Starting problem.. 1989 C4
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Joined: Apr 2003
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From: fall river ma
Re: Starting problem.. 1989 C4 (TheCorvetteKid)
i'll let u know how i make out with that new sensor. thanks for the input. i was told by a gm guy that the sensors sometimes increase or decrease the oohm to the ecm changing the on off temp. this is a sign to replace. funny that we have the same temps though. i feel less beaten up by my 89!!!!!!!!!
:cheers:
I bought a low temp sensor on at 200 off at 185 i'm goona see if it does the trick! I'll keeo you posted. Just to be sure, this sensor is located on pas side of block?? :cheers:
Hey blackvette89, the temp sensor that controls when the fan comes on and off is the one on the intake manifold on the front of the engine (just below the throttle body). It feeds the information to the ECM; it's the ECM that turns the fan on and off. The sensors on the heads are used for other things. One is used for the gauge display on the dash, and the other is used to turn on the boost fan in front of the rad (I forget which of the sensors does what though).
It's funny that you mention this problem actually 'cause my car started doing the same thing. I still haven't tried to swap out my ECM to see if it cures my hard starting problem (I have a few other issues with the car that I am trying to address first) but after I took the heads off to change the headgaskets, I noticed that my fans have also beem coming on later than before. And at the same temps that you mention too. Funny thing is, I've checked my existing temp sensor and it seems fine. Hmmm...makes me wonder what this could be.
[Modified by TheCorvetteKid, 12:00 AM 6/15/2003]
Hey blackvette89, the temp sensor that controls when the fan comes on and off is the one on the intake manifold on the front of the engine (just below the throttle body). It feeds the information to the ECM; it's the ECM that turns the fan on and off. The sensors on the heads are used for other things. One is used for the gauge display on the dash, and the other is used to turn on the boost fan in front of the rad (I forget which of the sensors does what though).
It's funny that you mention this problem actually 'cause my car started doing the same thing. I still haven't tried to swap out my ECM to see if it cures my hard starting problem (I have a few other issues with the car that I am trying to address first) but after I took the heads off to change the headgaskets, I noticed that my fans have also beem coming on later than before. And at the same temps that you mention too. Funny thing is, I've checked my existing temp sensor and it seems fine. Hmmm...makes me wonder what this could be.
[Modified by TheCorvetteKid, 12:00 AM 6/15/2003]
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Joined: Oct 2002
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From: Smithfield VA
Re: Starting problem.. 1989 C4 (SkipI)
:mad :mad :mad :mad
Well, I have a new AC Delco ECM and oil pressure sender/switch assembly and still long start! :lol: I did, however fix three things that were bothering me... 1. My oil pressure is 6-8 psi higher with the new switch... I like 23 PSI at idle a lot more than 15 psi. 2. The car goes to idle speed better now. The engine warms up a little and drops to 600 rpm. Before, I'd have to drive the car somewhere and when it got warm, sit stopped for 10-15 seconds and the idle would drift down to 600. 3. I had to remove the wiper motor to get a socket on the oil pressure sender (wish I'd replaced that when I replaced the intake manifold gaskets!) and when I put the wiper motor back on, I adjusted the wipers so they don't hit the windshield frame anymore. Oh well... the search sorta continues... I am out of budget for a little while. Maybe a new coil? :lol: There is ALWAYS something to spend $$$$ on!! You know, they say that a boat is a hole in the water that you throw money into... and they are made out of fiberglass also?! :skep:
Well, I have a new AC Delco ECM and oil pressure sender/switch assembly and still long start! :lol: I did, however fix three things that were bothering me... 1. My oil pressure is 6-8 psi higher with the new switch... I like 23 PSI at idle a lot more than 15 psi. 2. The car goes to idle speed better now. The engine warms up a little and drops to 600 rpm. Before, I'd have to drive the car somewhere and when it got warm, sit stopped for 10-15 seconds and the idle would drift down to 600. 3. I had to remove the wiper motor to get a socket on the oil pressure sender (wish I'd replaced that when I replaced the intake manifold gaskets!) and when I put the wiper motor back on, I adjusted the wipers so they don't hit the windshield frame anymore. Oh well... the search sorta continues... I am out of budget for a little while. Maybe a new coil? :lol: There is ALWAYS something to spend $$$$ on!! You know, they say that a boat is a hole in the water that you throw money into... and they are made out of fiberglass also?! :skep:
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Joined: Apr 2002
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From: Delanson NY
Re: Starting problem.. 1989 C4 (Frodo)
Same exact problems here, with my 89 coupe. They only started after I removed and rebuilt the motor and replaced. Hard satrt-ups when cold and so-so when heated up, but only after the rebuild. Replaced everything under the sun from sensors to ignition, some twice. After all I replaced the ecm, car started great hot or cold for about 3 weeks, now back to ground zero with hard start-ups again, not to mention that she likes to try and stall from time to time when hard breaking around a bend. Not sure if I should just replace the ecm again, had a L.T. warranty or look for something else first. Good luck with yours and I'll keep trying here. Later!
FRED
FRED
Drifting
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From: The Motor City
Re: Starting problem.. 1989 C4 (ONEBAD89)
Skip, Someone here at work suggested a new coil too. In fact, when I first bought my car, it had an Accel HEI Super Coil and I don't remember it giving me a problem starting. But, I only had the coil on the car for like a day - I hated the way the thing looked and I bought a new Delco unit and replaced it myself (along with a new cap, rotor, plug wires, and plugs). In fact, the guy here at work said to put the Accel coil back on the car and see if that makes a difference. If so, then BINGO! new coil needed (I've heard that Delco HEI coils have a WIDE variation in their outputs - even when new).
But it'll have to wait until this weekend for me. I'm still waiting on my new pushrods so that I can put the engine back together (should be in tomorrow night).
But it'll have to wait until this weekend for me. I'm still waiting on my new pushrods so that I can put the engine back together (should be in tomorrow night).
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From: fall river ma
Re: Starting problem.. 1989 C4 (TheCorvetteKid)
HEY I WAS HOPING IT WAS YOUR ECM LIKE MINE. I DEFINETLY KNOW YOUR FRUSTRATIONS. ITS NOT EVEN THE MONEY ITS THE DIAGNOSIS AND GET IT OVER WITH. I'M GONNA TALK WITH A GM GUY I KNOW AND LET HIM READ YOUR POSTS.I'LL UPDATE YOU! I DID REMEMBER HIM TALKING ABOUT POSSIBLE COILS WHEN HE WAS BRAINSTORMING MY PROBLEM. DIDYOU REPLACE THE AIC? :confused:
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Joined: Apr 2003
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From: fall river ma
Re: Starting problem.. 1989 C4 (TheCorvetteKid)
HEY CORVETTE KID, I HAD TO REORDER THAT LOW TEMP SWITH. IT WAS OUT OF STOCK. WHEN I GET IT I WAS TOLD I HAVE TO REWIRE BECAUSE I DON'T HAVE AN AUXILLARY FAN. CAN YOU GIVE ME A HEADS UP TO THE PROJECT. THANKS TOM :confused:
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From: Smithfield VA
Re: Starting problem.. 1989 C4 (blackvette89)
HEY I WAS HOPING IT WAS YOUR ECM LIKE MINE. I DEFINETLY KNOW YOUR FRUSTRATIONS. ITS NOT EVEN THE MONEY ITS THE DIAGNOSIS AND GET IT OVER WITH. I'M GONNA TALK WITH A GM GUY I KNOW AND LET HIM READ YOUR POSTS.I'LL UPDATE YOU! I DID REMEMBER HIM TALKING ABOUT POSSIBLE COILS WHEN HE WAS BRAINSTORMING MY PROBLEM. DIDYOU REPLACE THE AIC? :confused:
Skip
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Joined: Oct 2002
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From: Smithfield VA
Re: Starting problem.. 1989 C4 (SkipI)
HEY I WAS HOPING IT WAS YOUR ECM LIKE MINE. I DEFINETLY KNOW YOUR FRUSTRATIONS. ITS NOT EVEN THE MONEY ITS THE DIAGNOSIS AND GET IT OVER WITH. I'M GONNA TALK WITH A GM GUY I KNOW AND LET HIM READ YOUR POSTS.I'LL UPDATE YOU! I DID REMEMBER HIM TALKING ABOUT POSSIBLE COILS WHEN HE WAS BRAINSTORMING MY PROBLEM. DIDYOU REPLACE THE AIC? :confused:
Skip
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Drifting
Joined: May 2002
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From: The Motor City
Re: Starting problem.. 1989 C4 (blackvette89)
HEY CORVETTE KID, I HAD TO REORDER THAT LOW TEMP SWITH. IT WAS OUT OF STOCK. WHEN I GET IT I WAS TOLD I HAVE TO REWIRE BECAUSE I DON'T HAVE AN AUXILLARY FAN. CAN YOU GIVE ME A HEADS UP TO THE PROJECT. THANKS TOM :confused:
BTW, where did you get the low-temp sensor anyway (Ecklers, MidAmerica, etc...)? They usually have pretty good instructions that come with their kits. But either way, let me know I'll help wherever I can.
Pro
Joined: Apr 2001
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From: Rochester, NY
Re: Starting problem.. 1989 C4 (SkipI)
Have had a extended crank time on my 1989 for over one year (although this only occurs when the car has been sitting for over 6 hours - if warm it starts fine). Are any of you folks getting a code 54 ?? From all of the reading I've been doing it comes down to many items; injectors, ECM, fuel pump, fuel pump relay, fuel pump fuse, bad ground. Someone just call Gordon and pass on the informatin to us LOL
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From: Delanson NY
Re: Starting problem.. 1989 C4 (TheCorvetteKid)
I have a fairly new accel hei super coil, but after speaking with some other engine/motor friends they informed me that the accel line was all junk and to go with msd. So now I am ordering a complete kit, cap rotor, coil and msd wires, I believe it also includes a new HEI module. Supposed to provide a potent spark signal to 9000 rpms. Going to add that along with the MSD 6AL to complement the spark. Give that a try to see if it works........
Pro
Joined: Apr 2001
Posts: 539
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From: Rochester, NY
Re: Starting problem.. 1989 C4 (SkipI)
Have had a extended crank time on my 1989 for over one year (although this only occurs when the car has been sitting for over 6 hours - if warm it starts fine). Are any of you folks getting a code 54 ?? From all of the reading I've been doing it comes down to many items; injectors, ECM, fuel pump, fuel pump relay, fuel pump fuse, bad ground. Someone just call Gordon and pass on the information to us LOL
Drifting
Joined: May 2002
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From: The Motor City
Re: Starting problem.. 1989 C4 (SkipI)
New coil didn't fix it either. You know, if you built a corvette from parts, it would cost ____. I'll fill in the number later!! :lol:
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Joined: Apr 2002
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From: Delanson NY
Re: Starting problem.. 1989 C4 (TheCorvetteKid)
Although, as I mentioned earlier in another similar post, I replaced my ecm with a new one and the car started, idles and ran perfect for about 2 weeks, then back to same old hard start-ups, especially when cold and rough idle, tries to stall when breaking hard or at idle.
P.S. My 89 vette is also black.
[Modified by ONEBAD89, 4:23 AM 6/19/2003]
P.S. My 89 vette is also black.
[Modified by ONEBAD89, 4:23 AM 6/19/2003]
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From: Reno NV
Re: Starting problem.. 1989 C4 (ONEBAD89)
Hey can I join this Black 89 club?
Anyway, here’s one from the left field! 1989’s, and I would guess the 88’s, have a temp sensor mounted under the drivers side dash area. It’s sole purpose is to aid the ECM when starting at, or near below freezing temps. Now, as we already know from experience, when a sensor goes bad it can freak out, or even damage the ECM.
So, here’s my wild guess: Possibly this sensor has degraded over the last 14-15 years, and is causing the ECM problems?
This sensor is probably cheap, and it would be an interesting experiment for all of the others out there with this problem! Who knows maybe I’m just:crazy:!
:crazy:NanoBrain:crazy:
Anyway, here’s one from the left field! 1989’s, and I would guess the 88’s, have a temp sensor mounted under the drivers side dash area. It’s sole purpose is to aid the ECM when starting at, or near below freezing temps. Now, as we already know from experience, when a sensor goes bad it can freak out, or even damage the ECM.
So, here’s my wild guess: Possibly this sensor has degraded over the last 14-15 years, and is causing the ECM problems?
This sensor is probably cheap, and it would be an interesting experiment for all of the others out there with this problem! Who knows maybe I’m just:crazy:!
:crazy:NanoBrain:crazy:
Drifting
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From: The Motor City
Re: Starting problem.. 1989 C4 (NanoBrain)
Wait a sec! There's a temp sensor under the driver's side dash? Why is this the first I'm hearing of this?
Nano, you may have a good point! Anybody try this one? I'll check my Service manual when I get home tonight. If it's not that difficult a job, then it may be worth a try.
Nano, you may have a good point! Anybody try this one? I'll check my Service manual when I get home tonight. If it's not that difficult a job, then it may be worth a try.
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Re: Starting problem.. 1989 C4 (TheCorvetteKid)
Wait a sec! There's a temp sensor under the driver's side dash? Why is this the first I'm hearing of this?
He may be talking about the Ambient Over-ride Sensor, but that's for the Digital Dash, not the ECM.
Pro
Joined: Jun 2003
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From: OKC OK
Re: Starting problem.. 1989 C4 (blackvette89)
Nah...you boys got it all wrong...
The problem is quite obvious after reading all of the posts...what's the constant in all of these cars?
They're all BLACK!
Sure, there are other colors besides RED, ... But who cares? :reddevil
Just messin' with ya fellas. I'm on vacation and have waaaaaay too much time on my hands! Think I'll go for a drive! Good luck! :cool:
The problem is quite obvious after reading all of the posts...what's the constant in all of these cars?
They're all BLACK!
Sure, there are other colors besides RED, ... But who cares? :reddevil
Just messin' with ya fellas. I'm on vacation and have waaaaaay too much time on my hands! Think I'll go for a drive! Good luck! :cool: