My wife's 95 945T (90k miles) starts fine on a cold (below 40F) start, but idles like crap for 20 to 30 seconds. If I hold my foot on the gas and keep it at 1500 rpm for 8 to 10 seconds, its fine. Car idles nicely when warm, and runs like a dream. When I pull the plugs, they look great. Gas mileage is about 23 in mixed driving.

I just replaced the ECT sensor and checked wires, no change. Just about everything that can be easily replaced has been in the last 6 months (all filters, plugs, wires, cap, rotor, etc.). Recently cleaned TB, checked for intake man leaks using starter fluid method, none found. Ran some top engine spray cleaner through last month, and two weeks ago ran a bottle of BG-44k through system. Cleaned IAC two weeks ago, idle drops when hose pinched. Swapping coils and knock sensors with other 940T makes no difference.

I don't think its the O2 sensor, as it is not supposed to be active until the car is warm, and gas mileage is good.

I know this is a small thing, but I am really stumped, not sure what to try next. I am beginning to think maybe the ECU is wigging out (not regestering cold input signals?), but I thought ECU's are an all-or-nothing deal. Anyone with any insight would be mucho appreciado.

Cheers!

have you changed the rear tank filter recently?I have seen the return hose from the fuel injector rail get kinked and cause exceesive fuel pressure,and when the car is cold it blubbers and doesn,t want to idle.The engine will idle fine when hot becasue the coolant sensor leans down the fuel mixture enough that the increased fuel pressure doesn't affect the running of the engine.You might blow from the return hose up front and see if there is no restriction going back to the fuel tank,it is a cheap test.

Nice car...I didn't know they made the turbo after 93...two more years to look for a replacement for my 90 740T.

Anyway, if the service bulletin doesn't help, you can also check the intake valves for deposits...sometimes the BG44K won't take off the intake valve deposits (IMHO it's best for fuel system/fuel injectors rather than combustion chamber or IV deposits).

An engine with significant intake valve deposits will behave exactly as you note, runs crappy until the intake valve and deposits get hot enough to quickly vaporize the fuel that gets sprayed on them during the intake stroke.

There are machines that remove the intake valve deposits without pulling the head...have to take off the intake manifold to access the ports and then the machine is bolted up and blasts the intake valves/ports with crushed walnut shells and vacuums the shells out. A few shells left in won't hurt the engine when started and shot out at idle, even with a turbo.

JohnB:

I have had good luck in the past with the Mopar top engine cleaner (like the GM stuff) for valve deposits. I used some about 6 weeks ago. I know it is not as good as the walnut treatment. What's your opinion of these top engine sprays?

Go to a dealer and have them look at service bulletin 28-102 "modified e-prom for cold start with low rvp fuel".

This says the symptoms are: car starts and then immediately dies and requires re-start. Runs rough for the first 45 seconds and may hesitate on acceleration.

The fuel has changed per the EPA since the car was built and the e-prom is the fix to make it have correct fuel mixture computations for cold start.

This isn't warrantable unless the car is still under a new car warranty and I would think that the warranty is long expired on that car.

Thanks, Abe. As usual, your insight and knowledge on such matters is peerless!

Any ideas on what the scope of work would be to get this eprom update? When did this bulletin come out? I would have thought that the dealer would have already done this if it came out more than a couple of years back.

Would this bulletin apply to my 1991 940T? It seems to do fine on cold starts w/93 oct gas.

I listed the eprom as I assumed from what you posted, that the car has been cared for and dirty air filter, dirty throttle housing and faulty mass airflow sensor can be ruled out. The MAF sensor would likely be giving you other troubles if that were it.

The e prom is actually called for for up to 89-93 models w/LH 2.4 but has been used successfully for the 94 and 95 models as well.

Low octane fuel is actually better in regards to cold starting performance.

Does a 95 still have the cold start injector under the manifold? On the lh2.4 cars they caused all sorts of flooding problems. Unplug it and try. The 2.4 idle motors are also springloaded closed where the older cars tended to go open causing high idle. Maybe yours is getting tired?? It also seems the programming in the newer ecu has eliminated any high idle at cold start, so any tiny problem will magnify.

I was going to ask the same question as Jim but not that it might be flooding, But NOT supplying any gas.(not working)

Good luck

you may want to check the wiring harness in ALL areas where heat is present

do this during the cold stage of start up and twist the harness to see if this affact it if so open it where you noticed a change and examine it carefully

also another problem i had required a bombing of gasline antifreeze

one quart for each tank- 3 times

rough idle cleared up buy ONLY good fuel

please advise how you made out

good luck

kgb