PaulCarrera

1984 928 S2 euro
Decided to get my maf rebuilt so sent it off to the US to get done and thought I would replace all the fuel lines while I was waiting for it to come back. Since I had the injectors out I cleaned then up with my ultrasonic cleaner and replaced the seals. When I got the maf back I put it all together cleaning all the electrical connections with contact cleaner but when I went to start it it seems to be running on only about 4 cylinders if that, it won't keep running.
could I have damaged the injectors with the cleaning?
The only other thing I did was take all the air pump plumbing off and plug the back of the heads ( the actual pump has been disconnected for some time) There isn't a cat on my car it's a euro

ammonman

First, see if you can determine if the issue is from no spark or no fuel getting to the non-running cylinders. If you have a timing light with an inductive pick-up, check if you are getting spark to all the plugs. Since you had to disturb the wiring for the injectors I suspect there is either a break or short in one of the injector wiring loops. Since they are batch fired, a break or short in the wiring usually impairs half the injectors. Carefully peel back the boots on the injector plugs and see if the insulation on the wiring has failed, allowing a short at one of the connectors.

Mike

928 kiln

Just a random thought, in addition to the ground points and injector connections, it might be worthwhile to check that both distributors are turning given that on an S2 the second distributor is driven off a small belt between the two. In a case where only half of the injectors are firing it might be worth a look. Also, check both coils and their connections to the distributor caps.

PaulCarrera

Thanks guys good idea with the timing light I will check it in the morning and yes maybe I have disturbed the coil because I had it off the mount to remove the air pump filter. I did have a quick look when I put it back but may have missed something

Mrmerlin

first make a injector tester use a 9 volt battery and use a AMP 2 prong plug,
and test each injector to see if its clicking when applying power.

NOTE once this is done then with a helper run the engine,
and a with a long screwdriver put it on each injector the other end to your ear to see if its clicking,
if they are all clicking then they are working and you have an ignition issue ,
then check the coil wires

dr bob

^^^^ This. Test with timing light on every plug wire.

VERIFY that the wires on both distributors are in the correct order; you wouldn't be the first person to get plug wires mixed up on reassembly.

Injection is batch fire so all trigger at the same time. Stan's testing method is sound. (sorry...) If you have a mechanic's stethoscope, it may be faster/easier than the screwdriver-to-conductive-bone method. Be Sure to check that the grounds for the injection harness on the block are connected and secure/clean. Resistance in hose can keep some injectors from opening completely. Different or no clicking when you listen to some of them. If you still have the original crispy injector connectors, look at the wiring immediately behind the connector for breaks in the insulation as well as at the connectors themselves..

PaulCarrera

well I checked all the plug leads with the timing light and they checked out all ok and then took off the coil leads one at a time and the problem seems to be on the drivers side (passenger for you guys in the US)
i will check the injectors with the 9volt battery idea but I don't think the chances of all one side being no good and the other side ok are great.
i imagine I can check the wiring using a bulb onto the injector wiring??

Mrmerlin

Umm the injector test is to loosen any sticking injector,
since you cleaned them its possible the cleaning solution might cause the injector to stick.
if they all click then you know that they should all operate,
NOTE this should be a test performed before connecting the wires to the injectors.
NOTE if the coil leads are swapped at the distributors then the engine will not fire
NOTE The screwdriver test is to verify that the injectors are all getting a signal

PaulCarrera

Well I have pretty eliminated everything except the injectors at this stage

Ignition system is all working as it should be and no leads from coils and distributors have been mixed up because they have never been removed

The injectors are all receiving a signal, I tested each one with a bulb and cranked the engine
over

Checked the gas system and gas under pressure is getting to the fuel rails

I think that even although I cleaned the injectors in the ultrasonic bath maybe some of the loosened gunk has ended up inside further and has clogged everything up so I am going to remove the injectors and thoroughly clean them while pulsing them. I have a 10 litre bath and after the initial cleaning the water was brown so they were pretty gunked up

PaulCarrera

Pulled the injectors again and cleaned them all up with carb cleaner while switching the injectors with a 9 volt battery. They were pretty gunned up and after a good clean they were all showing a good spray pattern so put them back in and now it's all running really well. Thanks for the input

Mrmerlin

so you fixed your car by cleaning the injectors, thats great