[1976Seville]

Working on a buddys car for him a 1976 V8 Seville. Multi- port injection. New battery and alternator. Fuel pump works and there is pressure at the fuel rail. Starter works but can't get this thing to start. Where to start? Don't know much about these cars. I know the air temp sensor is broken and out of the car...the hole in the intake manifold is pluged with a bolt and the plug is disconncted. Would this cause the car not to start? Was this way before and the car ran without it...now it won't start. Also how do you read trouble codes on these cars? Is there a code reader you can buy? I found the computer under the das but can't see where you would plug a code reader into? Any help you guys can offer would be great. I know cars but othing about these ones...lol. Thanks guys!

 

[davesdeville]

Seems like it should run without the IAT. Might not run perfectly but should run. If the fuel's spraying, next thing to check is ignition system.

 

[SteveThefolkie]

An internal combustion engine - any internal combustion engine - requires three elements to function -
fuel
compression
ignition

in a diesel the last two are combined (a diesel functions through compression ignition) -

apparently you've got fuel - so it's either compression or ignition - you can check the compression with a compression check gauge (fairly cheap to buy and easy to use) - not sure what your compression in PSI should be - but it should be consistent across the cylinders.

Ignition - there are a couple ways to check it but the easiest and cheapest is to pull a plug wire, put a plug into it, ground the plug against the engine block or something else convenient and have someone else crank the engine over - you should be able to see a spark bridge between the plug and the ground - if you don't get a spark then you're not going to get any boogie -

If you've got no compression you've got an internal engine problem - could be as simple as a couple exhaust valves stuck open from carbon deposits to a broken camshaft or camshaft drive - or you could just have jumped a couple teeth on the cam chain (which would throw the timing of the valves out of phase with the crank rotation) -

if it's no spark - well - then you get to trace through the ignition components

If (and I'm not sure) but IF the vehicle has a circut just for the primary ignition (distributor/coil) check the fues for it before you do anything else - if it's got HEI you should get voltage to the modue on top of the distributor when the ignition is turned on at the key (a test light with a probe helps for testing this) -

Now let's say you've got compression, fuel AND spark - well - it could be that the distributor has shifted and the timing is way off (which will not allow the car to run 'cause the spark won't be happening around TDC on the compression cycle) - you can check that with a timing light -

Best of luck with it -

Steve

 

[1976Seville]

Thanks a lot guys for all your help.....I checked for spark yesterday and it seems like there is none. I have a feeling it's the ignition. It is an HEI system so Steve I will do the tests you suggested. Out of curiousity how do you pull trouble codes from these cars? Anyone know...can't find a code reader for it anywere?
Thanks.
Rog

 

[1976Seville]

No one knows how to pull codes?

 

[davesdeville]

Not on a car that old... Is it standard HEI or computer controlled HEI? I've got no experiance with CC HEI, but if it's standard, non CC, I'd start by opening up the distributor and replacing the ignition control module and coil. The ICM likes to die under high heat conditions. I think a few parts stores will test coils.

 

[SteveThefolkie]

No one knows how to pull codes?

I'm not sure about how to access your codes - the last car I had that didn't have a display function was a 1990 Buick - for that you bridged two contacts on a connector that was under the steering column and a light on the dashboard blinked.
You counted the blinks (and the spaces) and that gave you the trouble codes - the dealers would just hook to a computer and get the codes that way.
'76 would be pretty early for CC HEI ignition - I mean hell - they still sold regular leaded gas in '76 - I'd presume that it's not computer controlled - which would mean that parts for it will be rather cheap.

Best of luck with the car -

Steve

 

[tripleyellow78cad]

Depending where you live , my local autozone will check the ign mod for free
they did it on my 90 5.7 gmc, hope this helps

 

[davesdeville]

'76 would be pretty early for CC HEI ignition - I mean hell - they still sold regular leaded gas in '76 - I'd presume that it's not computer controlled - which would mean that parts for it will be rather cheap.

Well hell it's already got a "computer" controlling the injectors...

 

[Eldyfig]

Where did you check for spark? If at the plug, go further up the line. Is there spark from the coil? Like Dave said, check the distributor also, maybe the cap. A small, barely noticable crack in the cap will prevent startup.

 

[Cooper]

I have owned 7 Sevilles of the '76 thru '79 vintage. One of my favorite cars. The Olds 350 was a great workhorse ! When I had a starting problem with them it was almost always the coolant temperature sensor on the front of the intake manifold. There are 2 sensors on the intake manifold and they are identical and can be interchanged. At the time they were spendy little items so I went to a boneyard and got a few used ones as backup. Memory not so good but I think one of the sensors was for air temp on the backside of the intake manifold and coolant temp on frontside. I have a wife and 2 daughters and we all drove Sevilles at the time. They were always good starters even in very cold (Minneapolis, MN) winter weather when outside overnight. However if one wouldn't start and battery etc were all good, I would routinely replace the front sensor, 2 minutes and a 9/16 wrench. Again, can't remember details but I used to check them with an ohm meter, which you can do quite easily by uncoupling the disconnect plug. I would check both and see if they read the same cold, if not you probably have a bad one.

 

[Randy_W]

Well hell it's already got a "computer" controlling the injectors...

My '80 Grand Am with the T/A 4.9 came with electronically controlled HEI.

 

[Pjs]

Check the connectors to the ign module under the rotor. The HEI distributors with vacuum advance had a tendency to break the wires due to the advance plate moving back and forth. I've also had coils go bad without any warning...one day it works..next day it won't start. Make sure there is a good coating of dielectric grease under the ign module.

 

[SteveThefolkie]

Well hell it's already got a "computer" controlling the injectors...

The feedback loop required for the control of fuel injection (which, by the way, can be controlled without a computer - witness the Rochester fuel injection installed on the 327 Vette) would have been far less sophisticated than that used on a more recent vehicle. Depending on your definition of "computer" the rather basic PLC (Programmable Logic Controller) used in early feedback loop systems for fuel injection may or may not qualify. They did not perform the calculations that a "modern" control system will, rather they relied on boolean logic and feedback from sensors in various locations and, based on that feedback, changed their output based on imbedded ladder logic.
Modern computer controls are far more sophisticated - and in fact can "learn" your driving style and adapt accordingly, rather than just reacting to feedback sensors (temperature, throttle position, pressure drop over time) -
If you want to consider a couple of basic PLC's to be "computers" then I'll agree with you that a '76 had a computer - but you're comparing an ENIAC to a CRAY if you compare it to a modern OBD system.
The HEI system may have had some level of computer control - European cars from that era had knock sensors which would, when activated, retard the timing, for example, but again, that was simple logic executed in fixed steps within a non-adaptive logic system.

Steve

 

[davesdeville]

^^ Why do you think I put computer in quotes?