[Guest]

JRV,

I have had a plaguing

JRV,

I have had a plaguing strat problem with a 348 2.7 motronic. I can start the car and it runs fine. It is just the start-up issue. The last thing I have to change is the entire wiring harness. Out of laziness and frustration and cost I have not done it. My car is a track car anyway so if I spend anymore money on this black hole it will be for a conversion to Motec. That said, I believe the proper TDC sensisng is one of the primary inputs to the motronic. I bought new TDC sensors in the era of the "bad TDC's". Therefore, my new TDC's that may have solved a problem may be a new source of problem. Do you know if all the on the shelf TDC's have been corrected and if you think this bug could be my problem? Everything else checks out and just about everything has been replaced. Fuel pressure and injectors are good. Starting problem solved by spray of starter fluid thus appearing like a fuel starvation problem. It is more likely that something is preventing electronics from energizing the fuel injectors during cranking or uncoordination of spark and fuel on cranking.

Thanks!

 

[Guest]

BB,

have you checked and/or

BB,

have you checked and/or replaced the Thermal Time switch?

All the 348's I do start virtually instantly. RRRR boom. The system controls cold starting by increasing injector pulse width (lenght of time open), thus richening up the mixture to create a type of choke scenario. The input to the puter for this need for rich mixture is from the Thermal Time Switch located on the Water Crossover between the heads in the center of the engine (see my thread on 348 Electrolysis for pics).

If you have an Exhaust Gas Analyzer you should get readings even after the Cat (if so equiped) OF 3%-4% CO cold......if you arenot getting these rich readings cold start and first minutes of idle then I would suspect the computer is not recieving the signals telling it the engine is cold.

IMO it seems unlikely a tdc sensor would cause only cold start issues. They can cause general starting issues if the air gap is to large, but I'm sure you've taken that into account.

I talked with Algar about the TDC sensor issue and they have not had problems with there supply of sensors.

If you can get a few readings from the TTS & exhaust gas I bet we can get to the bottom of your problem.

Couple other things just came to mind, Fuel Pressure Regulator Condition, Vacum Leaks and the Fuel Pump Screens (inside the tanks)condition. Have you checked to insure the Manifold Balance Valve isn't stuck open?


Regards, JRV