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

[we4turbobuick]

I have a few problems with my car but ill start with the most weird problem that I have. first ill let everyone know what has been done to the car. its a 1987 we4 turbo T all stock but...... scan master, hot wire kit, walbro FP, TT chip burnt for 91, adj FP reg, Ls1 MAF w/ TRANSLATOR, heated O2 sensor, a/c bypass.sometim es my car runs perfect then all of a sudden the idle goes off like it has a miss ....it falls on its face under boost ..... regular driving it sputters when the throttle is pressed lightly. Then all of a sudden it goes back to running flawless      im confused !!!! I don't know whats going on, Or how to troubleshoot this. another problem that is going on is that I have very small sparks that jumping from the alt to the alt pulley where the belt is, but Its so small it can only be seen in pitch dark. there is another small spark jumping from the a/c bypass pulley to the belt as well. installed a ground kit to relocate the ground from behind the heads w/ no luck. I really need a turbo buick experts to help me with this problem. Im ready to  my TR. please help !!!

[Steve Wood]

Did this happen over a period of time and gradually get worse, or did it suddenly occur and the symptoms have been consistent from that point?  Had you worked on the car before it started?  Did you recently buy the car or have you had it a long time?

I understand from the above that you can see it at idle which makes it a bit easier because you don't have to drive the car to see the problem.

I would start with some basic things such as verifying that the ground cable to the turbo support bracket is firmly bolted down and that the small ground cable off the negative battery post is attached to the inner fender sheet metal as it should be.  Check to see if the coil/module is bolted down firmly against the mounting bracket and the bracket is bolted firmly to the intake/plenum.

Make sure the positive battery cable from the battery to the starter is firmly attached to the starter bolt and that neither the cable or the fusible link bundle that attaches to the starter post is touching, or can touch the headers or anything else that could short out the positive feed.

Does the Scan Master show any stored trouble codes and does the SES light come on, or flicker quickly when this problem happens?

Put your volt meter on AC and read the voltage across the battery when the car is idling.  It should be less than 0.5 v AC.

I would pull all the spark plugs and see if they all look like they are firing properly and none of them appear to be wet or seem to have not been firing.  I would replace them with a new set of properly gapped plugs no matter how they looked.

Then I would look at the Scan Master readings and write down the readings for O2, maf, blm, clt temp, and voltage when the car is idling properly plus I would write down the vacuum reading and the fuel pressure.

Then when the car is idling badly when the  problem occurs, write down all the same information again and see if anything stands out as being different.

With the car running, unplug the cam sensor and see if it keeps running right, still incurs the problem, or runs considerably different.  Don't forget to replug it after you turn it off or it will not start again.

I suspect the small sparks are static electricity created by the belt rubbing against the pulleys.  Unplug the connector off the ac compressor clutch to see if the car runs any differently in case the diode in the connector has gone bad and there is some "back feed" from the clutch coils.

Measure the resistance between the spark plug terminals on each coil pack (engine not running, of course) and see if the resistance falls between 11,000-13,000 ohms on each pack.

Check the base of the egr valve and make sure the clamp bolt is tight and there are zero leaks around the base and gasket.  When the car is cold, pull the cover off the egr so you can get to the egr.  Put your fingers under the egr and lift the diaphragm up and see if pops back down closed like it should.

Make sure the pcv valve is moving freely in its housing and is not "sticky".

Check the hose connections between the maf and the turbo and make sure all are properly installed and tight so there can be no air leaks.  If by any chance you are using the original style hose from maf to to turbo, be absolutely sure there are no holes in it.

Check the hose connections between the intercooler and the throttle body to make sure they are all properly in place and properly sealed.

Check to be sure the crank sensor is not loose and is properly centered over all three of the blades on the balancer.

[SuperSix]

Wow!

Awesome info there, Steve..

[Just a Six?]

I know he posted the LS1 & Translator but thats just how mine acted when I had a bad connection from the harness plug to stock MAF. The Ground wire pin was faulty & I tried about 4 MAF's until we figured it out. Only takes a minute to check that connection.

[PacecarTA]

put a fuel pressure gauge on it

[Steve Wood]

I know he posted the LS1 & Translator but thats just how mine acted when I had a bad connection from the harness plug to stock MAF. The Ground wire pin was faulty & I tried about 4 MAF's until we figured it out. Only takes a minute to check that connection.

guessing that would kick out on the scan master numbers when it went nuts?

[Just a Six?]

I know he posted the LS1 & Translator but thats just how mine acted when I had a bad connection from the harness plug to stock MAF. The Ground wire pin was faulty & I tried about 4 MAF's until we figured it out. Only takes a minute to check that connection.

guessing that would kick out on the scan master numbers when it went nuts?

Correct it would throw a code 34 or whatever MAF number is on SM? I never thought of that when I posted but it sure acted like his description.

[Steve Wood]

I guess he fixed it.

[we4turbobuick]

im still waiting for it to act up ......... it does it maybe 3 times a week . Im sure ill have some data for you in a few days. but the sparks always show no matter if its running good or not!!

[Just a Six?]

Awesome info there, Steve..

Wow!

Awesome info there, Steve..

This needs to be linked into the "search" when someone has "weird" car issues.
It covers a lot of questions. 
 

[Steve Wood]

a similar version is on my site in the troubleshootin g section under car does not run right sub group


http://www.vortexbuicks-etc.com/engine_starts_but_does_not_run_p.htm

[Just a Six?]

Steve I always send them to Vortex & GNTTYPE but especially the new owners.
 
I went to your link & the site is looking Good!!
Especially the pics of the oil pressure sending unit!   

[Steve Wood]

LOL...I chose a professional to do those pics for me!

[daveismissing]

Get a room you two
 
Wonder if those pulleys were powder coated or some unusual paint.
( made from cat fur? )

[tb3]

yikes!
seeing those sparks would make me very very nervous