not had time to check a lot actually. i got a wicked cold on saturday and have been down since. 5 days later im just starting to come back to my senses. but i did run out in pouring rain to run the vette a few times to make sure it wasnt just a random drain on the battery. it started fine and ran at 14.3-6 volts. im starting to think on the deep end of things and want to search for any vacuum leaks before i start buying new sensors and relays. check the hind end of things as it were. if the wires and connections wernt good, it would never start and need a boost most of the time but thats not the case at all. so im voting out bad battery wires and connections. and yes ive visually inspected them so far. cant vouch for a shitty battery though. that will get tossed weather its good or bad just so i feel better LOL

but i did manage to get my editing computer running again so videos will come :)
 
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Steve Fontaine
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#19
Have you replaced that battery and the cables yet?

Ignition stuff is the next direction I would be suggesting, like the coil as mentioned above, distributor cap, rotor, and wires.

But it is important to do one step at a time and see if there are differences. You can replace the entire ignition system, but if the battery ground cable is pooched, it won't make a lick of difference.
sorry but i dont know where your going with this. AceCole didnt have a code 36 or any code at all because the vette does not have sensors to detect what he had. he was just pointing out what his symptoms were. Mine is a Mass Airflow burnoff relay issue. Period. not sure why the ignition system should be changed to fix an air sensor and burnoff relay.
 
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Steve Fontaine
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#20
Steve if there was an award for preserving it would be hanging on the wall in your garage.

Good luck getting this sorted out, you will eventually become our C4 go to guy.:thumbs:
LOL id rather not be the goto guy. I i know nothing about cars except that i used to chase girls in automotive class back in the 80s. Back when my car cost $42000 American. $108000 with inflation... yes it makes me feel good.... and old.
 

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