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Cadillac & LaSalle Club Forums => General Discussion => Topic started by: R Schroeder on August 21, 2010, 04:40:09 PM

Title: 425 engine techs please.
Post by: R Schroeder on August 21, 2010, 04:40:09 PM
I have a 1978 Cadillac with the 425.
Car has 15,000 miles on it.
It has a slight flat spot when you step on the gas. It drives me nuts. This is the first car I have ever owned that has had this sort of a problem, that I couldn't get rid of it. If engine is running with the air clearer off,and I razz the throttle it picks up right away. Jets of gas are right there. Only happens when I drive the car.

I replaced ;
Cap. rotor ,wires and plugs.
EGR valve
All emission controls on the air cleaner.
All vacuum lines
Rebuilt the carburetor, new dash pots
New vacuum advance
New PCV valve
New thermostat
New radiator cap
 All vacuum ports are working at the right time.
Engine pulls 21 inches of vacuum at an idle, steady needle.
The only things I have not done anything to are the fuel pump and distributor.
Car takes off like a rocket after the flat spot.
Roy

  GO TO THE END IF YOU HAVE READ THIS BEFORE
Title: Re: 425 engine techs please.
Post by: bill henry on August 22, 2010, 07:33:05 AM
when I bought my 78 it did the same thing and also seemed to lack power. believe it or not it cleared up after I took the advice of my old mechanic and drove it like I stole it for a few weeks.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 22, 2010, 09:53:25 AM
I have put 3000 miles on it since this work was done.
Dont think that will help..............ha
Title: Re: 425 engine techs please.
Post by: bill henry on August 22, 2010, 10:19:33 AM
sounds carb related not electrical. Are you sure the secondary air door is not hanging up this will cause a flat spot until the vaccuum is high enough to pull it open.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 22, 2010, 10:20:09 AM
Is the mechanical advance working in the distributor?   Also its worth checking the pick up coil wires in the dizzy.  That low of miles you would not expect them to be broken but who knows.   Its under the rotor and has the white and green wires that go into the module which is also under the rotor.  Sometimes the wires crack internally so when the advance moves it looses the connection which causes the vacuum signal to change and they re connect.   Just unplug it and connect an ohm meter while flexing the wires.  Reading should stay steady.   You could also try running with the vacuum advance unhooked.  

Have you tried it with the EGR unhooked?  Its possible that maybe you got a part that is not quite right and its opening too soon or not closing fast enough.  

That low of miles you would not expect the carb to be worn or abused so that should have been a very straight forward rebuild.

Was there any little black chunks in the carb?  On my 78 something rotted out in the charcoal canister and was letting charcoal bits get sucked into the carb.  Those little bits got down in the jets and would just float around and mess things up when they felt like it.  At first I thought they were just bits of old fuel line but the second time after I had replaced all the lines (including back at the tank) I started looking for other causes.  Should have known that if it was hoses it would not have got past the filter.

Did you set the timing properly?   I dont remember the details but it seems like its something like 16* at 1800 rpm.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 22, 2010, 11:46:48 AM
BILL - secondary is good. I just cant believe its in the carb. It works so dam nice once your past the flat spot. This is taking off from a dead stop now.

TJ - I wonder about the advance , because it seems the return springs are weak. I did lube them with a light oil. They work ,but seem weak.
I'll have to check the wires under the dist. I found in the repair section about checking different components with the ohm meter.
Yes I plugged line to the EGR and a lot of other things and drove it. It still was there.

Carb wasn't dirty or worn when I rebuilt it. I was just going through everything to make sure it was good. I even did the front bushings on it, just because I had it out.

Timing. Here is another question. On the plaque on the car it says 22 degrees before TDC, at 1400 rpms. Vacuum plugged.  The repair manuals say 18 degrees, in all the books I have . What is right ? these are all Cadillac manuals I have too.
Roy
Title: Re: 425 engine techs please.
Post by: Otto Skorzeny on August 22, 2010, 12:32:24 PM
Did the flat spot exist prior to the carb rebuild?
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 22, 2010, 05:09:57 PM
Just got home.
Yes Otto, it was always there.
Its not like you have to hit the gas twice to get it going. Its just a 1/2 second hesitation, and then its fine.
Just enough to bug you, when you know it shouldnt be there.
Title: Re: 425 engine techs please.
Post by: Otto Skorzeny on August 22, 2010, 05:23:28 PM
That leads me to believe that the accelerator pump is defective.

Check also for low fuel pump pressure or low volume.

If it is an ignition problem it could be fouled plugs or plugs gapped incorrectly. A weak ignition coil could also cause the symptoms described.

I'm leaning toward the accelerator pump, however.

Title: Re: 425 engine techs please.
Post by: R Schroeder on August 23, 2010, 08:11:52 AM
Well Otto, I just cant say its the carb. It squirts gas in it right away when you open throttle. Everything is new in it too.
I never checked the fuel pump, because it was running well. I still don't know why low fuel pressure would cause this sort of a problem , because it does keep gas in the carb. I know the books always say low pressure will cause the problem, but I'm not sold on that just yet.
I feel its something in the distributor.
I am still working on my rear fender extensions, so I'll jump into this when those are done. They should be back from body shop tomorrow.
Weather is finally getting back to normal for me.   90 and muggy isn't my cup of tea. I can work on a car all day when its 60 or 70.

Title: Re: 425 engine techs please.
Post by: boper39 on August 23, 2010, 08:46:11 AM
If you are having this on a fairly heavy hit of the throttle, try increasing the spring tension of the secondary air door. There is a locking allen head that is at the top rear passenger side of the carb top cover and a small flat head screw in the side. The allen faces down, and the screw can be seen through the hole in the linkage. As soon as you loosen the allen the adjusting screw will unwind so use two hands and have a screw driver of the tension screw. Tighten clock wise to increase (try 1/4 turn). Hope this helps.  GG
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 23, 2010, 09:15:04 AM
Well, I'll go back and check this out. A couple of guys were hitting on the secondary door here already. Anything is possible.
Thanks.
Roy
Title: Re: 425 engine techs please.
Post by: Art Woody on August 23, 2010, 02:33:40 PM
No matter how few miles, your parts are old. Otto is telling you straight, accerator pump dried out or dirty and/or something in carb gummed up. Classic, off idle flat spot caused by accelerator pump if you are sure of timing. It does't matter how smooth it idles or runs past flat spot, you have no load sitting in park.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 23, 2010, 05:40:17 PM
ART - The carb was completely rebuilt, to include the pump.  I have a list in my first posting of all the things that were done to the engine area.
This secondary spring though is something I have to look at. Waiting for cool weather.
Title: Re: 425 engine techs please.
Post by: Art Woody on August 23, 2010, 08:28:46 PM
Seeing as you have the engine running reasonably well, and are confident in your carb rebuild and certain the float level is absolutely correct, I would set the carb and the timing with a vacuum gauge. But since you have a timing light, record current timing and advance a couple of degrees first and test drive. If you have lessened the flat spot, then advance again. Good luck, Art Woody
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 23, 2010, 10:20:52 PM
Will keep that in mind. Athough its pulling 21 inches steady now.
Going to be trying a few things here in the next week or so.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 23, 2010, 10:23:35 PM
You could try running with the vac advance unhooked.   If it does not stumble then you may be looking at a timing issue.  If it does then you are back looking at fuel.    You may have to bump the idle slightly because the 78 runs off manifold vac so you wont have any advance at idle.  

Title: Re: 425 engine techs please.
Post by: Mike Josephic CLC #3877 on August 23, 2010, 10:41:34 PM
Had the same problem on my '73 Eldo -- turned out to be the choke "pull-off" which
is a vacuum diaphram set up on the carb.  They were problematic.

Don't know if this applies to your engine, but since you've checked everything else
look into it!

Mike
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 23, 2010, 10:59:43 PM
TJ- that is one of the things I plan on trying this week. One more muggy day, and I'll get to the car again. I have had the idle set up faster and back down. That didnt seem to help any, if that helps.

MIKE - the pull offs are new too. I went whole hog on the rebuild.

I have read some interesting things here, and I plan on doing all of them.
Thanks for all the tips. Keep them coming if you have any. I'm sure one of them will hit on the problem.

Roy
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 23, 2010, 11:29:08 PM
Is the whole country muggy or are you in the midwest?   I dont ever remember having this many days with this sort of heat index.  Working on my car today I sweated enough all over the engine to clean it a bit.  Glad I had the hood to give me partial shade.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 23, 2010, 11:33:07 PM
Just had another thought,  did you look close at the carb to manifold gasket?  Seems like I remember one of the gaskets in the kits having a couple of slots around the primaries that would leak on the 425 intake.  Memory sort of blurs but I do remember there were some gaskets that did not work on some intakes.   
Title: Re: 425 engine techs please.
Post by: Otto Skorzeny on August 24, 2010, 12:07:59 AM
I live in Atlanta and we had 58 days straight of above 90F weather and high humidity that pushed the heat index to over 100 most of those days. I've basicly stayed in the house all summer.

The last couple days it's been in the high 80s.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 24, 2010, 07:21:50 AM
TJ - OTTO- I have friends that live in both of your states and they are not happy with the heat.
Two friends in Mechanicsburg , PA. One friend in Alanta, GA. All have invited my wife and I to visit this year, but the heat is no fun to travel in, so we didn't make the trip this year.
One friend from PA, did come here, but had to cut his trip short.
This has been the worst summer that I can remember in a long time. We may get 2 weeks in Aug that are hot and muggy.This year it has been all summer.
I live about 35 miles west of Milwaukee , Wi.  Milwaukee is all over You-tube this year. They have had 6 to 8 inch rain storms all summer. Flood videos all on You tube........ha

Anyway, back to the carb.  I think I remember the slots in the base gasket of the carb. But , I did spray little spurts of carb clean at the base to check for leaks while it was running. There were no leaks there.

Worked on a lot of cars in the last 50 years, but this one has me stumped. But , I will find it..............ha
Roy
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 24, 2010, 09:59:33 AM
If I am remembering the correct intake manifold I think the 425 has raised sections around the bores and screw holes but is otherwise open underneath so if you used that gasket with the slots it could be open to one of those gaps underneath.
Title: Re: 425 engine techs please.
Post by: Otto Skorzeny on August 24, 2010, 05:36:24 PM
That wouldn't be a bad idea but I think your advance isn't working right. Perhaps the engine is already timed too far advanced? Driving with the advance disconnected should normally have resulted in a decrease in performance at WOT.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 24, 2010, 06:56:02 PM
Well, I didnt do a WOT. I just went through the sub-division. Took off about 10 times and it was nice and smooth.
I'll play around with the timing tomorrow I guess. The decal under the hood says 22 degrees before TDC @ 1400 rpms. The repair manuals say 18 degrees . Going down to the 70's and very low humidity.
Title: Re: 425 engine techs please.
Post by: The Tassie Devil(le) on August 24, 2010, 07:02:37 PM
Quote from: R Schroeder on August 24, 2010, 06:56:02 PM
I'll play around with the timing tomorrow I guess. The decal under the hood says 22 degrees before TDC @ 1400 rpms. The repair manuals say 18 degrees . Going down to the 70's and very low humidity.  
Ah ha, I see the problem.   Timing at 70 Degrees is way too far advanced.   And too much humidity inside the engine bay will really hurt performance. ;)

Bruce. >:D

PS.   Sorry, couldn't resist. ;D

PPS.   It is the time the website uses.   But, it is 9.02 AM tomorrow down here.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 24, 2010, 07:19:41 PM
You say you have the 78 supplement manual?   Page 6D-6 has the specs for both mechanical and vac advances.   Most of the aftermarket vacuum cans have way too much movement in them, sort of a one size fits all.   Some of the 'performance' versions come with or you can get a little plate to limit the travel.   On stock ones I have used a washer under one of the mounting screws to limit how far it can return to.  This then does change your base setting but that is easily corrected.

Mechanical is only 9.5* and all in at 1450 for most models.
Vac is 14.5* at 20" or 29* at 20" depending on which dizzy you have assuming non ca non altitude non efi.
Some are as low as 5.5*
That 29 is a lot.  I dont think I have ever seen one that has that much but that is a non ca, non altitude, non efi, "C" car.   If the carb was not matched to that dizzy I could see issues.   It may be worth looking at the carb numbers and dizzy numbers in the manual and making sure you have the right combo.


And to Bruce, thats 70* F, perhaps it would work better at what about 20*C?    Does C stand for crank or cam?
Title: Re: 425 engine techs please.
Post by: The Tassie Devil(le) on August 24, 2010, 07:25:46 PM
Quote from: TJ Hopland on August 24, 2010, 07:19:41 PM
And to Bruce, thats 70* F, perhaps it would work better at what about 20*C?    Does C stand for crank or cam? 
Yes, that has to be it. ;)

But, seriously, all timing settings should be done with the Vacuum off and plugged.

Bruce. >:D
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 24, 2010, 08:44:14 PM
TJ - I'll have to read all the info tomorrow. I must admit , I'm a little lost with your posting. But ,it will sink in one day.
Yes I have the 78 book as well as the 77 book, plus all the body and parts books. Full house.
Carb is correct one for the engine. Non Ca , non efi, non altitude. I'll have to check the dist, but it is the one that came with the car.

BRUCE - what can I say. 70 is to much...............ha
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 24, 2010, 08:56:20 PM
Just look at page 6D-6 and it will make more sense.  There are charts that tell you what the advance should be at given rpms and inches of vacuum based on the distributor model.  You can then confirm that it is working as it should be. 

I was just thinking it was odd that there was such a difference in the vacuum specs for 2 different distributors.  The mechanical is almost identical for the two models but for some reason one has a heck of a lot more advance in the vacuum.   They both show as pretty normal applications so I am not sure what the reason would be.  I could see something crazy for altitude or ca but its listed as a standard car 'C' body car so its not like one is the commercial chassis.

The reason I was asking about the carb is with that huge of a difference in the advance spec the carb would have to have quite a different tune to it and I could see a stumble if they were not a match.   On my 'normal' car the distributor vac went straight to the manifold.  I wonder if perhaps that distributor with the 29* spec went to a port on the carb like many other models and years did.   On page 6D-5 there is a note on that model that says 'denotes later models' so it may have been a mid year change, perhaps what they did in 79?  I dont have a 79 book. 
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 24, 2010, 10:25:08 PM
Ya its in the book for what appears to be the later 78 regular C car distributor.   

If you set the timing by the plaque at 20* at 1400 that means the mechanical 7.5-9.5 should all be in so that would in theory mean that you would be at 10.5 - 12.5 at idle.  It then says that at 20" of vacuum (which you had unhooked when setting the timing) that it will pull in another 14.5 or 29 depending on the model.  So that means at idle with everything hooked up you should expect to see around 25 or 40 depending on the model.  25 seems pretty normal to me, 40 seems like a lot. Seems like I have had some engines that idled in the low 30's but 40 seems like a lot.  I really have no idea why they wanted it set at 1400.  They had to come up with a new timing marker and everything to do that.  Gotta love the way they they were trying to meet emissions in those days.   

Now looking at the vacuum diagrams the normal cars the distributor connects direct to the intake, its got a nipple right there on the #2 cylinder intake runner IIRC and its the only thing connected there.   The rest of the cars CA and Altitude show the distributor running through a thermal switch and getting mixed up with other devices.  My guess is the switch is located sort of under the dizzy pointing forward sort of hidden by the ps bracket.   If yours is or was one of those cars there could be issues with that switch or other devices connected to it.  I would also imagine that the carb and distributor itself would have a different tune to match those devices.  If any of that stuff has been altered or is not working you no longer have a matched system.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 24, 2010, 10:32:30 PM
My vacuum runs directly to the manifold. No switches.
I guess I'll do what the book says on the timing , and get back to you on what I have.
If it isn't advanced far enough ,would this cause the flat spot ?
Decal says 22 degrees before TDC. I think when I last checked it , it was 20 degrees before TDC.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 24, 2010, 10:39:43 PM
Just look at the charts in the book and confirm that both the mechanical and vacuum systems are doing what they should be doing.   You will need a hand vacuum gauge / pump to test the vacuum portion and either an advance timing light or more marks on the pulley to check it all.    Those hand pumps are really cheap now.  Harbor Freight has one with the brake bleeder option for something like $15.  My guess is you will find that either the mechanical or vacuum is not working in its proper range.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 24, 2010, 10:45:16 PM
OK, now I understand where you are getting the controlled vacuum from. I need the pump to do the set up.
I'll have too look into one of those.
Were getting up to speed now. I'll check with my local NAPA dealer tomorrow.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 24, 2010, 11:01:54 PM
Looking at Napa Online

I find one similar to the harbor freight one but does not include the can for doing brakes for about $55 and its in stock at my local store so there is a good chance your store has one also.  Looks the same as the one I bought at sears years ago. 
Part number is BK7002335
(http://partimages.genpt.com/partimages/223878.jpg)

But if I was going to spend that much (and had time to wait assuming its not in stock) I would spend a few more bucks and get this set because it has more uses.     
Part number is BK7003882   Price shows $70
(http://partimages.genpt.com/partimages/886053.jpg)

Title: Re: 425 engine techs please.
Post by: 35-709 on August 25, 2010, 10:11:45 AM
 ;D  You'll have mulch more fun working on the car!   ;D
Geoff N.
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 25, 2010, 09:29:54 PM
Better she wants wood chips vs. to put you in a wood chipper. 

Not sure if they still sell em or what name they are under now days but several years ago I bought a 4 stroke 'weed eater' that you could attach various ends to.  Mine was under the Ryobi name but I know I also saw them under the Sears name and seems like I have recently seen them at one of the large home stores under yet another name.  Anyway for that rig I got a sawzall on a stick attachment.   It will do up to about a 3" limb.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 25, 2010, 09:58:46 PM
Going out tomorrow again to look.
Looks like I wont get back to the car until Friday.
Title: Re: 425 engine techs please.
Post by: Tim Groves on August 25, 2010, 11:17:27 PM
Sounds like the APT (adjustable part throttle) metering rod is out of adjustment.  When the rebuild was done did the rebuilder reinstall that metering rod in the same position?  It is adjusted like idle screws, but is under the air horn, so the top has to be removed to adjust it.  They were factory adjusted, and it is a pain to adjust by trial and error.  The late 70s Quadrajets had these APT metering rods.  Tim
Title: Re: 425 engine techs please.
Post by: Glen on August 26, 2010, 02:53:05 AM
I was in Sears today and I saw those hand vacuum pumps there.    Be sure to get the ones made of metal.  The first version of those only came in plastic.  I went through at least three before I found Sears’ metal one.  It has lasted a long time. 

And they are very handy for a number of uses under the hood. 

Glen
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 26, 2010, 08:33:02 AM
TIM - I rebuilt the carb. I did not touch the setting on the rods.  I think we are more inclined to lean to the distributor at this point.

Glen - Thanks.
Roy

Title: Re: 425 engine techs please.
Post by: R Schroeder on August 27, 2010, 02:05:08 PM
OK, here is where I am at.
Today I pulled the cap and checked all connections . I pulled the plugs that are inside dist, and cleaned all terminals.
I then checked timing per decal on the car. 22* at 1600 rpms. I got 23 *, so I left it . It is very hard to get at the bolt for the dist.
I plugged the vacuum line to the vacuum advance, plus EGR valve , before setting timing. I set the idle way down, as low as I could go, and checked how much mechanical advance I had. It moved up 12 *. As long as it was set up like this , I used the vacuum gage to set idle screws again. Right one was one turn off. Had to go in about a turn .
Once I had that all set up, I turned idle back up and connected the vacuum advance.
It showed the timing at about 22* , past the 24 * mark , on the timing mark.
I do have the later distibutor in the car. The AT one. Found the number right on the coil cover.
It now runs pretty good. No flat spot at all in 30 miles of stop and start driving with the exception of a idle at the stop light , if the light is  long. Then it was slight. But that was the only time it did it.

I was checking the coil out per manual. 77 manual. It says I should read O or close to it, across the TACH and DIST connections. It did.
I then checked from the center post , of the 3 prong post , to the center of the cap. That was good. O reading.
It also said to check from the TACH to the center post. It was suppose to read O, but I had no reading.
Don't know if something is wrong with the coil or not. you would think it wouldn't work at all if there was a problem.
So, thats where I'm at.
Roy
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 29, 2010, 09:56:46 AM
I have not usually had that sort if intermittent issues with coils.  For the most part they seem to work or not only intermittent thing with the oil filled ones was they would sometimes get funky when they got hot.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 29, 2010, 10:04:14 AM
This is the coil thats inside the distributor cap. I don't think they are filled with oil, like the external ones.
Just seemed funny that the readings didn't come out like the book said.
Otherwise, I dont know what changed , but it is working good now.
Roy
Title: Re: 425 engine techs please.
Post by: TJ Hopland on August 29, 2010, 10:35:10 AM
Those readings seem a little strange.      The 3 pin connector on the cap is just a link to the batt terminal on one side then into the + of the coil.  The other side is tach which again is a link and then to the - of the coil.  The middle pin is usually a ground bar to connect to the coil body.  Sometimes its a wire.    On the harness side middle wire just goes to the body of the distributor.  Batt wire is the B terminal of the module which is power for the electronics in the module.   The other wire is C terminal which goes to the tach terminal and the - of the coil.  This terminal is the equivalent of the wire that used to go to points.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 29, 2010, 11:20:53 AM
I'm going to have to look at the book a little more. Wasnt a very clear picture in the book.
Title: Re: 425 engine techs please.
Post by: R Schroeder on August 30, 2010, 06:49:11 PM
OK. I checked the book again and I do have the correct readings on my wires. Only the center of the 3 prong plug reads when you have the cap off. So, all leads were good, as well as the readings.
Roy
Title: Re: 425 engine techs please.
Post by: R Schroeder on November 21, 2010, 07:07:49 PM
OK. I'm going to bring this back again.
My final change that I made on the car , was to set the timing to 18 * at 1400 RPMs. Plate on car says 22* at 1800 rpm's , I believe. Repair manuals call for the 18 *.  This got rid of the flat spot. I drove through , Sept, Oct and all was good. I ran the car on one last trip , and it started in with the flat spot again.
  Well, I just went down back today and pulled the carb again. I wanted to go through it one more time and check all the settings.
As I went to take out the two front bolts, I saw they were loose. I have a lock washer on them , but I dont think it worked to well. I plan on buying the star type locks tomorrow. I also think I'll put something on the threads to keep them tight too.
So, I'm doing the carb over , just for kicks and then I'll check all the rest later.
I have read other posts about guys having flat spots ,so check those hold down bolts out , if you have a problem.
Roy Schroeder

Title: Re: 425 engine techs please.
Post by: Bob Stahl on November 22, 2010, 07:40:58 PM
I had a 1979 Cadillac Coupe and it had the hesitation right of idle. It ended up being the valve in the air cleaner snorkel. I had the tube on the air cleaner that went down to the cover over the exhaust manifold but the valve in the air cleaner snorkel did not work. I replaced the valve and the car never had the hesitation again. I was surprised that the valve worked all the time opening and closing even when driving. Even in warmer weather my car would have a small hesitation and that went away too. Hope I helped some?
Title: Re: 425 engine techs please.
Post by: R Schroeder on November 22, 2010, 10:17:29 PM
Thanks Bob,
I did replace all the valves in the air cleaner. That is all working correctly.
I rebuilt the carb again today. This time I went by the Cadillac repair manual for all the settings.
The float was low . 1/8 low.  I put it back on , and it seems to run much better. I didn't take it out, because the weather is getting bad . Had a tornado just south of me tonight.
Had it put away for the winter. Hope to get one more warm sunny day to check it out.
I'm pretty sure this might solve the problem.
Setting the timing to what the repair manual says helped a lot too.
Always open to ideas.
Thanks
Roy
Title: Re: 425 engine techs please.
Post by: R Schroeder on November 26, 2010, 05:45:20 PM
I couldnt wait until spring for the test ride in the car. I took the cover off today , and took her out.
Man , what a differnce. It really runs well now, with setting the carb to the Cadillac repair manual.
Now  I dont have to think about it .
Roy