190E 2.3 - warm start problem
 

My Dad's '91 190E 2.3 has a warm start problem. Here's the scenario.

First start of the day, the car starts easily (crank for 1 to 2 seconds) and runs fine. After completely warm, if the engine is shut off and started within 30 minutes, it starts fine. If the car sits for between 30 minutes and 4 hours it requires 5 to 10 seconds of cranking and then it catches and idles poorly for several seconds before smoothing out. After which, it runs fine.

What's been done by an indy: new injectors and rebuilt fuel distributor. Didn't make any difference. They claim to have run diagnostics on all the sensors, fuel pressure, and OVP.

Now, two strange events:
I took the car to the dealer for diagnostics. They kept it for two days and could not find anything wrong with it. They claimed it started fine every time and they tried it at many different intervals. When I picked up the car, it started right up. The next day, I tried it and it behaved perfectly. The day after that, it exibited the same hard start condition I mention above.

On a whim, I ordered and installed a new fuel accumulator. For three days the car started perfectly all the time. Then it was back to misbehaving. :(

Any ideas??? Fuel pressure regulator?

Glen,

Have you checked the cap and rotor? Engine temp sending unit?

Haasman

Cap and rotor have about 25K miles but I haven't checked them recently. I think the problem is fuel related but I'm not sure what to check next. :confused:

Thanks for the reply.

<Any ideas??? Fuel pressure regulator?>

or FUEL PUMP CHECK VALVE or ACCUMULATOR . . .

Sounds like they JUST threw parts at it with NO PRESSURE/ VOLUME/LEAK-DOWN-REST PRESSURE TEST . . .

I tried the accumulator, the problem went away for three days but then returned. Fuel pump check valve...that's a possibility. How do I test it?

Thanks for the response :)

you've gone this far throwin' parts at it . . . just REPLACE IT . . . about 20 bucks . . .

Very true :(
Ok, I'm willing to take another $20 gamble...er, I should say my Dad is willing. ;)

Did you have it at Hoehn ? ? ?

Yep, they had it for two days and it would not misbehave for them at all.

You DON'T have your foot on the ACCELERATOR, do you ? ? ?

Nope. BUT, sometimes when it's particularly hard to start my Dad will press it slightly because it seems to help.

HOW many MILES on it ? ? ?

85K

You need to put a PRESSURE GAUGE in the system to monitor REST PRESSURE . . . or you're just pissin' in the wind . . .

The ONLY OTHER THING is that if there is EXCESSIVE carbon in the INTAKE PORT just downstream of the INJECTORS, which explains WHY it starts after it sits for a while . . .

Thanks :)