Volvo P1800 ES problems

Hello Phillip & Volker,

I take the liberty to respond in English as my written German is a grammatical catastrophy.. Very interesting to read this article and I believe this is the exact same problem I'm currently experiencing with my Volvo 1800 ES with B20F engine.

I borrowed a used MAP sensor from a friend but it only worked for a day or two while the random "fall outs" while driving continued -and eventually made it impossible to start the engine. I have tried, tested and meassured every single component and everything matches with the workmanual -but it still won't run. Waaay too much petrol is injected and feels like insufficient ignition but all appears to be ok.

It was only when searcing this forum and reading the article that it finally dawned on me that it could be "dass gebiss".
Big question which I couldn't read from the article is if you manage to adjust the contacts? According to the Volvo manual they cannot be adjusted but should be replaced -but where do you buy new ones?

Appreciate your earliest reply as my car is now since two days stuck at my workplace while I'm on my bicyle 18 km back and forth...


Kind regards
John

Hi John,

I moved this topic here as it is a new subject to discuss.

It is not unusual to find not just one but a combination of failures on an injection system. If not imminent, they are often a mis-adjustment to try to compensate ther first failure.If it was trigger contacts (Gebiss), you can notice it by failing injectors. Those you will identify by touching them and feeling vibrations. You should also check fuel pressure and ignition sparks.

Hi John and Welcome to the forum,
for checking and adjusting the trigger points you need jetronic.org/de/forum2/jetronic/6-werkze...-gebiss?limitstart=0 . the tool I 'invented' some years ago
If you have a lathe, you can produce it by yourself - you get a figure from me on request per PM.
Else, I ship the tool worldwide.

Don't know where you live. Shipment to the USA can take some weeks...

Contact me.

Regards
Norbert

Hi Volker,

All 4 injectors works (more than) perfect -in fact it is drowning the sparkplugs. And for those occassions where the engine finally fired up it runs smoothly -and then dies. Fuel pressure and all other D-jet measuring points have been checked and verified against the manual.

When reading about the problems Phillip had it all suddenly made perfect sense and confirmed my feeling that it was indeed an electric problem (aside from the MAP). The D-jet was turning me into Mr Desperado-Jet!

Hi Norbert,

Many thanks for your quick and kind reply. I'm located in Svendborg, Denmark so not that far away but I do actually have access to a lathe so I have sent you a PM now.

My only thought is that as per the Volvo workshop manual it is stated that the contacts can not be adjusted and should be replaced -maybe because they didn't bother to develop the same fine tool as what you have done. I really hope this will do the trick together with the refurbished MAP.

Kind regards
John

Hi John,

another issue: Your car should start with worn trigger contacts but then immediately stall. Cold start valve will open and ECU will operate injectors while cranking even without T.C.

Hi John,

sorry to say. But this is a typical US "mending". Drilling through the end stop screw and possibly destroying inner tuning screws is one of the worst ideas that one can have. You were lucky that inner adjustment screw was still okay. Otherwise I could not have helped as it is one of the view pieces I do not have as spare. But it was still bad enough. The potting blocks the thread of the end stop screw. So it is extremely difficult to remove it. You have to clean thread well before you do so. And then you need a good screw driver fitting into the slot of the end stop screw. Imagine what happens if the slot is gone due to someone drilling a hole into it and afterwards destroying the thread by brute force. Right: That is when the shit hits the fan!

To all those who want to repair a MAP sensor with a broken diaphragm: DO NOT DRILL INTO SLOTTED SCREW OR TRY TO REMOVE IT: Desctruction is what you are going to achieve.



I have rebuilt your thread, replaced the end stop screw with a new one and also replaced the broken rubber feet. They are important for damping the vibrations.

In your mail you seem to have confused secondary coil on MAP sensor with a secondary MAP sensor. There is no secondary MAP sensor, only primary and secondary coil on it.