Hey Guys! I am new to this, but here is my question.... I have had a problem with a rich condition at idle and real poor mileage. I had my LH rebuilt buy Electronik Repair ( GREAT service by the way! ) and reinstalled it this morning. The car ran great for about 6 miles and then won't idle without slight pressure on the throttle. The battery guage on the dash is at about 11 - 12 at idle... could the alt or battery be the culprit? I have had a fuel pressure regulator, temp switch and the LH unit rebuilt. I'm getting frustrated....

 

Welcome to the gong show.

Need a little more info on the state of tune of your car..............are all regular maintenance items new/good condition? Why was the LH brain rebuilt?

When the car ran great for 6 miles was that at all rpm's; idle through full throttle?

 

Everything is a good stae of tune... I just had it at a shop that checked everything... thy are the ones that replaced the fuel regulator and temp switch. Yeah, the car ran better the ever after the LH unit was rebuilt, it has never run better through the whole range, it just has a problem with idle. I have put my battery back on charge and am going to take it to be checked later on. Could the battery be the culprit? I charged it all night on 2amps, then this morning hooked it back up and the car was fine. When i reconnected the charger a few minutes ago,the battery charger showed it charging again...

 

The battery could be the culprit for a low idle if the alternator is not producing enough charge rate or the battery could have a dead cell(s). With a digital volt meter set on DC the battery should read +12v engine off and 13.8v - 14.2v with engine running above 2k rpms. If these tests are OK then the charging system is working. Is the battery not holding a charge for very long? If not it could be done........take it to a store that can perform load testing.

Is the poor idle in or out of gear or both?

 

S4Pilot,

Welcome to the group! Consider investing in membership, so you can add a signature line that tells us where you are.

Where are you? There are more than a few capable enthusiasts who might be able to take a look at the car and help with the diagnosis. Workshop manuals are a must for this, by the way. A Bosch Hammer or the John Speake replica are also way handy for doing the sensor checking. If your mechanic doesn't have the WSM, either buy one and share it with him or find a new wrench. The diagnostic tool may be around your area too.

 

Hey guys! Thanks for all the response... I took the battery and had it checked, and it was good. I did a good charge at 10 amps and filled the car with Chevron premium and went for a 30 mile test. All is well so far... I'll keep you posted! By the way if you ever need your LH unit rebuilt, Rich at Electronix Repair is great! Not only was the repair fast, he offered helpful suggestions as what to look for, AND he's a 928 owner to boot! Thanks agin... I'll be around! ( by the way i am from north georgia)

 

There are more than a few dedicated 928 listers from that area. Dave Roberts (928 Specialists) is just over the border a bit in NC, with a bit of knowledge and afew parts that might fit your car. Ace 928 Guru Wally Plumley is in the Atlanta area. Many more in that region along with you.

 

S4 Pilot, thanks for the kind words. I do my best to keep our 928s on the road! The LH unit was bad, didn't properly meter the fuel. S4 Pilot reports that his 928 has never ran so good!

I recommended that S4 pilot take the his "new" 928 out, fill the tank with fresh fuel, and to for a good long spin and knock the crud out of it. He reports so far, so good. It may have just needed the cobwebs cleared out of it.

The "rich running" LH failure mechanism can be a slow creep .... just getting worse and worse until the 928 eventually will not run. The constant extra rich fuel mixture can screw up things down the line, such as fould the spark plugs, and damage items like the intake gaskets, O2 sensor and catalytic convirter.

It also is possible that the idle speed regulator is clogged or going defective. Try spraying WD-40 down into it.

Good luck and let us know how it goes.

 

Hey guys! It's been about a week since Rich recommended putting some Chevron Premium and running the car a while. Everything is great! No more running problems. Thanks for all the support!