thanks hanky,,,

well i will say that there could have been something wrong with that crank sensor,,since i have been driving it the last two days and put about 250 or so miles on it i have noticed the tac has stopped the moving around it was doing,,,seems strong and steady now,,so i'm not gona say the sensor wasn't needed or didn't do anything,,,i guess it was worth the effort

as for the injector plug,,,well i had it on and off a few times,,,it fits snug on the injector,,,it looks like some one has cut the harness and soldered this new plug on,, the plug has about 2" of wire coming out of it and is attached to the harness,,,the wires on the plug are red and black i think,,and the harness wires were both a yellow or lite orange i would say,,,one was solid and one has a black line on it,,,the red wire on the plug is on the positive side of the injector,,as it will only fit on there one way,,but i don't know which wire is positive coming out of the harness,,,so,, who ever did the replacement could have gotten them switched if they weren't paying attention,,,does it matter,,,i don't know,,,, and i have asked this question to several people,,2 of which work on cars for a living,, like you i am assuming,, and they don't know if it would matter either???

ok now you know what i know,,, well i'm sure you know way more than i do,,,lol

thanks,,,please keep thinkin on this,,,i'm game,,i would like to put this thing to bed

ocharry

 

There is a very simple way to check the wiring.
Either with a test lite or voltmeter, turn the key on and check which terminal on the injector plugs you can get to, and unplug the plug. The same one on each injector plug should lite the lite or read 12 volts. They should all be in the same side of the injector plugs.
The other wire is the ground from the PCM to fire the injector and should show no reading when disconnected.

 

thanks for the info on the injector plug voltage,,sounds easy enough to check that out,,,i will try and get to it this weekend

they are saying we might have to work saturday,,,can't miss that,,but i will try and get to it and get you a report here on the wires

thanks a bunch

ocharry

 

Och,
I would also like to know the problem.
I have essentially the identical problem on my 2000 Lesabre.

I was driving along one day a week ago, and suddenly - the problem popped up. i.e. an intermittent miss, shudder or surge. It happens mainly after the engine has reached normal operating temperature.

I have done the following.
New crankcase position sensor
New throttle position sensor
New fuel filter
New Maf sensor
New ignition module and coils

None of these things have had any effect at all on the issue.

When I was driving the car today with a scan tool on the car, I noticed that the
ST FTRM 1 value changed from its normal .3 - 4 all of the way up to 12 or 15.

So, I assume that this is telling me that the engine is running very lean, and the computer is trying to increase the fuel mix to the engine.

After searching, and searching - and really coming up with nothing conclusive -
I am heading toward injector replacement.
I have found a new set of injectors for a decent price and I will have them in hand in a day or two.

I have checked the fuel pressure and it is a steady 44 - both before changing the fuel filter and after.
The car actually runs quite well if the MAF sensor is disconnected, but I assume that that is happenning because the engine is running very rich under this condition. Since the problem only happens when the engine is warm and has leaned out, the disconnected MAF sensor is masking the problem.

Since I was just driving when the problem suddenly occurred and has never disappeared since (i.e. for the last two weeks); I am leaning toward a partially plugged injector that is not giving me a good spray pattern.

I did run a heavy duty dose of injector cleaner through the vehicle, and it seemed to help for a very short time, but the problem is now; essentially the same as it was from the beginning.

If anyone has any more thoughts; I would certainly appreciate it.

 

Ok I'm back,,sorry for the delay

Haven't had time to mess with the car,, but this weekend I have an oil change due so I will be checking the voltage on these wires to the injectors.

hflier;

Glad you chimed in on this ,, sorry you are seeing my symptoms,,and since you changed the MAF and TPS,, I would think you just saved me a few bucks,,, but I am down to only a few things to swap out,,and like hanky has said it could very well be the BRAIN BOX,,lol

For you I have a little test,,and that is what kinda had me thinking about injectors.....

For 2 weeks i ran high test gas and a bottle of cleaner every time I filled up my 99 Lesabre,,and it did seem to help BUT it didn't make the problem go away,,,as soon as I went back to regular and no cleaner,,right back to the way it was

So this weekend I am going to do some checking with a volt meter like hanky has suggested and do some other checks to maybe stumble onto something that will flag a problem

If you change out the injectors,, PLEASE ,,PLEASE get back here with the results,,,I am really interested in what you find or if it changes anything

Thanks for all the input guys

ocharry

 

Usually when you disconnect the MAF sensor and the problem is gone indicates that the MAF sensor is defective. Just because it's new doesn't mean it can't be defective. Hope you purchased it from a GM dealership. They don't usually sell defective ones!

 

Ok I'm back

hanky;

I checked the voltage on the injector plugs,,looks like the different one is wired the same as the others,,I mean the pos. is on the same side or wire as the other two I checked

While I was there I checked the impedance across the front three injectors,, I was getting 1 ohm,,, I think I am reading the meter right,,when it was connected to the injector it didn't go to zero,,only went to the 1,,,just curios,,should the reading be zero??? or should I see some resistance???

Now I don't know if this is telling me anything or not,,I had the meter there and it seemed like the thing to do,,,lol

So I had 12v on the wires to the injector and 1 ohm resistance on the injector it's self??

Thanks

ocharry

 

Finally I gave up on trying to fix my car myself.
I took it to the garage who had $$$ worth of scanners that I did not own.
They found the problem to be the MAF sensor to be bad.

The 2nd thing that I had changed was the MAF sensor. But the "new" sensor that I had put into the vehicle was defective.

When I talked to the garage, they had found that they had had a very very high failure rate with rebuilt MAF sensors. So they have changed their policy to use only new Delco or Hitachi MAF sensors. Since they have changed their policy to using only New MAF sensors, they have had a very very log rate of return.

The car runs like new now.

Although I put in quite a few items that were not actually required to fix the hesitation issue, I am not really unhappy because it had been many thousands of miles since I had last worked on the vehicle and many of these items were at the normal time of replacement - i.e.
fuel filter, spark plugs, plug wires, injectors, coil and ignition module, and throttle position senor.

The vehicle runs like new.

Thanks so much for all of the feedback that I have received on this forum

REW
Minneapolis

 

hflier,
Thank you for sharing the solution with us. That's how we all learn.