: Problem with 1990 Seville 4.5



83CADMAN
09-29-11, 02:51 PM
I was driving, car was up to temp (208 deg) running great.
All of a sudden the thing stalls, I coast it off the street and try to restart.
After a few tries it fires up and I started making my way home.
When I gave it gas it sputtered like it was running out, (10 gal in the tank)
I managed to make it about half way home when it decided it was done stranding me with another roadside repair. I found a NAPA about ½ mi away and thinking fuel filter:suspect: did a quick R&R. It fired right up then died about 4 or 5 timed before it started and held a smooth idle.
But when I pulled the throttle open it sputtered and popped out the TB like the timing was off or something.:crying:
Any pointers on what to check first?

dennis93coupe
09-29-11, 04:18 PM
But when I pulled the throttle open it sputtered and popped out the TB like the timing was off or something.:crying:
Any pointers on what to check first?
This sounds like a camshaft problem. I'd go ahead and check timing, cap and rotor. If everything looks ok there, you'll need to take the valve covers off and look at rocker arms, bent push tubes. If you have a lobe going bad, you will be able to tell if the rocker arm doesn't have same movement as others. I don't remember the 4.5 having an issue with distributor gear, but that's another possibility.

83CADMAN
09-29-11, 07:50 PM
It has been about 7 years since its last tune-up. Sparkplugs were replaced about 4 years ago along with injectors.
So I opened up the dist to take a look and it really didn’t look all that bad. I replaced the old brittle internal dist wiring, ignition module, cap, coil and rotor.
It starts right up and idles sweetly…..throttle up a might and blahhhhh. I took a mechanics stethoscope and checked the injectors…all clicking like they ought to.
I can get it to rev-up but must do it gradually.
I havn't pulled any spark plugs yet through.
Man I hate to think it’s a camshaft, that will junk this car.

Sevillian273
09-29-11, 09:21 PM
Could be a MAP sensor or TPS issue. Both are used to control fuel delivery especially when opening the throttle. One senses the input from your foot on the pedal and the other senses the resulting change in manifold vacuum telling the computer when and how much fuel to add. OBD-I isnt the most sensitive system - many issues can exist without setting a code.

I think that if you had a bad cylinder (via bad camshaft, valve, etc) that the remaining 7 cylinders will be able to support higher RPMs albeit quite roughly.

ehall
09-30-11, 02:46 AM
If it's stalling on throttle then it's probably weak fuel delivery. Check pressure at the test port

dennis93coupe
09-30-11, 02:35 PM
:yeah: Also maybe a plugged cat....maybe. You will need to do a backpressure test which can be done with the fuel pressure gauge plugged into the O2 sensor. You don't want more than a couple pounds back pressure.

83CADMAN
09-30-11, 03:32 PM
Been reading up on the TPS for the 4.5……sounds like replacement is something I shouldn’t mess with, It involves stuff like disabling the generator by grounding it using a green test port near by??? My car has an alternator! And selecting PCM override PS 103 ICS actuator…PCM data PD 01TPS sensor….WHAT????? No access to OBD thru CCP!

How in the world do you test the TPS on this vehicle?
My books say to use a voltage meter and test with key on, engine not running. But how? Where do you connect the test equipment if the plug must remain attached to the sensor?
What happens if I unplug the TPS? Will it mess up the ISC settings?

Fuel pressure check is a good idea. I’ll have to get my hands on a gauge fitting set for GM.

dennis93coupe
09-30-11, 04:43 PM
Been reading up on the TPS for the 4.5……sounds like replacement is something I shouldn’t mess with, It involves 1232]stuff like disabling the generator by grounding it using a green test port near by??? My car has an alternator! And selecting PCM override PS 103 ICS actuator…PCM data PD 01TPS sensor….WHAT????? No access to OBD thru CCP!

How in the world do you test the TPS on this vehicle?
My books say to use a voltage meter and test with key on, engine not running. But how? Where do you connect the test equipment if the plug must remain attached to the sensor?
What happens if I unplug the TPS? Will it mess up the ISC settings?
In order to this you need the test harness. There are other ways to do those tests and adjustments. I doubt this your problem for now.


Fuel pressure check is a good idea. I’ll have to get my hands on a gauge fitting set for GM.

Sevillian273
09-30-11, 07:56 PM
They just call it a generator in the manual... dont worry about it.

I have the same year and model as you and I assure you that you CAN access OBD through the instrument panel. You can do the entire TPS procedure through the dash in fact. No need to mess with the DVM, grounding the alternator, etc. The numbers you posted are wrong for the seville/eldo's diagnostics anyway. Looks like you are reading from a haynes book!

A few months back I posted a detailed explanation of how to navigate the menus from the dash.... I'll try to find it again. In the meantime, I would chase down the fuel pressure both with key on engine off, and while running - observing the gauge when the engine dies.

83CADMAN
10-01-11, 05:59 PM
Got my hands on a fuel pressure gauge set this morning and hooked it up.
The results were:

· Key on, engine not running….. 2 lbs
· Engine running………………. 2 lbs gradually increases to 12 lbs (hard starting)
· Engine stalled………………… 12 lbs then slowly drops (dies on rapid throttle)

Not sure what it means, Can’t find what the fuel pressure is supposed to be.
Using a Chilton’s and a Hayne’s. Neither one is much help for this year car.

Sevillian273
10-01-11, 06:50 PM
Should be 34 to 38 psi!!

Fuel pump. :ill:

83CADMAN
10-01-11, 07:58 PM
I did finally find a reference to Fuel Pressure in one of my books; for the 4.5 it states 12 to 14 psi???? Considering the source…..
That’s a far cry from 34 to 38 psi!!!
Could it be the pressure regulator? It is up-line from the test port.
Since the spark plugs were 5 or 6 years old I pulled the front 4, two of them broke, all had a gap of .070 and were brown in color. I guess it’s about time.
Any tips on changing the rear bank’s spark plugs? Compression test?
Last time I paid to have the plugs done, but the times are a little different now, so I guess I must get greasy.

Sevillian273
10-01-11, 09:26 PM
This is what I hate about the haynes and chilton - the info is way too general. There are two 4.5's, '88 to '89 with TBI and 1990 with MPFI like the 4.9L. I could be wrong but I believe that spec is for the TBI 4.5. Either way you need 34 to 38.

I suppose the FPR could be bypassing too much fuel back to the tank but I've never heard of this. Not sure how you could verify it other than putting a test plug in the return line on the rail side and observing key-on pressure. (engine off)

On the plugs: http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/241440-change-spark-plugs-1989-seville-4-a.html#post2730262 Post #3. Its not fun but its do-able.

aeronca36606
10-01-11, 11:37 PM
With the pressures being sluggish to change and low on start up i would suspect a clogged fuel filter or a clogged line. You could also have a bad fuel pump. The pressure should come right up to full immediately and stay there through the entire engine power band. Should only vary a small percentage. If there is an obstruction of fuel flow and the engine uses it faster than it can be delivered, Then the pressures will be low and fluctuate. A failing fuel pump can also result in readings like these but fuel pumps generally either work half way decent or fail totally.

dennis93coupe
10-02-11, 12:08 AM
Your fuel pressure regulator will lower the fuel pressure when your engine is running. You might pull the vacuum hose on it and see if there is fuel coming out of the vacuum port. That would at least tell you if you have a blown diagphram in the regulator. I seriously doubt it would lower your pressure that much. I agree with Aeronca, change your fuel filter first because you should anyway. Check the pressure and make sure if the pressure is low you aren't losing fuel from an injector stuck open. It would be filling your intake with gas and I would think you would notice that. Make sure you don't have a kinked fuel line also, I saw that happen once.

Sevillian273
10-02-11, 12:12 AM
Post #1 - Fuel filter already replaced.

83CADMAN
10-02-11, 11:39 AM
Could a failed seal at the gas cap cause pressure issues?
The pump is pushing some gas. Never heard of a weak pump, weird I thought they either work or they don’t.
A new filter was first on my list. The last time it was replaced was about 5 or 6 years ago when the spark plugs were changed out. My had daughter accidentally put diesel in the tank prompting replacement of a few items, ie all 8 injectors, fuel pump, fuel filter, plugs and an oil/filter change. The car ran great up until recently.
I gona fight it out with the 4 rear spark plugs today.

dennis93coupe
10-02-11, 01:04 PM
Post #1 - Fuel filter already replaced.
Oops, sorry I missed that.:hide:

dennis93coupe
10-02-11, 01:10 PM
Could a failed seal at the gas cap cause pressure issues?
The pump is pushing some gas. Never heard of a weak pump, weird I thought they either work or they don’t.
A new filter was first on my list.
I remember having dealt with aftermarket pumps in the past, once we got all the aftermarket pumps replacede with OEM, problems seemed to go away. And yes they were low pressure. Don't forget the strainer on fuel pump either. I've see that problem too. You really can't rule anything out until you run tests.

Sevillian273
10-02-11, 02:07 PM
The only way the seal at the tank could possibly affect fuel pressure is if the tank vent line(part of the EVAP system) is blocked AND you have a perfect seal at the gas cap. This condition over time will create a vacuum inside the tank due to the pump sucking the fuel out of it. It takes a long time for this to occur and even longer for the vacuum to start affecting fuel delivery. So a bad seal at the filler neck will actually prevent this from occurring at all. Just unscrew the gas cap and check pressure if you want.

Blocking the return line at the rail will rule out the FPR and ensure that the fuel is not bypassing directly back to the tank. I have done this before with a 3/8" brass plug and some teflon tape. It's not perfect but it will get you an answer. (dont run the engine this way)

With the return blocked, there's no other place for the fuel to go except out of the FPR vacuum nipple in which case it would be shooting out profusely. :flame:

Even with a partially blocked line or filter, a healthy pump will still be able to generate good numbers on static pressure. It's the volume that will be cut short. So in that case it should make good psi with the engine off. Once you start the engine and the fuel starts moving, the pressure will then drop due to the volume demand. What I'm trying to say is, if the pump cant make more than 30 psi static then it's toast. Just for shits, turn the key on and off a few times with the gauge hooked up and see what you can get it up to.

ehall
10-02-11, 03:03 PM
I did finally find a reference to Fuel Pressure in one of my books; for the 4.5 it states 12 to 14 psi???? Considering the source…..
That’s a far cry from 34 to 38 psi!!!
The 4.1 and 4.5 engines through 1989 used throttle body injection (TBI) with two large injectors in the main housing. TBI systems typically have fuel pressure in the 10-20 range

The 1990 and later engines use port injection (PFI) with eight small injectors located near each cylinder. PFI systems typically have fuel pressure in the 30-50 range

Look at the front valve cover, does it say V8 PFI in big red letters?

83CADMAN
10-02-11, 08:21 PM
SOB! I finally got those bastards out! I see what you guys are talking about working blind. Good thing I’m long and thin, I wuz able to contort back and around but just barely.
Upon inspection the back four were fouled and burnt and looked very very old compared to the front four. Think I got took for a hundred bucks and four new plugs last time around, damit. Still puzzeling over the fuel pressure problem. Thanks ehall. Post #17 all 8 injectors were replaced. I think Sevillian273 is right "30 psi on the ready or the pump is toast. The pump I installed back when was an aftermarket from NAPA. Go figure. This time its GM.
Gota take a break before tackling the compression test.

Sevillian273
10-02-11, 08:57 PM
Assuming that the pump is in fact what failed, do you remember what brand it was(bosch, airtex, wells, etc)? And how many miles on it?

83CADMAN
10-03-11, 03:24 PM
I struggled for about 45 min trying to thread in my compression gauge hose before I decided the compression was OK, (the thing ran strong prior to this last mishap). Managed to get the new plugs installed.
Sevillian273, kudos to you. I re-tested the fuel pressure at the test port like you suggested;


Even with a partially blocked line or filter, a healthy pump will still be able to generate good numbers on static pressure. It's the volume that will be cut short. So in that case it should make good psi with the engine off. Once you start the engine and the fuel starts moving, the pressure will then drop due to the volume demand. What I'm trying to say is, if the pump cant make more than 30 psi static then it's toast. Just for shits, turn the key on and off a few times with the gauge hooked up and see what you can get it up to.

Ten, count em 10 “key on / engine off” cycles managed about 4.5 psi static pressure!!!!!
8 gals in the tank.

YEP! I’m convinced. I'll check what brand the old one is when it comes out of the tank and let you know.

dennis93coupe
10-03-11, 05:22 PM
Ten, count em 10 “key on / engine off” cycles managed about 4.5 psi static pressure!!!!!
8 gals in the tank.

YEP! I’m convinced. I'll check what brand the old one is when it comes out of the tank and let you know.

This sounds so familiar, and they were all NAPA that I had problems with. And they were all low pressure! We had about 10 that needed changed, some of the NAPA had only been in the tank a couple of months. I'm sure it was who NAPA's supplier at the time, after installing ACDelco problems went away.

83CADMAN
10-04-11, 05:53 PM
Dropped the tank this morning. When I removed the pump/sending unit carriage from the tank the strainer attached to it was plugged. This was probably the problem all along. No point putting the old pump back in through, no way to test it on the bench.
Priced out replacements:
GM: $125 / $30, pump/strainer
Napa: $85 / $7, pump/strainer “DEP & BOSCH”
$77 / $7, pump/strainer “NAPA”
This car has 330,000 miles on it; so on second thought, considering the cost difference, I think I’ll go cheap. The last pump did last 7 years and you just never know what will be next, whether or not it’ll junk the car.
Sure do give a shout out to all who contributed to this thread.

ehall
10-04-11, 05:58 PM
Bosch makes top-of-the-line fuel pumps, I would buy that first

Sevillian273
10-04-11, 06:02 PM
This car has 330,000 miles on it

http://explosiveisamu.files.wordpress.com/2011/05/holy_shit_a_shocking_face-s418x300-93419-580.jpg

dennis93coupe
10-05-11, 12:53 AM
Dropped the tank this morning. When I removed the pump/sending unit carriage from the tank the strainer attached to it was plugged. This was probably the problem all along.

:hmm: That's strange.... I thought I.....never mind.

aeronca36606
10-05-11, 03:37 AM
Good you found the problem. Even though you found a clogged intake filter, you will be better off replacing the pump rather than just replacing the intake filter. A plugged intake filter is much harder on the pump than a plugged line filter. The Fuel Pump is cooled and lubricated by the fuel moving through the pump. When it is blocked at the intake, The pump runs hot and dry. I am sure that even if the pump was Ok now, It is probably not long for this world.

I have no idea who makes the best pump. I am sure others on the board can answer that. I have had good luck with every pump i have replaced except for a AC Delco installed at a dealer due to a failure on a long trip. (Not even sure it was an AcDelco but that is what i was billed for). That pump lasted only a month!

83CADMAN
10-05-11, 12:00 PM
Don't forget the strainer on fuel pump either. I've see that problem too. You really can't rule anything out until you run tests.

Thanks dennis93coupe, you did point at the strainer as a possible culprit. Unfortunately the only test for the strainer is visual and if the whole unit has to come out both pump and strainer is going to get replaced. I'm just so grateful its not the camshaft. Also I’m installing the Bosch unit.

dennis93coupe
10-05-11, 12:41 PM
Thanks dennis93coupe, you did point at the strainer as a possible culprit. Unfortunately the only test for the strainer is visual and if the whole unit has to come out both pump and strainer is going to get replaced.

And pressure test, beings you had very low pressure it was starving the pump. Good idea, change em both.


I'm just so grateful its not the camshaft.

So am I.....


Also I’m installing the Bosch unit.

I've heard good things about them lately.

83CADMAN
10-11-11, 03:58 PM
I got the tank R&R with new pump finished up last Wednesday.:thumbsup: When I started to ask the NAPA clerk about pressure ratings on the replacement fuel pumps I found the Bosch unit had a rating of 28.:suspect: Their slightly higher priced OEM unit was 68, so was the cheaper NAPA unit. All three had the same warranty. I decided at the store to go cheep. What can I say? Less money, same warranty, higher pressure rating.:)
Anyway I put over 500 miles on the car this last weekend.:bouncy: Spent 3 days on a chartered jet boat fishing for Steelhead at the outlet of Hells Canyon on the Snake River near the Washington / Idaho boarder. YA! BABY!:thumbsup:
The car ran flawlessly the whole distance. Gas mileage avg was 20.1, and anyone who has driven eastern Washington State knows it’s a lot of up and down and twisty turney. Plus I like to take the path less traveled, zero traffic most of the time.
I want to say, “Thanks for all the advice and support in the diagnosis of my Seville. I got it repaired just in time”. :worship:

dennis93coupe
10-11-11, 09:45 PM
:highfive: Cool

ehall
10-11-11, 09:57 PM
the Bosch pump must have been for TBI

Sevillian273
10-12-11, 09:34 PM
Absolutely. That piece would have struggled to meet the demands of your fuel system and may have had you chasing the problem elsewhere!

The problem with the 'one-off' 1990's is that they all get roped in with the TBI 4.5s when it comes to aftermarket support. This happened to me at RadiatorClassic - I measured my radiator and found that it was bigger than the one they had listed for 1990 so I had to order the 91-95 model. A perfect fit! Same issue with the cam sensor which according to Advance Auto does not exist for the '90. Many others....

drewsdeville
10-12-11, 09:47 PM
Absolutely. That piece would have struggled to meet the demands of your fuel system and may have had you chasing the problem elsewhere!

The problem with the 'one-off' 1990's is that they all get roped in with the TBI 4.5s when it comes to aftermarket support. This happened to me at RadiatorClassic - I measured my radiator and found that it was bigger than the one they had listed for 1990 so I had to order the 91-95 model. A perfect fit! Same issue with the cam sensor which according to Advance Auto does not exist for the '90. Many others....


Interesting. I haven't run into this problem yet.

I was surprised by the Advance Auto cam sensor remark, so I took a look:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Ignition-Pickup-Stator-BWD_18240117-P_200_R|GRPTUNEAMS_1733067241____#fragment-2 (http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Ignition-Pickup-Stator-BWD_18240117-P_200_R%7CGRPTUNEAMS_1733067241____#fragment-2)

A lot of times my problems at these chain retail stores is the lack of knowledge from the n00b clerks. In the case of the cam sensor, you never know what category he searched under. Could have been windshield wipers for all we know. Many of them know how to match up the part number on the computer with the box on the shelf, and how to match the colors on battery cables. Beyond that, you never know who you'll run into.

dennis93coupe
10-12-11, 09:59 PM
Interesting. I haven't run into this problem yet.

I was surprised by the Advance Auto cam sensor remark, so I took a look:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Ignition-Pickup-Stator-BWD_18240117-P_200_R|GRPTUNEAMS_1733067241____#fragment-2 (http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Ignition-Pickup-Stator-BWD_18240117-P_200_R%7CGRPTUNEAMS_1733067241____#fragment-2)


A lot of times my problems at these chain retail stores is the lack of knowledge from the n00b clerks. In the case of the cam sensor, you never know what category he searched under. Could have been windshield wipers for all we know. Many of them know how to match up the part number on the computer with the box on the shelf, and how to match the colors on battery cables. Beyond that, you never know who you'll run into.
And they have a real problem deciphering Deville from Seville....

Sevillian273
10-12-11, 10:19 PM
Interesting. I haven't run into this problem yet.

I was surprised by the Advance Auto cam sensor remark, so I took a look:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Ignition-Pickup-Stator-BWD_18240117-P_200_R|GRPTUNEAMS_1733067241____#fragment-2



Haha! Looks like they finally caught up. I tried to buy the sensor in 2008. I witnessed the search myself and indeed it was not listed. I couldnt find it on their website either. Also when I got the car, the PO mentioned it had an eo41(open cam sensor circuit) but he taped over the CEL because "This car dont have a cam sensor." :histeric: Theres a couple more examples I've run into but I dont recall at the moment.