E4ME ghost problem

[Peer81]

Hello everybody,

Last week I was testing the E4ME with my dual A/F ratio meter. Everything was great with under normal idle and light accelerations numbers between 15 – 16:1 (14.7:1 is the ideal but can be leaned out to 17:1 under minimal load conditions). Under full throttle it was going between 12 – 13:1 (to be save 12.5:1 is best). So I was very happy. But now the problem. When testing my lock-up (see different topic in tech. The carb was loading up getting down to 6:1 almost stalling the engine. But driving in second gear the way home, high in the rpm I could get her going. I was thinking about something inside the fuel bowl so there was to much fuel coming in the carb.

But at home the thing changed around. No longer a rich problem but a very lean problem around 20:1 on both cylinder banks. I also hooked up the dwell meter and that thing also showed a very lean condition. I visually checked for vacuum leaks but didn’t find any and with the vacuum meter attached I got a healthy 15 – 18HG around 800rpm. I check the TPS but it was nice at 0.56v, I put the ignition back at factory 6 degrees BTDC. When placing my hand above the choke valve the rpm started climbing, better idle and the dwell got back round the normal 30 degrees. I can’t say I’m missing some cylinders because the problem is left and right. And with my hand on the choke valve the idle is smooth. Turning the engine off and on again the engine starts nice also around 15:1 and 30 degrees dwell but is within 10 seconds to fall back into full lean. No service engine lights and other problems I can think off. Maybe my ECM is on its way to heaven?

I hope somebody has an idea where to look for this problem.

Greetings Peter

 

[Peer81]

I'll start with resetting the ECM, maybe and hopefully it's all nothing but a bad dream.

Greetings Peter

 

[GerryLP]

I wonder if the vacuum hoses routing is correct? Is it perhaps recycling fumes with the EGR full-on or something?

How about the choke qualify?

GerryLP:cool

 

[Peer81]

I'll check that Gerry, thanks!

I'm thinking maybe internal in the carb there is a problem (as that is the only thing that changes all the time). I think maybe one or two primary rods are jammed in the jets. That way it's always on full extra lean an has no way to go into rich again. We'll see this weekend.

Greetings Peter

 

[TimAT]

If you can cover the carb with your hand and the idle smooths out, somewhere there's a vacuum leak.

And many places for that- have you checked the throttle shaft bushings?

It runs good until the ECM gets to closed loop, then falls apart, so the basic ECm is doing what it's supposed to. IT just can't compensate for where ever the extra air is coming from.

 

[Peer81]

I'll go by it step by step tomorrow. Shouldn't be to hard to find I hope

Greetings Peter

 

[Peer81]

I check everything. Nothing wrong with the vacuum hoses, no vacuum leaks to. The carb is rebuild with new bushings so no problem there (only some little vacuum leak at the secondarie throttle shaft. But my rebuild kit didn't come with bushings for them.

But as I started the engine it was idling with no problems and after the ECM found its way it was idling just fine. A/F was back at the 15-16:1 so no problems there. Still a little to lean for the perfect 14.7:1. The dwell meter showed a 15-20 degrees so I still need to get it up to 30 but no big problems.

Greetings Peter