Distributor rotors for a QV

Try putting the sensor on a DMM while the car is running, and see if the voltage output is doing odd things.

 

So you replaced and had problems with the rotors, bad enough that it wore down one and you think that it's running poorly because it sat up? When I have problems I always start with the last thing I did that took some fiddling. Pop those caps and see if the center carbon isn't fubar on one. Even a little FUBAR can cause problems.

YMMV

 

Kim,
My '85 Euro gave me similar symptoms once, I'd go back and double check your caps and rotors. Those are the bits you've been fiddling with and occum's razor says it is less likely another component has also just gone wrong and caused the same problem.

My power loss was intermittent so difficult to track down. I swapped coils and ignition modules bank to bank and changed out a pickup. Finally I swapped caps and wires and the problem migrated to the other bank. I can't remember where I sourced the replacements from but they were high quality aftermarket units that have functioned brilliantly since. I'm out of town for the weekend, I'll dig out my receipts when I get home.
Cheers,
-seth

 

So here’s the deal. The car has run flawlessly since I had Dave Helms rebuild the plug wires and check the OEM caps. I Replaced the rotors and extenders, also new plugs. Car hasn’t missed a beat in two years. So I leave it set for eight months and get around to starting it only to find that it has a slight miss and then this zero throttle response issue. After some discussion it was mentioned that distributor rotors will go bad so I replaced them In the car runs very smooth once again but didn’t address the throttle response issue.

 

Thanks Seth, I agree with what you’re saying but if I’ve only messed with rotors it doesn’t make sense that it would clear up then rear its head again. If a cap is cracked it’s going to continually miss and same with the rotor. Would a coil going out intermittently cause a no throttle response issue? Would certainly cause the momentarily loss of power issue

 

Re-read your post and in fact one of the center carbons was jacked up a bit, Spring holding it in position was bent up. I straightened it and thought it was fine. So you’re thinking this is the source of my problem?

 

If you get the Superformance caps, you need to get the rotors as well, because they are different heights than the OEM. Also the Superformance caps may need to be drilled out a bit more to get the wires in properly.

If your gas is more than 6 months old and is allowed to dry out of the injection system, you could have varnish on your injector screens, and the input to the warm up regulator. This will cause a very rough running engine, that needs to have those parts cleaned.

 

Thanks. Still running the OEM caps, Just changed rotors. Always run premium fuel in the car and did Drain both tanks, added Techron fuel injection cleaner when this first started.

 

I'm suggesting that you said that the fit was so bad on one rotor that the center electrode ground into it bad enough that you couldn't send the rotor back. That has to cause damage to the central electrode. Call it extremely accelerated wear. I think that it is a possible source of a one bank problem. You could run the car and see which bank isn't firing then swap coil wires to cap and see if that stays on the same bank.

 

Addition: I'm suggesting that you said that the fit was so bad on one rotor that the center electrode ground into it bad enough that you couldn't send the rotor back. That has to cause damage to the central electrode. Call it extremely accelerated wear. I think that it is a possible source of a one bank problem. You could run the car and see which bank isn't firing then swap coil wires to cap and see if that stays on the same bank. as you got it running well for a bit and then it failed I'm going with this as the problem.

 

Do you have a timing light? You're not going to use it to set timing, just to easily verify spark on each bank and then each cylinder. It will quickly get you pointed in the right direction. If all sparks are good then move on to fuel.

 

Thanks guys! Don’t have a timing light but I can certainly purchase one. Verifying spark would be first step all right. Should have mentioned yesterday that when I dropped it to idle position and then went to give it some throttle it was nonresponsive and finally just ended up quitting. Pushed it back into the garage for the evening. Was just messing around with it and it usually starts with very little effort. No such luck today just cranked over and would fire every now and then. Starting to wonder if all this is caused by a bad fuel pump? But will verify spark first. Have run out of time at home And will be gone for another two weeks at work. Will address then. Will also place an order for two new carbon centers for distributors.

 

Verify that the wire assignments are correct on the distributors as well. I've seen it happen.

 

I would take a good look at the warm up regulator input. This is the larger of the two banjo bolts. Remove the bolt and look closely a the regulator input with a bright light. You should see a clean filter screen. If clogged, shoot some carb cleaner in there. A clog there will increase your control pressure, and lean out your mixture. An easy way to tell if your mixture is lean is to press down slightly on your air vane, while the engine is running. If this smooths out the idle, you're probably running lean. Best is to hook up a fuel pressure gauge, and check your control and system pressures. Even if your tanks have been drained and filled with fresh fuel, there could still be varnish flakes inside your fuel distributor.

 

Thanks everyone! will look at the warm up regulator before I leave. Well, fuel is definitely not the issue as it was really flooded. Note to self.. if it’s idling rough and stumbling, increasing accelerator pressure isn’t the answer! LOL Just finished cleaning and installing the plugs.
Wires are all correct. Almost beer time here!

 

Just did a quick check of the screen in the warm-up regulator. It’s very clean. Thanks again for all your input!

 

I’ve been looking through archived old threads with QV run issues similar to mine. ( unresponsive throttle below 1000 RPM after sitting for a period of time.) M James posted in 2005 of similar issues and his response was..
“ The winner of the correct trouble area was , the Lambds (02) relay connected to the fuel injection computer. I traced my O2 sensor wire back into the rear right corner of the Car next to the power antenna and there is in fact a relay there. Can anyone verify that this is the relay he was speaking of? Sounds like dirty injectors will cause similar run issues also.

 

The lambda setup is really just a fine tuning of the fuel mixture through the frequency valve. I doubt it would cause a major loss of power. These motors run well on one bank of cylinders. Ignition faults generally affect only one cylinder, or one bank of cylinders. The two banks have their own components. I've lost a bank because of a failed coil assembly. And once because the coil to distributor wire came out while it was running. The motor becomes a four cylinder at that point. A big vacuum leak will cause very rough running. E.g. I've had the big hose to the AAV come off to cause this. It's possible you could have accidentally pulled a hose loose when working on it.

Does the motor run better when you press slightly on the air vane ?

K-Jet gauge kit:

https://www.toolsource.com/fuel-injection-test-sets-c-1321_182_184/cis-kjetronic-fuel-injection-tester-w-case-p-91535.html?sourceid=googleps&gclid=CjwKCAjwwo7cBRBwEiwAMEoXPNOtP1Xw3pY8Yvm3SksefO87GneH4IpvwewTHWApf5T-RKh9wpNawhoCh_0QAvD_BwE

 

Here's quick test setup for the fuel injectors.

https://www.ferrarichat.com/forum/threads/cheap-quick-cis-injector-cleaning-tester.531214/#post-144891409

 

Spicedriver thank you!
Went into the garage once again and started the car after drying the plugs out yesterday. All eight were wet. Car immediately fired up but with hesitant throttle response. Brought it up to about 2000 RPM for two or three minutes then let it drop back down to Idle where it just stumbled and quit. Garage smelled very gassy. Reached around and put my hand on the front bank header- ice cold. Quickly touched the rear bank header and it would burn you. Guess my issue is I have a four-cylinder Ferrari at the moment! At least I know where to start from here. Thanks again guys for all your help. Will address when I return home in two weeks.