I have a problem that no one can seem to figure out!!

[Steve Wood]

van de graaff generator

[we4turbobuick]

On my way to work my car started to act up again .... i got the scanmaster numbers ill post them up as soon as i get home..... thanks you guys!!

[Steve Wood]

hopefully something will look strange

[Scoobum]

I thot I'd seen it all with some of the stuff rolling into Dans shop. Definately keeping an eye on this thread. I've come to the conclusion that I'm never gonna see it all when it comes to these cars. As they say...you're never too old to learn.

[we4turbobuick]

When the car is running good at idle the scan master numbers are
O2 ~ 700`s- 800`s
Maf~ 04
Blm~ 133
Clt~ 184
Volts~ 13.6 to 13.8

When its running bad ......
O2~ 00 to low 100`s
Maf~ 04
Blm~ 138
Clt~ 184
Volts~ 14.0 to 14.3

All the turbo and intake connections are tight. The plugs are new and gaped properly. the a/c compressor is not on the car that's why I have the bypass pulley on till I can get it running correctly. The egr diaphragm is popping down. if I unplug the cam sensor it runs worse. The fuel pressure is 32 psi with vac line on 38 psi with it off, and its steady no matter how its running. All the grounds are tight. I know its hard to diagnose the problem when you can't see it. So if you guys are still stumped I might have to get a pro logger So I can share better data with everyone. But anyways.... Does anyone see any thing wrong with my data so far.........?

[Steve Wood]

well, it ran out of fuel when it started running badly....as to what caused that, I don't know...could be a shortage of fuel, or a big air leak of some kind.

Strange that it ran badly when you unplugged the cam sensor.  You should hardly be able to tell the difference.  Was it running good when you unplugged it?

The fuel pressure was about right plugged and unplugged, but, it should move a bit when you vary the rpm or load on the engine.  The Higher the vacuum reading, the lower the fuel pressure should read and the lower the vacuum, the higher the pressure should be.

So we have a few questions.  Why did the o2 read so low when the car ran badly.  Why did the car run badly when you unplugged the cam sensor assuming it was running good at the time you unplugged it.  I am not sure what happens if the cam sensor is set such that it can jump to the wrong cylinder but?  IF the fuel pressure was steady and you were not blipping the throttle, it is probably okay.

Does your boost gauge read vacuum as well as boost?  I would assume it the vacuum goes from something like 18 at idle in park to maybe 7? when it acts up?

Did you look at the fuel pressure when it acted up to see if it had dropped down into the 20's?



Just for the heck of it, loosen the clamp on the cam sensor and rotate the sensor counter clockwise about an 1/8" or a hair more and see if it runs better, or has less effect when you unplug it.

it does not look like the blms increased much when it went bad so that is a bit strange.

Does the problem exist when the engine is relatively cold, or only after it gets hot and has been driven for awhile?

[we4turbobuick]

my boost gauge doesnt show vacuum, my fp stays the same....When my car is running good i can uplug the cam sensor and the car runs fine, when its running bad if i unplug it the car runs worse .  Another thing i noticed is the car is getting a little harder to start, only when its hot outside when its cool out i will start with a quick twist of the wrist. Thanks for all the help with this problem!!!! Ohh and it doesnt matter if the car is hot or cold ...this problem comes and goes when it wants to.

[Steve Wood]

For some reason, the O2's dropped off the map when it ran badly.

If the fuel pressure stayed close then I think we can assume it is not a fueling problem from the delivery standpoint.    I would like to think that anyway

So that makes me wonder if the engine was not firing properly at the time so it was not burning the fuel in the cylinders and that made the O2's wonky.  Wonky is a canadian tech term.

So, I would probably swap the coil/module pack between my cars, and then the ecms....good reason to own more than one of these things.

Otherwise I would put my caspers coil tester on and see if I got a good solid spark

Or, I might separate the module from the coil pack and see if the "filling" was melting which is usually a sign of impending failure.


I don't know how one lives without a vacuum reading?

[we4turbobuick]

I dont mean to get off the subject but can u tell me what this plug and wire is? And where does it plug in at ......the other end right now goes to a switch under the dash that the last owner installed when i touch the wire the fan shuts off. Im trying to get everything fix what was rigged up.... thanks again!!

[Steve Wood]

without knowing where the wires are connected, who knows?  It sounds like someone rigged a manual fan switch to run the fan when the car was turned off, but, why the fan quits when you touch a wire, I have not a clue without having some idea as to where the wires run

[we4turbobuick]

Here is a pic

[we4turbobuick]

The fan quits because the wire doesn't fit the connector very well

[Steve Wood]

Not sure what I am looking at there, but someone rigged the wiring...eithe r because they thought it was something trick or because something was broken.

Fan wiring diagram at the bottom of this page   http://www.vortexbuicks-etc.com/fan.htm

[we4turbobuick]

Thanks for your expertise. Im getting a new coil and module and have the cam sensor checked out. And I do have a vacuum gauge but not on the boost gauge. I might just also replace the ecm with one that is known to work. I'll keep you updated, with any updates.

[Steve Wood]

Do you have a reason to buy all that stuff?