....vintage problems on my Lancia 2000 HF coupè (1972)...!

To the kind attention of Dr. D-Jet (and all that will be able to clearly help me!)

Dear Sir, I write from Ferrara, Italia, to ask your help.
I had to replace the vacuum advance unit because the car was running very badly.
After this substitution the car clearly shows a better behaviour but the engine drops down suddenly at 3000 rpm, when accelerating.
The electrician of the best Bosch service in my town suggested me to look for and replace the (MPS) Bosch 0280100024 but I cannot find it!
As a good, retired chemical engineer I did expect a clear, exact identification of the wrong Bosch part responsible for this…defect but I may understand that it’s not so easy.
After having read a lot of good articles about D-Jetronic…I do personally suspect that the faulty part is the throttle switch but even if it is so…..I have seen that this part too is not so easy to be found.
What do you suggest me to do?
I have been able to find at least 2 workshops that offer their service but they are far from my town and, most of all, they do not say in advance that they have the needed parts or that they surely will solve the problem!
I even got in touch with Bosch in Stuttgart, they replied very kindly but I fear that their answer could be (for the MPS or the throttle switch) that the part cannot be fixed anymore!
Can you help me please?
Your help will be highly appreciated and I very willingly.…..will reward you.
My best regards and thanks since now


Bruno zappaterra
Ferrara
italy





Inviata da Windows Mail

Hi Bruno,

welcome to our D-Jetronic forum with your nice Lancia. Recently I could help Michael (user kmk) closeby to repair his Lancia 2000 ie. It was standing for 2 years in a workshop and finally he asked me to check his ECU. He also got his MAP sensor repaired by Bosch and since then I have proper refrences for the 0 280 100 024 as well.

But MAP sensor and ECU are the last things to check. So let me ask some questions:

1. By vaccum advance unit you talk of the vacuum advance for the ignition distributor? When it was replaced, did your workshop verify both rpm advance and vacuum advance of your distributor?
2. Did someone pull a vacuum on your MAP sensor and check how quickly it drops from -0,5 Bar to -0,4 Bar? If it holds vacuum, it is very unlikely that it is the problem. Provided that original rivets are still there to close the housing. And yes after Michael's reference, I can now repair a broken diaphragm on your MAP sensor and adjust it.
3. The throttle switch cannot create a sudden stop at 3000 rpm. Are you sure it is really 3000 rpm and how does that limit feel? Like the engine has no more power to further accelerate or like the car hits a wall? If second, check and replace the ignition finger. It has a rev limiter (centrifugal operated). If that switches too early, then it will shortcut ignition.
4. Throttle switch is only responsible for good acceleration and idle-run. That cannot create your problem with 3000 rpm. But if you want, just pull its connector off for a test.

Resumee: Check vacuum on MAP sensor and if it holds it, search failures elsewhere. MAP sensor, ECU and trigger contacts are often assumed the faulty part when a workshop cannot locate the real failt. Mostly they are not.

PS: I removed your cell phone from your thread. Google and others might otherwise abuse it.

Hi Bruno,

have I scared you off? That was not my intention.

When reading your thread again, I have one clarification question: Is it so that you are above 3000 rpm gliding and then try to acclerate and then the rpm drop to 3000/min ? That could come from trhrottle switch. It has the task to send 10 impulses to ECU and if they do not come, then ECU does not enrich mixture. If your car (for some reason) is already running too lean, this might be caused by missing acceleration pulses from throttle switch. But normally you should just notice a suboptimal acceleration.