[ralphb]

I am now in the midst of replacing the intake gasket and the valve cover RTV on my 1988 307. I am amazed at the miles of vacuum hose, and the complexity of the vac hose routing, etc. Someone commented that the valve covers was a weekend job. I'd like to shake the hand of the person that can do that job in a weekend !

Q : When they went to TBI, did it simplify the need for so many vacuum lines and sensors, etc. ?

If anyone is knowledgeable, I would appreciate comment on the following :

* When did the use of serpentine accessory drive belts come into use on the Brougham ?

* When did the use of R-134 refrigerant start ?

* Do the 305 and 350, as used in the Brougham in 1991-92 have air pumps ?

* How do the automatic transmissions 200-4R and 4L60 compare as regards smootness of operation, as well as reliability ?

* Any other comments ref the 1987-89 era of Broughams compared to the 1991-92's ?

 

[N0DIH]

Stop on by to shake my hand! I did the valve covers in 2 hours. No problemo! That is also wrestling with the RTV that was being stubborn with drying properly.

It took me a day to swap the 307 for a 350 Olds, swapping on the entire CCC feedback Q-Jet system. Sorry if I come across as bragging, I am not.

But I have been around this engine family, carb and GM cars for years. I know every port on the carb, from E4MC/E4ME carbs to M4M and 4M carbs. That knowledge helps a lot. Put me on a SB Chevy or Buick V8 and I am lost. I would be willing to bet if you stripped of the entire vacuum system on a 307, I could get 90% of it back up, and running well. The 10% is the ones I didn't have on mine and I had removed (AIR pump stuff and second vacuum ball up front for the AIR system).

What do you need to know? I am one of those sickos who enjoys reading FSM's to learn what makes these cars run right and run good. I love to modify Q-Jets too.

R-134a, around 1994 was on all cars IIRC, 1991 it was starting.

 

[ralphb]

NODIH - Thanks for your response.

Hello - Is that an Airstream I see before me ?

About the '88 Brougham 307 - My first thought was to ditch the entire air pump and air injection system, but I presumed that this would screw up the O2 sensors and the computer, so I discarded the idea. Can this be done ?

 

[90Brougham350]

Yup, you can ditch the AIR pump. All it really does is to pump air into the exhaust to burn any unused fuel in the exhaust gasses. The computer does not know if you disable it or not. It really won't give you a power boost though, it's not a draw anything like the water pump or alternator.

 

[N0DIH]

I ditched it on my 85 Cutlass after I put in the 350, as it didn't have AIR ports in the heads. No issues. I did however, feel it ran slightly leaner without it. But the lack of noise was worth it all by itself.

The pumps often seize, but are actually easily rebuildable. Just polish it up with a croakus cloth or emery cloth to polish it. And that makes them much quieter too.

Yup, you can ditch the AIR pump. All it really does is to pump air into the exhaust to burn any unused fuel in the exhaust gasses. The computer does not know if you disable it or not. It really won't give you a power boost though, it's not a draw anything like the water pump or alternator.

 

[N0DIH]

....Hello - Is that an Airstream I see before me ?....

I swiped it from here: http://cadillacforums.com/cadillac/fleetwood/94flt.html and made the avatar with Photoshop.

Mine is a V4P, 7000# factory towing package. So the avatar is appropriate. Mine is tan in color, and a 94, that picture is actually a 93, but 93-94's are visually virtually identical. Primary differences are powertrain (LT1 in 94, L05 in 93)

 

[ralphb]

I think the purpose of the air injection system is to burn any remaining unburned fuel coming out the engine exhaust. So if one removes the air injection system, won't the O2 sensors be seeing a different mixture than with the air system and be feeding data to the computer that causes it to call for a change in the F/A mixture ?

I live in a state that does not have any kind of emmissions testing, so I am OK there, but I don't want to cause a long term effect on the converter or whatever .

I would like to hear from anyone who has actually removed the entire air injection system on a late 80's Cad with 307 to hear how they did it - what is removed; what has to be plugged, etc. On my engine the air pump has its own separate drive belt, so I'm Ok to just remove the pump and its mariad hoses and tubes. Each exhaust port has what looks like a large tubing nut attaching the air injection tubing directly to each cylinder head exhaust port, just before the mounting flange for the exhaust manifold. Looks like I could remove all of that and get 8 tubing nut plugs to plug the holes. Am I missing something ?

I would be thrilled beyond belief to get rid of that mess. Air Injection System - how do I hate thee ? Let me count the ways...

 

[N0DIH]

Like I said, I did it. Not a Cadillac, but a Cutlass "Y" 307. Same engine.

I pulled the AIR pump, as I put in the Olds 350, It didn't have the AIR passeges in the head. I damaged one of the connectors for the diverter valve, so I cut the wires off and tucked them in the looms so they would not be seen. I removed all vacuum lines and plugged them off nice and neat.

I'll look for a picture of the engine compartment, I have some. I might have to scan it in though. Looked factory. I added a home made dual snorkel air cleaner with dual ram air ducts under the front bumper.

Again, no issues. AIR is not checked by the ECM until ODBII. When engine was hot, I felt it was running a touch lean at cruse. But then again, the 307 always was a lean burner. I really needs some timing tweaks anyway.

 

[guidematic]

The 307 Olds was never available with any sort of fuel injection. The last year it was produced was 1990. It was replaced with the Chev 305 in 1991. This engine was Throttle body injected, and had the serpentine drive belt system.

The Chevrolet 350 became available in 1990 with the coachbuilder's package. It was also TBI and had the serpentine belt. In 1991 it became a regular option. Most all of these cars I have seen have this engine.

If you have any sort of emissions testing, do not remove the AIR system. This not only injects fresh air into the exhaust to help lower HC emissions, but also injects air into the 3-way cayalist to further lower emissons.

But, if you are free from this form of governmental abuse, then you can do it. It will greatly clean up the engine compartment. But don't expect any added power. This will not help one bit.

Mike

 

[ralphb]

Thanks to everyone for all the responses and comments to this thread.

My main concern about eliminating the air injection system was either messing up the converter, or maybe ending up with burned valves because the mixture was too lean. Also, with very lean mixtures, comes more likelyness to ping.

I really would like to get rid of this system, but I don't want to end up a year or two from now wishing I hadn't because of some long term problems that were inflicted on the engine and/or the driveability.

 

[90Brougham350]

Don't worry about it. The O2 sensor will compensate, or at least should. I'm running my 90 Brougham 350 with 6* initial advance, no AIR, and 92 octane. Runs like a champ with no pinging.

 

[the APEMAN]

Plan on gutting the converter. The 3 way ones are designed to work with the airpump air and will run too cold without. Sooner or later it will fail.

 

[ralphb]

Since we're on the subject :

What happens when a converter "fails" ? Does it just stop doing its job emissions-wise, or does it restrict flow, and have to be replaced ?


90Brougham350 - Did your engine originally have the AIR sytem ?

 

[90Brougham350]

It sure did. I haven't removed the pump yet, nor the rake going into the exhaust manifolds, but the wiring harnesses are disconnected and all the pumbing is gone. I don't have a cat, just a straight pipe.

 

[N0DIH]

Actually, if you have the cat gone, it is a good idea to at least ditch the air tube to what is left of the cat, to keep from any potential backfiring. Good enough excuse to axe it?