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HELP on the road! 77 Seville, runs fine for a while, dies, cools... repeat

Started by wmlink, August 28, 2006, 08:51:05 PM

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wmlink

Bought a 77 Seville (Im on the return road now), runs fine for a while...loses power until it stalls, no restart until it sits a while...then repeat! replaced BOTH fuel pumps and filters, new COMPLETE (EVERYTHING)Distributor...no change except Im lighter a bunch of money!  I have had catalytics pull this type of thing but I could here the pressure release after the car died...I do not hear this with this car. Any good guesses????

Chris Arneson #22170

Well you have my compassion for being broke down while on the road.  Where abouts are you?

As for getting the car running, have you checked for spark while it refuses to start in order to isolate the problem to either electrical or fuel related?  It sounds like so far youve tried things in both systems.

Here are some things that come to mind...

The distributor module was the first thing that came to mind but the "loses power until it stalls" makes me thing its more likely fuel related.

How about the gas cap, maybe not venting properly.

How far does it go before it stalls?

Chris.

Gene Moscicki

Wm Link is stuck in Redlands California, contimplating buying a new truck to tow the car home! Can someone help.

bill henry

dude sounds like the coil to me its in the top of the distributer cap so you cant pull the wire off  but they will fail when hot and run good cold

Jim Smith

Wm

Was speed sensor replaced with distributor?  Just had somewhat similar experience with 79 seville. Ran fine, didnt stall but refused to start when hot.  Started fine after cooling down.  Had speed sensor on distributor replaced yesterday and ok now.   Jim

Rob Bruining CLC12428

I had similar problems with my 77 a few years ago. These engines had a very common problem with the fuel pump circuit in the under dash computer. The easiest diagnosis was to install a rebuilt or good used computer. A friend loaned me one of his spares to try. Bingo, no more stalling problem. I too spent much time , money , and aggrevation until properly diagnosed. Last I knew this friend had a few spares still hanging around.   Rob

Wm Link

That was FUN! Im back home from this frustrating ordeal. A 6hr trip that took 3 days! I replaced with a WHOLE rebuilt distributer, coil assem, speed sensor...everything. BOTH fuel pumps/stainer and filter were replaced. NO improvement. I then replaced the Catalytic...and that made a BIG difference...it drove just PERFECT!!!! err, huh well for about 80 miles @ 85 mph. Then it crapped out with no restart until it felt like it. Hotter than the hubs of hell outside. I came up with some interesting stuff in the middle of the desert for one 6 HOUR afternoon episode as simis rocked the car as they roared past. The beast WILL NOT/WOULD NOT start until its good and ready. It was getting spark AND fuel...I think now it was actually flooding to death... I rigged up a hot wire to the rail fuel pump...and disconnected its original computer feed. When I SHUT off the rail pump the car started again and ran PERFECT @ 85 MPH for about 20 miles...then it started to act up again, the fuel economy light went from green to yellow, car was surging and sputtering...I turned the rail pump back on and it started to recover...back and forth, on...off...while in between there were still periods where the car ran just perfect.  I was able to massage the fuel enough where needed to at least keep it barly running eventually able to limp it home. The results were not aways successful or consistant, but generally that was how it went. I am guessing the following: The choke assembly is suspect, a large intermitant vacuum leak, maybe intake manifold?  Computer of coarse, MAP sensor, or fuel pump relay? Thank you for your input! Wm Link      

Bruce Reynolds # 18992

Gday William,

I am, like everyone else is, waiting with baited breath to hear what the actual culprit was.

But, it is good to know that you are home safely.

When will the book be coming out?

Bruce,
The Tassie Devil(le),
60 CDV

FRED ZWICKER #23106

I had a similar experience with a 1952 Pontiac back in 1954, while in college. It always started and ran perfectly, but occasionally when it got down to around 1/4 tank of fuel, it would slowly and gradually stop running, almost as if it was running out of gas.  The car positively would not start, but after letting it sit for around 20 minutes, it would start up and run well.  This went on for several months.  I replaced just about everything (fuel pump, carburetor, spark plugs and wires, points and condenser, coil, etc.). One friend even suggested new seat covers! Still the problem continued.

So one night around midnight, the car stopped in a snowstorm in the middle of a bridge and would not start.  I left the car on the bridge, as had no money for towing and walked home (about 2 miles) in the snowstorm and caught a few hours sleep. I then walked back and the car started and I drove it home. I finally decided I would check the last possible thing - remove the gas tank. The temperature was near zero outside and we had no garage.

So I jacked up the car (in the snow in my driveway) and crawled under the car and removed the gas tank. (Tank was around 1/4 full, as was usual when the problem occured).  I removed the gas gauge sensing unit that was located on the top of the tank and looked inside the tank with a flashlight. The inside of the tank was spotless.  

I was just about to give up when I spotted a small piece of tan paper that had hung up on one of the supports inside the tank. I got 2 wire hangers and made a hook on the end of each and carefully hooked the paper and pulled it out.

Looking at the paper, recognized it as the same paper that the gas stations used when cleaning your windshield or checking your oil (yes they used to do this even with a $1 purchase). My theory is that the gas station attendant used the paper to help open the gas tank cap and somehow a small chunk of paper somehow fell into the tank. The paper was only about 2" square with ragged edges, but as this paper was so durable, it would stay in good shspe inside the tank.

So (my theory continues) this paper floated around inside the tank and when the tank got low on fuel, the paper would get sucked over the outlet fuel line from the tank, stopping the flow.  Then when car sat for awhile, it floated away and car would start.  When tank was full, the paper floated up higher and everything was OK.  I kept an extra fuel pump in the car and one time changed the fuel pump on the side of the road and car started afterwards.  I thought the problem was solved, but what really happened was that the paper floated away while the new fuel pump was being installed, so the problem continued.

I would have sold the car, but had no money to buy another. After I found the problem, the car ran perfectly for another 50,000 miles.  This was the most frustrating experience that I have ever had with any car and something I will never forget. Sometimes the most difficult problems are so simple once you figure it out. If you havent checked the inside of the gas tank, it might be a good idea to do so.

Fred Zwicker
1939 LaSalle Convertible - Maroon

Jerry

About 20 years ago I was driving an early 70s Olds station wagon and had a similar problem as Fred Zwicker. It was also a very cold and snowy night, the whole family was in the car and we were about 90 miles from home when the problem started.  

The car would drive for a while without any problems and then suddenly stall.  It would occur sometimes when I was rounding a corner or accelerating - other times on the straight road.  The car would restart shortly afterwards and we could drive again for a while until the problem re-occured.  We finally made it home in the middle of the night - many hours later.  

When I dropped the tank I determined that there was a piece of screen on the gas line that was becoming blocked. I corrected the problem and the car still drives great to this day.

Wm Link

Right now its abandonded in the back yard...I have a TON of stuff to catch up on. I think more and more its a vacuum leak issue. A vacuum leak would cause the computer to think its WOT (wide open throttle). It actually seems to be getting TOO much fuel when it acts up.

mechanic80

I've got the identical problem!  replaced distributor, fuel pumps, rewired fuel pump circuit,  ECM rebuilt.  It's not excessive temperature, it dies @ 65 degrees.  It seems time and altitude are an issue.  I say this because it stumbles and dies on the way home from work.  About 20 minutes into the trip from Albuquerque and an added 1000 feet of elevation, it starts to stumble (lasts for a couple of minutes) and then REALLY stumbles and dies.  Wait 20-30 minutes, starts and she's fine for another 7 to 10 minutes.  I'm getting really tired of it.  I cant trust it to use in a wedding Sunday.
I think it was Bruce Rowe(?) who offered to check the function of the rebuilt ECM.  Bruce, is that offer still good?  it's been in the body shop for ten months and is now out.  It LOOKS great.  Now if it would keep running.  Fuel level has no affect.
mechanic80

Scot Minesinger

I think this it.  look at your EGR valve and gasket. 

You have to get a real good Felpro gasket intended for exhaust duty.  Had the same problem on a 76 Cadillac where to keep it running after a highway drive had to have foot on brake and gas pedal.  The new NAPA gasket under EGR failed leaving the valve in the open position because no good seal between intake and exhaust.  Once I put a good gasket on the EGR the car ran smooth.  Another possibility is that the EGR is opening by control with good gasket when it should not.  Disconnect EGR vacuum hose and plug.  If it smooths out and has a good gasket, you know control is bad. 
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

bcroe

The 76-79 Cad fuel injection is the first electronic fuel injection here, using the
just available integrated circuit technology.  Since microprocessors were not
available in time, it uses a completely different (analog) design than subsequent
systems.  One item was the MAP sensor, built into this computer.  Unfortunately
this early electro-mechanical MAP sensor turned out to have a very high failure
rate, esp in recent years.  The output voltage will drop or quit, and you get no fuel. 

What I have seen, is the car will run while the cold enrichment is multiplying the
fuel by 2 or 3.  As it warms up, the fuel decreases and the engine leans out.  There
are no replacements for this MAP, which runs on 9.5V instead of a modern 5V, and
puts out 7.5V instead of 4.5V.  To solve this problem I have designed a drop in PCB
that regulates the supply voltage down to 5V, and uses an amp to boost the MAP
output to 7.5V.  The MAP is a currently available solid state device. 

There are other 70s ECU components that can cause similar problems. 

I have seen more than one bad 70s ECU that a supplier had declared good.  I don't
know if it failed later, or the suppliers don't have the resources to service the old design. 
Its best to have a spare ECU which can easily be swapped in, to eliminate all doubt
(or just to get you home).  Bruce Roe  CLC #14630

olds34dude

An Oldsmobile 350 Edlebrock intake and carb, oops, sorry, couldn't help myself. Dvarney
D. Varney

mechanic80

I hope I can get this out without being too wordy (as usual.)  I had the SAME issue with my 77 Seville bit it always happened about 10 miles into a 1000' rise in altitude from town to home.  Seemingly unrelated, I was really tired of listening to the darn external pump hum, so I decided to install a KESHEN KS68 electric pump in place of the in-tank, low pressure original.  I had replaced both pumps well over a year ago and although things were ok the first  few trips up the hill. the same problem returned and I looked elsewhere for the problem.  Here's what I found upon taking out the in-tank unit this time: The original pump did not have clamps on the short hose from the pump out to the steel line in the sending unit so I didn't think of putting any on with the new one several months ago.  Taking the tank pump out last weekend, I found a stretched out, horribly fitting hose in place of what was a fresh, snug hose only months earlier.  Ain't ethanol great?!  A great deal of gasoline was just recirculating in the tank because there was a huge gap, top and bottom of that little hose.  Where I was thinking it was the altitude causing my problem (7300'), it was the length of time that poor pump could hold out and provide enough low pressure flow to the high pressure frame rail pump.  To make a long story short, (TOO LATE) the new in tank high pressure pump solved the noise problem and(so far) the runs, dies, cools, repeat issue.   I hope this is helpful.     Next item: exhaust system.  Any input would be welcome. 
mechanic80

TMoore - NTCLC

yes, that hose can cause issues.  I spent a lot of time (and had to drop the tank multiple times) before I discovered a hairline crack in that hose.

Gene Beaird

Norbert,

So you have found a pump that fits in the tank in the factory location?!?  I cannot find an image of that pump, and searching for 'KS68' on the Keshen web site is a FAIL.  Where did you get it, and what does it look like? 

Thanks.

Quote from: mechanic80 on June 24, 2015, 09:06:44 AM
I hope I can get this out without being too wordy (as usual.)  I had the SAME issue with my 77 Seville bit it always happened about 10 miles into a 1000' rise in altitude from town to home.  Seemingly unrelated, I was really tired of listening to the darn external pump hum, so I decided to install a KESHEN KS68 electric pump in place of the in-tank, low pressure original.  I had replaced both pumps well over a year ago and although things were ok the first  few trips up the hill. the same problem returned and I looked elsewhere for the problem.  Here's what I found upon taking out the in-tank unit this time: The original pump did not have clamps on the short hose from the pump out to the steel line in the sending unit so I didn't think of putting any on with the new one several months ago.  Taking the tank pump out last weekend, I found a stretched out, horribly fitting hose in place of what was a fresh, snug hose only months earlier.  Ain't ethanol great?!  A great deal of gasoline was just recirculating in the tank because there was a huge gap, top and bottom of that little hose.  Where I was thinking it was the altitude causing my problem (7300'), it was the length of time that poor pump could hold out and provide enough low pressure flow to the high pressure frame rail pump.  To make a long story short, (TOO LATE) the new in tank high pressure pump solved the noise problem and(so far) the runs, dies, cools, repeat issue.   I hope this is helpful.     Next item: exhaust system.  Any input would be welcome.
Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

bcroe

Quote from: mechanic80I had the SAME issue with my 77 Seville bit it always happened about 10 miles into a 1000' rise in altitude from town to home.  Seemingly unrelated, I was really tired of listening to the darn external pump hum, so I decided to install a KESHEN KS68 electric pump in place of the in-tank, low pressure original.  I had replaced both pumps well over a year ago and although things were ok the first  few trips up the hill. the same problem returned and I looked elsewhere for the problem.  Here's what I found upon taking out the in-tank unit this time: The original pump did not have clamps on the short hose from the pump out to the steel line in the sending unit so I didn't think of putting any on with the new one several months ago.  Taking the tank pump out last weekend, I found a stretched out, horribly fitting hose in place of what was a fresh, snug hose only months earlier.  Ain't ethanol great?!  A great deal of gasoline was just recirculating in the tank because there was a huge gap, top and bottom of that little hose.  Where I was thinking it was the altitude causing my problem (7300'), it was the length of time that poor pump could hold out and provide enough low pressure flow to the high pressure frame rail pump.  To make a long story short, (TOO LATE) the new in tank high pressure pump solved the noise problem and(so far) the runs, dies, cools, repeat issue.   I hope this is helpful.     

Next item: exhaust system.  Any input would be welcome.

I'm not sure what the pump looks like, but I'll find out when it gets here.  After the GN I'll be putting it in
my rebuilt diesel (24 gallons) tank with single pump, and 100 % new copper lines to replace the rusted out
steel ones I patched up earlier.  And some kind of simple in line filter to replace that cartridge.  I'm rerouting
all of them and the emissions canister to the right side, because its too crowded on the left with my TH425
switch pitch trans. 

That car needs at minimum a 2.5" exhaust with good flow components all the way.  I build mine from 304
stainless steel, because I want this time to be the last time.  Can't bend it, but buy pre bent U sections and
cut as much of the angle as needed, butt MIG weld curves & straights together to make a system.  The
original cat is junk and probably slowing you down; a monolithic style is legal, much smaller, and has much
less back pressure.  I use plenty of hangers; the 3" I just put on my 79 Eldo has 4 custom modified hangers. 

I'd guarantee a good exhaust and a switch pitch trans would take more than a second off a 77 Seville
0-60, and probably increase mileage as well.  Bruce Roe

mechanic80

It was an e(something)y  purchase from auto replacement parts inc, in miami FL.  It fits with little modification (wires), but because the strainer is on the opposite side, the pump installs at a slight angle so the float and strainer are on the same side for ease of installation.  It was good and hot in New Mexico yesterday and she ran like a top.
No stumble, no fumble no nothin!  Keshen fuel pump KS68 pulls up by description on my yahoo search.  Thanks for the exhaust advice, Bruce.
mechanic80