Fuel Injectors or Trigger points

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cweed

Fuel Injectors or Trigger points

Post by cweed » Thu Jul 31, 2003 11:46 am

2.0 74 914
Then engine is running really rough all of a sudden. I pulled off the spark plug wires off of each spark plug while the engine was running to see which cylinder was affected. Two cyclinders seem to be affected. They are diagonal opposites. I am not sure if I should concentrate my efforts or money on the trigger points or the fuel injectors. My next test will be to pull out the fuel injectors and look at the amount of fuel that exits each one. Or should I look at the trigger points?

Guest

Post by Guest » Thu Jul 31, 2003 11:55 am

My guess is the trigger points. It's not too likely that two injectors would get clogged up simultaneously.

philinjax

cweed

Post by cweed » Thu Jul 31, 2003 2:53 pm

I tried to take out the distributor by first removing the cap (two clips). The next step I was not sure of. My porsche book describes two screws but I did not clearly see two screws. Any thoughts?

Guest

Post by Guest » Thu Jul 31, 2003 5:48 pm

To remove the dizzy, use a long 10mm wrench to loosen the bolt that tightens the shaft. Twist the dizzy out of the way, like you are doing the timing. Then you will see a nut that needs to re removed. Thats all it takes. Make sure you get the washer from that nut. Getting it back in can be tricky, but essentially insatllation is opposite of removal!
Chris

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Dave_Darling
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Post by Dave_Darling » Thu Jul 31, 2003 6:06 pm

You will, of course, have to set the timing after you're done. If you can do it accurately, mark the rotation of the distributor as it currently sits. That will at least get you close to the right timing when you re-install it.

Trigger points pair up the injectors diagonally. The grounds are paired front two and aft two. Crap in the fuel usually affects the two right side injectors, then the two left side ones. When you have two cylinders dropping out, which ones drop out gives you a direction to start troubleshooting.

First guess here would be trigger points.

BTW, the bolt that Chris mentions usually just looks like a long piece of metal lying on the crankcase poking out from under the distributor. If you look closely, you will see that the piece has a hexagon cross-section, and in fact this is the clamp nut that you loosen to be able to turn the distributor.

--DD

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raygreenwood
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Post by raygreenwood » Thu Jul 31, 2003 6:35 pm

Yep...my bet would be the triggers first...and the injector ground bundles second. I would check everything. Use a piece of construction paper or no less than 2000 grit sandpaper to clean the trigger points. Then clean with contsact cleaner. Use a Q-tip with cleaner to get the oldgrease of the cam. Lightly grease the cam with something with a very high drop poinjt...minimum 350 F +. Check the resistance. Both sides of the triggers should be under 1.0 ohm. They shoul also be with .1-.2 ohms of each other. An excellent example would be.... .7 ohm left .5 ohm right...as maximum deviation. Open and close each contact while testing. If they will not return to what they were reading before opening...clean them again with contact cleaner...and dry them with air....and test again.

If they still won't stay consistent....ist probably high resistance in the center ground or the wire from that particular side to the plug. They may need to be replaced at that point. Oh....and it could very well be the plug to the distributor as well. That is very common. Ray

cweed

Post by cweed » Fri Aug 01, 2003 11:07 am

Thanks for the info!! Dave - thankyou for describing the clamp that holds the distributor FYI-I too live in Sunnyvale. I will look at it this weekend and report back.

Guest

Post by Guest » Fri Aug 01, 2003 5:50 pm

The grounds are paired front two and aft two
Clarification:

The left and right sides are paired by grounds. So an injector ground failure is suspect if cyl 1-2 or 3-4 are dead at the same time.

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raygreenwood
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Post by raygreenwood » Fri Aug 01, 2003 10:56 pm

At a glance...injector ground failures would seem to always run in the pair, per side. That is far from the reality of how these ground bundles survive. The wires are piggybacked on a single terminal. Two wires crimped into one terminal....not leading to a single wire pere pair. The bottom wire in the paired terminal crimp fails commonly due to poor contact in the strain relief of the crimping. Its almost too small toreach around both wires without cutting the insulation on the bottom one. It fails from vibration and oil. Its common to have a single wire loose in each pair causing you not to see the need to check your grounds. Each time I have found this happening on different vehicles...I played for hours...steadfastly believing that if it were the ground bundle....both injectors on one side would be affected...instead of diagonally. Check your grounds. Its part of the process. Ray

cweed

UPDATE

Post by cweed » Mon Aug 04, 2003 11:02 am

I took out the distributor but carefully marked the location of the outside of the distributor and the engine so that I could place it back at the same location and I marked the shaft in the distributor. The idea was so I won't affect the timing. Anyway, I pulled out the trigger points and sanded them lightly (took me a second to figue out what exactly where the trigger points were). Put everthing back, changed the oil, and she fired up and sounded great! I pulled the spark plug wires on each cylinder to see if that affected the idle and sure enough each cylinder did. I drove it and to my relief power was restored and the car ran great! Thanks everyone for you info!!!!!
Unfortunately, I had some electrical problem while I was driving. I have a volt indicator and it went to zero while I was driving. It was at night and I did have the lights on. The car struggled so I turned off the radio and the lights and the car sort of regained a normal idle. I carefully drove in home. I will look at that this evening. Alternator? Loose wire maybe caused by the rough running engine?

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raygreenwood
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Post by raygreenwood » Mon Aug 04, 2003 11:22 am

Cweed...its sounds like you are on the right track for the alternater problem. Simple things first...check the tansmission to chassis ground strap and all connections. Then do a voltage test t make sure you are getting a bare minimum of 13.5 volts. If not...take the alternator to the local parts storeand have it tested. If it puts out 14V...which it should....and all of the connectors in your system are good...chances are...its the regulator. Ray

cweed

UPDATE

Post by cweed » Tue Aug 05, 2003 10:16 am

UPDATE
I read about the alternator and voltage regulator prior to looking at either. Some info I read mentioned that you may have battery acid around the battery if the regulator fails. It turns out recently I got a new battery because the old one wasn't charging and it had some battery acid on it. Therefore I decided to replace the regulator. So I did and the car seems to be great. On to the next issue - idle. It seems to 'hunt' (I think that is the right word. Since I just worked on the distributor I probably need to make sure the timing is right and then adjust the idle using the screw adjustment. Any thoughts? Thanks for all the info. I drove the car to work today and she was running great!

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raygreenwood
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Post by raygreenwood » Tue Aug 05, 2003 4:01 pm

Hunting idle is caused by a vacume leak. The fuel injection will tolerate "0" vacume leaks. Check everything. Especially the manifold pressure sensor. It may have a cracked diaphram in it. All hoses, valve covers, oil filler gasket, intake boots, TB gasket, advance canister and lines and injector seals. There must be no leaks. Ray

cweed

UPDATE

Post by cweed » Wed Aug 06, 2003 12:25 pm

UPDATE
I started checking the aux air reg. (with the engine running) I tried to remove one of the hoses and as I did the idle change significantly. It got much much better. I wiggled the unit a little and the engine all of a sudden was running really good. I took her out of a spin and she was back!! The aux air reg is bolted to the engine. Is there some seal between the engine and the reg? I wouldn't think so since the reg just is a valve for air flow. So that means one of the hoses was not sealed to the reg? I guess. I will double check tonight after work and make sure it still runs good.

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raygreenwood
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Post by raygreenwood » Thu Aug 07, 2003 12:01 am

Yes, there is a little rubber fittting. On some cars it hasa small vacume line running to the deceleration valve. Make sure of two things (1) that the valve is closing properly after about 8 minjutes of running. If you pull off the hose on the outside (not between the AAR and the plenum)...ther should be no suction. If it does have suction...check that it is grounded well and that the wire is hooked up...and that the coil has the proper resistance. Check the fuse too. (2) check that rubber fittingThere can be no leaks. Ray

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