Need help to stop surging
Thread Starter
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Joined: Feb 2005
Posts: 61
Likes: 6
From: Gilbert Arizona
Need help to stop surging
Hey Guys I just recently aquired my 1984 Vette. It is a cross fire injection. Whenever I am in idle or even when I am cruising the engine surges. I have had it put on a scanner and it came back with the computer saying everything was normal. Do you guys have any idea of what may be causing it to surge like that?
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Surging is kind of common with a modded fi car. If your car is stock, I would check the common stuff. Fuel pressure, o2 sensor, vacuum leak map sensor, air cleaner etc could be the root of your problem. Rather than "poke and hope" I would start with tune up stuff and go from there.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
That sounds like a "lean surge". I had a similar, but milder, problem that turned out to be the the EGR valve. The return spring had weakened over the years and the valve was opening sooner and further than it should giving me a lean misfire. Not to be confused with the nickname for our cars. The best diagnosis is to have the car scoped, where they car read the A/F ratio.
RACE ON!!!
Instructor
Joined: Jan 2005
Posts: 141
Likes: 0
From: Tucson AZ
possibly caused by plugged cat converter. Mine was gunnybag and it surged at both highway speed and sometimes idle. The muffler shop guy pounded on it with a big rubber hammer and it just went 'clunk-chucka-' the whole interior had gone to pieces. If that's it, you could put in a free flow replacement and get a little gain while you're at it.
Thread Starter
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Joined: Feb 2005
Posts: 61
Likes: 6
From: Gilbert Arizona
Thanks a lot. I will give that stuff a shot and see what works. I have another question I was thinking about putting flowmasters 40's on my vette once I got it running better would that give me the deep throaty sound I want without to much resonance?
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Regular Flow 40's are pretty Loud. They have the 40 Force out which is supposed to be a quieter version of that. I just ordered the Delta Flo 50's supposedly the least amount of resonance. Try Brad or Dean at www.performancepeddler.com . These guys are great!
Drifting
Joined: Aug 2004
Posts: 1,400
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From: Oceansaide CA
I'm dealing with the same right now, only on a TPI L98
Replaced a ton of **** that had to be replaced anyway (cap, rotor, plugs, wires OHMed out OK, o2)
But it idles like crap when everything gets nice and hot and it goes into closed-loop. I guess my next step is to clean the MAF, and then if that doesn't work I'm suspecting injectors.
Replaced a ton of **** that had to be replaced anyway (cap, rotor, plugs, wires OHMed out OK, o2)
But it idles like crap when everything gets nice and hot and it goes into closed-loop. I guess my next step is to clean the MAF, and then if that doesn't work I'm suspecting injectors.
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Thread Starter
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Joined: Feb 2005
Posts: 61
Likes: 6
From: Gilbert Arizona
I got the surging fixed
Hey Guys thanks a lot I got the car to stop surging. It appears to be running great. I really just got lucky though I reset the tbs sensor and basically moved a bunch of wires around and some where in the process of checking the wires it started to run well. So I hope it stays fixed but thanks for the help.
