Severe Stumble Intermittingly on my 90

[moesvette]

Ok, so I tried to pull codes last night (wire to pin K, and grounded to frame). I got nothing....no 12 flashes, nothing. I have never tried to pull codes before, so could be my inexperience, but I tried multiple times, even grounding to negative term of battery. Any suggestions? I did not use a paper clip in the K pin location, simply stuffed the wire in, but was sure I made contact with the brass part of the pin. HOWEVER, interestingly enough I just happened to check the battery cable to positive side of battery and it was loose. How stupid I am if that is all that was wrong. Tightened and fired up for 20 minutes at different idle revs, and never missed a beat. Couldn't take a drive as weather was bad so that will be tonight. Also checked fuel pressure: Static 48 psi, and after starting engine 42, when revving, it jumped up to 50. Thank you Shrade for the suggestion. Any ideas on how to figure out if I can pull codes?

[Schrade]

Sounds good; looks like your FPR is responding properly to vacuum too.

Dash LED still should show testing tho', when you jump the ALDL connectors. I think first 2 pins should initiate the diagnostics



AC/Delco batteries had a problem with battery sockets stripping out of the case - maybe put some dielectric grease on cable screws into battery for good measure...

[XfireZ51]

Originally Posted by Kevin

no idea but mine does the same thing. runs fine cold, soon as it warms up it stumbles and sets a code.

Sounds like once it goes Closed Loop, then ...
Any chance you observed coolant temps when that occurs?

[Kevin]

Originally Posted by XfireZ51

Sounds like once it goes Closed Loop, then ...
Any chance you observed coolant temps when that occurs?

i was looking at the oil temp so no. Let's keep this on the TS problems. don't want to clutter up the thread.

[Kevin]

everyone says use a paper clip but if you're like me you don't even want to eat a sandwich you made yourself because it has blood and bits of finger in it. buy the fault grounding plugs from gordon https://www.gordonkillebrew.net/Products top right. best $45 ever

[Paul Workman]

Originally Posted by XfireZ51

Sounds like once it goes Closed Loop, then ...
Any chance you observed coolant temps when that occurs?

Originally Posted by Kevin

i was looking at the oil temp so no. Let's keep this on the TS problems. don't want to clutter up the thread.

Say what? A perfectly good question, methinks! Open/Closed loop would certainly be of interest, Kevin, especially since CLOSED loop brings the O2*s into the picture.

*BTDT: A faulty O2 on one of my Vettes resulted in mild to severe stumbling, after going CLOSED loop.

[Kevin]

Originally Posted by Paul Workman

Say what? A perfectly good question, methinks! Open/Closed loop would certainly be of interest, Kevin, especially since CLOSED loop brings the O2*s into the picture.

*BTDT: A faulty O2 on one of my Vettes resulted in mild to severe stumbling, after going CLOSED loop.

I didn't want to clutter up this thread with problems with my car. I've got a handle on them, more or less.

[mike100]

My car has a ton of new parts in it and I recently had a weird hesitation coming off of coast to light throttle tip-in. The only thing original is the ign wire/coils which I was starting to suspect, but I did examine the plugs, and checked the fuel pressure was 43-52 as it ought to be etc etc. full power was ok, cold running ok...

Long story short it turned out to be a bad tank of gas... (too much ethanol maybe-I'll probably never know).

[moesvette]

So....am I supposed to jumper A & B, then ground K to get the codes? I only tried grounding pin K. The idea of getting the jumper from Gordon is a great idea. Will get it ordered. Thanks to all for the help. I hope the battery correct will solve the issue. I will post after I have had a chance to validate.

[Kevin]

Originally Posted by moesvette

So....am I supposed to jumper A & B, then ground K to get the codes? I only tried grounding pin K. The idea of getting the jumper from Gordon is a great idea. Will get it ordered. Thanks to all for the help. I hope the battery correct will solve the issue. I will post after I have had a chance to validate.

may want to throw his hood opening tool into the order since you're there