Engine doing some wierd stuff sometimes.. What could it be??
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Burning Brakes
Joined: Nov 2003
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From: Beverly, NJ
Engine doing some wierd stuff sometimes.. What could it be??
Sometimes when I get on it, like WOT it, then lets say I totally let off the gas, it is almost like for a second that the engine wants to stall, then it returns to idle speed. What does this sound like? I am already under the impression that the wrong engine might have been installed, and my tune is obviously off too, becuase of the possibility of wrong engine. BTW-does 86 block have 2 bolt main or 4 bolt main? What about an 87 block? Thanks!
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Tell us more about your setup. For example a different short block with the same heads / cam / intake on top of it might run very well with the same tune. When you say "wrong engine" what do you mean by that?
As far as I know all the TPI cars were two bolt mains.
If you have put a different engine in the car and it has anything other than the exact same heads / cam specs as the stocker you really do need to program the computer to reflect the changes. Tuning for wide open throttle is the easy part, it's the driveability that takes a while. It's not so much hard, just time consuming.
As far as I know all the TPI cars were two bolt mains.
If you have put a different engine in the car and it has anything other than the exact same heads / cam specs as the stocker you really do need to program the computer to reflect the changes. Tuning for wide open throttle is the easy part, it's the driveability that takes a while. It's not so much hard, just time consuming.
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I had similar symptoms, along with a little rough idle at times.
In my case it wasn't allways that it felt like it wanted to stall, in a couple on instances it did stall
My problem turned out to be IAC
Do you have a scan tool?
In my case it wasn't allways that it felt like it wanted to stall, in a couple on instances it did stall
My problem turned out to be IAC
Do you have a scan tool?
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 935
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From: Beverly, NJ
Originally Posted by Nathan Plemons
Tell us more about your setup. For example a different short block with the same heads / cam / intake on top of it might run very well with the same tune. When you say "wrong engine" what do you mean by that?
As far as I know all the TPI cars were two bolt mains.
If you have put a different engine in the car and it has anything other than the exact same heads / cam specs as the stocker you really do need to program the computer to reflect the changes. Tuning for wide open throttle is the easy part, it's the driveability that takes a while. It's not so much hard, just time consuming.
As far as I know all the TPI cars were two bolt mains.
If you have put a different engine in the car and it has anything other than the exact same heads / cam specs as the stocker you really do need to program the computer to reflect the changes. Tuning for wide open throttle is the easy part, it's the driveability that takes a while. It's not so much hard, just time consuming.
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 935
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From: Beverly, NJ
Originally Posted by jackdaroofer
I had similar symptoms, along with a little rough idle at times.
In my case it wasn't allways that it felt like it wanted to stall, in a couple on instances it did stall
My problem turned out to be IAC
Do you have a scan tool?
In my case it wasn't allways that it felt like it wanted to stall, in a couple on instances it did stall
My problem turned out to be IAC
Do you have a scan tool?
Mine never ever stalled on me, but it just sometimes feels like the engine wants to kick off, then it doesn't. Kinda like removing the power for a slit second, if that makes any sense. I changed the IAC with a new one back in April. I think it came preadjusted out of box, but I did not adjust anything on the IAC itself. I have heard about adjusting the pintle, but I can't understand how.
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From: The Top of Utah
Originally Posted by darkman5001
On the tag it says 86 vette 4bolt main roller block. I assume that it is a roller cam block, which was not used in 86 yet. Also, I hear that the L98 engines for vette then came with 2 bolt main. The only problem with this is the cam configuration is not made for my stock iron corvette heads.
Originally Posted by darkman5001
I changed the IAC with a new one back in April. I think it came preadjusted out of box, but I did not adjust anything on the IAC itself. I have heard about adjusting the pintle, but I can't understand how.
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Thread Starter
Burning Brakes
Joined: Nov 2003
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From: Beverly, NJ
Originally Posted by CFI-EFI
Apparently the remanufacturer isn't aware that L98s were never made with 4 bolt blocks. That is your gain. Some late flat tappet cammed engines came with roller blocks. Again, no foul. Your heads will never know or care if they are bolted to a "roller block". And if it has a roller cam? So much the better.
There is no adjustment for the IAC. Retracting the pintle is for installing it without doing damage to the pintle, pintle seat, or the IAC motor its self. Once installed and cycled, there is no "adjustment". I believe the reference to the idle has to do with the IAC AND the IAC passages, being clean.
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There is no adjustment for the IAC. Retracting the pintle is for installing it without doing damage to the pintle, pintle seat, or the IAC motor its self. Once installed and cycled, there is no "adjustment". I believe the reference to the idle has to do with the IAC AND the IAC passages, being clean.
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When I installed the new IAC, all I did was rip the plastic bag open that it was packed in, and removed the rubber cap covering the pintle. Then I installed it into the new throttle body done by David Koldos. I did not retract it or anything, just assume it was alright. Did I miss a step? How do I retract the pintle? If I did not do it right, then I will pull it back out tomorrow and fix. Thanks!
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From: The Top of Utah
Originally Posted by darkman5001
I did not retract it or anything, just assume it was alright. Did I miss a step? How do I retract the pintle?
Thanks!
Thanks!
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Originally Posted by darkman5001
Mine never ever stalled on me, but it just sometimes feels like the engine wants to kick off, then it doesn't. Kinda like removing the power for a slit second, if that makes any sense. I changed the IAC with a new one back in April. I think it came preadjusted out of box, but I did not adjust anything on the IAC itself. I have heard about adjusting the pintle, but I can't understand how.
There is a "adjustment" of sorts. In the Helms and maybe other manuals there is a dimension from the tip of the pintle to the collar on the motor housing. It escapes me for the moment, but it is in the books. "adjusting the pintle" is in their also. Sorry my books are a block away in my shop.
IMHO!!! When you come off the gas, the Throttle body closes rapidly. If the MAF senses no air flow, for like two seconds, it shuts down the fuel pump. If you are rolling and you step on the throttle, it senses air flow and restarts the fuel pump...at least that's how it seemed to work on my car. Mine actually stalled out three times, at all times doing 90 degree left turns (not sure what that means)
I replaced the relays on the MAF, the IAC and thoroughly cleaned the TB and it runs better than ever
Jack
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From: The Top of Utah
Originally Posted by jackdaroofer
There is a "adjustment" of sorts. In the Helms and maybe other manuals there is a dimension from the tip of the pintle to the collar on the motor housing. It escapes me for the moment, but it is in the books. "adjusting the pintle" is in their also.
Jack
Jack
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