new member with vital question

[cheerfullman]

Eighty one year old retired physician here and new member as of 4 10 2015 with 1992 bonnie ss1 bought in 2006 with low mileage but now with over 200,000 miles
Love the car!
Amazingly, in my experience, the engine is still strong and uses no oil -- but it has a flaw which my wife is sure will prove fatal to car and driver some day: when driving a distance of over 30 miles in weather 75 to 80 degrees or above and climbing even a modest hill the engine will often begin to hesitate or sputter and loose power. Unless I pull over quickly for a while it will cut off.
The problem occurs only in hot weather such as we are having in Charleston, South Carolina, which I am currently visiting. Rarely has the hesitation occurred when driving in upstate
New York where my family has had a farm for many generations.
Experienced mechanics in Charleston and in Albany, NY, have been unable to make a diagnosis but after looking over some of the threads here I plan to have the upper an lower intake manifold gaskets replaced for the first time.
Other suggestions will be appreciated.
Roswell Eldridge MD

[FiendScurro]

Well welcome to the club:-) its still pretty quiet here until the warm weather comes more consistently but I'm sure you'll get some responses soon. I'll try searching for a place to start with your problem. Does it happen without the a/c on? Is your check engine light on or flashing during the problem?

[FiendScurro]

Other questions. How does the car do when idling after long trip? How are your fluid levels? Coolant temp high? (Should be near 200) any smells, smoke, or noises?

[KM AXer]

Welcome, Roswell!

I've only been wrenching on my '93 SSE for the last 2.5 years, as before that it was owned by first my father, then my brother. But I have been doing my own maintenance and repairs for nearly 50 years now...

Dan's question about warning lights of any type on the dash is an important place to start.
Since you have had the car looked at, those mechanics should have had access to any error codes which may have been set when the motor was struggling. But if that were so, then one of them should have been able to find the root of the problem, if it was electronic in nature, or could have been detected by a sensor in the system. But they may have had an obstacle to the data retrieval.
Part of the issue with diagnosis for cars of this vintage is that when built, the OBD (On Board Diagnostics) systems were still in development, and ours are kind of "tweener" years, at OBD1.5. Most cars since 96 or so are OBD2. What that means is that the current OBD2 scan tools often won't pick up issues that the 1.5 system has stored in memory. There have been discussions on this board about the lucky members who have found a mechanic who owns and knows how to use a 1.5 device.

As a preface, allow me to say that such a problem will be found in one of three places: 1. Fuel system. 2. Ignition system. 3. Engine management/controls/sensors system.

To help ascertain which might be the culprit, a few questions:

Has this only occurred when additional power is needed to ascend an incline, or also when cruising in a more flat area?

Cruise control on, off, or no difference/happens both ways?

If you pull over to the side, does the car idle normally?

Your car is the SSEi, with the supercharged engine, correct? Do you use premium (91 - 93 octane) fuel?

Do you know when the last time the spark plugs were changed?

Do you know when the last time the fuel filter was changed?

Do you know whether the fuel pressure was checked by the mechanics?

Do you know if they checked the Mass Air Flow (MAF) and Intake Air Temperature (IAT) sensors?

When the problem occurs, have you opened the fuel door and carefully removed the filler cap to see if positive or negative pressure existed in the tank?


There are some great technicians on this board, and I am sure that someone will be able to point you in the right direction.

[myfirstbonnie]

When was the last time it had a good tune up (plugs and wires), MAF cleaned etc? Has the regular maintenance been kept up?

If so, I would start looking at either a bad ignition control module or crank position sensor. You can go to a local JY and get an ICM or two pretty cheap and only takes 10 minutes to swap. Just remove all 3 coils and unplug the connector. You could even replace the coils too. Those are pretty simple to check using the procedure posted in the tech info section.

The 92 is not usually known for the gasket issues, but you never know. It was the 95+ that does. Also, is yours an SSE or SSEi, SS1 is not a correct.

KM axer, being a 92, it is OBD I and you can access the codes with a simple piece of wire by jumpering the terminals and watching the SES light flash the codes. This procedure is also in Tech info (tab at top of all forum pages).

All 1987 to 1994 were OBD I, 1995 is when the OBD1.5 came in.

It has also been known that ICMs, coils and the CPS are known to fail at times when the temps start to rise. Also take note of the tachometer when it acts up. Does it drop out, keep steady, or bounce around?

[RJolly87]

It's also possible it still has the Magnavox ignition system, which is the single coil pack unit with plug wires down both sides, and notoriously problematic. Most swap with the newer style (plug wires all in a row, 3 individual coil packs). I am going to lean towards something ignition control related too, and away from Crank Position sensor. Usually when those go, they won't allow the car to restart for a while when shutting off, and usually don't affect normal driving until they worsen.

[cheerfullman]

thanks everybody -- new to this and appreciate interest and patience.

NOTE my bonnie is not supercharged and is probably an SSE

to move along let me BEGIN a reply to AKer:

"To help ascertain which might be the culprit, a few questions:

Has this only occurred when additional power is needed to ascend an incline, or also when cruising in a more flat area? ALMOST ALWAYS THE FORMER


Cruise control on, off, or no difference/happens both ways? NEVER USE CRUISE CONTROL

If you pull over to the side, does the car idle normally? NORMALLY -- UNLESS THE ENGINE HAS ALREADY CUT OUT

Your car is the SSEi, with the supercharged engine, correct? Do you use premium (91 - 93 octane) fuel? NOTE NOTE--NO SUPERCHARGER/USE REGULAR

Do you know when the last time the spark plugs were changed? NO BUT THEY HAVE BEEN CHANGED WITHOUT EFFECT

Do you know when the last time the fuel filter was changed? NO BUT SEVERAL TIMES WITHOUT EFFECT

Do you know whether the fuel pressure was checked by the mechanics? NO

Do you know if they checked the Mass Air Flow (MAF) and Intake Air Temperature (IAT) sensors? NO

When the problem occurs, have you opened the fuel door and carefully

[cheerfullman]

reply to AKer--conclusion:


"Do you know whether the fuel pressure was checked by the mechanics? NO

Do you know if they checked the Mass Air Flow (MAF) and Intake Air Temperature (IAT) sensors? NO

When the problem occurs, have you opened the fuel door and carefully removed the filler cap to see if positive or negative pressure existed in the tank? NO--BUT SCREW CAP SEEMS TO FIT LOOSELY

thanks AKer

( :

roswell

[KM AXer]

KM axer, being a 92, it is OBD I and you can access the codes with a simple piece of wire by jumpering the terminals and watching the SES light flash the codes. This procedure is also in Tech info (tab at top of all forum pages).

All 1987 to 1994 were OBD I, 1995 is when the OBD1.5 came in.

Thanks. Apparently I have been under a mistaken impression regarding that for some time...

[J Wikoff]

When my 92 was acting pretty much exactly like that, my fuel pump was dying. The warmer it got, the lower the fuel pressure got and situations that required higher fuel caused major stumbling. A weak fuel pressure regulator was a minor contributing factor as well. Mine would do it on flat ground as well, when I tried to apply "too much" throttle.

The intake manifold gaskets don't have the high failure rate that the later 95+ models do. That said, they can fail in the same way eventually, just not near as likely. If they are original, I'd replace the lower intake manifold gaskets for preventative maintenance. You'll find that your upper intake manifold doesn't really have a gasket to the lower intake. I think it's just a bead of RTV.

[KM AXer]

Roswell,

I'm leaning in the same direction as J Wikoff: Fuel delivery.

For sure have the fuel pressure checked. Fuel pumps don't last forever... They can do a complete fail and not produce enough pressure to even start a car, or they can fade away and be unable to deliver needed volume. On my Suburban, it began with the bumbling stumbling failure to achieve highway speed, but quit entirely within a couple of miles.

And replace that gas cap. The wrong one, or a loose/missing gasket or O-ring can cause evap system problems.