xu10j2c running on 3 cylinders

[Atlaskrukvaxt 5]

Hi everyone!

Some time lurker, recently registered and first time poster here. 

 

In early February I bought a -95 405 GTX "style" with the XU10J2C engine in it. Car is driven 160k km and in otherwise good condition.

The previous owner said the headgasket needed replacing and exhaust needed welding.

So, I've replaced the headgasket which was definetly needed and exhaust is under construction.

 

Today was the first time we test started it and noticed it's firing on only 3 cylinders, 1,2 and 4 (counted from the left).

We thought no big deal, we have dealt with similar issues on motorbikes and old volvos before.

 

First we took out the spark plug and turned the engine to see if it sparked, it did.

Second we moved over the injector from cylinder 4 to cylinder 3 and cylinder 4 kept working while cylinder 3 stayed dead.

We then did a compresison test on cylinder 3 and got  9:1 compression ratio.

We checked continuity on the cable to injector 3 and there was continuity with 0,004 ohm compared to 0,005 on injector 4.

Voltage to both injector 4 and injector 3 was tested and was all over the place but pretty much in the same range for both cylinders.

When spraying starter spray in the throttle body it starts running on all 4 cylinders

 

The injector cables to no.3 are damaged where they popp up from the center of the intake manifold but we assume (for now) that the damage isn't of importance as continuity and voltages are similar.

I read in another thread something about some relays that might need changing or perhaps even the control unit itself. Suggestions and where can I find the control unit for the injection system?

 

P.s. I have a wrecked 405 with a XU7JP (LFZ) engine which I can use for parts. 

 

Thank you in advance.

 

(pic semi related, it's a XU10J2C)

 

[Atlaskrukvaxt 5]

Update:

 

Turns out it was misdiagnosed yesterday. 

Engine runs only on 2 cylinders and now to be accurate to the way peugeot has numbered them I will go from right to left

Cylinders 1,2 are dead. Only no.2 was suspected yesterday. I have played with the ignition wires, cleaned them with no success. 

As I said yesterday too, the engine wakes up when start spray is sprayed in the intake.

I swapped the injection wiring for injectors 1 and 2 (from the right) but no difference was noticed. 

I numbered the injector cables and have now turned order completely around so going from right to left it's now 4,2,3,1and it is still only firing on cylinders 3 and 4.

 

Bad injectors are back on my suspect list as yesterday I swapped the injectors between 1 and 2 (that are dead today, and probably were dead yesterday) with no difference noticed. 

I'll number the injectors according to cylinders and swap them around too and see if there's any difference noticed. 

 

If that doesn't work I don't know what I'll do next.

 

Comments and suggestions are always welcome.

 

Thank you for reading. 

[calvinhorse 870]

I chased a similar problem that turned out to be a faulty coilpack, have you got a replacement on the xu7 you could try?

 

you could maybe try the injectors from the xu7, they won’t run well on the xu10 but if in good condition they will run well enough to highlight if it’s an injector problem or not 

[Atlaskrukvaxt 5]

1 hour ago, calvinhorse said:

I chased a similar problem that turned out to be a faulty coilpack, have you got a replacement on the xu7 you could try?

 

you could maybe try the injectors from the xu7, they won’t run well on the xu10 but if in good condition they will run well enough to highlight if it’s an injector problem or not 

Thanks for the suggestion!
The ignition wires are at least completely different on the xu7. I went there to look how they were plugged in when I was suspecting spark issues.

 

I have now swapped the injectors around completely and I'm now firing on cylinders 1 and 2 so the injectors that were originally in cylinders 3 and 4 are working and the injectors from cylinders 1 and 2 are bad. 

I have an excel table with different PSA engines, models they were used in, engine specs and so on. 

The XU7JPZ L3 in the 405 sometimes uses the same Marelli 8p injection system (same as I currently have) but unfortunately I noticed mine uses (probably) the Motronic mp5.1 system. 

 

 

 

All in all, two of the injectors were bad so I'll put them in ultrasonic cleaner and hope they work after.

If not I'll see if we have any compatible injectors from some old volvo red blocks or something, last solution is local spareparts store or ebay.

 

I'll update again when I have cleaned/new injectors. 

 

[welshpug 1,657]

xu7 leads wont ve that different, the coil end will be the same, plug end may have a different shape boot but will still physically clip onto the spark plug.

[Atlaskrukvaxt 5]

4 hours ago, welshpug said:

xu7 leads wont ve that different, the coil end will be the same, plug end may have a different shape boot but will still physically clip onto the spark plug.

Thank you for the clarification!

I got her up and running now.

 

I let the two failing injectors take a ultrasonic gasoline bath for 10 minutes but they didn't start working after. So I now have two working spare IW-054 injectors if anyone needs. 

I got a set of 4 green Bosch injectors with 208ccm installed instead of the original 190ccm. These were taken from a box of what I assume is volvo 740 parts.

I also put some white grease on the O rings as they seemed to be a bit flat but they are holding. 

 

 

I had to modify the cable connection a little bit to fit the Bosch injectors but it doesn't affect the functionality if I ever want to put the original injectors back. Not very pretty but it gets the job done.

 

With the new injectors installed the engine fired up instantly.

 

Here's a pic of the car while it's still wet as to hide all smaller imperfections. I'll maybe post more pics of it somewhere else when it's completely done. Thank you all for reading and commenting. 

 

 

 

 

 

Edited April 24, 2020 by Atlaskrukvaxt

[welshpug 1,657]

That is a great colour I think, I once had a phase2 Mi16 in the same Alhambra red.