85 corvette rev limit
07-26-2014, 05:52 AM
#21
Le Mans Master
In my experience regulator's Dump fuel in the plenum and leak and pumps just go bad and don't work like turning off a light switch {but sometimes the damn sock collapses on the pump in the tank and wont do it all the time, it's a real pain to find that one} and Injectors leak down and stop working
Its up to u to figure if thats even whats going on and or which one.
Pulling the vacuum line on the reg should get ya 40psi and it will run rich and may make ur motor pull harder, if you don't mind cleaning plugs under anything but maybe full throttle.
I'd say u need to run a full can or 2 of Injector clean hooked up on the rails with the pump line pinched or shut off and put ur wires off of any head or manifolds or maybe move them around in the dark along with some fresh plugs and filters if u haven't done so lately
Also the firing order always needs to be straightened out on all 1975 to 1991 V-8's It's 1-8-4-3-5-6-7-2 Cly #'s 4,& 3 and really 5 & 6 need to never cross or touch from the dist to the spark plugs
It will/can cause a mid to upper rpm breakup,miss fire not really when the wires r new but when they get a little older and kinda dry out
So thats what I would be doing or have done
Its up to u to figure if thats even whats going on and or which one.
Pulling the vacuum line on the reg should get ya 40psi and it will run rich and may make ur motor pull harder, if you don't mind cleaning plugs under anything but maybe full throttle.
I'd say u need to run a full can or 2 of Injector clean hooked up on the rails with the pump line pinched or shut off and put ur wires off of any head or manifolds or maybe move them around in the dark along with some fresh plugs and filters if u haven't done so lately
Also the firing order always needs to be straightened out on all 1975 to 1991 V-8's It's 1-8-4-3-5-6-7-2 Cly #'s 4,& 3 and really 5 & 6 need to never cross or touch from the dist to the spark plugs
It will/can cause a mid to upper rpm breakup,miss fire not really when the wires r new but when they get a little older and kinda dry out
So thats what I would be doing or have done
07-27-2014, 09:02 AM
#23
Melting Slicks
if you've got signs of lean , then its probably your knock sensor cutting in,
the knock sensor WILL make the engine nose over just like a rev limiter !
the knock sensor WILL make the engine nose over just like a rev limiter !
07-27-2014, 04:36 PM
#25
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Is there a resistance or voltage test for the knock sensor to test it? Or is this just a replace it and see if it takes care of the problem?
07-27-2014, 05:52 PM
#26
Burning Brakes
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No never a replace it and see what happens. Thats Hack work. I don't have the codes off the top of my head. I'm sure someones will chime in. But if it's a knocking and the knock senors cuts or hears it I think u can go in the ECU and it might have a memory/code but not sure if it stores for an activation or just a fault of the thing
07-27-2014, 05:56 PM
#27
Burning Brakes
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But u can try this. Maybe a little bit of hack work but worth a try Back off the timing a bit and run ur gas real low and try a few gals of Premo and go for a blast. See if its still breaking up. Worth a try. Not hard to do
07-28-2014, 04:29 AM
#28
Melting Slicks
Where is the rev limiter on my 85 corvette?
I pulled out of a buddies house yesterday and got into it about half throttle, came out sideways and right around 5,000 ish it started cutting out during the spin. Like a rev limiter. So my question is, what is the actual rev limiter on it? It is all stock except a high output coil and opened air filter lid.
I just want to know if there is a miss or I'm hitting the limiter. I've searched but can't really come up with an actual answer.
I pulled out of a buddies house yesterday and got into it about half throttle, came out sideways and right around 5,000 ish it started cutting out during the spin. Like a rev limiter. So my question is, what is the actual rev limiter on it? It is all stock except a high output coil and opened air filter lid.
I just want to know if there is a miss or I'm hitting the limiter. I've searched but can't really come up with an actual answer.
a lot of the advice from the other guys is right, its a combination of things, the L98 is not designed to go above 5000 rpm in stock form, if the injectors and pump are original then it WILL lean out at 5000 and the knock sensor will cut in.
Last edited by blackozvet; 07-28-2014 at 04:35 AM.
07-28-2014, 09:25 AM
#29
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are the injectors and fuel pump original ?
a lot of the advice from the other guys is right, its a combination of things, the L98 is not designed to go above 5000 rpm in stock form, if the injectors and pump are original then it WILL lean out at 5000 and the knock sensor will cut in.
a lot of the advice from the other guys is right, its a combination of things, the L98 is not designed to go above 5000 rpm in stock form, if the injectors and pump are original then it WILL lean out at 5000 and the knock sensor will cut in.
The injectors are original, the pump was replaced a few years ago, not sure on the exact time it was replaced.
Need to get a fuel pressure gauge and check the pressure. Just waiting until I get some free time. Hopefully this week I'll be able to.
07-30-2014, 07:51 PM
#30
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Just did a fuel pressure test. Didn't have tike to go buy a proper set up so I rigged an oil pressure guage i had laying around into it. I was getting at idle about 28-30 psi and wen I have it about quarter throttle it stayed the same. Then my line started spewing gas, so that's when I stopped. I then started just lookig around at vacuum lines and I found a little plastic block that had vacuum lines going into it on the passenger side of the distributor. Right next to the distributor actually. And on the back of it it has a little hole that I can feel it sucking through the hole a bit. Is there supposed to be a hose connected to this fitting on the back? I did not see and hoses that looked like they were disconnected. Took some pictures of it:
The first is of it, you can see a but of the distributor in the background.
And the second picture is of the port I am speaking of. The one in the middle of it. I can feel some suction from it. Is there supposed to be a vacuum line here? Or is this supposed to not have any vacuum at all and shouldn't be sucking?
The first is of it, you can see a but of the distributor in the background.
And the second picture is of the port I am speaking of. The one in the middle of it. I can feel some suction from it. Is there supposed to be a vacuum line here? Or is this supposed to not have any vacuum at all and shouldn't be sucking?