Suzuki cutting out, chapter 2

See previous discussions cali emissions thread on my 02 Suzuki XLZ 4WD. It has 149,000 miles, has had a new starter, new fuel pump and lines, and new brakes in the past year. Bought it a couple of weeks ago and took it straight to shop, so I have no personal history with this car.

Now: have replaced all catalytic converters and exhaust pipe. Have also replaced Mass Air Flow Sensor. Great news - all computer codes are cleared. Runs great when in park or neutral (30 min or more). Mechanics then moved it around parking lot with no problem, so they trusted it enough to take it on a test drive on the open road. Made it out of sight of shop (not sure how far, but it was an improvement over the last time!)…but required tow back. Hooked back up to diagnostic computer, and found NO error codes. They are doing what they call “exploratory surgery” (yikes). Am I wrong in thinking this is probably a TPS issue? What are the other things that could cause this inconsistent power/stalling when it is put in gear?

One thing that can cause stalling when the vehicle is put into gear is a dirty/faulty Idle Air Control valve.

The IAC valve controls the engine idle speed under all conditions.

So for example, when the vehicle is shifted into gear, and the drive train puts a load on the engine, the IAC valve prevents the engine from stalling when that load is imposed on the engine.


Great! Thanks, Tester.

Not the IAC Valve, and not the TPS. Still no error codes. Wondering if computer is on the fritz too. Also checking out electrical system (short ? versus harness?). If it’s the harness I’m throwing in the towel.

I was extremely skeptical about the converter business from the beginning but I’m also afraid that I can’t be of much help due to the unknowns.

It’s possible to have faults that will not show up as a code; even a hard failure.

If the engine will not start at the moment all I can say is what I would do.
Verify ignition spark.
Verify fuel pressure.
Verify injector pulse.
If it has those 3 things it should run.

Compression can be a cause of a no-start but not likely in this case as the problem is intermittent in nature.
No way I’m wild guessing at wire looms and ECMs at this point and if the truth be known the cause is something relatively simple although it may not seem that way at the moment.
Sometimes the can’t see the forest for the trees factor takes over. :frowning:

Not that I know anything but just because there are no codes does not mean something is not wrong. It just narrows the field to those items that aren’t monitored by the computer, like fuel pump, wiring, etc. I never did find out why my Buick was stalling and I had replaced fuel pump and wiring, relays, ignition switch, crank and cam sensors, cleaned grounds, swapped computers, and many other items I can’t recall. I’d run around with the fuel pressure tester taped to the windshield and the test light hooked up and it’d stall at 5-7 miles and no codes. The last stall was at the stop light outside the dealer when I traded. I suspect the former owner will not be answering calls but may have a list of other things tried.

Have they tested the egr yet?

@ok4450 Starting and running for 30-45 minutes is no problem. No sputters or bucks at all when in park. The problem is getting from stop to go…although it is certainly better now than it was before the MAF was replaced.

@Bing The former owner told me what he had already replaced, and what he planned to try next. We have been through those and more! Sorry to hear about your troubles. If this isn’t resolved next week I’ll likely be making some different decisions too.

Today’s update: We have now checked the electrical system, and there’s a short in the fuel pump. In addition the fuel check valve was broken. At this point, I am not about to quit…especially since the pump/installation are free if that doesn’t fix the problem. More next weekend, when the parts are in.

No problem for me. Its been a few years now and couldn’t be happier I put it out of its misery.

Hope the fuel pump and wiring does the trick. You should also replace the pump relay and the pigtail as a general rule. Also I’d make sure you’ve got good connections at the pump plug. Had that problem on another Buick. Towed and cleaned the connector and all was fine again for a few years.

WooHoo! With the new fuel pump, the new fuel check valve, and a cleaned-out gas tank, we are up and running!! She is purring like a kitten, and took a 60 mile road trip just to be sure she was ready for pickup. Big shout out to the folks at Meineke on Indian River Road in Virginia Beach, Va.

Thanks for posting the result. Glad you are back on the road. Best of luck.

Congratulations and sincere thinks for posting the final outcome.