Stalling? I need some ideas?

[92qatlanta]

Dear NOCO Team,

I need some ideas.

While I was away, my wife was driving our 1992 Q45. No history of problems. On two seperate occassions, the car stalled. After coming to a complete stop, she restarted the car and completed her journey without incident.

Some background and specifics:- My wife is a very cautious and sometimes slow driver. - Incident 1 occurred in the middle of making a turn at an intersection. She braked upon approaching the intersection and the car stall halfway into the turn.- Incident 2 occurred while slowly going over a going over a bump in a shopping center parking lot

Since I have returned, it has not happened again. But again, my foot is a little heavier.

I have checked that the battery cables were clean and tight and did a visual under the hood.

My instincts tell me it is either a very low idle, a connection or both. But again, I have not been able to replicate the problem.

Any specific things to look for?

Thank you in advance for your assistance.

Jim

[kimrober]

Sounds like MAF sensor..

[maxnix]

Any maintenance history? Miles? Intake path cleaning? BG44K?

Do tell us the timing chain guides have been replaced.

[elwesso]

Its gonna be a maf or fuel pump, is your fuel pump humming?

[92qatlanta]

Thank you kimrober, maxnix and elwesso for your input.

First, more history. Regularly maintained. 131,000 miles. Intake flushed at ~115,000. Chain guides replaced at 107,000 (BTW, chain guides were 90%+ intact, I was surprised). Plugs NGKs, but changed before 100,000. No abnormal noises from the fuel pump.

Last evening I cleaned the connection of the MAF sensor. Some visible corrosion removed. I am taking it for a test drive to the airport after this post.

Jim
Modified by 92qatlanta at 11:00 AM 8/26/2006

[maxnix]

Good. Should have no more than 60K on plugs. Around 40K-50K is best time to change.

Let us know about your airport run.

[92qatlanta]

Dear NICO Team,

Airport run uneventful. Running strong. But again, I have the heavier foot. I'll just have to wait to see if the wife has any more problems. She gets skittish after every hiccup and decides she doesn't want to drive. So I must do 'something' to restore her confidence. She knows I has writing emails and then under the hood with a bunch of 'tools and stuff', so I think she is back to driving with confidence.

My short-term 'to do' is to take it to Dynolab in Smyra, GA and do a dyno run. They have a no appointment, Thursday Night Power Test Special of three runs for $50. This should give me a good baseline to compare against some of the others who posted their results.

I think cleaning the connection to the MAF sensor could have helped. About a year back, I was experiencing poor mileage, degraded performance and occasionally some black smoke at idle. The connection had some corrosion. I cleaned it and what a difference. It was very noticeable.

Thank you again for all your assistance. Should the ghost resurrect, you provided a 2nd tier set of options to explore.

Jim

[Peterofdevon]

Its amazing how that little three prong Qconnector can wreak havok. The Blue Q started to drop idle the other day (like down to 200rmp) and began stalling.

I cleanded the MAF connector and like wow...new car.

I bet that may be it.

Peter now of Paoli

[maxnix]

My short-term 'to do' is to take it to Dynolab in Smyra, GA and do a dyno run.

While this will be a good "before" baseline, you will learn much more if you took it to T-3 for a Power Balance test.

[Q45tech]

While this will be a good "before" baseline, you will learn much more if you took it to T-3 for a Power Balance test.

Then a injector resistance test to correlate with power balance and a driven fuel pressure test to make sure the the pump/fpcu can handle the stress of maximal flow.

In a couple of hours of testing every part of a Q can be diagnosed.

One should test alot and think alot then test some more and think some more before replacing the first component!