J30 injector problem?

[[email protected]]

I have had a bad injector in my 1993 Infinity J30 in forth cylinder (failed resistance test). Together with a friend we replaced all six injectors with brand new Bosh injectors. After this operation, the sixth cylinder started to fail. While the engine still cold, the sixth cylinder does not work. The engine shakes and there is smell of gas from the exhaust. After 10-15 minutes, the engine start to work smoothly, however some time it gets longer than 20 min. Please advise, what could cause the problem? Replacement of the ignition coil and the spark does not solve the problem. Could it be a defective injector? Thanks.

[coolyun_98]

It sounds like gas somehow leaks into the 6th cylinder. According to the sympton, the leaks somehow stops once the engine fully warms up. It appears that the leak comes from o-rings (that's why the leak stops once the o-ring expands as the car warms up)

Did you use new o-rings? Did you applied petrolium jelly to the o-rings during installation? from my experience, those o-rings will not seat properly unless they are coated with petrolium jelly during installation.

[[email protected]]

Thanks for the comment. Yes, we have used new two o-rings for each injector. I can not recall if we used that particular jelly, however, we definitely used something. What I can recall, one of the injectors did not produce a click at the end of insertion. We have actually come to a similar conclusion that there might be a leak of gas into the 6th cylinder. However, we were thinking about an improper injected gas volume (e.g. to much) or unfavorable shape of the injected gas cloud, for example a single spout instead of fine mist. The spout might evaporate faster in a hot cylinder and thus the cylinder shows a better performance while hot. I realized, there is no alternative to a new manifold removal to inspect that injector. What I need is a good advice how to test the injector once it is removed. Replacing the o-rings would be a cheap solution if the injector will cooperate and will stay undamaged after removal.

[Infinitiguy19]

What type of injectors do you guys have... Phase 1, Phase 2?

Might want to look in to a company called BWD because one of our Q45 members tried some of there E10 (Ethanol) proof injectors and he is OK so far.

[coolyun_98]

Other than measuring the resistance of the injector, I can not think of any way to actually measure the "spray pattern" of "speary volume" of the injector.

Maybe Q45Tech can help us here?

[yodawill2000]

First thing to try is swapping the coil with another cylinder and see if the prob follows the coil.

[[email protected]]

Thanks for the comment. Yes, we have used new two o-rings for each injector. I can not recall if we used that particular jelly, however, we definitely used something. What I can recall, one of the injectors did not produce a click at the end of insertion. We have actually come to a similar conclusion that there might be a leak of gas into the 6th cylinder. However, we were thinking about an improper injected gas volume (e.g. to much) or unfavorable shape of the injected gas cloud, for example a single spout instead of fine mist. The spout might evaporate faster in a hot cylinder and thus the cylinder shows a better performance while hot. I realized, there is no alternative to a new manifold removal to inspect that injector. What I need is a good advice how to test the injector once it is removed. Replacing the o-rings would be a cheap solution if the injector will cooperate and will stay undamaged after removal.

[[email protected]]

Other than measuring the resistance of the injector, I can not think of any way to actually measure the "spray pattern" of "speary volume" of the injector.

Maybe Q45Tech can help us here?

We done that - the resistance is within the normal range.

What I looking for is how to maintain the gas pressure in the gas rail once the manifold is removed, and how the injector can be switched to "open" in order to test the spray and the volume? Any experience in this? Thanks.

[[email protected]]

First thing to try is swapping the coil with another cylinder and see if the prob follows the coil.

That was done - the problem remains in the 6th cylinder