need some help

[ryanelco]

first off my friend purchased an 84 grand national for 800 bucks. thats right 800. car is straight too, the worst part of the car, are the typical door rot problems, but its complete. now we tried getting it running, new starter, and igntion control pack but it still wont start. the electric fuel pump also sounds like its working and the car does have fuel, are there any other simple things i can check, or any sensors that typically go bad on these cars? is it possible that the plugs and wires are that bad? any help is greatly appreciated. thanks, ryan.

 

[85 Cutlass Brougham]

Use an inductive timing light on all 6 cylinders to see if the ignition system is working. (watch for a steady flash out the business end) You may have a bad coil pack ( if that year had them) or module. I would also probe an injector or 6 with a test light to see if they are being fired by the computer. As for sensors going bad, it's a 25 year old car with EFI. If it's not a sensor or 3 then the wiring harness may be bad. The connectors get brittle with age and can crack when taken apart. If the contacts are good and you break off the tab, use a zip tie to cinch them together.

You can also test the plug wires with a volt ohm meter. I forget the spec for ohms/foot though, so maybe someone else can post it.

 

[1986montecarlols]

Same boat as me

sorta. Check the battery cables as I was told for corrosion, check to make sure battery is ok obviously. Pull out the plugs or simply replace them.

 

[dan2286]

I have to ask, are you using the gas that came with the car? If you are, who knows how old that stuff is. That might cause a starting problem. Have you checked compression on all cylinders? Get an injector noid light and see if they are actually working. I am not sure how these older fuel injected engines worked off of but, newer cars do need a signal from a cam or crank sensor to know when to deliver spark and/or fuel. You need to check for any type of output from those sensors.

Since this is a fuel injected car, I would highly recommend that you get a factory service manual. It will have charts to go off of to tell you exactly what to check and what is wrong.

 

[TexasT]

We will assume that the thing is tuning over. It is right? Check the fuse for the ECM.

With a digital VOM check the terminals on the the coil pack. The terminals should check 11k-13k ohms across the coil(front to back) for each coil. Have you removed a plug and grounded it, and spun the engine over to see if you have spark? Careful that thing will set u back if you get shocked.

Fuel. Are you seeing fuel pressure at the rail? Get a gauge and measure. Noid light as suggested will tell if the injectors are firing.

Compression? Do you have any? All cylinders? Equal? Oil look good? Milky?

If these things check out, a more in depth diagnosis is in order. The cam sensor might not be set properly or not working at all. The crank sensor might have stopped functioning or be misadjusted.

 

[ryanelco]

i replaced the coil pack, but the wiring harness going to it looks pretty crusty, i need to fix that. im pretty sure its a spark issue because i sprayed a little starting fluid in the throttle body and nothing. im assuming that being that the fluid is combustible, i would have noticed some difference. im going to replace the plugs and wired and possibly the crank sensor. thanks i appreciate the help, ill keep you guys posted. ryan

 

[85 Cutlass Brougham]

Do some testing first before you go out and spend the money. A timing light will go a long way towards telling you what is happening.

 

[TexasT]

Do some testing first before you go out and spend the money. A timing light will go a long way towards telling you what is happening.

I concur, if you don't have one, a digital VOM is a better investment that throwing parts at it.
If you already replaced the coil pack and the connections were 'crusty', I'd start there by cleaning up the connections.

Are you seeing any spark at the plug when you turn it over? Getting it to spark is the main thing. Getting it timed right can be done easily.

 

[midwestls]

gas+spark will usually get almost anything running. I agree with everything suggested above, check at the plug ends of the wires for spark to start it off. That's what I'd do. Then go from there. It that don't work, sell it to me 😀 😀 . Good luck, I'm sure you'll get lotsa help on this one 8)