Fuel Injector Going Bad?, FIXED - Thanks 914 World! Options

[saigon71]

74 2.0 D-Jet. Car is in a fine state of tune. Verified fuel pressure at 30 PSI. Removed distributor, cleaned & lubed advance plates and tested vacuum canister. Verified TPS is set correctly. MPS tested fine. ORIGINAL fuel injection harness. I went around the engine bay today and re-seated all FI related connections. The injectors are in unknown condition - came with the car.

This is different than the bucking I used to experience. I intermittently have a cylinder drop off. It happens at all speeds, but is really noticeable at idle. I had it running for a while in my driveway tonight and the exhaust fumes spelled especially "gassy."

When it's not missing, it runs fantastic and idles perfectly.

I think I have a fuel injector going bad. Can they fail intermittently? Anyone else experience something like this?

I figured I would just pull all four injectors, run the fuel pump and measure the fuel...but I'm not sure I could find the faulty one if it functions correctly during the test.

Pretty boring video (IMG:style_emoticons/default/dry.gif) Engine starts running rough intermittently at :40 (engine bay sound) and 2:07 exhaust.

https://www.youtube.com/watch?v=xQoMS-NeOag...eature=youtu.be

Any advice is appreciated.

[saigon71]

Well, the problem is fixed!

I filled up the tank last night and checked my gas mileage - 22 MPG. I normally get about 28. The car was running rich at all times...idle would drop to about 250 RPM.

Before popping on a new Blowsby FI harness, I wanted to rule everything else out first. Jim gave me a loaner ECU so I swapped it out today - no difference.

I went back to the good old d-jet bible in the troubleshooting section under "my car runs rich and I don't know why" for a comprehensive list of things to check.

http://members.rennlist.com/pbanders/DJetParts.htm

Ran through the list one by one - nothing helped. Then I got to the trigger points. Several world members indicated that they may be the problem. I had previously assumed these were not the problem because I cleaned and inspected them over the winter when I cleaned & lubed the disty.

Well, some grease from the lube job had collected on the trigger points. I swapped them out with another clean set, started the car and reset the timing/dwell. She is running as good as ever again! I think my old trigger points will be fine with a good cleaning - I'll test the theory next time I have the dizzy out.

I've spent a few very frustrating weeks on this...lesson learned - don't rule anything out because you "just serviced it." (IMG:style_emoticons/default/headbang.gif)

Thanks for all of the advice on this topic - much appreciated. (IMG:style_emoticons/default/beerchug.gif)

(IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif)

[DRPHIL914]

Well, the problem is fixed!

I filled up the tank last night and checked my gas mileage - 22 MPG. I normally get about 28. The car was running rich at all times...idle would drop to about 250 RPM.

Before popping on a new Blowsby FI harness, I wanted to rule everything else out first. Jim gave me a loaner ECU so I swapped it out today - no difference.

I went back to the good old d-jet bible in the troubleshooting section under "my car runs rich and I don't know why" for a comprehensive list of things to check.

http://members.rennlist.com/pbanders/DJetParts.htm

Ran through the list one by one - nothing helped. Then I got to the trigger points. Several world members indicated that they may be the problem. I had previously assumed these were not the problem because I cleaned and inspected them over the winter when I cleaned & lubed the disty.

Well, some grease from the lube job had collected on the trigger points. I swapped them out with another clean set, started the car and reset the timing/dwell. She is running as good as ever again! I think my old trigger points will be fine with a good cleaning - I'll test the theory next time I have the dizzy out.

I've spent a few very frustrating weeks on this...lesson learned - don't rule anything out because you "just serviced it."

Thanks for all of the advice on this topic - much appreciated. (IMG:style_emoticons/default/beerchug.gif)

(IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif)

Awesome! Congratulations!
Glad it was that simple, many times it's the simple one that's hard to find, or we dismiss it and don't go back and recheck it ! I spent 3 months trying to figure out a similar issue and ended up just putting in new cap and rotor, that was the issue!
Now drive it lime you stole it!