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coughing above 5k rpm?

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So it's been quite a few years since I've really maintained a car (like the late 80's) and I'm now 6+ months into my 02 adventure. I'm trying to rely less on my mechanic and want to start to do more of the work on my own.

My 74 tii seems to be starved for fuel at the higher end of the rev band. Once I'm over 5k rpm, it coughs and backfires. So my question is what would you look at first? Is it the fuel filter? I hope it's not the injection system as that will require me taking back to the shop ( I think...)

The car was in storage for 7 years prior to me purchasing it last August. I had a local 02 mechanic give it a good going over so I could use it as a daily driver and it was running great after that, but I've notice these symptoms just recently.

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I would look at a fuel starvation problem first.

1. replace the large metal filter on the front clip

2. check and clean the other filters, one at the tank pick-up, fuel pump and at the Kugelfischer. Jim Gerock has posted the whereabouts of these filters before. Do a site search if you need some help in finding them.

3. Check your tank for gunk, empty, clean and coat it especially if these problems are coincidental with a low fuel level in the tank.

4. Replace all of your "rubber" fuel lines with the proper high pressure lines. Remember there is one between the the tank and the pump and the pump and hard line in the rear of the car.

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...and to expand on Bill's list:

1. fuel pressure test, and fuel volume test

1a. replace the large metal filter next to battery -

blow into the OUTLET end of the filter

so the gas and trapped crud comes out of the

INLET side of the filter into a glass jar.

I want to see a photo of what you collect in that jar.

2. check and clean the other filters, one at the

tank pick-up, fuel pump and at the Kugelfischer.

Jim Gerock has posted the whereabouts of

these filters before. Do a site search if you

need some help in finding them.

3. Check your tank for gunk, empty, clean and coat it

especially if these problems are coincidental with

a low fuel level in the tank.

3a. Read the tii Kugelfischer Manual available by link here

and adjust the fuel system linkages !BY THE BOOK!.

If any springs are missing, any linkage is worn

and sloppy fitting, lots of play between points -

the motor will not run right untill the linkage is

tight and adjusted correctly throughout.

Read and understand the function of the Warm-up

Regulator for cold start, warm-up, and fully 'off' when hot

and what should be happening during those periods.

4. Replace all of your "rubber" fuel lines with the proper

high pressure metric hose. Remember there is one

between the the tank and the pump and the pump

and hard line in the rear of the car.

5. Ignition dwell and timing is set BEFORE any idle

or idle mixture adjustments are made

6. COMPRESION TEST for a basic condition base line

which rules over all of the above for any poor

running. And you need it for later after this car

is driven a few 100 miles and 'stuff begins to happen'

after sitting dormant for so long. Stuff like coolent leaks,

unusual amounts of exhaust smoking. High use of motor oil......

7. this is a partial list but will get you started

down a good logic system path...

we need photos of your motor so we can see stuff

that your not......

Welcome to the Class

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This is great feedback. Thanks. I'll post some pictures on Friday or Saturday. I plan to replace the Alternator bushings this weekend and will take a look at the recommendations above at the same time.

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This weekend got away from me when I went in to replace my Alternator bushings and ended finding out that the previous owner put in a bushless alternator that mounted incorrectly. So I'm now procuring a new tii specific alternator. I'm assuming that some if not all of my coughing and backfiring above 5k rpm could be related to my alternator issues...

I did take a photo as requested and hope to get to checking both fuel filters tomorrow night. There are a few disconnected vacuum hoses that i can't figure out. Anything else stand out about my engine compartment besides the battery and alternator being removed? :)

post-22379-13667670089531_thumb.jpg

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Ok so I flushed the fuel filter on the front clip and the gas that came out looked ok. I finally found the right alternator for the tii (picked it up from Viking auto in Novato -- great guy), but when I put the battery back in after putting everything else back together the wires to the voltage regulator started to smoke.

I give up... My first real mechanical repair project in 25 years just took a turn for the worse. Having it towed to the mechanic. Hopefully when it comes back it won't be running rough above 5k anymore either.

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I give up

My standard 2002 was doing this earlier in the week. Saw moisture in the distributor cap so I washed it out with WD-40. Runs good now.

Probably not the same issue as yours, but in case anyone hits this thread curious with similar issues, that's something they can consider.

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Take CD's list in to the shop with you. Odds are alternator issue is unrelated to power loss/backfire at 5k RPM.

Have them sort out the vacuum lines as well, as it appears you the stock 74 dizzy with vacuum can.

GL!

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Did you run a ground from alternator case to the block ?

Yeah, did that, but maybe I should confirmed that the ground went somewhere since the old alternator "bushless" could have grounded through the mounts.

The car is now over at A1 Auto who knows these cars well. I'd expect that JP will figure out the running rough issues as well. Just hope I didn't fry any of the wiring or electronics.

Thanks for the feedback.

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Well you guys were right. It was the ground. JP also adjusted the mixture, so we'll see how she runs tonight when I pick her up.

Thanks again for the feedback.

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