Anybody's LT1 do this?
Thread Starter
Pro
Joined: Oct 2009
Posts: 679
Likes: 0
From: vero beach florida
Anybody's LT1 do this?
Car starts off getting 27-29mpg highway and after driving an hour or so it is getting 24-25 and running a little rough and I notice this everytime.
Then after cooling down, the idle is smooth and the car gets 27-29 mpg.
Car is a 92 and over the course of the 50k miles I have replaced just about everything.
Then after cooling down, the idle is smooth and the car gets 27-29 mpg.
Car is a 92 and over the course of the 50k miles I have replaced just about everything.
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
Cruise-In IV Veteran
St. Jude Donor '12
What kind of temps are you seeing on the digital gage?
Before I replaced my ICM and coil for the second time I had a similar issue at the race track. The third time I replaced them I put a few washers between the head and the ICM/coil mounting plate. That was a year ago and a few hundred track miles ago and I'm starting to get the same issue again. Time for another ICM and coil - wish I could find OEM parts instead of these crap knock offs.
Before I replaced my ICM and coil for the second time I had a similar issue at the race track. The third time I replaced them I put a few washers between the head and the ICM/coil mounting plate. That was a year ago and a few hundred track miles ago and I'm starting to get the same issue again. Time for another ICM and coil - wish I could find OEM parts instead of these crap knock offs.
Thread Starter
Pro
Joined: Oct 2009
Posts: 679
Likes: 0
From: vero beach florida
What kind of temps are you seeing on the digital gage?
Before I replaced my ICM and coil for the second time I had a similar issue at the race track. The third time I replaced them I put a few washers between the head and the ICM/coil mounting plate. That was a year ago and a few hundred track miles ago and I'm starting to get the same issue again. Time for another ICM and coil - wish I could find OEM parts instead of these crap knock offs.
Before I replaced my ICM and coil for the second time I had a similar issue at the race track. The third time I replaced them I put a few washers between the head and the ICM/coil mounting plate. That was a year ago and a few hundred track miles ago and I'm starting to get the same issue again. Time for another ICM and coil - wish I could find OEM parts instead of these crap knock offs.
Car has done this since I first got it and it drives me NUTS!!!
O2's work fine, car does seem to run rich, but this problem started before that.
Melting Slicks
Joined: Mar 2004
Posts: 2,141
Likes: 2
From: Pittsburgh Pa
Trust me, I am on my 2nd OEM coil and ICM and they do not last, I think it is the heat and position of these parts or maybe the wires are shorted?
Car has done this since I first got it and it drives me NUTS!!!
O2's work fine, car does seem to run rich, but this problem started before that.
Car has done this since I first got it and it drives me NUTS!!!
O2's work fine, car does seem to run rich, but this problem started before that.
Navigator
Joined: Oct 2009
Posts: 9
Likes: 0
92 corvette
I have the same thing .do not know what is it
right now it run like crap don't event pick up speed .
I have the icm to is it a black box(opticq) by the cam shap next to power stering oil tank .where the dist.?is it the one think under or behigh water pump?can you give me some input Thanks
If it miss fire what need to change ICM Coil oroptic ?
I can not fine any optic like that ?plase help...
right now it run like crap don't event pick up speed .
I have the icm to is it a black box(opticq) by the cam shap next to power stering oil tank .where the dist.?is it the one think under or behigh water pump?can you give me some input Thanks
If it miss fire what need to change ICM Coil oroptic ?
I can not fine any optic like that ?plase help...
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Le Mans Master
Joined: Aug 2004
Posts: 5,141
Likes: 7
From: Metairie Louisiana
http://www.ttspowersystems.com/DataM...downloads.html
http://www.moates.net/product_info.p...roducts_id=127
You'll also need to pick up a cheap laptop if you dont already have one. You can get one new for $350-400 or check ebay for a really inexpensive used one.
Last edited by rickneworleansla; Nov 4, 2009 at 09:31 AM.
Drifting
Joined: Nov 2005
Posts: 1,324
Likes: 5
From: Charlotte NC
I use this cable:
http://www.aldlcable.com/sc/details.asp?item=aldlobd1
It works perfectly with the Datamaster package. You'll just have to pull some screws from another serial cable to use on it as it did not come with them.
http://www.aldlcable.com/sc/details.asp?item=aldlobd1
It works perfectly with the Datamaster package. You'll just have to pull some screws from another serial cable to use on it as it did not come with them.
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
http://www.ttspowersystems.com/DataM...downloads.html
http://www.moates.net/product_info.p...roducts_id=127
You'll also need to pick up a cheap laptop if you dont already have one. You can get one new for $350-400 or check ebay for a really inexpensive used one.
I just bought my ALDL cable (Moates) and started using DataMaster. It is sooooooooooooooooooo much nicer to use and analyze then trying to watch a handheld while driving.
Money well spent!
-Corvette145 - My 92 gets 24-26 MPG as well so you might want to start looking into yours!
Thread Starter
Pro
Joined: Oct 2009
Posts: 679
Likes: 0
From: vero beach florida
I am talking hwy mileage, atleast that is what I think your asking.
Ohm the FI's, if under 13 replace.
Check vacuum lines for leaks.
Check and replace all fouled plugs.
At night w/car running look for arcing SP wires, replace all if there is arcing.
Coils and ICM's are known problems on early LT1's, if over 50k miles on them then replace.
replace o2's.
Ohm the FI's, if under 13 replace.
Check vacuum lines for leaks.
Check and replace all fouled plugs.
At night w/car running look for arcing SP wires, replace all if there is arcing.
Coils and ICM's are known problems on early LT1's, if over 50k miles on them then replace.
replace o2's.
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
Cruise-In IV Veteran
St. Jude Donor '12
Mine is getting 14 - 15 on a short commute, should be 17 - 19
Long trips are around 20, should be closer to 30
My issue is a bad adjustment on one of the valves when reinstalling the head.
My "fix" this winter is to have a spare set of heads cleaned, new springs, then install them along with long tube headers and new O2 sensors. This time I'll adjust the valves myself correctly.
I hope the ICM and coil make it till then. Anyone know of an ICM that will last more than a year?
Long trips are around 20, should be closer to 30
My issue is a bad adjustment on one of the valves when reinstalling the head.
My "fix" this winter is to have a spare set of heads cleaned, new springs, then install them along with long tube headers and new O2 sensors. This time I'll adjust the valves myself correctly.
I hope the ICM and coil make it till then. Anyone know of an ICM that will last more than a year?
