Seville

[Charlie Chops 1940]

After setting for the last 6 years or so I decided to put air in the flat and a good battery and fire the old girl up. It's a '78 Caddy Seville Elegante 4 door with the 350 Olds engine with the throttle body fuel injection.

I got it to fire but it won't keep running unless I keep pumping the throttle, and then just above idle. I believe the fuel filter canister is under the car near the external electric pump somewhere. I can hear the pump run but of course I can't hear the filter clogging. Any educated guesses which is the culprit?

Thanks,

Charlie

[enjenjo]

Check the throttle position sensor. They stick when the car sets for extended periods, and cause the problem you are having.

[wayne petty]

first generation cad fuel injection info

a warning... these cadillac EFI units switch the positive side of the injectors with all of the grounds o a fuel rail hold down bracket..

if the injector connectors are broken... and the wires fall off or touch ground with the engine running MAY BURN OUT THE ECM.....  not a good thing...$$$$$$$$$  

there is a rotating magnet in the distributer that closes reed switches in the black block ... it only triggers each one for a degree or so...
there are 3 wires in the connector... use your continuity beep function to test it... with the engine cranking...  

coolant temp sensor and air temp sensors need to be within 3 ohms of each other when tested in cold water and in hot water...   they do go bad...and are almost impossible to get new...  

-20f =600 ohms  
+250f = 1600 ohms...
+80f should be around 980 ohms...

(don't throw out any old coolant or air temp sensors from these models...   send me a pm... for their secret... you will be happy you saved them...

throttle position switch should have continuity with the throttle closed between pins 12 and 17...  put a 0.020  feeler gauge in the throttle stop and you should still have continuity...   put in a 0.025 and it should show open on the ohm meter...
the switch has gold plated contacts inside.. so it can possibly opened and cleaned with qtips and rubbing alcohol...

these are the usual failures... except for burned connections at the ecm...  do to being unplugged too many times...  if it burns ... you have to replace it and the connector... except ... when i change them... i only cut and splice the burned wire ends with the junk yard connectors... i use pointed tools to bend the terminals to grab onto the circuit board
edge connector tighter


the fuel filter is usually around the rear axle... and uses an autozone # FF4425  same  filter is used on ford mechanical fuel pumps... so they are available everywhere ....


the only other problem with these are the rear brake calipers... they get out of adjustment and the  brake pedal gets too close to the floor...

i will post that info later...

need more info.. ask.. i know them inside out....

i still have one customer with one but his was a diesel... after wearing out 2 motors... somebody told him a izusu 3.9 turbo diesel would fit.....

pics to come...

[Charlie Chops 1940]

Thanks Frank and Wayne.

I have the throttle position sensor off the car. The plug and wires all look god. No critter gnawing evident. I tested between terminals 12 and 17 and get a beep in the closed position and nothing through any of the travel to fully open.

I pulled the cover off the assembly and nothing fell out but some very small organic debris. Usually when I disassemble something like this at least 2 springs and a ball bearing propel themselves from the unseen depths of the part - never to be found again.

There is heavy tracking on the strip for terminal 9, 12 and 14. One contact starts out on 12, goes onto 2/14 and then 17 at full open. I'll try cleaning it later and see if it makes any difference.

Charlie

[Charlie Chops 1940]

Wayne,

I know about the brakes. Went through all of that 10 years or so ago. Did all the calipers and a master cylinder. I've had this car for 19 years. It's got a real nice body, crappy paint, a leaky sun roof and dried out leather...but other than that it's a cherry.....

Charlie

[wayne petty]

glad you are familiar with the quirks of the brake system ...

mom has an 79 eldorado... the biarritz version...  i managed to get the moon roof seal changed...  not an easy job.. i think that if i ever had a leaker.. i would open the top part way.. and try to recoat the outer face of the seal with something after a light cleaning... letting it cure before closing it...

when i took the seal off... i found that it was not stuck  down all the way around... along with cracks in the sealing edge...

i was only able to get the seal properly replaced by pulling the entire sunroof ..   a bear of a job....

the 12 and 17 pin continuity tells the ecm that the throttle shaft is closed and at idle position...     if the throttle switch does not open the circuit at 0.022 to 0.025 off the throttle stop  the fuel control will not happen at the right spot..

as for the other pins... they do cycle back and forth as the throttle is moved... and a pair of contacts that close when it opens or closes depending on which way it is moving..      there are small triangular things that fit in the corners of the tps case... i think they are some kind of ferrite? .. their purpose ?  az list the # TPS145 as the replacement..

[Grandadeo]

Getting it ready for NSRA meets??

Lee

[Charlie Chops 1940]

Getting it ready for NSRA meets??

Lee

Yeah, it's the real deal - none of that fauxtina for this old guy.

Charlie

[Charlie Chops 1940]

Thanks Wayne, I will krep this in mind when I reinstall. Ferrite triangles - anti-magnetic? only 3 in place, At $66.99 I'll probably replace it, and a filter. AZ list 3 pump p/n's and says 2 low pressure pumps, 1 in tank, 1 external on both and the a 3rd p/n which says 2 high pressure pumps. That doesn't make a lot of sense and none of the verbiage tells what's what.

Charlie

(quote)the 12 and 17 pin continuity tells the ecm that the throttle shaft is closed and at idle position...     if the throttle switch does not open the circuit at 0.022 to 0.025 off the throttle stop  the fuel control will not happen at the right spot..

as for the other pins... they do cycle back and forth as the throttle is moved... and a pair of contacts that close when it opens or closes depending on which way it is moving..      there are small triangular things that fit in the corners of the tps case... i think they are some kind of ferrite? .. their purpose ?  az list the # TPS145 as the replacement..[/quote]

[wayne petty]

were you able to measure the coolant temp sensor.. and the air temp sender with the engine totally cold??    or by taking them out and dunking the ends in cold water , Ohming them... while still in the water...

set ohm meter to 2K ohm scale...

then in warm water or hot water... and testing..

i guess the autozones in different areas have different pricing.. the tps is less than 50 in zip code 90026...

[Charlie Chops 1940]

Didn't get that far yet. What does it cause if either ot both are bad?

Charlie

were you able to measure the coolant temp sensor.. and the air temp sender with the engine totally cold??    or by taking them out and dunking the ends in cold water , Ohming them... while still in the water...

set ohm meter to 2K ohm scale...

then in warm water or hot water... and testing..

i guess the autozones in different areas have different pricing.. the tps is less than 50 in zip code 90026...

[wayne petty]

this is an analog system without an oxygen sensor... so without the exact voltage input.. the fuel mix will be wrong....

takes 2 minutes to check them on a stone cold motor...

5 minutes to check them on a warm motor as you really need to unscrew them and drop the threaded ends in a plastic cup of ice water while measuring the resistance at the pig tail connection...

they have to match within 3 ohms.. or the system will backfire through the intake...

[wayne petty]

how much fuel pressure do you have???  

37 to 42 psi with the key on engine off...  measured at the fuel rail...
the fuel rail has a conventional sae flair fitting with a schrader valve that the 20 buck fuel pressure tester at most parts stores...


how is the freshness of the fuel?? changed the fuel filter yet???

put a bucket under the filter housing.. cycle the key on a few times...  don't start the motor... the fuel pump will run for 2 seconds...

there is a chance that the fuel injectors are dirty from sitting all that time with old fuel...

how are the spark plugs??   i know they are a pain to get too... but pull out a few easy ones....      clean...  tan...   brown and covered with corrosion ,,,   black   fouled with oil and excess gasoline...

got a vacuum gauge?   hook it to the intake manifold... see when you rev the motor up... if the vacuum increases...   as you might also have a blocked exhaust system...  muffler fill with mice bedding...

so many things it could be... but it really is the simplest system out there...