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Car is running perfect... then starts randomly jerking (quick cut outs).. even at idle.. then back to perfect.
Reminds me of when I had cracked DME / ECU solder.. but I pulled it and can't find any this time.
KLR hasn't ever been opened. Stands to reason that it may have bad solder joints too, no? Why does no one ever mention the KLR in this respect?
I'd like to try bypassing it.. read you can jumper plug #s 9 and 16. How do you do that? Simply unplug the KLR and connect these two slots with a wire then try starting & driving?
I'd also like to observe fuel pressure but can't find the right adapter for the rail end (12 x 1.5?) and anyway, not sure how I'd observe this while driving.
I hate this kind of random issue-with-a-million-possible-causes ... makes the daily drive nerve wracking!!
Intermittent electrical problems are the worst. Hopefully that sensor is your problem.
Ed and I actually had a long thread on RL back in the day about cracked solder joints in his KLR. They were triggering an intermittent Full Load signal when idling/cruising and were a serious pain to track down -- primarily because the issue would happen so infrequently and randomly. We reflowed the solder joints in the KLR and the issue has never returned.
Aha! First I've heard about KLR solder joints. Ok.. I'll check them out. But in the meantime, I'm having a heck of a time finding out which exact MAP sensor the A-Tune uses.
Also, seems LR no longer sells their A-tune version and of course Rogue tuning is long defunct.
Maybe I can just use any old MAP sensor? Many look similar?
danmartinic wrote: Sun Feb 04, 2024 3:24 pm
Aha! First I've heard about KLR solder joints. Ok.. I'll check them out. But in the meantime, I'm having a heck of a time finding out which exact MAP sensor the A-Tune uses.
Also, seems LR no longer sells their A-tune version and of course Rogue tuning is long defunct.
Maybe I can just use any old MAP sensor? Many look similar?
danmartinic wrote: Sun Feb 04, 2024 3:31 pm
PS.. did this full-load signal cause quick cut-outs while driving? What were the symptoms?
No, it wouldn't cut out -- the car just got super rich to the point where the idle would falter and the car would bog a little. Cracked solder joints can have infinite symptoms though. In Ed's case, we were able to pin-point a cracked solder joint at the main KLR connector pin for the TPS potentiometer signal -- so it would randomly think the car was floored when it wasn't. If you had a cracked solder joint on one of the KLR's ignition signals (or a bunch of other places), however, that could cause a cut out.
The one thing that helped when my own car had a random cut out was to pay attention to what happens as/when the cut out occurs. Does the tach cut out too, suggesting ignition. Does the boost gauge cut out, suggesting power was cut to the KLR? Big back fires suggest fuel is still pulsing in but not getting ignition until it's too late. No backfires suggest no fuel (and maybe no spark). Etc...
Thanks for this info. Been looking... a ton of knock-offs but hard to determine what an original GM part would be.
Best I could find is something that came on a 1989 Firebird 3.8 V6.. a Delphi part but looks a bit different. The one that looks identical (same green material at receptacle, similar cutouts, etc) is an ACDelco unit on Amazon that I can't confirm is 3 bar.
Lots of 1 or 2 bar. All look similar. And the prices are anywhere from $15-150! To top it off, the original Delphi part appears to be also made in China.
This being such a precision measuring part, I'm looking for a quality unit that will definitely receive the plug I hard-wired in from the A-Tune kit. Apparently, some of the original GM units have some sort of tabs in the plug receptacles that won't take aftermarket plugs which I assume the kit came with?
This is turning out to be more complicated than expected !
danmartinic wrote: Sun Feb 04, 2024 3:31 pm
PS.. did this full-load signal cause quick cut-outs while driving? What were the symptoms?
No, it wouldn't cut out -- the car just got super rich to the point where the idle would falter and the car would bog a little. Cracked solder joints can have infinite symptoms though. In Ed's case, we were able to pin-point a cracked solder joint at the main KLR connector pin for the TPS potentiometer signal -- so it would randomly think the car was floored when it wasn't. If you had a cracked solder joint on one of the KLR's ignition signals (or a bunch of other places), however, that could cause a cut out.
The one thing that helped when my own car had a random cut out was to pay attention to what happens as/when the cut out occurs. Does the tach cut out too, suggesting ignition. Does the boost gauge cut out, suggesting power was cut to the KLR? Big back fires suggest fuel is still pulsing in but not getting ignition until it's too late. No backfires suggest no fuel (and maybe no spark). Etc...
I'm pretty convinced the MAP sensor is causing my issue; the measurements I made are very erratic!
I've been trying to note what happens for a couple of weeks now... and it is baffling to say the least:
-will run absolutely perfect every morning drive into work. The problem only appears later in the day (if at all)
-none of the dash gauges do anything unusual. The quick-cutting at cruising or on-throttle happens so quick that the tach doesn't even drop; then only action is during idle: when that bad idle feeling starts, the tach shows a bit of a drop along with the oil pressure etc during the period but then when over, back to perfectly normal
-generally no backfires... though when a bout of cutting-out starts, I sometimes try to get it boosting hard and if it jerks then, there might be a little pop
Just nuts this random condition.. even the cracked ECU solders were at least more concrete: car would eventually stall.
I've got so many newer parts over the years but the coil is original as is the DME Relay (yes--still says Made in W. Germany). Of course, I did switch out a spare relay but no difference. Coil measures fine... fuel pumps usually don't slowly die in my experience... and fuel regulator seems ok as there's no fuel leaking out back and it responds properly when vac line pulled etc.
I didn't even think of the MAP sensor until one time it seemed to enter "rougher idle" mode for a little longer so I pulled over and started wiggling all kinds of connections. I even "rotated" the MAP sensor (it hangs off of wires in the firewall) and noticed a slight improvement when I turned it. Today I back-probed it and wow it's all over the place.
danmartinic wrote: Sun Feb 04, 2024 3:31 pm
PS.. did this full-load signal cause quick cut-outs while driving? What were the symptoms?
No, it wouldn't cut out -- the car just got super rich to the point where the idle would falter and the car would bog a little. Cracked solder joints can have infinite symptoms though. In Ed's case, we were able to pin-point a cracked solder joint at the main KLR connector pin for the TPS potentiometer signal -- so it would randomly think the car was floored when it wasn't. If you had a cracked solder joint on one of the KLR's ignition signals (or a bunch of other places), however, that could cause a cut out.
The one thing that helped when my own car had a random cut out was to pay attention to what happens as/when the cut out occurs. Does the tach cut out too, suggesting ignition. Does the boost gauge cut out, suggesting power was cut to the KLR? Big back fires suggest fuel is still pulsing in but not getting ignition until it's too late. No backfires suggest no fuel (and maybe no spark). Etc...
I'm pretty convinced the MAP sensor is causing my issue; the measurements I made are very erratic!
I've been trying to note what happens for a couple of weeks now... and it is baffling to say the least:
-will run absolutely perfect every morning drive into work. The problem only appears later in the day (if at all)
-none of the dash gauges do anything unusual. The quick-cutting at cruising or on-throttle happens so quick that the tach doesn't even drop; then only action is during idle: when that bad idle feeling starts, the tach shows a bit of a drop along with the oil pressure etc during the period but then when over, back to perfectly normal
-generally no backfires... though when a bout of cutting-out starts, I sometimes try to get it boosting hard and if it jerks then, there might be a little pop
Just nuts this random condition.. even the cracked ECU solders were at least more concrete: car would eventually stall.
I've got so many newer parts over the years but the coil is original as is the DME Relay (yes--still says Made in W. Germany). Of course, I did switch out a spare relay but no difference. Coil measures fine... fuel pumps usually don't slowly die in my experience... and fuel regulator seems ok as there's no fuel leaking out back and it responds properly when vac line pulled etc.
I didn't even think of the MAP sensor until one time it seemed to enter "rougher idle" mode for a little longer so I pulled over and started wiggling all kinds of connections. I even "rotated" the MAP sensor (it hangs off of wires in the firewall) and noticed a slight improvement when I turned it. Today I back-probed it and wow it's all over the place.
... makes the daily drive nerve wracking!!
