Odd and Even Banks on Northstar

[Logan]

There is no real relationship between engine vacuum and fuel pressure. A clogged cat will not cause low fuel pressure by itself. The engine vacuum will cause a mild change in pressure...but not anywhere near what has been suggested.

The easiest way to check exhaust back pressure is to remove a o2 sensor...install a bung fitting...use a long vacuum hose and old style vacuum / fuel pressure gauge...anything over about 2 psi at 2000rpm is a bad cat.

[KHE]

I am actually looking forward to doing this job, its challenging but not too challenging unless I blow myself up . TexasJim called me to give me a 5% discount for Rockauto and even though I had already completed the order, they credited me with the discount so it more than paid for the shipping. Thanks Jim

The pipe is on back order from Cadillac, it was suppose to be in yesterday and now it wont be in till next week, amazing. The fuel pump that I ordered at 1 PM today from ROCKAUTO already shipped.... I ordered the Delphi unit, its cheaper than the AC DELCO but not as cheap as the Carter or Spectra units.

While I am under the car, I need to look over the leveling system, his "mechanic" added a MANUAL fill valve to the system but he failed to realize that the bladders on the shocks leaked. amazing.

Did someone hear my calling, I think I missed it..... (especially when I see mechanics that short cut and misdiagnose)

You're not going to blow yourself up unless you decide to smoke or have an open flame nearby.

The mechanic didn't think the air from the manual fill port would leak out the rotted bladders? After you get the engine running properly, I'd get rid of the manual fill valve on the leveling system and install a set of Monroe passive shocks - I used #40046 on my STS and they were a direct fit and the factory air lines plugged right into them. They are only missing the actuators that would make them identical to the OEM electronic shocks. I used a 4700 ohm resistor to keep the SERVICE RIDE CONTROL message from displaying. The car levels out properly and rides much better than with the old leaking shocks.

What was the cost of the fuel filler pipe? There are several places on the web that have fuel filler pipes but none list the Seville - they are all for the Deville and I haven't checked to see if the part no. is the same.

I hear you on the "missing your calling" when you see things misdiagnosed/shortcutted.

[KHE]

My vote is bad pump or leaking coupler.

Logan, what is the "leaking coupler" you refer to?

[BodybyFisher]

I am actually looking forward to doing this job, its challenging but not too challenging unless I blow myself up . TexasJim called me to give me a 5% discount for Rockauto and even though I had already completed the order, they credited me with the discount so it more than paid for the shipping. Thanks Jim

The pipe is on back order from Cadillac, it was suppose to be in yesterday and now it wont be in till next week, amazing. The fuel pump that I ordered at 1 PM today from ROCKAUTO already shipped.... I ordered the Delphi unit, its cheaper than the AC DELCO but not as cheap as the Carter or Spectra units.

While I am under the car, I need to look over the leveling system, his "mechanic" added a MANUAL fill valve to the system but he failed to realize that the bladders on the shocks leaked. amazing.

Did someone hear my calling, I think I missed it..... (especially when I see mechanics that short cut and misdiagnose)

You're not going to blow yourself up unless you decide to smoke or have an open flame nearby.

The mechanic didn't think the air from the manual fill port would leak out the rotted bladders? After you get the engine running properly, I'd get rid of the manual fill valve on the leveling system and install a set of Monroe passive shocks - I used #40046 on my STS and they were a direct fit and the factory air lines plugged right into them. They are only missing the actuators that would make them identical to the OEM electronic shocks. I used a 4700 ohm resistor to keep the SERVICE RIDE CONTROL message from displaying. The car levels out properly and rides much better than with the old leaking shocks.

What was the cost of the fuel filler pipe? There are several places on the web that have fuel filler pipes but none list the Seville - they are all for the Deville and I haven't checked to see if the part no. is the same.

I hear you on the "missing your calling" when you see things misdiagnosed/shortcutted.

The filler pipe was close to 400 but he got it for 297 after making a fuss and stating it was for a business. I am still not optimistic that they said its on BACK ORDER, that is an bad sign. I am not sure what I will do if there is no replacement available, I was thinking scrap yards, hoping that one had been replaced toward the end of its life.

THanks for the strut info, I had checked arnott and rockauto for them. Do you recall how much they were?

[Logan]

A lot of GM (and others) have a coupler between the actual fuel pump and the metal fuel line inside the gas tank. There is rubber inside this coupler that can rupture and leak.

[BodybyFisher]

A lot of GM (and others) have a coupler between the actual fuel pump and the metal fuel line inside the gas tank. There is rubber inside this coupler that can rupture and leak.

Thanks Logan, that is good to know, is it something that is replaceable?

[Logan]

Yes. That would apply to older GM pumps. Some pumps will actually come with a chunk of standard fuel hose to replace the coupler.

The newer stuff is considered a fuel module assembly. Typically sold as a complete fuel module unit. On my long gone '93...I replaced just the pump after taking the fuel module unit apart. Maybe $50 for the pump instead of $300 for the fuel module unit.

[KHE]

The filler pipe was close to 400 but he got it for 297 after making a fuss and stating it was for a business. I am still not optimistic that they said its on BACK ORDER, that is an bad sign. I am not sure what I will do if there is no replacement available, I was thinking scrap yards, hoping that one had been replaced toward the end of its life.

THanks for the strut info, I had checked arnott and rockauto for them. Do you recall how much they were?

$400.00 for a fuel filler pipe??? Talk about a gouge-job! That part should be around $50.00. GM's servce part prices sure have skyrocketed in the last few years.

The Monroe shocks were about $100 each. Arnott's are around $316 for the pair. The Arnotts are made in China (which I cannot stand...) while the Monroes are made in USA. I used Arnotts on my '96 SLS and was not impressed. For one, they were made in China and two, the resistors they use to supress the SERVICE RIDE CONTROL message were poor quality. There were no provisions for mounting the resistors other than using zip ties to fasten them to something under the car... The resistors rusted and the contacts rotted away after two years of service. Arnott replaced them free of charge but they were backordered at the time and I had to wait two or three weeks for them to arrive, then crawl under the car to install them. In my opinion, a quality product should last for more than just two years...

The Monroe shocks I installed on the STS were less expensive than the Chinese Arnotts, and they are made in USA, I used a 4700 ohm resistor sodered across the harness cut from the old shocks. I weatherproofed the connection and it works just fine.

[BodybyFisher]

That Arnott description sounds a lot like my experience with the now defunct Boston Suspensions, where I bought my rear struts/shocks for the 96 Deville

Thanks for the info on the Monroe shocks, I will look into them, this owner has been spending a lot lately but I think it will be worth it, his engine is very sound.

[BodybyFisher]

Ok I started dropping the tank today. Started late at 3 pm but I got quite a bit done before the frikken mosquitos became so aggressive that I had to run for cover...at about 530

I got the rusted fuel fillter pipe out, here is a photo of it at the wheel wheel

There are two rubber fuel line hoses between the filler pipe and the tank

Here is where those hoses connect to the tank, it was easy to get to the clamp screws

Here is where the hoses connect to the fuel filler pipe, the clamp screws were NOT easy to get to and it took a surgeon's hands with a 1/4 inch drive socket to get the two clamps off, note the rust. My camera did quite a good job here

I pulled the hoses off and capped the tank with rubber stoppers to fit the approximate 1 inch and 1/2 inch hose nipples on the tank to keep fuel from spilling and fumes at bay. Quite a good idea if you ask me!

Here are the old and new fuel filler pipes, you will notice that the new pipe has a bracket on it, that the old one does not have, not sure if this will create problems with the installation I may need to cut that bracket off. This was not the exact part, the exact part was discontinued according to GM. This part probably will fit with some mods

She is a good looking 95 Eldo

I loosened the exhaust system heat shield so I could get at one of the tank strap bolts, and loosened all 4 bolts. Disconnected the pump electrical connector.

The pipes oddly were not rusted though, that is great because I will not need to clean out the tank, and that will save time.

Will be on this early in the morning to finish up, I am a little nervous about balancing this tank on the way down, I need to raise the car about 4 inches more to improve clearance to pull the tank out.

So far so good

[JohnnyG]

Don't rule out a tank cleaning just yet. You'll know more after you pull the fuel pump out and see exactly what's going on. I'd say your at least 60% done though. So, next question, where did the fuel smell come from if the filler neck is solid?

[JimD]

Food for thought when the repair is complete and you can relax.

I understand installing a new filler pipe when you are dropping the tank for another season. But that surface rust on a vehicle driven in snow country would not alarm me.

What caught my eye was the use of screw clamps. I have a little trouble with the idea that GM was still using screw clamps in 1995. Makes me wonder if someone else has been in there before today.

[BodybyFisher]

Don't rule out a tank cleaning just yet. You'll know more after you pull the fuel pump out and see exactly what's going on. I'd say your at least 60% done though. So, next question, where did the fuel smell come from if the filler neck is solid?

That is a good question, I have to look at the EVAP system.

[BodybyFisher]

Food for thought when the repair is complete and you can relax.

I understand installing a new filler pipe when you are dropping the tank for another season. But that surface rust on a vehicle driven in snow country would not alarm me.

What caught my eye was the use of screw clamps. I have a little trouble with the idea that GM was still using screw clamps in 1995. Makes me wonder if someone else has been in there before today.

I was thinking the same thing about the clamps Jim

The reason why we ordered the pipe is because it was rusted and because there was a fuel smell that was pretty strong. It could be a problem with the EVAP system and i assumed that the pipe was rusted through as we have seen here before. I may consider putting the old pipe back and having him return the pipe for $300. I tried to poke a hole in it and was unable to, and scratching it showed clean steel under the rust. I may clean it up with a wire wheel and see what it looks like.

[Texas Jim]

Mike,

If the filler pipe cleans up good... paint it with Zinc Chromate paint.

That will help keep it from rusting again.

[KevinW]

About 6 years ago, I replaced the fuel filler pipe on a 1996 Concours. The corrosion was heaviest at the horizontal section around the position of the bracket on the new part pictured above (apparently for a DeVille), and there were loose, flaky bits everywhere; fuel odour and some seepage was observed for a short period after fuel additions were made, but there was not enough of an air leak to trigger any EVAP codes. I painted the used, rust-free, replacement part (from Arkansas) using some flat black rust paint (Tremclad), and today, this part is still free of visible rust. I believe the screw clamps are original parts.

[BodybyFisher]

About 6 years ago, I replaced the fuel filler pipe on a 1996 Concours. The corrosion was heaviest at the horizontal section around the position of the bracket on the new part pictured above (apparently for a DeVille), and there were loose, flaky bits everywhere; fuel odour and some seepage was observed for a short period after fuel additions were made, but there was not enough of an air leak to trigger any EVAP codes. I painted the used, rust-free, replacement part (from Arkansas) using some flat black rust paint (Tremclad), and today, this part is still free of visible rust. I believe the screw clamps are original parts.

Thanks for that info Kevin, I did have the screw clamp pipe. I really dont think this pipe is leaking, Ill look at it closer tomorrow.

Does anyone know why the owner would suddenly have difficulty filling the tank, where the pump clicks off often? Could that be related to the EVAP system? The breather line I believe stops the tank from pressurizing on fill up correct?

[Cadillac Jim]

The breather does indeed allow free flow into the tank by allowing free flow of air back out to the filler neck, where the newer pumps have scavenger fans to recycle the vapors. The question as to why the owner had difficulty filling the tank probably relates to the screw hose clamps seen on the filler tube. I suspect that you will find the answer when you look inside the tank.

[BodybyFisher]

Ok, job is done, dropped the tank, replaced the pump, no debris in the tank, the sock filter was clean.

I scrapped and wire brushed the filler pipe, pressure tested it for leaks (actually drew a 30 psi vacuum, sprayed it with a self etching metal paint that eliminates rust and reinstalled the old pipe.

There was only a little fuel in the tank so it was easy to move around. Replaced the clamps on the hose that runs between the filler pipe and the tank

With the KEY ON, I got 42 then it dropped to 40, on run, I got 36, and when I accelerated the engine I got 40, the pressure ROSE, instead of dropped as before. The old pump looks like an aftermarket no name pump, there are no markings on it, Ill post a photo.

It has a lot more power, it still has a mild miss at idle and just above idle that goes away up the rpm range, which could be the corroded coil towers that I described earlier, and the ISC motor is messed up and I get a hunting idle. I plan to swap in a known good coil into each position to see if it makes a difference, clean the ISC, clean the throttle body and check for vacuum leaks. Ill post some more photos later

Thanks for all who helped me through this job with the details and diagnostics.

[BodybyFisher]

When I did the ignition wires, the tops of many of the coils were corroded and rusted. I am still getting a misfire, anyone think this could be due to those coil towers, I cleaned them up with emory cloth, but?

Tank out, note plugs on tank nipples

Pump with lines disconnected

Scraped, wire brushed and sprayed with self etching metal primer by Rustoleum, looks like new, I forgot to take a photo while it was out of the car, it looked amazing! I also used rubber stoppers to plug the two lines, and drew a vacuum of thirty PSI, I know that I said I pressurized it earlier, but in reality, I used my Mity-Vac with gage, and sucked a vacuum of -30 psi, and she held for over an hour....no leaks,

I am having the owner return the pipe to GM, I hope they take it back without a restocking fee. I did NOT want to take this car apart and NOT have that pipe available to me, afterall, i did smell fumes and it was badly rusted, to the logical conclusion was that it was leaking. To take a bad pipe out would have done more damage to it, it was not readily available at the dealer, so it was necessary to have on hand, since it was good, I didnt want to waste $300. If worst comes to worst, Ill sell it on EBAY, they are getting hard to find..... the old filler pipes turned out great , thanks guys for giving my confidence in the old pipe, I still don't know where the fumes came from, but I have not smelled them since!

I want to disect the old pump Ill post photos of it, thanks for all the help

[JimD]

Good job, Mike. I'm sure you are happy to be out from under the back end of that beast.

The fuel pressure numbers you reported in post #94 are within a pound or two of what I expected. Obviously the various pressure figures reported as published in Service Manuals are incorrect/misleading, OR, the test conditions were not completely explained. The pressure figures I posted earlier were obviously static (engine OFF).

On the misfire situation, ignition is the first place I would investigate. Swapping in known good coils is a reasonable methodical approach. But since you probably do not know the complete service history of the vehicle, pay attention the high voltage wires also. The end connectors might not be making good contact with the carbonized conductor and/or vibration and temperature change can create intermittent changes in the character of the wires.

[BodybyFisher]

Good job, Mike. I'm sure you are happy to be out from under the back end of that beast.

The fuel pressure numbers you reported in post #94 are within a pound or two of what I expected. Obviously the various pressure figures reported as published in Service Manuals are incorrect/misleading, OR, the test conditions were not completely explained. The pressure figures I posted earlier were obviously static (engine OFF).

On the misfire situation, ignition is the first place I would investigate. Swapping in known good coils is a reasonable methodical approach. But since you probably do not know the complete service history of the vehicle, pay attention the high voltage wires also. The end connectors might not be making good contact with the carbonized conductor and/or vibration and temperature change can create intermittent changes in the character of the wires.

That is for sure Jim, I have pains in places I forgot I had muscles, the front of my neck from holding it up under the car, is really really sore! The sides of my hits from laying on the concrete are bruised.....

Thanks Jim, earlier in this thread, I reported that I replaced the ignition wires, plugs, FPR and air filter, the old plugs and wires were without a doubt the worst I have ever seen with some of the plug gaps in excess of .070 with missing pads. The ends of the igntion wires were blown off many of the wires especially the coil end, the coil towers at least 5 of them were seriously corroded and rusted almost like water was getting into the connection. I cleaned the NIP up with emory cloth, but its possible, i didnt clean them enough, or, I have a bad coil or ICM, or PCM, but that is jumping the gun. I did notice that the heater pipes were replaced by hoses interesting idea.

The ranging idle is no doubt the clicking ISC motor that is nicely tucked down low almost out of sight....

I have a few P codes that I need to look up, most of them were benign power disconnect codes if I recall. but Ill post them again.

She can miss somewhat noticably sort of like she is shuddering, then it goes away, he uses techron regularly. I need to drive it more to get more of a feel as to what it is. I have no way of measuring misfires on OBD1,

Gas pedal response is poor, my Deville would have stomped on this car. I think the throttle body cleaning may be part of that, no doubt its going to look bad when I get in there given the state of this car.

I have a 94 manual, this is a 95, I hope to review the OBD/DIC system real time parameter retrieval and see what I can explore. I want to check for vacuum leaks, hoses, injector orings/seating, clean the throttle body, and make sure the ignition wires are seated on both ends.

The positive battery cable is connected to the battery in a real rube goldberg method, no lead lug, just sandwidged and tightened to the battery, amazing, i need to check that, these coils draw a lot of current and a battery unable to deliver steady current is a problem.

I am 100% sure the throttle body throat and plate has never been cleaned. Will attached a vacuum gage to the engine to see what happens on initial throttle opening.

I am hoping that the coils are messed up, I have two replacements, easy swap, cant wait, to see how this engine responds to a little tender loving care..

There was a great writeup on the ISC motor cleaning by BARRY94, I need to grab that and link to it. Does clicking mean its FAILED, or can I clean it up or adjust it to stop the clicking? There is a closed throttle contact that gets corroded.

This car while well kept physically, has not been maintained well, which has been compounded by the fact that whoever has worked on this car likes to rube goldberg short cut. It needs rear struts, the mechanic eliminated the compressor and put a MANUAL schader valve in the trunk...and the compressor cycles at start up and during the code retrieval process, so it freaking works and this positive battery connection and replacing the heater pipes with hoses..... These types of things are like finger nails on a blackboard for me

I am all ears with any ideas, thanks Jim

[KHE]

That is for sure Jim, I have pains in places I forgot I had muscles, the front of my neck from holding it up under the car, is really really sore! The sides of my hits from laying on the concrete are bruised.....

Thanks Jim, earlier in this thread, I reported that I replaced the ignition wires, plugs, FPR and air filter, the old plugs and wires were without a doubt the worst I have ever seen with some of the plug gaps in excess of .070 with missing pads. The ends of the igntion wires were blown off many of the wires especially the coil end, the coil towers at least 5 of them were seriously corroded and rusted almost like water was getting into the connection. I cleaned the NIP up with emory cloth, but its possible, i didnt clean them enough, or, I have a bad coil or ICM, or PCM, but that is jumping the gun. I did notice that the heater pipes were replaced by hoses interesting idea.

The ranging idle is no doubt the clicking ISC motor that is nicely tucked down low almost out of sight....

I have a few P codes that I need to look up, most of them were benign power disconnect codes if I recall. but Ill post them again.

She can miss somewhat noticably sort of like she is shuddering, then it goes away, he uses techron regularly. I need to drive it more to get more of a feel as to what it is. I have no way of measuring misfires on OBD1,

Gas pedal response is poor, my Deville would have stomped on this car. I think the throttle body cleaning may be part of that, no doubt its going to look bad when I get in there given the state of this car.

I have a 94 manual, this is a 95, I hope to review the OBD/DIC system real time parameter retrieval and see what I can explore. I want to check for vacuum leaks, hoses, injector orings/seating, clean the throttle body, and make sure the ignition wires are seated on both ends.

The positive battery cable is connected to the battery in a real rube goldberg method, no lead lug, just sandwidged and tightened to the battery, amazing, i need to check that, these coils draw a lot of current and a battery unable to deliver steady current is a problem.

I am 100% sure the throttle body throat and plate has never been cleaned. Will attached a vacuum gage to the engine to see what happens on initial throttle opening.

I am hoping that the coils are messed up, I have two replacements, easy swap, cant wait, to see how this engine responds to a little tender loving care..

There was a great writeup on the ISC motor cleaning by BARRY94, I need to grab that and link to it. Does clicking mean its FAILED, or can I clean it up or adjust it to stop the clicking? There is a closed throttle contact that gets corroded.

This car while well kept physically, has not been maintained well, which has been compounded by the fact that whoever has worked on this car likes to rube goldberg short cut. It needs rear struts, the mechanic eliminated the compressor and put a MANUAL schader valve in the trunk...and the compressor cycles at start up and during the code retrieval process, so it freaking works and this positive battery connection and replacing the heater pipes with hoses..... These types of things are like finger nails on a blackboard for me

I am all ears with any ideas, thanks Jim

Mike,

You need to buy a creeper that has an adjustable headrest - it makes a huge difference.

Most of the time, the closed throttle switch in the ISC motor assembly gets corroded and does not make good contact. I can't remember what icon is the indicator of the closed throttle switch on the climate control display - it should be the same as the '94.

Have the plugs been replaced or are there still plugs in the engine without platinum pads? Not sure what you mean when you say the ends of the wires are blown off. If the plug wires have been damaged, they need to be replaced.

[BodybyFisher]

Hi Kevin, Ill look into that creeper, my neck is still sore and side of my hips are bruised from laying on the concrete. Never noticed these types of problems before.. old age gotta love it

What I mean about the wire ends being blown off, is that the contacts that connect to the coil towers are damaged beyond repair from corrosion. I replaced both the ignition wires and plugs. I am a little concerned that the coil towers are still corroded, but I am going to swap new coils in and see if it makes a difference

Thanks for the info on the ISC closed throttle contact icon within the diagnostic, Ill check that

[BodybyFisher]

Ok as I noted the fuel pump, plugs, wires restored the engine's power but I still had a misfire at idle that 'seemed' to go away up the RPM range. It was sucking gas badly, and the idle was ranging due to a wacky ISC motor or bad adjustment of it

I pulled the coils and tested the primary and secondary windings against a known good coil, and to my surprise, one of the coils had an OPEN secondary, I replaced the coil and the misfire was gone and the engine purred nicely!

On to the ISC motor, I really did not want to remove the throttle body so I took the ISC motor off, one of the nuts was nearly impossible to get off. I disassembled the ISC motor, cleaned, the gears, contacts, motor brushes (with 600 grit wet and dry paper) to get them nice and smooth, greased the gears and reassembled it.

The nut I had a hard time removing was impossible to reinstall, so I ended up removing the throttle body, I figured that I could clean it up good anyway, which i did, it looks beautiful.... shoot me now... I forgot that the ORING that is behind the throttle body swells up and is impossible to reinstall, so I went to the dealer and it was NOT in stock.... they ordered it, it will be in tomorrow, for get this $30......HUH?, $30 for a 3 inch o-ring? Oh well...

Will advise as to how she runs when I reinstall the throttle body...looking good so far

Can someone point me to the guru's manual ISC adjustment that involves retracting the pindle and disconnecting the connector? thanks