kandelino

Hello!

I'm an exchange student from Germany living in Oregon (so please excuse my bad English) and I bought a 1985 Oldsmobile Delta 88 with the 307 Cody Y Engine.

I always had a Code 21 Error so I replaced the bad TPS-Sensor two days ago. I installed a new airhorn gasket and a new one between the carb and the manifold. I also replaced the fuel filter.

First it took me 20 minutes till the car ran smooth at curb idle. I had to keep it over 2000RPM otherwise it wouldn't have been running.

Today it was much better but now the car won't start randomly. Sometimes it starts immediately, sometimes after a 10min. brake there is no spark. If I spray some "easy start spray" on the air filter and crank a while (suddenly I can see flashes on my timing light) it will start.

I haven't found a orderliness for that symptom and it only occured after I had the carb off.

When I spray some brake cleaner around the carb. and the vacuum hoses the idle won't change, so it doesn't look like a vacuum leak.

Do you have any suggestions where I can start looking for this crazy issue?

Thanks a lot!

Best regards, Andreas

Lady72nRob71

Welcome!
I do not see a reason why a carb rework woul dhave brought on random ignition problems. Only thing I can think of is getting some electrical connector on the distributor loosened.

The pink wire to the disty should be 12V when key is in run. Check to see if you have that when you go into a no-spark condition.
Also, the black/orange should be 0V (ground)
If those are right, then pop the cap off (note all wire positions first!) and check for damage or excess corrosion.

If that looks okay, I am guessing it could be an ignition coil or pickup issue. A 'new' disty unit from a junkyard will be a good try. The coil should be the first to swap.
Will it will not start when hot or does not matter?

From what I have heard, the engine will run without the computer module connected - just not very well. Therefore i do not think it is a computer issue.

I often get double problems at once - not sure why. I just had a battery die at 6 years old then the voltage regulator died when i replaced the battery!

BTW, your English is better than that of most Americans!

kandelino

Thank you Rob!

I've changed already: Distributor Cap, Rotor, Sparks, Spark Plugs and Wires. The only thing I haven't replaced is the coil. Maybe I will try to change this one too.

So, there should always be a spark right from the start? There is no coherence between a bad carb and the ignition?

Yessterday I went to the gas station, everything was fine. Ten minutes later after a 10 minute shopping it wouldn't start again and I had no spark for maybe 5 minutes. Than It started again.

When I changed the fuel filter I found one difference. The new one has a little "valve" with a spring and a rubber gasket in it. The old one was just straight. Could this be a problem for the fuel pump because of the stronger resistance it now has to deal with?

Regards, Andy

henryk8398

It sounds like a coincidence to me. It sounds like your HEI module is going bad. Otherwise there should be no relation between the carb and ignition. That sounds like a classic symptom of that problem (Starts runs, won't restart for a few minutes). I would replace that and the coil with QUALITY parts (AC Delco, Standard, etc). Make sure that you use the right grease under the module, too. DO NOT USE dielectric grease. You need to use heat sink compound, the same stuff that's between the processor and fan on your computer!

By the way, your English is fine and you have great taste in cars! Good luck!

Lady72nRob71

Sounds like the coil to me...
The flap and spring in the fuel filter is a check valve to keep fuel from flowing back out of the carb. Fuel should pass the other way just fine. Still, this has nothing to do with no spark.

Go for the coil next.

chequenman

Where do you get a code "21" from as your car being an eighty five shouldn't have a computer? Check the wires going to your coil that the casing isn't cracked from getting brittle caused by the |Engine heat over the years. If any of your wires are brittle the wire strands may be breaking down under the casing creating an open circuit. Look closely!!

kandelino

Allright, thank you!

the only shop in town which has the parts in stock is Knecht's Auto Parts.
Unfortunately I need the car tomorrow to pick up my girlfriend from the airport and all my roomates are back home with their families.

Knecht's has got a ignition coil and two ignition modules. Could the module also be damaged?

@henry:
I bought this car because I wanted to drive and own a V8 once in my life. A gallon of Gas is almost 8$ in Germany and we have to pay tax depending on the cui and the CO2 emissions of our cars. That's why I have a 1.8L car with 250HP and one with 0.7L and 110HP back home. In addition, I hate Japanese cars and all those others without "heart and soul".

here are some pictures of the car when I bought it 2 months ago. In the meantime I've changed the cracked stearingwheel, distributor cap and rotor, ignition cables, sparkplugs, put a new TPS in the carburetor, installed a stereo, tachometer and many other things.







It's no beauty queen but it was cheap, has a new tranny and a lot of other new parts.

Best regards, Andy

kandelino

@chequenman:

It's a CCC car and I can check around 20 troble codes via the ALDL interface.

It's primitive but it works.

kandelino

I started the car 4hours ago without any problems and drove 10miles with it. Now I tried to start the with the engine still a little bit warm but it doesn't start. There is no spark. I stopped trying after some minutes without success.

I start to hate this car....

henryk8398

Nice car, don't hate it, fix it!

I'm sticking to my story. Change the module and coil. Don't forget the correct grease like I mentioned before. If that doesn't cure the problem, the distributor pickup could be a problem as well, but those don't fail very often, so I wouldn't change that yet. If you're still showing code 21, make sure the new TPS is adjusted correctly. When you replaced the TPS, did you put the spring underneath it back in as well as the small metal piece (looks like a small, solid pipe) on top of it? Have you checked the adjustment? The previous owner may have messed it up. Is the TPS connector in good shape?

kandelino

Where exactly do I have to put the grease? Last time I replaced the rotor and cap there was some silicone included which I put between the old coil, the rubber washer and the distributor cap.

I only had the code 21 with the old tps-sensor because this one was totally dead. I replaced it with a new one and used the spring and small rod which were included. The new tps works fine but it is not adjusted. I should have 0.41V at idle but the voltage is around 1V. I have to find a cheap power drill to drill out the acces plug.
Although the new tps isn't adjusted properly there are no error codes.

to be honest, I don't thing the coil is the problem. Once the car runs everything is perfect. It runs great for hours, never dies but after I turn it of, it won't spark.

Well, the good thing is, I've alreay aquired a lot of knowledge how to fix US-Cars and my technical-vocabulary is getting better too ;-)

BILL DEMMER

here's another thought...
when you have the car running, move the thin wires connected to the distributor(not the spark plug wires) around some-without unplugging them. you may find your problem in the wiring.

the silicone grease you mentioned in your previous post is the dielectric type, and you put it in the right place. heat sink compound is not the same as the dielectric grease(as mentioned by henryk).


bill

henryk8398

The bottom side of the module is where the grease goes, to help conduct heat out of the HEI module to the dist. body.

1v is too much at idle so good job on checking it out!

Lady72nRob71

From what I can remember from the service manual schematic, that pink 12V feed wire comes off a fuse in the fuse box - just cannot remember which one. I think it would be good to make sure it is getting good connection.

If you have a local junkyard, you might be able to score a complete disty unit to help narrow your problem down.
I still suspect the coil, as I have seen them run fine, but not start when hot later on. Not sure if starting requires a hotter spark or what.
The Ignition control module is that the computer uses to adjust the timing with - separate item from the coil. That could be a problem, if it is not using the right timing curve when starting...

Here is a neat little procedure for adjusting the TPS:
http://tlentz.oldsgmail.com/howto.html#TPS
I need to adjust or replace the one in my '86 some day...

Did you dump the error codes to see if there is any relating to the ignition timing module?

cutlassefi

He's not getting any spark at all, that has nothing to do with it.

Lady72nRob71

He mentioned not having the TPS adjusted, so I gave him the procedure in case he needs it.
He had replaced the TPS, then the ignition problem came up.
Agreed 100% that the TPS has nothing to do with no spark.

NorTown Olds

Well this is one great MYSTERY! I'm learning TONS here in this thread -- THIS is EXACTLY what makes this Forum so fantastic! GREAT collaboration and YEARS of EXPERIENCE trouble shooting this kind of stuff! I was at a loss after it didn't seem to be isolated to just the coil...but, again I'm learning TONS here! GOOD STUFF! HOPE you get it fixed! as others have said, don't hate the car, hate the problems! (think of how THRILLED you'll be once you finally narrow this thing down and SOLVE your troubles completely!! ) Hang in there and Good Luck!