1981 EGR removal
09-19-2001, 08:50 AM
#1
Safety Car
Thread Starter
1981 EGR removal
My car has had the EGR removed but all pipes & solenoids are still in place. Due to a thermostat housing bolt snapping off :mad the TVS for the EGR (RHS of stat housing) is now in lots of little pieces :rolleyes: The top vacuum pipe from this TVS is blanked off (should go to the EGR valve?) & the lower pipe goes to the EGR solenoid which is also connected to a vacuum source at the front of the carb. So, the solenoid, under ECM control, adjusts the amount of vacuum going to the EGR valve, via the TVS which only passes the vacuum once the coolant has reached a certain temperature? But there is an EGR bleed solenoid also connected to the vacuum pipe from the front of the carb (via a "T" piece), the other pipe on it goes to the back of the carb. Does this regulate the amount of vacuum supplied to the EGR solenoid? :confused:
The main question here is: do I really need the 2 solenoids in place to keep the ECU happy, or can I just bin the whole lot & blank off the 2 vacuum sources on the carb? Has anybody done this & if so, is the operation of the ECU OK ie TCC lockup, spark advance & m/c unaffected?
Thanks
Paul
The main question here is: do I really need the 2 solenoids in place to keep the ECU happy, or can I just bin the whole lot & blank off the 2 vacuum sources on the carb? Has anybody done this & if so, is the operation of the ECU OK ie TCC lockup, spark advance & m/c unaffected?
Thanks
Paul
09-20-2001, 09:40 AM
#3
Melting Slicks
Re: 1981 EGR removal (UKPaul)
Ah, remembering an '86 Camaro I had.... Computer cars.
I'll bet you will get EGR codes if you remove any of the EGR pieces, even if you plug off the vacuum lines. Will it cause the computer to "degrade" the engine based on the error it sees? I don't know. My Camaro used to get EGR codes (service engine light comes on and a code was stored) the dealer replaced the ECM, EGR, solenoids, vacuum lines, etc. all under warrenty to no avail..... but I didn't notice any engine problems. They had given up trying to find the problem! I sold the car a couple of years ago, and it was still doing it.
I'll bet you will get EGR codes if you remove any of the EGR pieces, even if you plug off the vacuum lines. Will it cause the computer to "degrade" the engine based on the error it sees? I don't know. My Camaro used to get EGR codes (service engine light comes on and a code was stored) the dealer replaced the ECM, EGR, solenoids, vacuum lines, etc. all under warrenty to no avail..... but I didn't notice any engine problems. They had given up trying to find the problem! I sold the car a couple of years ago, and it was still doing it.
09-20-2001, 11:52 AM
#4
Drifting
Re: 1981 EGR removal (UKPaul)
UKPaul,
How are things in the UK? My wife and I were over in early August.
I have an 80 which is similar except for the ECM controller.
If you do not require emissions testing I would do the following:
Obtain a now ECM controlled carb (spreadbore design to match intake). I would recommend a 1979 or 80 rochester because everything will hook up and you can use the stock aircleaner. You will also need to obtain a 1975 to 1980 distributor with vacuum advance (non ECM type). This will cover the engine.
For the trans, I removed my lockup solenoid from the bottom of the trans because it would lockup at the 2nd to 3rd shift point which is not correct.
The EGR does help reduce pinging (detonation), but since it is removed it seems to be having no notice able effect on performance. I say remove the solenoids or disconnect them to see the effect and if none, then take them off.
How are things in the UK? My wife and I were over in early August.
I have an 80 which is similar except for the ECM controller.
If you do not require emissions testing I would do the following:
Obtain a now ECM controlled carb (spreadbore design to match intake). I would recommend a 1979 or 80 rochester because everything will hook up and you can use the stock aircleaner. You will also need to obtain a 1975 to 1980 distributor with vacuum advance (non ECM type). This will cover the engine.
For the trans, I removed my lockup solenoid from the bottom of the trans because it would lockup at the 2nd to 3rd shift point which is not correct.
The EGR does help reduce pinging (detonation), but since it is removed it seems to be having no notice able effect on performance. I say remove the solenoids or disconnect them to see the effect and if none, then take them off.
09-21-2001, 12:36 PM
#5
Safety Car
Thread Starter
Re: 1981 EGR removal (DaveL82)
Thanks for the replies.
KenSny
The EGR valve had been removed when I bought the car & the computer SEEMS to be OK about it. The vacuum pipe that (I hope) went to the EGR valve had been blanked off with a bolt, so last night I removed the pipe from the solenoid to the TVS on the assumption that the TVS wasn't doing anything for the system (& the fact that I have completely wrecked it had a bearing on it! :rolleyes: ). Once I get everything working properly again (just the TCC lockup to go) then I'll unplug the solenoids & see what happens.
Dave
Our has summer ended (overnight) & we've had quite a bit of rain. It's now dark by 7.30 (was 10.00pm at the end of June) & tops off evening cruising is coming to an end :(
I remember that we didn't have very good weather in early August (although the last 2 weeks were good). Hope you enjoyed your stay here.
I had thought about junking the ECM, etc but it would mean buying another carb & distributer as you point out. I figured that if I can get it running nicely with a computer hooked up then I should, theoretically, get good economy & power, as the ECU should adjust for an almost perfect mixture (and I wouldn't have the hassle of re-jetting when I change cam/exhausts/manifold/etc). I hope!
The main reason that I'm asking about the EGR solenoids is that my lockup has stopped working which has resulted in my fuel consumption increasing. I found a bad relay in the system, which I've fixed, but there is still something wrong. Looking at the wiring diagrams it is possible that the ECU could be using the condition of the EGR system as part of the decision process in operating the TCC lockup ie. no lockup possible until current flows through the solenoids (but I'm probably clutching at straws here). Some of the emission control systems may be interdependant on others & I was hoping somebody may have done all this themselves. It seems suspicious that some things, eg AIR, have been completely removed, but the EGR has only had the valve removed & everything else related is still in place.
If pinging ever becomes a problem then I'll start filling up with Super Unleaded (97 octane - normal unleaded is 95).
How does the '80 lockup work? Is it done on pressure?
Regards
Paul
KenSny
The EGR valve had been removed when I bought the car & the computer SEEMS to be OK about it. The vacuum pipe that (I hope) went to the EGR valve had been blanked off with a bolt, so last night I removed the pipe from the solenoid to the TVS on the assumption that the TVS wasn't doing anything for the system (& the fact that I have completely wrecked it had a bearing on it! :rolleyes: ). Once I get everything working properly again (just the TCC lockup to go) then I'll unplug the solenoids & see what happens.
Dave
Our has summer ended (overnight) & we've had quite a bit of rain. It's now dark by 7.30 (was 10.00pm at the end of June) & tops off evening cruising is coming to an end :(
I remember that we didn't have very good weather in early August (although the last 2 weeks were good). Hope you enjoyed your stay here.
I had thought about junking the ECM, etc but it would mean buying another carb & distributer as you point out. I figured that if I can get it running nicely with a computer hooked up then I should, theoretically, get good economy & power, as the ECU should adjust for an almost perfect mixture (and I wouldn't have the hassle of re-jetting when I change cam/exhausts/manifold/etc). I hope!
The main reason that I'm asking about the EGR solenoids is that my lockup has stopped working which has resulted in my fuel consumption increasing. I found a bad relay in the system, which I've fixed, but there is still something wrong. Looking at the wiring diagrams it is possible that the ECU could be using the condition of the EGR system as part of the decision process in operating the TCC lockup ie. no lockup possible until current flows through the solenoids (but I'm probably clutching at straws here). Some of the emission control systems may be interdependant on others & I was hoping somebody may have done all this themselves. It seems suspicious that some things, eg AIR, have been completely removed, but the EGR has only had the valve removed & everything else related is still in place.
If pinging ever becomes a problem then I'll start filling up with Super Unleaded (97 octane - normal unleaded is 95).
How does the '80 lockup work? Is it done on pressure?
Regards
Paul
09-21-2001, 12:47 PM
#6
Melting Slicks
Re: 1981 EGR removal (UKPaul)
..... as the ECU should adjust for an almost perfect mixture (and I wouldn't have the hassle of re-jetting when I change cam/exhausts/manifold/etc). I hope!
09-21-2001, 01:40 PM
#7
Safety Car
Thread Starter
Re: 1981 EGR removal (KenSny)
Paul, that may only be true if the stock ECU parameters allow it. If not you will have to get an aftermarket chip.
I have been offered a Hypertech chip & I have some questions about it (but I'll leave it for a while as it's difficult keeping up with all these posts!).
Cheers
Paul
09-21-2001, 02:53 PM
#8
Drifting
Re: 1981 EGR removal (UKPaul)
UKPaul,
We were there in early August but even though it did rain some, most of the time it was fine. The wife and I went to Derbyshire for a few days to do some fly fishing for trout. We spent most of our times in the Midlands which is where most of my family lives.
Car stuff:
I think the 81 has the Turbo350C trans which is the same as the 80. On my 80 to lockup the trans, it uses a temp switch on the thermostat housing (full temp before lockup can occur), there is also a vacuum switch that disengages at low vacuum (wide open throttle) and the govenor in the trans will not allow lockup until it is in 3rd gear. Also there is a switch on the brake pedal to deactivate lockup when the brakes are applied. Its really a simple system.
If you get a factory shop manual for your car it should show everything. I doubt if changing the mufflers would have anything to do with it, unless a wire was pulled loose from the trans or one of the sensors.
We were there in early August but even though it did rain some, most of the time it was fine. The wife and I went to Derbyshire for a few days to do some fly fishing for trout. We spent most of our times in the Midlands which is where most of my family lives.
Car stuff:
I think the 81 has the Turbo350C trans which is the same as the 80. On my 80 to lockup the trans, it uses a temp switch on the thermostat housing (full temp before lockup can occur), there is also a vacuum switch that disengages at low vacuum (wide open throttle) and the govenor in the trans will not allow lockup until it is in 3rd gear. Also there is a switch on the brake pedal to deactivate lockup when the brakes are applied. Its really a simple system.
If you get a factory shop manual for your car it should show everything. I doubt if changing the mufflers would have anything to do with it, unless a wire was pulled loose from the trans or one of the sensors.
